Plant Stress Responses Research Articles

Computational analysis and expression profiling of NAC transcription factor family involved in biotic stress response in Manihot esculenta.

The Nascent polypeptide-Associated Complex (NAC) family is among the largest plant-specific TF families and plays an important role in plant growth, development, and stress responses. NAC TFs have been extensively studied in plants such as rice and Arabidopsis; however, their characterization, functions, evolution, and expression patterns in Manihot esculenta (cassava) under environmental stress remain largely unexplored. Here, we used bioinformatic analyses and biotic stress responses to investigate the physicochemical properties, chromosome location, phylogeny, gene structure, expression patterns, and cis-elements in promoter regions of the NAC TFs in cassava. We identified 119 M. esculenta NAC (MeNAC) gene families, unevenly distributed on 16 chromosomes. We investigated expression patterns of all identified MeNAC TFs under Xanthomonas axonopodis pv. manihotis (Xam) infection, strain CHN11, at different time points. Only 20 MeNAC TFs showed expression of significant bacterial resistance. Six MeNACs (MeNAC7, 26, 63, 65, 77, and 113) were selected for functional analysis. qRT-PCR assays revealed that MeNAC7, 26, 63, 65, 77, and 113 were induced in response to XamCHN11 infection and may participate in the molecular interaction of cassava and bacterial blight. Interestingly, MeNAC26, MeNAC63, MeNAC65, and MeNAC113 responded to XamCHN11 infection at 3 h post-inoculation. Furthermore, we identified 13 stress-related cis-elements in promoter regions of the MeNAC genes that are involved in diverse environmental stress responses. Phylogenetic analysis revealed that MeNAC genes with similar structures and motif distributions were grouped. This study provides valuable insights into the evolution, diversity, and characterization of MeNAC TFs. It lays the groundwork for a better understanding of their biological roles and molecular mechanisms in cassava.

Unraveling barley's PAL gene family: a genome-wide study on defense mechanisms against Puccinia graminis f. sp. tritici

Phenylalanine ammonia lyase (PAL) is a pivotal enzyme bridging primary and secondary phenylpropanoid metabolism, influencing plant growth, development, and stress responses. Despite extensive studies on PAL genes across various plant species, their investigation in barley, a critical staple food globally, has been relatively scarce. In this study, we have successfully identified 10 HvPAL genes, designated as HvPAL genes, in Hordeum vulgare (barley). These HvPAL genes were categorized based on their conserved sequences, which revealed patterns through MEME analysis and multiple sequence alignment. Interestingly, we found cis elements related to stress in the promoter regions of HvPAL genes, indicating their involvement in the response to pathogens. Furthermore, these gene promoters contained components associated with light, development, and hormone responsiveness. This suggests that they may play a role in hormonal developmental processes. MicroRNAs were also identified as regulators of the HvPAL genes we identified highlighting their significance in barley. To further investigate these gene expression patterns, we analyzed the RNA-seq data revealed the upregulating of HvPAL 2, HvPAL3, and HvPAL8, and downregulating HvPAL 5, HvPAL 6, and HvPAL9 genes in this study. This study focused on the regulation of PAL genes in response to 23 different races of Puccinia graminis f. sp. tritici in barley. These results suggest ways to improve traits and develop barley varieties that are resistant to pathogens by selectively increasing the expression of certain HvPAL genes that were not previously regulated. This thorough investigation aims to expand our knowledge of the versatility of the PAL gene family, providing insights for advancements in host -pathogen genetics.

Euphorbiaceae superoxide dismutase, catalase, and glutathione peroxidase as clues to better comprehend high drought tolerance in castor bean

