Genome-wide search and structural and functional analyses for late embryogenesis-abundant (LEA) gene family in poplar

Genome-wide identification of the LEA gene family in Panax ginseng: Evidence for the role of PgLEA2-50 in plant abiotic stress response

Ginseng frequently encounters environmental stress during its growth and development. Late Embryogenesis Abundant (LEA) proteins play a crucial role in combating adversity stress, particularly against abiotic challenges In this study, 107 LEA genes from ginseng, spanning eight subfamilies, were identified, demonstrating significant evolutionary conservation, with the LEA2 subfamily being most prominent. Gene duplication events, primarily segmental duplications, have played a major role in the expansion of the LEA gene family, which has undergone strong purifying selection. PgLEAs were unevenly distributed across 22 chromosomes, with each subfamily featuring unique structural domains and conserved motifs. PgLEAs were expressed in various tissues, exhibiting distinct variations in abundance and tissue specificity. Numerous regulatory cis-elements, related to abiotic stress and hormones, were identified in the promoter region. Additionally, PgLEAs were regulated by a diverse array of abiotic stress-related transcription factors. A total of 35 PgLEAs were differentially expressed following treatments with ABA, GA, and IAA. Twenty-three PgLEAs showed significant but varied responses to drought, extreme temperatures, and salinity stress. The transformation of tobacco with the key gene PgLEA2-50 enhanced osmoregulation and antioxidant levels in transgenic lines, improving their resistance to abiotic stress. This study offers insights into functional gene analysis, focusing on LEA proteins, and establishes a foundational framework for research on ginseng's resilience to abiotic stress.

Functional in vitro diversity of an intrinsically disordered plant protein during freeze-thawing is encoded by its structural plasticity

Intrinsically disordered late embryogenesis abundant (LEA) proteins play a central role in the tolerance of plants and other organisms to dehydration brought upon, for example, by freezing temperatures, high salt concentration, drought or desiccation, and many LEA proteins have been found to stabilize dehydration-sensitive cellular structures. Their conformational ensembles are highly sensitive to the environment, allowing them to undergo conformational changes and adopt ordered secondary and quaternary structures and to participate in formation of membraneless organelles. In an interdisciplinary approach, we discovered how the functional diversity of the Arabidopsis thaliana LEA protein COR15A found in vitro is encoded in its structural repertoire, with the stabilization of membranes being achieved at the level of secondary structure and the stabilization of enzymes accomplished by the formation of oligomeric complexes. We provide molecular details on intra- and inter-monomeric helix-helix interactions, demonstrate how oligomerization is driven by an α-helical molecular recognition feature (α-MoRF) and provide a rationale that the formation of noncanonical, loosely packed, right-handed coiled-coils might be a recurring theme for homo- and hetero-oligomerization of LEA proteins.

Identification of the lateral organ boundary domain gene family and its preservation by exogenous salicylic acid in Cerasus humilis

The gene family known as the Lateral Organ Boundary Domain (LBD) is responsible for producing transcription factors unique to plants, which play a crucial role in controlling diverse biological activities, including their growth and development. This research focused on examining Cerasus humilis'ChLBD gene, owing to its significant ecological, economic, and nutritional benefits. Examining the ChLBD gene family's member count, physicochemical characteristics, phylogenetic evolution, gene configuration, and motif revealed 41 ChLBD gene family members spread across 8 chromosomes, with ChLBD gene's full-length coding sequences (CDSs) ranging from 327 to 1737 base pairs, and the protein sequence's length spanning 109 (ChLBD30)-579 (ChLBD35) amino acids. The molecular weights vary from 12.068 (ChLBD30) to 62.748 (ChLBD35) kDa, and the isoelectric points span from 4.74 (ChLBD20) to 9.19 (ChLBD3). Categorizing them into two evolutionary subfamilies: class I with 5 branches, class II with 2, the majority of genes with a single intron, and most members of the same subclade sharing comparable motif structures. The results of collinearity analysis showed that there were 3 pairs of tandem repeat genes and 12 pairs of fragment repeat genes in the Cerasus humilis genome, and in the interspecific collinearity analysis, the number of collinear gene pairs with apples belonging to the same family of Rosaceae was the highest. Examination of cis-acting elements revealed that methyl jasmonate response elements stood out as the most abundant, extensively dispersed in the promoter areas of class 1 and class 2 ChLBD. Genetic transcript analysis revealed that during Cerasus humilis' growth and maturation, ChLBD developed varied control mechanisms, with ChLBD27 and ChLBD40 potentially playing a role in managing color alterations in fruit ripening. In addition, the quality of calcium fruit will be affected by the environment during transportation and storage, and it is particularly important to use appropriate means to preserve the fruit. The research used salicylic acid-treated Cerasus humilis as the research object and employed qRT-PCR to examine the expression of six ChLBD genes throughout storage. Variations in the expression of the ChLBD gene were observed when exposed to salicylic acid, indicating that salicylic acid could influence ChLBD gene expression during the storage of fruits. This study's findings lay the groundwork for additional research into the biological role of the LBD gene in Cerasus humilis.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12298-024-01438-5.

