Peanut (Arachis hypogaea L.) is an important legume cultivated mostly in drought-prone areas where its productivity can be limited by water scarcity. The development of more drought-tolerant varieties is, therefore, a priority for peanut breeding programs worldwide. In contrast to cultivated peanut, wild relatives have a broader genetic diversity and constitute a rich source of resistance/tolerance alleles to biotic and abiotic stresses. The present study takes advantage of this diversity to identify drought-responsive genes by analyzing the expression profile of two wild species, Arachis duranensis and Arachis magna (AA and BB genomes, respectively), in response to progressive water deficit in soil. Data analysis from leaves and roots of A. duranensis (454 sequencing) and A. magna (suppression subtractive hybridization (SSH)) stressed and control complementary DNA (cDNA) libraries revealed several differentially expressed genes in silico, and 44 of them were selected for further validation by quantitative RT-PCR (qRT-PCR). This allowed the identification of drought-responsive candidate genes, such as Expansin, Nitrilase, NAC, and bZIP transcription factors, displaying significant levels of differential expression during stress imposition in both species. This is the first report on identification of differentially expressed genes under drought stress and recovery in wild Arachis species. The generated transcriptome data, besides being a valuable resource for gene discovery, will allow the characterization of new alleles and development of molecular markers associated with drought responses in peanut. These together constitute important tools for the peanut breeding program and also contribute to a better comprehension of gene modulation in response to water deficit and rehydration.

中文翻译：

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来自限水环境的野生花生的转录组分析揭示了耐旱候选基因

花生 (Arachis hypogaea L.) 是一种重要的豆科植物，主要​​种植在干旱易发地区，其生产力可能因缺水而受到限制。因此，开发更耐旱的品种是全世界花生育种计划的优先事项。与栽培花生相比，野生近缘种具有更广泛的遗传多样性，并构成对生物和非生物胁迫的抗性/耐受等位基因的丰富来源。本研究利用这种多样性，通过分析两种野生物种 Arachis duranensis 和 Arachis magna（分别为 AA 和 BB 基因组）的表达谱来识别干旱响应基因，以响应土壤中逐渐缺水的情况。来自 A. duranensis 的叶和根的数据分析（454 测序）和 A. magna（抑制消减杂交（SSH））强调和对照互补DNA（cDNA）文库在计算机上显示了几个差异表达的基因，其中44个被选择用于通过定量RT-PCR（qRT-PCR）进一步验证。这允许鉴定干旱响应候选基因，如扩展蛋白、腈水解酶、NAC 和 bZIP 转录因子，在两个物种的胁迫施加期间显示出显着水平的差异表达。这是关于鉴定野生花生属物种干旱胁迫和恢复下差异表达基因的第一份报告。生成的转录组数据除了是基因发现的宝贵资源外，还将允许表征新的等位基因和开发与花生干旱反应相关的分子标记。