Superoxide dismutase (SOD), Catalase (CAT), and Glutathione peroxidase (GPX) enzymes exert a central role in reactive oxygen species (ROS) scavenger in plants, being an important part of enzymatic antioxidant system. Despite the importance of these enzymes in ROS metabolism and in different signaling pathways related to plant development and stress response, their gene families have not yet been comprehensively characterized in many crop plants. Among different crops, the Euphorbiaceae family has some species highly tolerant to drought stress. However, the gene families that encode the antioxidant enzymes, as well as their role in this drought stress tolerance, remains not characterized. Here, the SOD, CAT, and GPX genes of castor bean (Ricinus communis), cassava (Manihot esculenta), jatropha (Jatropha curcas), rubber tree (Hevea brasiliensis), petty spurge (Euphorbia peplus), and annual mercury (Mercurialis annua) were identified and characterized. The comprehensive phylogenetic and genomic analyses allowed the classification of the genes into different classes and revealed the duplication events that contribute to the expansion of these families within plant genomes. The expression patterns of SOD, CAT, and GPX genes were examined in castor bean, cassava, jatropha, and rubber tree by RNA-seq analysis revealing differential expression during stress. Additionally, the castor bean gene expression was confirmed by RT-qPCR. Among castor bean genes, RcGPX4 appears to be induced in castor bean roots under drought stress, but the heterologous expression in Arabidopsis thaliana does not improve the drought tolerance. Altogether, this data has significantly contributed to characterizing the expression patterns and conducting evolutionary assessment of these genes in Euphorbiaceae. This bridge a gap in understanding the proposed functions of core components within the antioxidant mechanism in an economically significant group of plants, particularly during stress responses

Imaging the spatial distribution of structurally diverse plant hormones: A comprehensive review.

Plant hormones are essential and structurally diverse molecules that regulate various aspects of plant growth, development, and stress responses. However, the precise analysis of plant hormones in complex biological samples poses a challenge due to their low concentrations, dynamic levels, and intricate spatial distribution. Moreover, the complexity and interconnectedness of hormone signaling networks make it difficult to simultaneously trace multiple hormone distributions. In this review, we provide an overview of the currently recognized small-molecule plant hormones, signal peptide hormones, and plant growth regulators, along with the analytical methods employed for their analysis. We delve into the latest advancements in mass spectrometry imaging and in situ fluorescence techniques, which enable the examination of the spatial distribution of plant hormones. The advantages and disadvantages of these imaging techniques are further discussed. Finally, we propose potential avenues for future research in this field to further enhance our understanding of plant hormone biology.

The transcription factor ZmbHLH105 confers cadmium tolerance by promoting abscisic acid biosynthesis in maize

Cadmium (Cd), a highly toxic heavy metal, profoundly impacts crop productivity. The bHLH-type transcription factors regulate plant stress responses, yet their involvement in maize's Cd stress response remains unclear. Here, we studied ZmbHLH105, a maize bHLH gene induced by Cd exposure. Overexpression of ZmbHLH105 in maize seedlings, which were treated with 1.0 mM CdCl2 for 7 days, increased endogenous ABA levels, decreased Cd accumulation, and enhanced Cd stress tolerance. ZmbHLH105 directly bound to promoter regions of two key ABA biosynthesis genes ZmNCED1/2, activating their transcription, thus boosting ABA levels and Cd tolerance. ZmbHLH105-overexpression promoted lignin synthesis, while ZmbHLH105-RNAi attenuated this effect. Exogenous ABA supplementation increased lignin content in Cd-stressed maize roots, suggesting ZmbHLH105-mediated Cd tolerance involves ABA-induced lignin deposition and cell wall thickening. Moreover, Cd transport-related gene expression was suppressed in ZmbHLH105 overexpression lines. Our findings demonstrate that ZmbHLH105 decreases Cd accumulation, improving Cd tolerance by enhancing ABA biosynthesis, increasing lignin deposition, thickening cell walls, and inhibiting Cd absorption in maize roots. This study unveils ZmbHLH105's mechanisms in Cd tolerance, highlighting its potential in breeding low Cd-accumulating crops for food and environment safety.

The sucrose signalling route controls Flavescence dorée phytoplasma load in grapevine leaves.

Flavescence dorée (FD) is a phytoplasma disease transmitted by insects, causing severe damage to vineyards across Europe. Infected plants cannot be cured and must be removed to prevent further spread. Different grapevine cultivars show varying susceptibility to FD, and some exhibit symptom remission, known as recovery, although the mechanisms behind this are unclear. Diseased plants accumulate soluble sugars, including sucrose, which influences the concentration of trehalose-6P (T6P), a signalling molecule affecting plant growth and stress responses. It is hypothesized that sucrose-mediated signalling via T6P could trigger defence mechanisms, reducing FD pathogen load and increasing plant recovery. Testing this, two grapevine genotypes with different susceptibility to FD were compared, revealing increased sucrose level and TPS activity in the more tolerant cultivar. However, FD-infected plants showed inhibited sucrose-cleaving enzymes and no activation of TPS expression. Attempts to enhance sucrose levels through trunk infusion and girdling promoted sucrose metabolism, T6P biosynthesis, and defence gene expression, facilitating symptom recovery. Girdling particularly enhanced T6P biosynthesis and defence genes above the treatment point, reducing FD pathogen presence and promoting recovery. These findings suggest that elevated sucrose levels, possibly signalling through T6P, may limit FD pathogen spread, aiding in plant recovery.