Genome-Wide Analysis of Cotton MYB Transcription Factors and the Functional Validation of GhMYB in Response to Drought Stress

MYB transcription factors play important roles during abiotic stress responses in plants. However, little is known about the accurate systematic analysis of MYB genes in the four cotton species, Gossypium hirsutum, G. barbadense, G. arboreum and G. raimondii. Herein, we performed phylogenetic analysis and showed that cotton MYBs and Arabidopsis MYBs were clustered in the same subfamilies for each species. The identified cotton MYBs were distributed unevenly on chromosomes in various densities for each species, wherein genome-wide tandem and segment duplications were the main driving force of MYB family expansion. Synteny analysis suggested that the abundant collinearity pairs of MYBs were identified between G. hirsutum and the other three species, and that they might have undergone strong purification selection. Characteristics of conserved motifs, along with their consensus sequence, promoter cis elements and gene structure, revealed that MYB proteins might be highly conserved in the same subgroups for each species. Subsequent analysis of differentially expressed genes and expression patterns indicated that most GhMYBs might be involved in response to drought (especially) and salt stress, which was supported by the expression levels of nine GhMYBs using real-time quantitative PCR. Finally, we performed a workflow that combined virus-induced gene silencing and the heterologous transformation of Arabidopsis, which confirmed the positive roles of GhMYBs under drought conditions, as validated by determining the drought-tolerant phenotypes, damage index and/or water loss rate. Collectively, our findings not only expand our understanding of the relationships between evolution and function of MYB genes, but they also provide candidate genes for cotton breeding.

Genome-wide identification of late embryogenesis abundant protein family and their key regulatory network in Pinus tabuliformis cold acclimation

Cold acclimation is a crucial biological process that enables conifers to overwinter safely. The late embryogenesis abundant (LEA) protein family plays a pivotal role in enhancing freezing tolerance during this process. Despite its importance, the identification, molecular functions and regulatory networks of the LEA protein family have not been extensively studied in conifers or gymnosperms. Pinus tabuliformis, a conifer with high ecological and economic values and with high-quality genome sequence, is an ideal candidate for such studies. Here, a total of 104 LEA genes were identified from P. tabuliformis, and we renamed them according to their subfamily group: PtLEA1-PtLEA92 (group LEA1-LEA6), PtSMP1-PtSMP6 (group seed maturation protein) and PtDHN1-PtDHN6 (group Dehydrin). While the sequence structure of P. tabuliformis  LEA genes are conserved, their physicochemical properties exhibit unique characteristics within different subfamily groupings. Notably, the abundance of low-temperature responsive elements in PtLEA genes was observed. Using annual rhythm and temperature gradient transcriptome data, PtLEA22 was identified as a key gene that responds to low-temperature induction while conforming to the annual cycle of cold acclimation. Overexpression of PtLEA22 enhanced Arabidopsis freezing tolerance. Furthermore, several transcription factors potentially co-expressed with PtLEA22 were validated using yeast one-hybrid and dual-luciferase assays, revealing that PtDREB1 could directly bind PtLEA22 promoter to positively regulate its expression. These findings reveal the genome-wide characterization of P. tabuliformis  LEA genes and their importance in the cold acclimation, while providing a theoretical basis for studying the molecular mechanisms of cold acclimation in conifers.

