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

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.

Identification and Expression Analysis of Stress Responsive Genes in Lentil (Lens culinaris)

Plants during their growth, experience periodic stress conditions both abiotic (adverse environmental conditions) as well as biotic (infection by pathogens). They appear to respond to these adverse conditions by modulating the expression of many genes. One of the pronounced effects of stress on plant is the enhanced synthesis of a set of proteins-termed ' stress proteins'. Lentil contains asset of genes/proteins which helps this crop to overcome abiotic stresses. In the present study, HSP70 (Heat Shock Protein), LEA (Late Embryogenesis Abundant) and Aldolase genes were identified and cloned in pTZ57RT vector followed by sequencing. Expression analysis was done through Q-PCR which was assessed by using cDNA from all the heat, drought and salinity stressed and unstressed lentil cotyledons. The highest level of transcript of HSP70 was realized upon exposure to heat at 45°C for 3 hour followed by at 45°C for 2 hour and lowest at 40°C for 1hour. LEA gene was identified under drought and salinity stress and highest transcript was at 20% PEG for 3 hour (drought stress) and in salinity stress highest transcript was at 150 mm for 6 hour. For Aldolase gene highest transcript was recorded after 3, 6 and 12 hr at 100 mM, 150 mM, 200 mM of salinity stress respectively. From these studies it can be concluded that heat shock protein gene, LEA, and aldolase present in lentil which can be exploited in overcoming the abiotic stresses for obtaining the higher productivity in crop plants through genetic engineering.

Genome-wide identification of and functional insights into the late embryogenesis abundant (LEA) gene family in bread wheat (Triticum aestivum)

Late embryogenesis abundant (LEA) proteins are involved in the responses and adaptation of plants to various abiotic stresses, including dehydration, salinity, high temperature, and cold. Here, we report the first comprehensive survey of the LEA gene family in “Chinese Spring” wheat (Triticum aestivum). A total of 179 TaLEA genes were identified in T. aestivum and classified into eight groups. All TaLEA genes harbored the LEA conserved motif and had few introns. TaLEA genes belonging to the same group exhibited similar gene structures and chromosomal locations. Our results revealed that most TaLEA genes contained abscisic acid (ABA)-responsive elements (ABREs) and various cis-acting elements associated with the stress response in the promoter region and were induced under ABA and abiotic stress treatments. In addition, 8 genes representing each group were introduced into E. coli and yeast to investigate the protective function of TaLEAs under heat and salt stress. TaLEAs enhanced the tolerance of E. coli and yeast to salt and heat, indicating that these proteins have protective functions in host cells under stress conditions. These results increase our understanding of LEA genes and provide robust candidate genes for future functional investigations aimed at improving the stress tolerance of wheat.

A LEA Gene from a Vietnamese Maize Landrace Can Enhance the Drought Tolerance of Transgenic Maize and Tobacco

Maize (Zea mays) is a major cereal crop worldwide, and there is increasing demand for maize cultivars with enhanced tolerance to desiccation. Late embryogenesis abundant (LEA) proteins group 5C is involved in plants’ responses to various osmotic stresses such as drought and salt. A putative group 5C LEA gene from Z. mays cv. Tevang 1 was isolated, named ZmLEA14tv, and cloned into a T-DNA for expression in plants. The deduced amino acid of ZmLEA14tv showed a conserved Pfam LEA_2 domain and a high proportion of hydrophobic residues, characteristic of group 5C LEA proteins. Transgenic tobacco and maize plants expressing ZmLEA14tv were generated. During drought simulation conditions, the ZmLEA14tv-expressing plants of tobacco showed improved recovery ability, while those of maize enhanced the seed germination in comparison with the non-transgenic control plants. In addition, the survival rate of ZmLEA14tv transgenic maize seedlings was twice as high as the control. These results indicated that ZmLEA14tv might be involved in the drought tolerance of plants and could be a candidate gene for developing enhanced drought-tolerant crops.