The SET-Domain-Containing Protein MdSDG26 Negatively Regulates Alternaria alternata Resistance in Apple.

Apple leaf spot is one of the most devastating diseases in the apple industry, caused by Alternaria alternata f. sp mali (A. alternata). SET-domain group (SDG) proteins function as the histone methyltransferases and participate in plant development and stress responses. However, whether SDG proteins are associated with A. alternata resistance is largely unclear. Here, we describe the pathogen-inducible MdSDG26 gene in apple (Malus × domestica). MdSDG26 has two transcript variants that function similarly in catalyzing histone methylation and A. alternata resistance. Transient overexpression of MdSDG26 increased the global levels of H3K4me3 and H3K36me3, whereas knockdown of MdSDG26 only reduced the H3K36me3 level. Transcriptome analysis revealed that MdSDG26 affected the genome-wide transcriptome changes in response to A. alternata infection. ChIP-qPCR analysis demonstrated that MdSDG26 modulates the levels of H3K36me3 and H3K4me3 at both the promoter and exon regions of MdNTL9. As a negative regulator of A. alternata resistance in apples, MdNTL9 plays a pivotal role in MdSDG26-mediated resistance to A. alternata. Therefore, our findings provide compelling evidence for the regulatory function of MdSDG26 in histone methylation and its molecular role in conferring resistance to A. alternata.

Genome-wide identification of oxidosqualene cyclase genes regulating natural rubber in Taraxacum kok-saghyz.

Nine TkOSC genes have been identified by genome-wide screening. Among them, TkOSC4-6 might be more crucial for natural rubber biosynthesis in Taraxacum kok-saghyz roots. Taraxacum kok-saghyz Rodin (TKS) roots contain large amounts of natural rubber, inulin, and valuable metabolites. Oxidosqualene cyclase (OSC) is a key member for regulating natural rubber biosynthesis (NRB) via the triterpenoid biosynthesis pathway. To explore the functions of OSC on natural rubber producing in TKS, its gene family members were identified in TKS genome via genome-wide screening. Nine TkOSCs were identified, which were mainly distributed in the cytoplasm. Their family genes experienced a neutral selection during the evolution process. Overall sequence homology analysis OSC proteins revealed 80.23% similarity, indicating a highly degree of conservation. Pairwise comparisons showed a multiple sequence similarity ranging from 57% to 100%. Protein interaction prediction revealed that TkOSCs may interact with baruol synthase, sterol 1,4-demethylase, lupeol synthase and squalene epoxidase. Phylogenetic analysis showed that OSC family proteins belong to two branches. TkOSC promoter regions contain cis-acting elements related to plant growth, stress response, hormones response and light response. Protein accumulation analysis demonstrated that TkOSC4, TkOSC5 and TkOSC6 proteins had strong expression levels in the root, latex and plumular axis. Comparison of gene expression patterns showed TkOSC1, TkOSC4, TkOSC5, TkOSC6, TkOSC7, TkOSC8 and TkOSC9 might be important in regulating NRB. Combination of gene and protein results revealed TkOSC4-6 might be more crucial, and the data might contribute to a more profound understanding of the roles of OSCs for NRB in TKS roots.

A Bamboo HD-Zip Transcription Factor PeHDZ72 Conferred Drought Tolerance by Promoting Sugar and Water Transport.

