Abiotic Stress in Tree Species

A special issue of Forests (ISSN 1999-4907). This special issue belongs to the section "Forest Ecophysiology and Biology".

Deadline for manuscript submissions: 15 May 2024 | Viewed by 18802

Special Issue Editors

College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China
Interests: abiotic stress; leaf senescence; drought; poplar; hormone regulation; genome editing
State Key Laboratory of Tree Genetics and Breeding, Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091, China
Interests: abiotic stress; leaf senescence; hormone regulation; tree genetic breeding

Special Issue Information

Dear Colleagues,

Most terrestrial biodiversity is built on the living foundations of trees. Trees are unique with their woody bodies, which requires water and nutrient uptake from underground to tens of meters elevated photosynthetic canopies. The growth and development of trees are susceptible to environmental changes such as drought, soil salinity, heavy metal ion stress and extreme temperatures. Therefore, abiotic stress signaling and physiological response might distinct with herb plants. This Special Issue plans to give an overview of the most recent advances in the research field of abiotic stress in tree species. This Special Issue is aimed at providing selected contributions on advances in the stress sensing, signal transduction, physiological response of tree species under water deficit, salinity, cold, heat, heavy metal stress and other environmental changes.

Potential topics include, but are not limited to:

  • Drought stress signaling and responses;
  • Cold and heat stress signaling and responses;
  • Ionic stress signaling;
  • Ca2+ and ROS signaling;
  • ER stress;
  • ABA response and signaling;
  • Stomata movement regulation;
  • Organelle interaction in abiotic stress.

Dr. Hou-Ling Wang
Dr. Liu-Qiang Wang
Guest Editors

Manuscript Submission Information

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Keywords

  • drought
  • cold
  • heat
  • ionic stress
  • signaling
  • response
 

Published Papers (18 papers)

