Dataset Information

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

ABSTRACT:

Background

The Late Embryogenesis-Abundant (LEA) gene families, which play significant roles in regulation of tolerance to abiotic stresses, widely exist in higher plants. Poplar is a tree species that has important ecological and economic values. But systematic studies on the gene family have not been reported yet in poplar.

Results

On the basis of genome-wide search, we identified 88 LEA genes from Populus trichocarpa and renamed them as PtrLEA. The PtrLEA genes have fewer introns, and their promoters contain more cis-regulatory elements related to abiotic stress tolerance. Our results from comparative genomics indicated that the PtrLEA genes are conserved and homologous to related genes in other species, such as Eucalyptus robusta, Solanum lycopersicum and Arabidopsis. Using RNA-Seq data collected from poplar under two conditions (with and without salt treatment), we detected 24, 22 and 19 differentially expressed genes (DEGs) in roots, stems and leaves, respectively. Then we performed spatiotemporal expression analysis of the four up-regulated DEGs shared by the tissues, constructed gene co-expression-based networks, and investigated gene function annotations.

Conclusion

Lines of evidence indicated that the PtrLEA genes play significant roles in poplar growth and development, as well as in responses to salt stress.

SUBMITTER: Cheng Z

PROVIDER: S-EPMC7903804 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BackgroundLEA (late embryogenesis abundant) proteins have first been described about 25 years ago as accumulating late in plant seed development. They were later found in vegetative plant tissues following environmental stress and also in desiccation tolerant bacteria and invertebrates. Although they are widely assumed to play crucial roles in cellular dehydration tolerance, their physiological and biochemical functions are largely unknown.ResultsWe present a genome-wide analysis of LEA proteins and their encoding genes in Arabidopsis thaliana. We identified 51 LEA protein encoding genes in the Arabidopsis genome that could be classified into nine distinct groups. Expression studies were performed on all genes at different developmental stages, in different plant organs and under different stress and hormone treatments using quantitative RT-PCR. We found evidence of expression for all 51 genes. There was only little overlap between genes expressed in vegetative tissues and in seeds and expression levels were generally higher in seeds. Most genes encoding LEA proteins had abscisic acid response (ABRE) and/or low temperature response (LTRE) elements in their promoters and many genes containing the respective promoter elements were induced by abscisic acid, cold or drought. We also found that 33% of all Arabidopsis LEA protein encoding genes are arranged in tandem repeats and that 43% are part of homeologous pairs. The majority of LEA proteins were predicted to be highly hydrophilic and natively unstructured, but some were predicted to be folded.ConclusionThe analyses indicate a wide range of sequence diversity, intracellular localizations, and expression patterns. The high fraction of retained duplicate genes and the inferred functional diversification indicate that they confer an evolutionary advantage for an organism under varying stressful environmental conditions. This comprehensive analysis will be an important starting point for future efforts to elucidate the functional role of these enigmatic proteins.

Project description:BackgroundLate 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.ResultsIn 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.ConclusionIn 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.

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