Drought drastically affects plant growth, development and productivity. Plants respond to drought stress by enhancing sugar accumulation and water transport. Homeodomain-leucine zipper (HD-Zip) transcription factors (TFs) participate in various aspects of plant growth and stress response. However, the internal regulatory mechanism of HD-Zips in moso bamboo (Phyllostachys edulis) remains largely unknown. In this study, we identified an HD-Zip member, PeHDZ72, which was highly expressed in bamboo shoots and roots and was induced by drought. Furthermore, PeSTP_46019, PeSWEET_23178 and PeTIP4-3 were identified as downstream genes of PeHDZ72 in moso bamboo by DAP-seq. The expressions of these three genes were all induced by drought stress. Y1H, DLR and GUS activity assays demonstrated that PeHDZ72 could bind to three types of HD-motifs in the promoters of these three genes. Overexpression of PeHDZ72 led to a remarkable enhancement in drought tolerance in transgenic rice, with significantly improved soluble sugar and sucrose contents. Meanwhile, the expressions of OsSTPs, OsSWEETs and OsTIP were all upregulated in transgenic rice under drought stress. Overall, our results indicate that drought stress might induce the expression of PeHDZ72, which in turn activated downstream genes PeSTP_46019, PeSWEET_23178 and PeTIP4-3, contributing to the improvement of cellular osmotic potential in moso bamboo in response to drought stress.

The Small Auxin-Up RNA 50 (SAUR50) Gene from Ammopiptanthus nanus Negatively Regulates Drought Tolerance.

Drought stress is a primary abiotic stress that causes significant losses to forestry and agricultural production. Therefore, exploring drought-responsive genes and their regulatory mechanism is crucial for plant molecular breeding for forestry and agriculture production safety. Small auxin-up RNA (SAUR) proteins are essential in plant growth and development but show functional diversity in stress response. In this study, the transcriptome sequencing data of Ammopiptanthus nanus seedlings revealed that the expression of AnSAUR50 was continuously downregulated under drought stress. Hence, the AnSAUR50 gene was cloned and functionally analyzed in drought response. The results showed that the coding sequence of AnSAUR50 was 315 bp in length and encoded 104 amino acids. The AnSAUR50 protein showed high conservation, possessed a SAUR-specific domain, and localized in the nucleus and cell membrane. The heterologous expression of the AnSAUR50 gene enhanced the drought sensitivity of the transgenic Arabidopsis with a lower survival rate, biomass, and higher malondialdehyde content and relative electrolyte leakage. Moreover, transgenic plants showed shorter root lengths and bigger stomatal apertures, resulting in facilitating water loss under drought stress. The study indicates that AnSAUR50 negatively regulates drought tolerance by inhibiting root growth and stomatal closure, which provides insights into the underlying function and regulatory mechanism of SAURs in plant stress response.

The impact of irrigation with harvested rainwater containing asbestos cement matrix on the germination characteristics of Solanum lycopersicum

AbstractThe study aims to investigate how the transfer of matrix materials from eroded asbestos cement products induces stress responses in plants. The paper evaluates the exposure and risk factors of plants, water, and soil to asbestos cement materials. Additionally, the experimental results provide empirical evidence for plant stress responses based on physiological and germination parameters. Contamination of irrigation water with asbestos cement raises environmental concerns due to its potential toxicity to plants and soil quality. Asbestos in irrigation water can lead to toxic stress for plants, affecting germination processes and growth. The paper analyzes the effects of preset doses of irrigation water containing asbestos cement matrix on the germination process and physiological parameters of Solanum lycopersicum in a controlled experiment setting. This research proposes methodological developments that could be valuable for environmental plant protection professionals.

Long intergenic non-coding RNAs modulate proximal protein-coding gene expression and tolerance to Candidatus Liberibacter spp. in potatoes

Long intergenic non-coding RNAs (lincRNAs) are emerging as regulators of protein-coding genes (PCGs) in many plant and animal developmental processes and stress responses. In this study, we characterize the genome-wide lincRNAs in potatoes responsive to a vascular bacterial disease presumably caused by Candidatus Liberibacter solanacearum (CLso). Approximately 4397 lincRNAs were detected in healthy and infected potato plants at various stages of zebra chip (ZC) disease progression. Of them, ~65% (2844) were novel lincRNAs, and less than 1% (9) were orthologs of Arabidopsis and rice based on reciprocal BLAST analysis, suggesting species-specific expansion. Among the proximal lincRNAs within 50 kbp from a PCG, ~49% were transcribed from the same strand, while ~39% and ~15% followed convergent (head-to-head) and divergent (tail-to-tail) orientations, respectively. Approximately 30% (1308) were differentially expressed following CLso infection, with substantial changes occurring 21 days after infection (DAI). Weighted Gene Co-expression Network Analysis (WGCNA) of lincRNAs and PCGs identified 46 highly correlated lincRNA–PCG pairs exhibiting co-up or co-downregulation. Furthermore, overexpression of selected lincRNAs in transgenic potato hairy roots resulted in perturbation of neighboring PCG expression and conferred tolerance to CLso infection. Our results provide novel insights into potato lincRNAs’ identity, expression dynamics, and functional relevance to CLso infection.