Transcriptome Sequencing and WGCNA Reveal Key Genes in Response to Leaf Blight in Poplar

Leaf blight is a fungal disease that mainly affects the growth and development of leaves in plants. To investigate the molecular mechanisms of leaf blight defense in poplar, we performed RNA-Seq and enzyme activity assays on the Populus simonii × Populus nigra leaves inoculated with Alternaria alternate fungus. Through weighted gene co-expression network analysis (WGCNA), we obtained co-expression gene modules significantly associated with SOD and POD activities, containing 183 and 275 genes, respectively. We then constructed a co-expression network of poplar genes related to leaf blight resistance based on weight values. Additionally, we identified hub transcription factors (TFs) and structural genes in the network. The network was dominated by 15 TFs, and four out of them, including ATWRKY75, ANAC062, ATMYB23 and ATEBP, had high connectivity in the network, which might play important functions in leaf blight defense. In addition, GO enrichment analysis revealed a total of 44 structural genes involved in biotic stress, resistance, cell wall and immune-related biological processes in the network. Among them, there were 16 highly linked structural genes in the central part, which may be directly involved in poplar resistance to leaf blight. The study explores key genes associated with leaf blight defense in poplar, which further gains an understanding of the molecular mechanisms of biotic stress response in plants.

Genome-wide identification and characterization of members of the LEA gene family in Panax notoginseng and their transcriptional responses to dehydration of recalcitrant seeds

BACKGROUND

Late embryogenesis abundant (LEA) proteins play an important role in dehydration process of seed maturation. The seeds of Panax notoginseng (Burkill) F. H. Chen are typically characterized with the recalcitrance and are highly sensitive to dehydration. However, it is not very well known about the role of LEA proteins in response to dehydration stress in P. notoginseng seeds. We will perform a genome-wide analysis of the LEA gene family and their transcriptional responses to dehydration stress in recalcitrant P. notoginseng seeds.

RESULTS

In this study, 61 LEA genes were identified from the P. notoginseng genome, and they were renamed as PnoLEA. The PnoLEA genes were classified into seven subfamilies based on the phylogenetic relationships, gene structure and conserved domains. The PnoLEA genes family showed relatively few introns and was highly conserved. Unexpectedly, the LEA_6 subfamily was not found, and the LEA_2 subfamily contained 46 (75.4%) members. Within 19 pairs of fragment duplication events, among them 17 pairs were LEA_2 subfamily. In addition, the expression of the PnoLEA genes was obviously induced under dehydration stress, but the germination rate of P. notoginseng seeds decreased as the dehydration time prolonged.

CONCLUSIONS

We found that the lack of the LEA_6 subfamily, the expansion of the LEA_2 subfamily and low transcriptional levels of most PnoLEA genes might be implicated in the recalcitrant formation of P. notoginseng seeds. LEA proteins are essential in the response to dehydration stress in recalcitrant seeds, but the protective effect of LEA protein is not efficient. These results could improve our understanding of the function of LEA proteins in the response of dehydration stress and their contributions to the formation of seed recalcitrance.

Late Embryogenesis Abundant Proteins Contribute to the Resistance of Toxoplasma gondii Oocysts against Environmental Stresses

