The threat of heat stress on crop production increased dramatically due to global warming leading to the rise on the demand of heat-tolerant crops and understanding their tolerance. The leguminous forage crop Guar [Cyamopsis tetragonoloba (L.) Taub] is a high-temperature tolerant plant with numerous works on its tolerance at morph-physiological levels but lack on molecular thermotolerance level. In the current study, the differential gene expression and the underlying metabolic pathways induced by heat treatment were investigated. An RNA-Seq study on Guar leaves was carried out to estimate gene abundance and identify genes involved in heat tolerance to better understand the response mechanisms to heat stress. The results uncovered 1551 up- and 1466 downregulated genes, from which 200 and 72 genes with unknown function could be considered as new genes specific to guar. The upregulated unigenes were associated with 158 enzymes and 102 KEGG pathways. Blast2GO, InterProScan, and Kyoto Encyclopaedia of Genes and Genomes packages were utilized to search the functional annotation, protein analysis, enzymes, and metabolic pathways and revealed hormone signal transduction were enriched during heat stress tolerance. A total of 301 protein families, 551 domains, 15 repeats, and 3 sites were upregulated and matched to those unigenes. A batch of heat-regulated transcription factor transcripts were identified using the PlantTFDB database, which may play roles in heat response in Guar. Interestingly, several heat shock protein families were expressed in response to exposure to stressful conditions for instance small HSP20, heat shock transcription factor family, heat shock protein Hsp90 family, and heat shock protein 70 family. Our results revealed the expressional changes associated with heat tolerance and identified potential key genes in the regulation of this process. These results will provide a good start to dissect the molecular behaviour of plants induced by heat stress and could identify the key genes in stress response for marker-assisted selection in Guar and reveal their roles in stress adaptation in plants.

中文翻译：

---

瓜尔瓜[Cyamopsis tetragonoloba（L.）Taub]中热响应基因的鉴定。

由于全球变暖导致耐热作物的需求增加并了解其耐受性，因此高温胁迫对作物生产的威胁急剧增加。豆科饲料作物瓜尔豆（Cyamopsis tetragonoloba）（L.）Taub]是一种耐高温植物，在形态生理水平上对它的耐受性有很多研究，但是在分子耐热水平上却缺乏。在当前的研究中，研究了热处理诱导的差异基因表达和潜在的代谢途径。对瓜尔豆叶片进行了RNA-Seq研究，以估计基因丰度并鉴定参与耐热性的基因，以更好地了解对热胁迫的响应机制。结果揭示了1551个上调基因和1466个下调基因，其中200个和72个功能未知的基因可被视为瓜尔豆特有的新基因。上调的单基因与158种酶和102条KEGG通路相关。利用Blast2GO，InterProScan和《京都议定书》中的“基因和基因组百科全书”软件包搜索功能注释，蛋白质分析，酶和代谢途径以及揭示的激素信号转导在热应激耐受期间被丰富。共有301个蛋白家族，551个结构域，15个重复序列和3个位点被上调并与那些单基因匹配。使用PlantTFDB数据库鉴定了一批热调节的转录因子转录本，这可能在瓜尔豆的热反应中起作用。有趣的是，响应于暴露于应激条件，表达了几个热休克蛋白家族，例如小的HSP20，热休克转录因子家族，热休克蛋白Hsp90家族和热休克蛋白70家族。我们的结果揭示了与耐热性相关的表达变化，并确定了调控此过程的潜在关键基因。