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21 pages, 6384 KiB  
Article
Adaptation Strategies of Populus euphratica to Arid Environments Based on Leaf Trait Network Analysis in the Mainstream of the Tarim River
by Shiyu Yao, Jie Wang, Wenjuan Huang, Peipei Jiao, Chengzhi Peng, Ying Li and Shuangfei Song
Forests 2024, 15(3), 437; https://doi.org/10.3390/f15030437 - 25 Feb 2024
Viewed by 579
Abstract
Populus euphratica, a key tree species in the ecologically fragile area of the Tarim River Basin, plays a crucial role in maintaining the ecological balance of the desert. In order to explore the response of Populus euphratica leaves to river water resources [...] Read more.
Populus euphratica, a key tree species in the ecologically fragile area of the Tarim River Basin, plays a crucial role in maintaining the ecological balance of the desert. In order to explore the response of Populus euphratica leaves to river water resources and drought climate change, the complex topological relationship between the leaf traits of Populus euphratica was comprehensively analyzed by establishing the leaf trait network of the mainstream of the Tarim River, and the central traits that play a key role in regulating the phenotype of Populus euphratica were identified. The adaptation strategies of Populus euphratica to different environments were clarified from the perspective of the overall leaf trait network. The results show that, with a decrease in river water flow, the internal coordination of the leaf traits weakened, forming a looser network structure. In the hyper-arid region, the leaf traits were more independent, the network was simpler, and it was easier for the leaf to coordinate the aggregation of specific traits. Leaf thickness and the related photosynthetic traits are the key to adaptive strategies, particularly the cuticle thickness and midvein vascular bundle area. Leaf anatomical traits are more critical than stoichiometry traits in drought resistance. Leaves tend to give priority to the relationship between structural traits. Populus euphratica leaves adjust their trait modularization through a trait substitution strategy to manage different drought conditions. Full article
(This article belongs to the Special Issue Abiotic Stress in Tree Species)
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21 pages, 2648 KiB  
Article
Effects of Drought, Phosphorus Fertilization and Provenance on the Growth of Common Beech and Sessile Oak
by Antonia Vukmirović, Željko Škvorc, Saša Bogdan, Daniel Krstonošić, Ida Katičić Bogdan, Tomislav Karažija, Marko Bačurin, Magdalena Brener and Krunoslav Sever
Forests 2024, 15(1), 219; https://doi.org/10.3390/f15010219 - 22 Jan 2024
Viewed by 667
Abstract
The negative impact of drought on plant growth may be modified by the different availability of mineral nutrients and by their adaptation to different local habitat conditions. In this study, we examine the impact of drought, fertilization with phosphorus and provenance, as well [...] Read more.
The negative impact of drought on plant growth may be modified by the different availability of mineral nutrients and by their adaptation to different local habitat conditions. In this study, we examine the impact of drought, fertilization with phosphorus and provenance, as well as their interactions, on the growth and allometric growth relationships between the belowground and aboveground organs of common beech (Fagus sylvatica L.) and sessile oak (Quercus petraea (Matt.) Liebl.). The research was conducted on saplings originating from two mature mixed stands (dry and wet provenances) dominated by these species. In the common garden experiment, saplings were exposed to regular watering and drought in interaction with moderate and high phosphorus concentrations in the growing substrate (achieved by phosphorus fertilization). The obtained results indicate the negative impact of drought and phosphorus fertilization on the growth of both species. In common beech, a negative impact of phosphorus fertilization on the adaptive capacity to drought was demonstrated by unfavorable ratios between fine root mass and the mass of other organs. The sessile oak provenances under the impact of drought showed a different root collar diameter/stem height increment ratio, which indicates their different phenotypic plasticity as a consequence of adaptation to different frequencies of dry periods in their natural habitats. Full article
(This article belongs to the Special Issue Abiotic Stress in Tree Species)
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18 pages, 2747 KiB  
Article
Multi-Omics Analysis of Gene and microRNA Expression in Diploid and Autotetraploid Poplar under Drought Stress by Transcriptome, microRNA, and Degradome Sequencing
by Qiang Han, Kang Du, Yufei Xia and Xiangyang Kang
Forests 2023, 14(11), 2268; https://doi.org/10.3390/f14112268 - 19 Nov 2023
Viewed by 878
Abstract
Drought-induced forest death has become a global phenomenon, which is hindering the development of sustainable forestry. Polyploidy breeding has been considered as an effective method of genetic improvement for tree stress resistance. However, the response mechanisms of tetraploid poplars to drought stress are [...] Read more.
Drought-induced forest death has become a global phenomenon, which is hindering the development of sustainable forestry. Polyploidy breeding has been considered as an effective method of genetic improvement for tree stress resistance. However, the response mechanisms of tetraploid poplars to drought stress are unclear. In this study, based on high-throughput sequencing of transcriptome, small RNA, and degradome for these samples, which selected three genotypes of tetraploid poplars and their counterpart diploids for drought stress and rewatering trial in the experiment, we performed multi-omics analyses to investigate the distinction in drought resistance between tetraploid and diploid. A total of 3391 differentially expressed genes (DEGs) were found from the Dro-Di vs. CK-Di, 3753 DEGs from the Re-Di vs. Dro-Di, 3857 DEGs from the Dro-Te vs. CK-Te, and 4177 DEGs from the Re-Te vs. Dro-Te. Of the above DEGs, 1646 common-DEGs were identified significantly related to drought-stress response, 2034 common-DEGs related to rewater response, 158 and 114 common-DEGs showed opposite expression patterns between diploid and tetraploid, implying that these DEGs might play important roles in response to drought stress as a result of differences in ploidy. Additionally, 586 known miRNAs and 72 novel miRNAs were identified through analysis of 18 small RNA libraries, among which eight common-miRNAs were significantly related to drought-stress response, and four were related to rewater response. The degradome sequencing analysis revealed that 154 target transcripts for 24 drought-stress-associated differentially expressed miRNAs (DEmiRs), and 90 for 12 rewatering-associated DEmiRs were identified in the tetraploid based on both degradome and TargetFinder analyses. These findings provide valuable information for further functional characterization of genes and miRNAs in response to drought stress in Populus polyploidy, and potentially contribute to drought-resistant breeding of polypoid in the future. Full article