Toxoplasma gondii oocysts, which are shed in large quantities in the feces from infected felines, are very stable in the environment, resistant to most inactivation procedures, and highly infectious. The oocyst wall provides an important physical barrier for sporozoites contained inside oocysts, protecting them from many chemical and physical stressors, including most inactivation procedures. Furthermore, sporozoites can withstand large temperature changes, even freeze-thawing, as well as desiccation, high salinity, and other environmental insults; however, the genetic basis for this environmental resistance is unknown. Here, we show that a cluster of four genes encoding Late Embryogenesis Abundant (LEA)-related proteins are required to provide Toxoplasma sporozoites resistance to environmental stresses. Toxoplasma LEA-like genes (TgLEAs) exhibit the characteristic features of intrinsically disordered proteins, explaining some of their properties. Our in vitro biochemical experiments using recombinant TgLEA proteins show that they have cryoprotective effects on the oocyst-resident lactate dehydrogenase enzyme and that induced expression in E. coli of two of them leads to better survival after cold stress. Oocysts from a strain in which the four LEA genes were knocked out en bloc were significantly more susceptible to high salinity, freezing, and desiccation compared to wild-type oocysts. We discuss the evolutionary acquisition of LEA-like genes in Toxoplasma and other oocyst-producing apicomplexan parasites of the Sarcocystidae family and discuss how this has likely contributed to the ability of sporozoites within oocysts to survive outside the host for extended periods. Collectively, our data provide a first molecular detailed view on a mechanism that contributes to the remarkable resilience of oocysts against environmental stresses. IMPORTANCE Toxoplasma gondii oocysts are highly infectious and may survive in the environment for years. Their resistance against disinfectants and irradiation has been attributed to the oocyst and sporocyst walls by acting as physical and permeability barriers. However, the genetic basis for their resistance against stressors like changes in temperature, salinity, or humidity, is unknown. We show that a cluster of four genes encoding Toxoplasma Late Embryogenesis Abundant (TgLEA)-related proteins are important for this resistance to environmental stresses. TgLEAs have features of intrinsically disordered proteins, explaining some of their properties. Recombinant TgLEA proteins show cryoprotective effects on the parasite's lactate dehydrogenase, an abundant enzyme in oocysts, and expression in E. coli of two TgLEAs has a beneficial effect on growth after cold stress. Moreover, oocysts from a strain lacking all four TgLEA genes were more susceptible to high salinity, freezing, and desiccation compared to wild-type oocysts, highlighting the importance of the four TgLEAs for oocyst resilience.

Genome-wide identification, characterization, and expression pattern of the late embryogenesis abundant (LEA) gene family in Juglans regia and its wild relatives J. mandshurica

BACKGROUND

Late Embryogenesis Abundant (LEA) proteins are a class of proteins associated with plant stress resistance. Two Juglans species, Juglans regia and J. mandshurica, are both diploid (2n = 32), monoecious perennial economic tree species with high edible, pharmaceutical, and timber value. The identification, characterization, and expression patterns of LEA proteins in J. regia and its wild relative, J. mandshurica, would not only provide the genetic basis of this gene family, but it would also supply clues for further studies of the evolution and regulating mechanisms of LEA proteins in other tree species.

RESULTS

In this study, we identified 25 and 20 members of the LEA gene family in Juglans regia and its wild relative, Juglans mandshurica, respectively. The results of phylogenetic analysis showed that the LEA members were divided into eight main subgroups. Predictions of their physicochemical properties showed the variable characteristics of LEA proteins, and the subcellular localization analysis indicated that most LEA proteins are localized in the nucleus. Chromosomal localization analysis and gene replication pattern prediction indicated that WGD is the predominant duplication mode of LEA genes. The results of the comparative analysis indicated a high level of collinearity between the two Juglans species. Analysis of cis-acting elements indicated that LEA genes had a relatively wide range of responses to abiotic stresses and phytohormonal processes, particularly in two phytohormones, methyl jasmonate and abscisic acid. Transcriptome profiling and qRT-PCR experiments showed that JrLEAs are commonly expressed in leaves, green husks, and male and female flowers, and most JmLEAs are more highly expressed in male flowers. We also hypothesized that JrLEAs are involved in the process of anthracnose resistance. Anthracnose-resistant varieties of JrLEAs presented relatively high expression levels at later stages.

CONCLUSION

In this study, we provide a theoretical basis for the functional study of LEA genes in J. regia and J. mandshurica. Analysis of cis-acting elements and gene expression indicated that JrLEAs and JmLEAs play important roles in resistance to biotic stresses in these species.

