Drought remains one of the most serious environmental stresses because of the continuous reduction in soil moisture, which requires the improvement of crops with features such as drought tolerance. Guar [Cyamopsis tetragonoloba (L.) Taub], a forage and industrial crop, is a nonthirsty plant. However, the information on the transcriptome changes that occur under drought stress in guar is very limited; therefore, a gene expression analysis is necessary in this context. Here, we studied the differentially expressed genes (DEGs) in response to drought stress and their metabolic pathways. RNA-Seq via an expectation-maximization algorithm was used to estimate gene abundance. Subsequently, an Empirical Analysis of Digital Gene Expression Data in the R Bioconductor package was used to identify DEGs. Blast2GO, InterProScan, and the Kyoto Encyclopedia of Genes and Genomes were used to explore functional annotation, protein analysis, enzymes, and metabolic pathways. Transcription factors were identified using the PlantTFDB database. Our study identified 499 upregulated and 191 downregulated genes in response to drought stress. Of those, 32 upregulated and six downregulated genes were deemed as novel genes exclusive to guar. An aggregate of 137 protein families, 306 domains, 12 repeats, and two sites were upregulated. The proton-dependent oligopeptide transporter family and transferase, aquaporin transporter, calcium/calmodulin-dependent/calcium-dependent protein kinase, aspartic peptidase A1 family, UDP-glucuronosyl/UDP-glucosyltransferase, and major intrinsic protein were the most upregulated protein families. The upregulated unigenes were associated with 88 enzymes and 77 KEGG pathways. Finally, the MYB-related, MYB, and ERF transcription factor families were upregulated. These data may be useful for understanding the plant molecular response to drought stress.

中文翻译：

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瓜尔瓜[Cyamopsis tetragonoloba（L.）Taub]中差异表达的干旱反应基因的鉴定。

由于土壤水分的持续减少，干旱仍然是最严重的环境压力之一，这需要改良具有耐旱性等特征的农作物。瓜尔豆[ Cyamopsis tetragonoloba（L.）Taub]是一种牧草和工业作物，是一种不渴植物。但是，关于瓜尔豆干旱胁迫下转录组变化的信息非常有限。因此，在这种情况下，基因表达分析是必要的。在这里，我们研究了响应干旱胁迫及其代谢途径的差异表达基因（DEG）。通过期望最大化算法的RNA-Seq用于估计基因丰度。随后，使用R Bioconductor软件包中的数字基因表达数据进行了经验分析，以识别DEG。Blast2GO，InterProScan和《京都基因与基因组百科全书》被用于探索功能注释，蛋白质分析，酶和代谢途径。使用PlantTFDB数据库识别转录因子。我们的研究确定了499个上调基因和191个下调基因，以应对干旱胁迫。在这些基因中，有32个上调基因和6个下调基因被认为是瓜尔豆专有的新基因。上调了137个蛋白质家族，306个结构域，12个重复序列和两个位点的总数。质子依赖性寡肽转运蛋白家族和转移酶，水通道蛋白转运蛋白，钙/钙调蛋白依赖性/钙依赖性蛋白激酶，天冬氨酸肽酶A1家族，UDP-葡萄糖醛酸/ UDP-葡萄糖基转移酶和主要内在蛋白是上调程度最高的蛋白家族。上调的单基因与88种酶和77条KEGG通路相关。最后，MYB相关，MYB和ERF转录因子家族被上调。这些数据可能有助于了解植物对干旱胁迫的响应。