(This article belongs to the Special Issue Abiotic Stress in Tree Species)
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17 pages, 3450 KiB  
Article
The Effect of Hot Wind on Needle and Stem Water Status: Response Strategies in Resprouting and Non-Resprouting Pine Species
by Pilar Pita, Rosana López and Luis Gil
Forests 2023, 14(11), 2174; https://doi.org/10.3390/f14112174 - 01 Nov 2023
Viewed by 763
Abstract
High temperatures threaten tree survival and regeneration. A few pine species, such as Pinus oocarpa and Pinus canariensis, resprout after complete defoliation, a likely consequence of evolving in volcanic environments. Pinus pinea and Pinus pinaster rely on other mechanisms to survive wildfires. [...] Read more.
High temperatures threaten tree survival and regeneration. A few pine species, such as Pinus oocarpa and Pinus canariensis, resprout after complete defoliation, a likely consequence of evolving in volcanic environments. Pinus pinea and Pinus pinaster rely on other mechanisms to survive wildfires. We hypothesized that the needle water potential (Ψ) and needle osmotic potential (Ψs) would decrease more under hot wind in resprouting species, a strategy of needle sacrifice in accordance with the hydraulic segmentation hypothesis. We submitted two-year-old seedlings to a two-phase hot wind treatment, consisting of one hour at 39 °C followed by five minutes at 70 °C. Phase 2 killed all needles. In non-resprouting species, Ψ decreased steeply at the beginning of Phase 1 and remained between −2 MPa and −4 MPa afterward, maintaining the loss of stem hydraulic conductance below the 50% threshold. On average, resprouting species had 15% lower wood densities and kept 51% higher stem water contents than non-resprouting species after Phase 2. The loss of hydraulic conductance did not affect resprouting. The increase in hydraulic conductance toward the base of the stem was lowest in P. canariensis, suggesting a lower degree of conduit tapering in the only species that had not undergone heteroblastic change. We measured the lowest Ψ and highest Ψs in the most xeric P. canariensis and the opposite in the most mesic P. oocarpa, highlighting the roles of xylary and extra-xylary hydraulic resistances in compartmentalizing the needle to preserve the stem. The measurement of both Ψ and Ψs allowed us to characterize the strategies of response to hot wind in resprouting and non-resprouting pine species. Full article
(This article belongs to the Special Issue Abiotic Stress in Tree Species)
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17 pages, 3120 KiB  
Article
Early Growth Characterization and Antioxidant Responses of Phellodendron chinense Seedling in Response to Four Soil Types at Three Growth Stages
by Yao Yang, Yun-Yi Hu, Wen-Zhang Qian, Ya-Juan Wang, Hong-Yu Ren, Shun Gao and Guo-Xing Cao
Forests 2023, 14(9), 1746; https://doi.org/10.3390/f14091746 - 29 Aug 2023
Cited by 1 | Viewed by 697
Abstract
Soil type is an important environmental factor that affects plant growth and development, especially during the early growth stage. In this study, P. chinense (Phellodendron chinense) seedlings were cultivated on red soil (RS), yellow soil (YS), acidic purple soil (ACPS), and [...] Read more.
Soil type is an important environmental factor that affects plant growth and development, especially during the early growth stage. In this study, P. chinense (Phellodendron chinense) seedlings were cultivated on red soil (RS), yellow soil (YS), acidic purple soil (ACPS), and alkaline purple soil (ALPS), and the influence of soil types on the growth parameters and physiological responses at three growth stages were investigated. The results show that soil types and growth stages can significantly influence seedling height, base diameter, and biomass in P. chinense seedlings. Moreover, the significant variations in chlorophyll, total polyphenols, soluble protein, soluble sugar, and malondialdehyde (MDA) content, as well as superoxide dismutase (SOD), peroxidase (POD), phenylalanine ammonia-lyase (PAL), and polyphenol oxidase (PPO) activity, were recorded at three growth stages among four soil types. These results show that P. chinense seedlings can grow normally in four soil types, and ACPS may be more beneficial for the artificial cultivation of P. chinense seedlings than those of RS, ALPS, and YS. Principal component analysis (PCA) reveals a strong correlation and clear differences in the test parameters between growth stage and organs in four soil types, and the cumulative contribution percentages of the total biplot range from 74.44% to 81.97%. This present information will be helpful for farmers in selecting soil type for the large-scale cultivation of P. chinense seedlings. Full article
(This article belongs to the Special Issue Abiotic Stress in Tree Species)
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15 pages, 7789 KiB  
Article
Identification and Characterization of the AREB/ABF/ABI5 Gene Family in Sandalwood (Santalum album L.) and Its Potential Role in Drought Stress and ABA Treatment
by Xiaojing Liu, Renwu Cheng, Yu Chen, Shengkun Wang, Fangcuo Qin, Dongli Wang, Yunshan Liu, Lipan Hu and Sen Meng
Forests 2023, 14(8), 1691; https://doi.org/10.3390/f14081691 - 21 Aug 2023
Viewed by 988
Abstract
AREB/ABF/ABI5 (ABA-responsive element-binding protein/ABRE binding factors and ABA INSENSITIVE 5) transcription factors are involved in regulating the expression of ABA (abscisic acid)-related genes and improving plant adaptability to environmental stress. To explore the influence of AREB/ABF transcription factors on santalol synthesis, we conducted [...] Read more.