Genome-wide study and functional characterization elucidates the potential association of late embryogenesis abundant (LEA) genes with lotus seed development

Late embryogenesis abundant (LEA) proteins are extremely hydrophilic proteins imperatively associated with plant growth and development, as well as cell protection from abiotic stress. However, the genome-wide characterization of LEA gene family remains limited, especially in aquatic species such as lotus (Nelumbo spp.). Here, 57 putative LEA genes, including 28 NnLEAs and 29 NlLEAs were identified in the N.nucifera and N.lutea genomes, respectively. A total of 27 homologous LEA gene pairs were identified, indicating high degree of sequence homologies between the two Nelumbo species. Secondary structure prediction indicated high prevalence of alpha (α) helix structure among LEA proteins in the LEA_1, LEA_4, and SMP groups. Screening of putative promoter cis-elements revealed that NnLEA genes were involved in diverse biological processes. Most NnLEA genes were predominantly expressed in the late cotyledons and plumules development stages, suggesting their potential vital roles in lotus seed maturation. In addition, genes co-expressed with NnLEAs were involved in ABA signaling, seed maturation, and development processes. Overall, this study provides new insights for the in-depth understanding of the functions of NnLEA proteins in lotus seed development, and could act as a useful reference for the molecular breeding of seeds with prolonged lifespan.

The LEA gene family in tomato and its wild relatives: genome-wide identification, structural characterization, expression profiling, and role of SlLEA6 in drought stress

BACKGROUND

Late embryogenesis abundant (LEA) proteins are widely distributed in higher plants and play crucial roles in regulating plant growth and development processes and resisting abiotic stress. Cultivated tomato (Solanum lycopersicum) is an important vegetable crop worldwide; however, its growth, development, yield, and quality are currently severely constrained by abiotic stressors. In contrast, wild tomato species are more tolerant to abiotic stress and can grow normally in extreme environments. The main objective of this study was to identify, characterize, and perform gene expression analysis of LEA protein families from cultivated and wild tomato species to mine candidate genes and determine their potential role in abiotic stress tolerance in tomatoes.

RESULTS

Total 60, 69, 65, and 60 LEA genes were identified in S. lycopersicum, Solanum pimpinellifolium, Solanum pennellii, and Solanum lycopersicoides, respectively. Characterization results showed that these genes could be divided into eight clusters, with the LEA_2 cluster having the most members. Most LEA genes had few introns and were non-randomly distributed on chromosomes; the promoter regions contained numerous cis-acting regulatory elements related to abiotic stress tolerance and phytohormone responses. Evolutionary analysis showed that LEA genes were highly conserved and that the segmental duplication event played an important role in evolution of the LEA gene family. Transcription and expression pattern analyses revealed different regulatory patterns of LEA genes between cultivated and wild tomato species under normal conditions. Certain S. lycopersicum LEA (SlLEA) genes showed similar expression patterns and played specific roles under different abiotic stress and phytohormone treatments. Gene ontology and protein interaction analyses showed that most LEA genes acted in response to abiotic stimuli and water deficit. Five SlLEA proteins were found to interact with 11 S. lycopersicum WRKY proteins involved in development or resistance to stress. Virus-induced gene silencing of SlLEA6 affected the antioxidant and reactive oxygen species defense systems, increased the degree of cellular damage, and reduced drought resistance in S. lycopersicum.

CONCLUSION

These findings provide comprehensive information on LEA proteins in cultivated and wild tomato species and their possible functions under different abiotic and phytohormone stresses. The study systematically broadens our current understanding of LEA proteins and candidate genes and provides a theoretical basis for future functional studies aimed at improving stress resistance in tomato.

LEAfing through literature: late embryogenesis abundant proteins coming of age-achievements and perspectives

To deal with increasingly severe periods of dehydration related to global climate change, it becomes increasingly important to understand the complex strategies many organisms have developed to cope with dehydration and desiccation. While it is undisputed that late embryogenesis abundant (LEA) proteins play a key role in the tolerance of plants and many anhydrobiotic organisms to water limitation, the molecular mechanisms are not well understood. In this review, we summarize current knowledge of the physiological roles of LEA proteins and discuss their potential molecular functions. As these are ultimately linked to conformational changes in the presence of binding partners, post-translational modifications, or water deprivation, we provide a detailed summary of current knowledge on the structure-function relationship of LEA proteins, including their disordered state in solution, coil to helix transitions, self-assembly, and their recently discovered ability to undergo liquid-liquid phase separation. We point out the promising potential of LEA proteins in biotechnological and agronomic applications, and summarize recent advances. We identify the most relevant open questions and discuss major challenges in establishing a solid understanding of how these intriguing molecules accomplish their tasks as cellular sentinels at the limits of surviving water scarcity.