Genome-Wide Identification of the Soybean AlkB Homologue Gene Family and Functional Characterization of GmALKBH10Bs as RNA m6A Demethylases and Expression Patterns under Abiotic Stress.

Soybean (Glycine max (L.) Merr) is one of the most important crops worldwide, but its yield is vulnerable to abiotic stresses. In Arabidopsis, the AlkB homologue (ALKBH) family genes plays a crucial role in plant development and stress response. However, the identification and functions of its homologous genes in soybean remain obscured. Here, we identified a total of 22 ALKBH genes in soybean and classified them into seven subfamilies according to phylogenetic analysis. Gene duplication events among the family members and gene structure, conserved domains, and motifs of all candidate genes were analyzed. By comparing the changes in the m6A levels on mRNA from hair roots between soybean seedlings harboring the empty vector and those harboring the GmALKBH10B protein, we demonstrated that all four GmALKBH10B proteins are bona fide m6A RNA demethylases in vivo. Subcellular localization and expression patterns of the GmALKBH10B revealed that they might be functionally redundant. Furthermore, an analysis of cis-elements coupled with gene expression data demonstrated that GmALKBH10B subfamily genes, including GmALKBH10B1, GmALKBH10B2, GmALKBH10B3, and GmALKBH10B4, are likely involved in the cis-elements' response to various environmental stimuli. In summary, our study is the first to report the genome-wide identification of GmALKBH family genes in soybean and to determine the function of GmALKBH10B proteins as m6A RNA demethylases, providing insights into GmALKBH10B genes in response to abiotic stresses.

The MdIAA29-MdARF4 complex plays an important role in balancing plant height with salt and drought stress responses.

Breeding dwarf apple (Malus domestica) varieties is a recent trend in agriculture because such varieties are easy to maintain and have high yields; however, dwarf apple trees generally have poor stress tolerance. Balancing apple plant height and stress response has been an important breeding goal. In this study, aux/indole-3-acetic acid 29 gene in apple (MdIAA29) overexpression lines (#1, #2, #3) had reduced plant height by 39%, 31%, and 35%, respectively, suitable for close planting applications. Surprisingly, the dwarf MdIAA29-overexpression lines also showed increased plant tolerance to salt and drought stresses. Further analysis showed that MdIAA29 inhibited the regulation of auxin response factor 4 (ARF4) on Gretchen Hagen 3.9 (GH3.9) gene and 9-cis-epoxycarotenoid dioxygenase 3 (NCED3) gene in apple and changed the contents of auxin and abscisic acid in different tissues, thus achieving a balance between plant height and stress tolerance. In addition, we also found that MdIAA7 enhanced the inhibitory effect of MdIAA29 on MdARF4. In brief, the MdIAA29-MdARF4 complex significantly impacts the height of apple plants and their ability to respond to salt and drought stress.

Geography and associated bioclimatic factors differentially affect leaf phenolics in three ivy species (Hedera L.) across the Iberian Peninsula

The biosynthesis of secondary metabolites in plants, especially that of phenolic compounds, is stimulated to protect against several environmental stress factors such as cold temperatures, drought, and UV-irradiance. As a result, when a species occurs under different climatic conditions, differences in phenolic accumulation are expected across species distribution in response to the environmental cues. However, our understanding of phenolic compounds' natural variation is limited, as most of our knowledge on secondary metabolite biosynthesis stems from experimental studies conducted under controlled conditions. In this study we analyze phenolic content and its relation to climatic and geographic variation in three closely related Hedera species (H. helix, H. hibernica and H. iberica) across their southwestern range limits in the Iberian Peninsula (82 populations, 401 individuals). The Iberian Peninsula concentrates the highest global species richness of Hedera, with the three species sharing range boundaries along the latitudinal and longitudinal climatic gradient of the region. We found that the three species exhibited different climatic and geographic patterns of phenolic content variation in the study area. The phenolic production in H. helix increased with elevation in relation to the decrease of temperature and the increase of temperature contrast, whereas in H. hibernica varies with latitude in relation to summer temperature and precipitation regimes, increasing in areas with no summer drought. In contrast, we did not find any environmental variables associated with phenolic content in H. iberica, likely due to its narrow geographic and climatic range and a higher influence of microclimatic conditions. Although the three Hedera species are closely related, our results suggest that leaf phenolic production may be triggered by different environmental conditions in each species. Our study underscores the species-specific nature of phenolic compounds' role in plant stress response.