AREB/ABF/ABI5 (ABA-responsive element-binding protein/ABRE binding factors and ABA INSENSITIVE 5) transcription factors are involved in regulating the expression of ABA (abscisic acid)-related genes and improving plant adaptability to environmental stress. To explore the influence of AREB/ABF transcription factors on santalol synthesis, we conducted a genome-wide analysis of the AREB gene family in sandalwood, identified 10 SaAREB genes, and divided them into five subfamilies. We found that all SaAREB genes encoded unstable hydrophilic proteins and the subcellular localization prediction of SaAREBs was that they are located in the nucleus. AREB/ABF genes belong to the bZIP-A subfamily and we found that the 10 AREB proteins all contained bZIP (basic region leucine zipper) and four potential phosphorylation sites (RXXS/T). According to the collinearity analysis results, four of the SaAREB genes were involved in two fragment duplication events. Through qRT-PCR (real-time fluorescence quantitative PCR), we explored the expression profile of SaAREB in different tissues; the effects of ABA treatment and drought treatment on AREB transcription factors were predicted. From the expression of different tissues, we found that SaAREB1 not only responded to prolonged drought but also was highly expressed in stems. Moreover, SaAREB3, SaAREB7, and SaAREB8 specifically respond to ABA treatment. Based on RNA-seq (RNA sequencing) data, we found that SaAREB6 and SaAREB8 were highly expressed in the sapwood and transition regions. Regarding SaCYP736A167, as a key gene in santalol synthesis, its promoter contains the most ABRE cis-reactive elements. These results provide a basis for further analysis of the role of the Santalum album L. (S. album) ABRE/ABF/ABI5 genes in the formation of santalols. Full article
(This article belongs to the Special Issue Abiotic Stress in Tree Species)
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18 pages, 5478 KiB  
Article
The Most Suitable Calcium Concentration for Growth Varies among Different Tree Species—Taking Pinus tabuliformis, Pinus sylvestris var. mongolica, Populus, and Morus alba as Examples
by Hui Li, Yaoyao Zhao, Xiaohang Weng, Yongbin Zhou, Songzhu Zhang, Liying Liu and Jiubo Pei
Forests 2023, 14(7), 1437; https://doi.org/10.3390/f14071437 - 13 Jul 2023
Cited by 1 | Viewed by 918
Abstract
Ca2+ is a crucial second messenger in plant cells that plays a vital role in various physiological and biochemical processes, including plant growth and development, photosynthesis, and enzyme regulation. Exogenous calcium concentrations can have different effects on plant growth. The purpose of [...] Read more.
Ca2+ is a crucial second messenger in plant cells that plays a vital role in various physiological and biochemical processes, including plant growth and development, photosynthesis, and enzyme regulation. Exogenous calcium concentrations can have different effects on plant growth. The purpose of this study was to determine the appropriate calcium concentration for the growth of four tree seedlings, namely Pinus tabuliformis, Pinus sylvestris var. mongolica, Populus, and Morus alba seedlings, and whether this optimal calcium concentration varies among different tree species. This study utilized five calcium concentration gradients (0, 100, 200, 400, 800 mg·kg−1) for each species with three repeated treatments. To determine each species’ calcium concentration needs, several growth indices, photosynthetic metrics, chlorophyll fluorescence parameters, water usage efficiency, and antioxidant enzyme activities were analyzed. The results showed that exogenous calcium significantly affected the growth and development of each seedling. The growth, biomass, photosynthetic parameters, photosynthetic products, photosynthetic pigments, water use efficiency, and antioxidant enzyme activity all increased initially and then decreased with the increasing calcium concentration. The exogenous calcium supply increased the concentration of calcium in the leaves. Thus, there was an optimal calcium concentration for plant growth, and a high or low calcium concentration was not conducive to plant growth. Furthermore, this study found that the optimum calcium concentration of different tree species was different. The optimal calcium concentration for Pinus tabuliformis, Pinus sylvestris var. mongolica, Populus, and Morus alba seedlings was 100, 100, 200, and 400 mg·kg−1, respectively, with broadleaf seedlings requiring higher calcium concentrations than coniferous seedlings. Full article
(This article belongs to the Special Issue Abiotic Stress in Tree Species)
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19 pages, 4438 KiB  
Article
Transcriptome Analysis Reveals the Hormone Signalling Coexpression Pathways Involved in Adventitious Root Formation in Populus
by Qiqi Zhang, Meirong Shi, Fang Tang, Nan Su, Feiyang Jin, Yining Pan, Liwei Chu, Mengzhu Lu, Wenbo Shu and Jingcai Li
Forests 2023, 14(7), 1436; https://doi.org/10.3390/f14071436 - 13 Jul 2023
Cited by 1 | Viewed by 1082
Abstract
Adventitious roots (ARs) occur naturally in many species and are important for plants to absorb nutrients and water. AR formation can also be induced from explants of trees, whose clonal propagation is needed. AR formation is gridlock for many woody plant mass propagations. [...] Read more.
Adventitious roots (ARs) occur naturally in many species and are important for plants to absorb nutrients and water. AR formation can also be induced from explants of trees, whose clonal propagation is needed. AR formation is gridlock for many woody plant mass propagations. Plant hormones have been regarded as playing a key role in AR formation, and the molecular regulatory mechanisms need to be elucidated. In this study, RNA-Seq was performed to reveal the molecular mechanisms in the different periods of AR formation from hybrid poplar clone 84K (Populus alba × P. glandulosa) and AUXIN SIGNALING F-BOX (PagFBL1-OE). To understand the importance of differentially expressed genes (DEGs), we found that many genes involved in signal transduction mechanisms were induced at 12, 24 and 48 h in 84K and PagFBL1-OE cells by NOG classification. We also found that many DEGs were enriched in hormone signal transduction only for the first 12 h in 84K and PagFBL1-OE by KEGG pathway enrichment. Notably, more DEGs appeared in indole-3-acetic acid (IAA), abscisic acid (ABA), ethylene (ETH), jasmonic acid (JA), brassinolide (BR), cytokinin (CTK) and gibberellin (GA) signal transduction for the first 12 h in PagFBL1-OE than in 84K. Moreover, ARF (Pop_G01G075686), IAA14 (Pop_A10G047257), SAURs (Pop_A03G019756, Pop_A12G067965, Pop_G03G055849 and Pop_G12G008821), JAR1s (Pop_A14G000375 and Pop_G14G044264), CTR1 (Pop_A17G052594 and Pop_G09G030293), CRE1s (Pop_G07G086605 and Pop_G07G086618), GID1 (Pop_A04G026477), BKI1 (Pop_A02G066155), PYR/PYLs (Pop_A03G050217 and Pop_G01G089222), and TGAs (Pop_A04G059310, Pop_G04G060065 and Pop_G05G008153) were only specifically expressed in PagFBL1-OE and could play an important role in AR formation, especially in the first 12 h under plant hormone signal transduction. These results show that the complex biological process of AR formation is primarily influenced by the hormone signalling pathway in Populus. This study reveals the initial regulation of AR formation in woody plant cuttings and thus contributes to further elucidating the molecular mechanism by which hormones interact. Full article