Genome-Wide Identification and Expression Patterns of the F-box Family in Poplar under Salt Stress

The F-box family exists in a wide variety of plants and plays an extremely important role in plant growth, development and stress responses. However, systematic studies of F-box family have not been reported in populus trichocarpa. In the present study, 245 PtrFBX proteins in total were identified, and a phylogenetic tree was constructed on the basis of their C-terminal conserved domains, which was divided into 16 groups (A–P). F-box proteins were located in 19 chromosomes and six scaffolds, and segmental duplication was main force for the evolution of the F-box family in poplar. Collinearity analysis was conducted between poplar and other species including Arabidopsis thaliana, Glycine max, Anemone vitifolia Buch, Oryza sativa and Zea mays, which indicated that poplar has a relatively close relationship with G. max. The promoter regions of PtrFBX genes mainly contain two kinds of cis-elements, including hormone-responsive elements and stress-related elements. Transcriptome analysis indicated that there were 82 differentially expressed PtrFBX genes (DEGs), among which 64 DEGs were in the roots, 17 in the leaves and 26 in the stems. In addition, a co-expression network analysis of four representative PtrFBX genes indicated that their co-expression gene sets were mainly involved in abiotic stress responses and complex physiological processes. Using bioinformatic methods, we explored the structure, evolution and expression pattern of F-box genes in poplar, which provided clues to the molecular function of F-box family members and the screening of salt-tolerant PtrFBX genes.

Identification, Structural, and Expression Analyses of SPX Genes in Giant Duckweed (Spirodela polyrhiza) Reveals Its Role in Response to Low Phosphorus and Nitrogen Stresses

SPX genes play important roles in the coordinated utilization of nitrogen (N) and phosphorus (P) in plants. However, a genome-wide analysis of the SPX family is still lacking. In this study, the gene structure and phylogenetic relationship of 160 SPX genes were systematically analyzed at the genome-wide level. Results revealed that SPX genes were highly conserved in plants. All SPX genes contained the conserved SPX domain containing motifs 2, 3, 4, and 8. The 160 SPX genes were divided into five clades and the SPX genes within the same clade shared a similar motif composition. P1BS cis–elements showed a high frequency in the promoter region of SPXs, indicating that SPX genes could interact with the P signal center regulatory gene Phosphate Starvation Response1 (PHR1) in response to low P stress. Other cis–elements were also involved in plant development and biotic/abiotic stress, suggesting the functional diversity of SPXs. Further studies were conducted on the interaction network of three SpSPXs, revealing that these genes could interact with important components of the P signaling network. The expression profiles showed that SpSPXs responded sensitively to N and P deficiency stresses, thus playing a key regulatory function in P and N metabolism. Furthermore, the expression of SpSPXs under P and N deficiency stresses could be affected by environmental factors such as ABA treatment, osmotic, and LT stresses. Our study suggested that SpSPXs could be good candidates for enhancing the uptake ability of Spirodela polyrhiza for P nutrients in wastewater. These findings could broaden the understanding of the evolution and biological function of the SPX family and offer a foundation to further investigate this family in plants.

Genome-Wide Analysis of Late Embryogenesis Abundant Protein Gene Family in Vigna Species and Expression of VrLEA Encoding Genes in Vigna glabrescens Reveal Its Role in Heat Tolerance