Genome-wide analysis of the WOX gene family and function exploration of RhWOX331 in rose (R. 'The Fairy').

WOXs are a class of plant-specific transcription factors that play key roles in plant growth and stress responses. However, the mechanism by which WOXs influence adventitious root development in Rosa hybrida remains unclear. In this study, RcWOX gene family in rose was identified and phylogenetically analyzed using bioinformatics analysis. A total of 381 RcWOX gene members were localized on seven chromosomes except of nine members. The main cis-acting elements involved in hormonal, light, developmental, and abiotic stress responses were identified in the promoters of RcWOX genes, suggesting their regulation by these signals. Nine RhWOX genes had significant different expression during rooting process of rose. RhWOX331, RhWOX308, RhWOX318 were positive with the formation of rose roots. RhWOX331 was positively involved in the formation of adventitious root primordia, which gene coding a transcription factor localized in the nucleus. The HOX conserved domain in the protein contributed to the self-activating activity of RhWOX331. We obtained genetically modified Arabidopsis to validate the function of RhWOX331. Overexpression of RhWOX331 gene alleviated the inhibition of root length of A. thaliana primary roots by high concentration of IBA and NPA, and significantly increased the number of lateral roots on the primary roots, as well as the height of A. thaliana plants. Additionally, RhWOX331 promoted adventitious root formation in A. thaliana and mitigated hormonal inhibition by exogenous 6-BA, NPA, and GA3. The RhWOX331 promoter contained cis-acting elements such as ABRE, Box 4 and CGTCA-motif et.al. GUS activity analysis showed that the gene acted at the cotyledon attachment site. Taken together, these studies identified a significant expansion of the RcWOX gene family, inferred roles of certain branch members in adventitious root formation, elucidated the function of RhWOX331 in adventitious root initiation, and laid the foundation for further research on the function of WOX gene family in roses.

Characterization of TBP and TAFs in Mungbean (Vigna radiata L.) and Their Potential Involvement in Abiotic Stress Response.

The TATA-box binding protein (TBP) and TBP-associated factors (TAFs) constitute the transcription factor IID (TFIID), a crucial component of RNA polymerase II, essential for transcription initiation and regulation. Several TFIID subunits are shared with the Spt-Ada-Gcn5-acetyltransferase (SAGA) coactivator complex. Recent research has revealed the roles of TBP and TAFs in organogenesis and stress adaptation. In this study, we identified 1 TBP and 21 putative TAFs in the mungbean genome, among which VrTAF5, VrTAF6, VrTAF8, VrTAF9, VrTAF14, and VrTAF15 have paralogous genes. Their potential involvement in abiotic stress responses was also investigated here, including high salinity, water deficit, heat, and cold. The findings indicated that distinct genes exerted predominant influences in the response to different abiotic stresses through potentially unique mechanisms. Specifically, under salt stress, VrTBP, VrTAF2, and VrTAF15-1 were strongly induced, while VrTAF10, VrTAF11, and VrTAF13 acted as negative regulators. In the case of water-deficit stress, it was likely that VrTAF1, VrTAF2, VrTAF5-2, VrTAF9, and VrTAF15-1 were primarily involved. Additionally, in response to changes in ambient temperature, it was possible that genes such as VrTAF5-1, VrTAF6-1, VrTAF9-2, VrTAF10, VrTAF13, VrTAF14b-2, and VrTAF15-1 might play a dominant role. This comprehensive exploration of VrTBP and VrTAFs can offer a new perspective on understanding plant stress responses and provide valuable insights into breeding improvement.