(This article belongs to the Special Issue Abiotic Stress in Tree Species)
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19 pages, 11695 KiB  
Article
Comparative Transcriptome Analysis Reveals Key Genes and Pathways Associated with Phosphate-Sensitive Behaviors in Cunninghamia lanceolata (Lamb.) Hook.
by Ruping Wei, Dehuo Hu, Jinhui Chen, Huiquan Zheng and Jisen Shi
Forests 2023, 14(6), 1203; https://doi.org/10.3390/f14061203 - 10 Jun 2023
Viewed by 804
Abstract
Cunninghamia lanceolate (Lamb.) Hook. (Chinese fir) is one of the most important wood-producing species, supplying ~20% of commercial timber by plantations in China. However, the genetic potential of the bred variety is limited by soil degrading in the long term and requiring continuous [...] Read more.
Cunninghamia lanceolate (Lamb.) Hook. (Chinese fir) is one of the most important wood-producing species, supplying ~20% of commercial timber by plantations in China. However, the genetic potential of the bred variety is limited by soil degrading in the long term and requiring continuous replanting, and especially the shortage and supply of active and efficient phosphorus. Recently, great attention has been paid to the genotypic variation in phosphorus conversion and utilization efficiency by tree breeders. In this study, the morphological characteristics were used to evaluate the Chinese fir clonal Pi-efficiency stress. A Pi-tolerant clone and a Pi-sensitive clone were selected for RNA sequencing, respectively. In addition, gene function annotation and weighted correlation network analysis (WGCNA) were performed. A total of 60 hub genes were selected, combining phosphate accumulation under Pi-deficiency stress. We also used RNA-seq data to analyze the differences in the response of Pi-sensitive clones and Pi-tolerant clones to Pi-deficiency stress, and real-time quantitative polymerase chain reaction (RT-PCR) analyses were used to test the validity of transcriptome data. The present study provided new insights into the molecular mechanisms of Pi-efficient utilization in Chinese fir clones. Full article
(This article belongs to the Special Issue Abiotic Stress in Tree Species)
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17 pages, 4821 KiB  
Article
Rahnella aquatilis JZ-GX1 Alleviate Salt Stress in Cinnamomum camphora by Regulating Oxidative Metabolism and Ion Homeostasis
by Pu-Sheng Li, Wei-Liang Kong and Xiao-Qin Wu
Forests 2023, 14(6), 1110; https://doi.org/10.3390/f14061110 - 26 May 2023
Viewed by 1385
Abstract
Salt stress is an environmental stress that severely limits plant growth, development and productivity. The use of symbiotic relationships with beneficial microorganisms provides an efficient, cost-effective and environmentally friendly preventative method. The plant growth-promoting rhizobacteria (PGPR) Rahnella aquatilis JZ-GX1 is a moderately salinophilic [...] Read more.
Salt stress is an environmental stress that severely limits plant growth, development and productivity. The use of symbiotic relationships with beneficial microorganisms provides an efficient, cost-effective and environmentally friendly preventative method. The plant growth-promoting rhizobacteria (PGPR) Rahnella aquatilis JZ-GX1 is a moderately salinophilic strain with good probiotic properties, although its ability to improve woody plant salt tolerance has not been reported. In this study, the effect of JZ-GX1 on Cinnamomum camphora under different salt concentrations (0, 50 and 100 mM NaCl) was investigated to reveal the mechanism by which JZ-GX1 improves salt tolerance in C. camphora. The results showed that JZ-GX1 promoted plant growth and root development. The relative electrolyte leakage (REL) and malondialdehyde (MDA) production of inoculated C. camphora plants were reduced by 37.38% and 21.90%, respectively, and the superoxide dismutase (SOD) activity in the leaves was enhanced by 321.57% under a 100 mM NaCl treatment. It was observed by transmission electron microscopy that under 100 mM salt concentration conditions, the inoculated C. camphora leaf cells showed a significant reduction in plasma membrane–cell wall separation and intact chloroplast structures, with tightly packed thylakoids. Importantly, inoculation reduced Na+ accumulation and promoted K+ accumulation in the seedlings, and these changes were consistent with the upregulated expression of the K+ channel SKOR and the vesicular membrane (Na+, K+)/H+ reverse cotransporter NHX1 in the plant roots. This study revealed the mechanism of the Rahnella aquatilis JZ-GX1 enhancing salt tolerance of C. camphora. Full article
(This article belongs to the Special Issue Abiotic Stress in Tree Species)
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13 pages, 7216 KiB  
Article
Genome-Wide Identification of the Argonaute Protein Family and Its Expression Analysis under PEG6000, ABA and Heat Treatments in Populus alba × P. glandulosa
by Hongying Li, Zhengbo Wang, Yanwu Gao, Mengdi Chen, Ziyuan Hao, Xi Chen, Lili Guo, Chunjie Fan and Shutang Zhao
Forests 2023, 14(5), 1015; https://doi.org/10.3390/f14051015 - 15 May 2023
Viewed by 996
Abstract
The argonaute (AGO) protein, as an important member of the small RNA (sRNA) regulatory pathway gene-silencing complex (RNA-induced silencing complex, RISC), is a key protein that mediates gene silencing and plays a key role in the recruitment of sRNAs. In this study, bioinformatics [...] Read more.