Late embryogenesis abundant (LEA) proteins are identified in many crops for their response and role in adaptation to various abiotic stresses, such as drought, salinity, and temperature. The LEA genes have been studied systematically in several crops but not in Vigna crops. In this study, we reported the first comprehensive analysis of the LEA gene family in three legume species, namely, mung bean (Vigna radiata), adzuki bean (Vigna angularis), and cowpea (Vigna unguiculata), and the cross-species expression of VrLEA genes in a wild tetraploid species, Vigna glabrescens. A total of 201 LEA genes from three Vigna crops were identified harboring the LEA conserved motif. Among these 55, 64, and 82 LEA genes were identified in mung bean, adzuki bean, and cowpea genomes, respectively. These LEA genes were grouped into eight different classes. Our analysis revealed that the cowpea genome comprised all eight classes of LEA genes, whereas the LEA-6 class was absent in the mung bean genome. Similarly, LEA-5 and LEA-6 were absent in the adzuki bean genome. The analysis of LEA genes provides an insight into their structural and functional diversity in the Vigna genome. The genes, such as VrLEA-2, VrLEA-40, VrLEA-47, and VrLEA-55, were significantly upregulated in the heat-tolerant genotype under stress conditions indicating the basis of heat tolerance. The successful amplification and expression of VrLEA genes in V. glabrescens indicated the utility of the developed markers in mung bean improvement. The results of this study increase our understanding of LEA genes and provide robust candidate genes for future functional investigations and a basis for improving heat stress tolerance in Vigna crops.

Characterization of a Novel TtLEA2 Gene From Tritipyrum and Its Transformation in Wheat to Enhance Salt Tolerance

Late embryogenesis-abundant (LEA) proteins are critical in helping plants cope with salt stress. "Y1805" is a salt-tolerant Tritipyrum. We identified a "Y1805"-specific LEA gene that was expressed highly and sensitively under salt stress using transcriptome analysis. The novel group 2 LEA gene (TtLEA2-1) was cloned from "Y1805." TtLEA2-1 contained a 453 bp open reading frame encoding an 151-amino-acid protein that showed maximum sequence identity (77.00%) with Thinopyrum elongatum by phylogenetic analysis. It was mainly found to be expressed highly in the roots by qRT-PCR analysis and was located in the whole cell. Forty-eight candidate proteins believed to interact with TtLEA2-1 were confirmed by yeast two-hybrid analysis. These interacting proteins were mainly enriched in "environmental information processing," "glycan biosynthesis and metabolism," and "carbohydrate metabolism." Protein-protein interaction analysis indicated that the translation-related 40S ribosomal protein SA was the central node. An efficient wheat transformation system has been established. A coleoptile length of 2 cm, an Agrobacteria cell density of 0.55-0.60 OD₆₀₀, and 15 KPa vacuum pressure were ideal for common wheat transformation, with an efficiency of up to 43.15%. Overexpression of TaLEA2-1 in wheat "1718" led to greater height, stronger roots, and higher catalase activity than in wild type seedlings. TaLEA2-1 conferred enhanced salt tolerance in transgenic wheat and may be a valuable gene for genetic modification in crops.

Plant Group II LEA Proteins: Intrinsically Disordered Structure for Multiple Functions in Response to Environmental Stresses

In response to various environmental stresses, plants have evolved a wide range of defense mechanisms, resulting in the overexpression of a series of stress-responsive genes. Among them, there is certain set of genes that encode for intrinsically disordered proteins (IDPs) that repair and protect the plants from damage caused by environmental stresses. Group II LEA (late embryogenesis abundant) proteins compose the most abundant and characterized group of IDPs; they accumulate in the late stages of seed development and are expressed in response to dehydration, salinity, low temperature, or abscisic acid (ABA) treatment. The physiological and biochemical characterization of group II LEA proteins has been carried out in a number of investigations because of their vital roles in protecting the integrity of biomolecules by preventing the crystallization of cellular components prior to multiple stresses. This review describes the distribution, structural architecture, and genomic diversification of group II LEA proteins, with some recent investigations on their regulation and molecular expression under various abiotic stresses. Novel aspects of group II LEA proteins in Phoenix dactylifera and in orthodox seeds are also presented. Genome-wide association studies (GWAS) indicated a ubiquitous distribution and expression of group II LEA genes in different plant cells. In vitro experimental evidence from biochemical assays has suggested that group II LEA proteins perform heterogenous functions in response to extreme stresses. Various investigations have indicated the participation of group II LEA proteins in the plant stress tolerance mechanism, spotlighting the molecular aspects of group II LEA genes and their potential role in biotechnological strategies to increase plants' survival in adverse environments.