Cotton Late Embryogenesis Abundant (LEA2) Genes Promote Root Growth and Confer Drought Stress Tolerance in Transgenic Arabidopsis thaliana

文献类型： 外文期刊

第一作者： Richard Odongo Magwanga;;Pu Lu;;Joy Nyangasi Kirungu

作者： Richard Odongo Magwanga;Pu Lu;Joy Nyangasi Kirungu;Qi Dong;Yangguang Hu;Zhongli Zhou;Xiaoyan Cai;Xingxing Wang;Yuqing Hou;Kunbo Wang;Fang Liu

作者机构：

关键词： LEA2 proteins; miRNAs; Drought stress; Expression analysis; Transgenic plant; Oxidants; Antioxidants

期刊名称：G3-GENES GENOMES GENETICS （ 影响因子：3.154； 五年影响因子：3.369 ）

ISSN： 2160-1836

年卷期： 2018 年 8 卷 8 期

页码：

收录情况： SCI

摘要： Late embryogenesis abundant (LEA) proteins play key roles in plant drought tolerance. In this study, 157, 85 and 89 candidate LEA2 proteins were identified in G. hirsutum, G. arboreum and G. raimondii respectively. LEA2 genes were classified into 6 groups, designated as group 1 to 6. Phylogenetic tree analysis revealed orthologous gene pairs within the cotton genome. The cotton specific LEA2 motifs identified were E, R and D in addition to Y, K and S motifs. The genes were distributed on all chromosomes. LEA2s were found to be highly enriched in non-polar, aliphatic amino acid residues, with leucine being the highest, 9.1% in proportion. The miRNA, ghr-miR827a/b/c/d and ghr-miR164 targeted many genes are known to be drought stress responsive. Various stress-responsive regulatory elements, ABA-responsive element (ABRE), Drought-responsive Element (DRE/CRT), MYBS and low-temperature-responsive element (LTRE) were detected. Most genes were highly expressed in leaves and roots, being the primary organs greatly affected by water deficit. The expression levels were much higher in G. tomentosum as opposed to G. hirsutum. The tolerant genotype had higher capacity to induce more of LEA2 genes. Over expression of the transformed gene Cot_AD24498 showed that the LEA2 genes are involved in promoting root growth and in turn confers drought stress tolerance. We therefore infer that Cot_AD24498, CotAD_20020, CotAD_21924 and CotAD_59405 could be the candidate genes with profound functions under drought stress in upland cotton among the LEA2 genes. The transformed Arabidopsis plants showed higher tolerance levels to drought stress compared to the wild types. There was significant increase in antioxidants, catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD) accumulation, increased root length and significant reduction in oxidants, Hydrogen peroxide (H2O2) and malondialdehyde (MDA) concentrations in the leaves of transformed lines under drought stress condition. This study provides comprehensive analysis of LEA2 proteins in cotton thus forms primary foundation for breeders to utilize these genes in developing drought tolerant genotypes.

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