The argonaute (AGO) protein, as an important member of the small RNA (sRNA) regulatory pathway gene-silencing complex (RNA-induced silencing complex, RISC), is a key protein that mediates gene silencing and plays a key role in the recruitment of sRNAs. In this study, bioinformatics was used to identify the AGO gene family in poplar and study its expression in various tissues and in response to abiotic stress treatments. A total of 15 PtAGO genes were identified in poplar, which were unevenly distributed in 9 chromosomes. Most proteins were predicted to be located in the nucleus and chloroplast. The PtAGOs had similar motif structures and conserved motifs, except for PtAGO3. All the PtAGO genes could be clustered into 3 groups, and Group II, including PtAGO2/3/7, had the smallest number of exons, while the others had more than 20 exons. Cis-regulatory elements involved in light response, growth and development, abiotic stress and hormone-induced responses were found in the promoters of PtAGO members. Further expression analysis found that the PtAGO genes had tissue-specific expression patterns. For example, PtAGO7 and PtAGO10b were mainly expressed in the xylem and might be involved in secondary xylem development. Furthermore, abiotic stress tests, including heat, ABA and PEG treatments, showed that most PtAGO genes could respond quickly to ABA treatment, and multiple PtAGO genes were constantly regulated under heat-shock stress. These results provide a basis for the elucidation mechanism of PtAGO genes and further molecular breeding in poplar. Full article
(This article belongs to the Special Issue Abiotic Stress in Tree Species)
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13 pages, 2024 KiB  
Article
The Effects of Dual Ozone and Drought Stresses on the Photosynthetic Properties of Acer rubrum and A. pictum
by Lifan Wang, Laiye Qu, Haimei Li, Tong Wang, Xuemei Hu, Xiangyang Yuan and Xiao Guo
Forests 2023, 14(5), 998; https://doi.org/10.3390/f14050998 - 12 May 2023
Cited by 1 | Viewed by 1262
Abstract
Ozone (O3) pollution is accompanied by drought stress, especially at high temperatures. Tree species in cities often face dual stresses from O3 and drought. In this study, Acer rubrum ‘Autumn Blaze’ and A. pictum were used as test plants in [...] Read more.
Ozone (O3) pollution is accompanied by drought stress, especially at high temperatures. Tree species in cities often face dual stresses from O3 and drought. In this study, Acer rubrum ‘Autumn Blaze’ and A. pictum were used as test plants in open-top-chambers (OTCs) to investigate the trees most tolerant to increasing O3 and drought stresses in urban gardens. The results showed that the dual stresses induced a change in A. rubrum’s leaf coloration from green to red. The leaf representation in A. rubrum was more variable than that of A. pictum. The leaf pigment content affected the plant leaf color difference, and the Chl and Car contents of both species were negatively correlated with L*. Under the dual stresses of O3 and drought, the changes in the net photosynthetic rate (Pn) and transpiration rate (Tr) were less variable in A. rubrum than A. pictum. The stomatal conductance (Gs) was more sensitive to higher O3 stress, the effect of which was enhanced by moderate drought (MD) conditions on Gs. The Tr decreased more significantly under drought stress, which mitigated the effect of O3 stress on the stomatal limit value (Ls). A. rubrum displayed differential color changes, resulting in greater structural heterogeneity within the garden landscape. The saplings adjusted their photosynthetic parameters under the dual stresses, whereas the dual stresses played an antagonistic role in protecting A. rubrum, suggesting that A. rubrum can resist O3 and drought. Our study suggests that A. rubrum is an alternative tree species for inclusion in urban gardens exposed to increasing O3 and drought stresses. Full article
(This article belongs to the Special Issue Abiotic Stress in Tree Species)
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19 pages, 14328 KiB  
Article
Study on the Origin and Classification of Two Poplar Species on the Qinghai–Tibet Plateau
by Yu-Jie Shi, Jia-Xuan Mi, Jin-Liang Huang, Fang He, Liang-Hua Chen and Xue-Qin Wan
Forests 2023, 14(5), 1003; https://doi.org/10.3390/f14051003 - 12 May 2023
Cited by 1 | Viewed by 1163
Abstract
Poplar not only has important ecological and economic value, but also is a model woody plant in scientific research. However, due to the rich morphological variation and extensive interspecific hybridization, the taxonomy of the genus Populus is very confused, especially in the Sect. [...] Read more.
Poplar not only has important ecological and economic value, but also is a model woody plant in scientific research. However, due to the rich morphological variation and extensive interspecific hybridization, the taxonomy of the genus Populus is very confused, especially in the Sect. Tacamahaca. Based on the extensive investigation of Populus on the Plateau and its surrounding areas, two taxa (Populus kangdingensis and Populus schneideri var. tibetica) that are very similar in morphology and habitat and are in doubt in taxonomy were found. First of all, we set up 14 sample sites, carried out morphological investigation and statistics, and found that there were a few morphological traits that could be distinguished between the two taxa. Further phylogenetic analysis based on the whole genome resequencing data showed that the two taxa were hybrid progenies of P. xiangchengensis and P. simonii. Through gene flow detection and genetic differentiation analysis, it was found that there was still strong gene flow from P. xiangchengensis to the two taxa, and there was almost no differentiation between the two taxa. Therefore, P. schneideri var. tibetica should be classified into P. kangdingensis as same taxa. Finally, the population history was reconstructed by PSMC and ABC models, and it was found that they all belonged to a hybrid origin, and the change in population size was closely related to the Quaternary ice age. In addition, the hybrid population has better adaptability, and the suitable distribution area may expand in the future. This study provided a novel and comprehensive method for the phylogeny of Populus and laid a foundation for the development and utilization of poplar resources. Full article
(This article belongs to the Special Issue Abiotic Stress in Tree Species)
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19 pages, 4784 KiB  
Article