Proteomic analysis of MsFtsH8 overexpression reveals enhanced salt stress response in alfalfa through PSII stability and antioxidant capacity improvement

The FtsH (Filamentous temperature sensitive H) proteases, known for their crucial roles in protein quality control and maintaining the integrity of photosynthetic machinery, have emerged as key regulators of stress responses in plants. Our previous study revealed the overexpression of MsFtsH8, an FtsH gene from alfalfa (Medicago sativa L.), confers salt stress tolerance to the plant. By comparing the proteomic profiles of MsFtsH8-overexpressing alfalfa and wild type under salt stress conditions, we elucidate the molecular pathways underlying MsFtsH8-mediated salt stress resilience. We identified 730 differentially expressed proteins (DEPs) in MsFtsH8-overexpressing alfalfa under salt stress, compared to 498 DEPs in wild type alfalfa under the same growth condition. Our results reveal significant alterations in the expression of proteins involved in the photosynthetic system, consistent with the chloroplast subcellular localization of MsFtsH8. Specifically, MsFtsH8 overexpression stabilizes key components of Photosystem II (PSII) and enhances electron transport processes, leading to increased photosynthetic efficiency and oxidative photodamage repair capacity under salt stress. Moreover, MsFtsH8-overexpressing alfalfa exhibits elevated levels of antioxidative enzymes, further mitigating oxidative damage induced by high salinity. These findings deepen our understanding of the regulatory role of MsFtsH8 in salt stress response and highlight its potential for improving crop resilience under adverse environmental conditions.

The module consisting of transcription factor WRKY14 and thaumatin-like protein TLP25 is involved in winter adaptation in Ammopiptanthus mongolicus.

Thaumatin-like proteins (TLPs) are conserved proteins involved in the defense and stress responses of plants. Previous studies showed that several TLPs were accumulated in leaf apoplast in Ammopiptanthus mongolicus in winter, indicating that TLPs might be related to the adaptation to winter climate in A. mongolicus. To investigate the roles of TLPs in winter adaptation, we first analyzed the expression pattern of TLP genes in A. mongolicus and then focused on the biological function and regulation pathway of AmTLP25 gene. Several TLP genes, including AmTLP25, were upregulated during winter and in response to both cold and osmotic stress. Overexpression of the AmTLP25 gene led to an increased tolerance of transgenic Arabidopsis to freezing and osmotic stress. Furthermore, the elevated AmWRKY14 transcription factor during winter activated AmTLP25 gene expression by specifically binding to its promoter. It is speculated that the AmWRKY14 - AmTLP25 module contributes to the adaptation to temperate winter climate in A. mongolicus. Our research advances the current understanding of the biological function and regulatory pathway of TLP genes and provides valuable information for understanding the molecular mechanism of temperate evergreen broad-leaved plants adapting to winter climate.

Csn-miR171b-3p_2 targets CsSCL6-4 to participate in the defense against drought stress in tea plant

Drought stress is a serious natural challenge for tea plants that significantly affects tea yield and quality. miR171s play critical roles in plant stress responses, however, their role in drought stress tolerance in tea plants (Camellia sinensis) is poorly understood. This study experimentally verified the expression patterns of csn-miR171b-3p_2 and its target, scarecrow-like (SCL). We found that csn-miR171b-3p_2 could target and regulate CsSCL6-4 to play an important role in the defense against drought stress in tea plants. CsSCL6-4 is located in the nucleus and is self-activated in vivo. In addition, we obtained 819 putative binding regions of CsSCL6-4 using DNA affinity purification sequencing analysis, which were assigned to 786 different genes, four of which were drought-resistant genes (CsPrx, CsSDR, CsFAD7, and CsCER1). Yeast one-hybrid and dual-luciferase reporter assays revealed that CsSCL6-4 directly promoted the expression of these four drought resistance genes by binding motifs 1/2/3 in their promoter regions. Both overexpression and suppression of CsSCL6-4 proved that CsSCL6-4 participated in the defense against drought stress in tea plants by regulating the expression of CsPrx, CsSDR, CsFAD7, and CsCER1. In addition, suppression of csn-miR171b-3p_2 expression significantly increased the expression of CsSCL6-4 and activated CsSCL6-4-bound gene transcription under drought stress. Therefore, the csn-miR171b-3p_2-CsSCL6-4 module participates in tea plant resistance to drought stress by promoting the expression of drought resistance genes. Our results revealed the function of csn-miR171b-3p_2 in tea plants and provided new insights into the mechanism of tea plant resistance to drought stress.