Identification and Expression Pattern of the Carotenoid Cleavage Oxygenase Gene Family in Lycium Suggest CCOs Respond to Abiotic Stress and Promote Carotenoids Degradation
by Weinan Li, Jiahang Che, Qile Lian, Cuiping Wang, Guoli Dai and Jinhuan Chen
Forests 2023, 14(5), 983; https://doi.org/10.3390/f14050983 - 10 May 2023
Viewed by 1388
Abstract
Carotenoids are key metabolites in goji (Lycium), a traditional Chinese medicine plant; however, the carotenoid content varies in fruits of different goji species, and the mechanism of this variation is not clear. Carotenoids participate in signal transduction and photosynthesis, and function as [...] Read more.
Carotenoids are key metabolites in goji (Lycium), a traditional Chinese medicine plant; however, the carotenoid content varies in fruits of different goji species, and the mechanism of this variation is not clear. Carotenoids participate in signal transduction and photosynthesis, and function as colorants and photoprotectors. Members of the carotenoid cleavage oxygenase (CCO) gene family are involved in the regulation of phytohormones, pigments, and aromatic substances, such as abscisic acid (ABA), β-carotenoid, and α-ionone, by degrading carotenoids. Some CCO genes are also related to an abiotic stress response. Here, a total of 12 LbCCO genes were identified and analyzed from the L. barbarum genome. CCO genes were divided into six subfamilies based on the constructed phylogenetic tree, including LbNCEDs, LbCCD1, LbCCD3, LbCCD4, LbCCD7, and LbCCD8. Among them, CCD3 was reported for the first time. The gene structure and motif analysis revealed the conservation of CCO subfamilies. Pseudogene generation and the importance of each subfamily in CCOs were revealed by collinearity analysis. The spatiotemporal transcriptomes of L. barbarum and L. ruthenicum were compared, suggesting that CCD4-1 may dominate carotenoid degradation in goji fruits. Cis-acting elements prediction and environment responsive gene expression analyses indicated that salt-alkali stress and photothermal conditions might influence the expression of CCOs in goji. The results of this study enhance our understanding of the carotenoid degradation pathway, and the functions and responses of CCOs in goji species. Full article
(This article belongs to the Special Issue Abiotic Stress in Tree Species)
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16 pages, 3412 KiB  
Article
PIP2;10 Enhances Drought Tolerance via Promoting Water-Retaining Capacity in Populus
by Xiao-Qian Yu, Wanlong Su, Chao Liu, Hou-Ling Wang, Weilun Yin and Xinli Xia
Forests 2023, 14(4), 696; https://doi.org/10.3390/f14040696 - 28 Mar 2023
Viewed by 1047
Abstract
Drought is an adverse environmental factor for plant growth and development. Aquaporins play an influential role in water uptake and transport in plants. However, the function of PagPIP2;10 in response to drought stress remains largely unclear. Here, we report that the plasma membrane [...] Read more.
Drought is an adverse environmental factor for plant growth and development. Aquaporins play an influential role in water uptake and transport in plants. However, the function of PagPIP2;10 in response to drought stress remains largely unclear. Here, we report that the plasma membrane intrinsic protein PagPIP2;10 was in the cell membrane and induced by dehydration in the poplar 84K hybrids. The overexpression of PagPIP2;10 in poplars enhanced drought tolerance. The PagPIP2;10ox lines maintained a higher water retention content, photosynthetic rate, and proline content. Meanwhile, a lower content of MDA and transpiration and stomatal conductance were observed under drought stress than in that of the WT plants. A further analysis found that the PagPIP2;10ox lines decreased the stomatal aperture and accumulated more ROS in guard cells compared with WT after ABA treatment with the exception that the root hydraulic conductance of the PagPIP2;10ox lines was higher than that of the WT plants. These results imply that PagPIP2;10 played a positive role in enhancing drought stress via enhancing water-retaining capacity under drought stress. Full article
(This article belongs to the Special Issue Abiotic Stress in Tree Species)
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17 pages, 1745 KiB  
Article
Effects of Water Deficit Stress on Growth Parameters of Robinia pseudoacacia L. Selected Clones under In Vitro Conditions
by Iwona Szyp-Borowska, Joanna Ukalska, Marzena Niemczyk, Tomasz Wojda and Barb R. Thomas
Forests 2022, 13(12), 1979; https://doi.org/10.3390/f13121979 - 23 Nov 2022
Cited by 4 | Viewed by 1096
Abstract
Rapid screening methods for drought-resistant genotypes are urgently needed in tree improvement programs in the face of current climate change. We used a plant tissue culture technique to assess the phenotypic response of three highly productive genotypes of Robinia pseudoacacia to water deficit [...] Read more.
Rapid screening methods for drought-resistant genotypes are urgently needed in tree improvement programs in the face of current climate change. We used a plant tissue culture technique to assess the phenotypic response of three highly productive genotypes of Robinia pseudoacacia to water deficit induced by mannitol and sucrose in a range of water potentials from 0 MPa to −1.5 MPa in an eight-week experiment. Our study showed genotype-specific responses to induced drought stress, indicating the potential for tree improvement in productivity and stress tolerance. Considering that all plantlets were constantly supplied with carbon, from the medium during the drought-induced experiment, our results suggest that hydraulic failure rather than carbon starvation may be the main cause of drought-induced mortality. Furthermore, our results showed different metabolic pathways of sucrose depending on the concentration of sucrose in the medium and different responses to osmoticum (mannitol vs. sucrose) and its concentration among the clones tested. We believe, that for large-scale breeding programs wanting to select for drought-tolerant genotypes, the use of culture media containing 90 gL−1 mannitol or 90 gL−1 sucrose at an early selection stage should provide satisfactory screening results. However, lab-based screening should be supported by further field trials, preferably at multiple sites, to assess the long-term impact and phenotypic stability of the early selection strategies. Full article
(This article belongs to the Special Issue Abiotic Stress in Tree Species)
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Review

Jump to: Research

15 pages, 1603 KiB  
Review
Genetic Transformation of Forest Trees and Its Research Advances in Stress Tolerance
by Yi Li, Yanhui Yuan, Zijian Hu, Siying Liu and Xi Zhang
Forests 2024, 15(3), 441; https://doi.org/10.3390/f15030441 - 26 Feb 2024
Viewed by 758
Abstract
Forests represent a vital natural resource and play a crucial role in climate regulation and maintaining biodiversity. However, the growth and development of forest trees are increasingly challenged by rising environmental pressures, particularly detrimental abiotic stressors. To address these challenges, genetic transformation technologies [...] Read more.
Forests represent a vital natural resource and play a crucial role in climate regulation and maintaining biodiversity. However, the growth and development of forest trees are increasingly challenged by rising environmental pressures, particularly detrimental abiotic stressors. To address these challenges, genetic transformation technologies have emerged as effective solutions. Despite various difficulties in genetic transformation for forest trees, including prolonged life cycles, genetic diversity, interspecies variations, and complex regeneration systems, significant research progress has been achieved in tree gene editing, transgenic technology, and methods for delivering exogenous molecules. These technologies have the potential to enhance tree quality, increase productivity, and improve resistance to abiotic stress. This review provides an overview of the main methods and transformation receptors in tree genetic transformation. Additionally, we summarize several novel techniques, such as nanoparticle-mediated gene transformation, advanced gene editing technology, various novel delivery carriers, and non-genetically modified protein function interference through peptide aptamer. Notably, we also place emphasis on several referable genes from forest trees and common crops, together with their potential function for improving abiotic stress responses. Through this research, we aspire to achieve sustainable utilization and conservation of tree resources, thereby providing substantial support for future livelihoods and economic development. Full article
(This article belongs to the Special Issue Abiotic Stress in Tree Species)
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11 pages, 7318 KiB  
Review
Beat the Heat: Signaling Pathway-Mediated Strategies for Plant Thermotolerance
by Zidan Cao, Enbo Wang, Xinyi Xu, Chenheng Tong, Xia Zhao, Xiqiang Song, Jian Wang, Hou-ling Wang, Xinli Xia and Ying Zhao
Forests 2023, 14(10), 2026; https://doi.org/10.3390/f14102026 - 10 Oct 2023
Viewed by 996
Abstract
The frequent high temperatures caused by climate change have a very adverse impact on the growth and development of plants at different growth stages. Almost all cellular processes in plants are highly sensitive to high temperatures, but plants have their unique heat-resistant strategies. [...] Read more.
The frequent high temperatures caused by climate change have a very adverse impact on the growth and development of plants at different growth stages. Almost all cellular processes in plants are highly sensitive to high temperatures, but plants have their unique heat-resistant strategies. The plasma membrane usually senses temperature changes through changes in membrane fluidity. The accumulation of damaged proteins and reactive oxygen species in biofilms also helps calcium ions and thermal sensors cascade signals to transcription factors, thereby resisting high temperatures. There are also misfolded proteins in the endoplasmic reticulum and cytoplasm due to heat stress, which act as heat conduction signals. Carbohydrates commonly found in organisms can also serve as signaling molecules and participate in heat stress response. Heat shock transcription factor can effectively regulate the expression of heat-induced genes, producing heat shock proteins to maintain intracellular homeostasis. Full article
(This article belongs to the Special Issue Abiotic Stress in Tree Species)
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