ICAR-Indian Grassland and Fodder Research Institute, Jhansi, 284003, India.
International Crops Research Institute for Semi-Arid Tropics, Patancheru, 502324, India.
BMC Plant Biol. 2024 Oct 5;24(1):928. doi: 10.1186/s12870-024-05579-3.
Dinanath grass (Pennisetum pedicellatum Trin.) is an extensively grown forage grass known for its significant drought resilience. In order to comprehensively grasp the adaptive mechanism of Dinanath grass in response to water deficient conditions, transcriptomic and metabolomics were applied in the leaves of Dinanath grass exposed to two distinct drought intensities (48-hour and 96-hour). Transcriptomic analysis of Dinanath grass leaves revealed that a total of 218 and 704 genes were differentially expressed under 48- and 96-hour drought conditions, respectively. The genes that were expressed differently (DEGs) and the metabolites that accumulated in response to 48-hour drought stress mainly showed enrichment in the biosynthesis of secondary metabolites, particularly phenolics and flavonoids. Conversely, under 96-hour drought conditions, the enriched pathways predominantly involved lipid metabolism, specifically sterol lipids. In particular, phenylpropanoid pathway and brassinosteroid signaling played a crucial role in drought response to 48- and 96-hour water deficit conditions, respectively. This variation in drought response indicates that the adaptation mechanism in Dinanath grass is highly dependent on the intensity of drought stress. In addition, different genes associated with phenylpropanoid and fatty acid biosynthesis, as well as signal transduction pathways namely phenylalanine ammonia-lyase, putrescine hydroxycinnamoyl transferase, abscisic acid 8'-hydroxylase 2, syntaxin-61, lipoxygenase 5, calcium-dependent protein kinase and phospholipase D alpha one, positively regulated with drought tolerance. Combined transcriptomic and metabolomic analyses highlights the outstanding involvement of regulatory pathways related to secondary cell wall thickening and lignin biosynthesis in imparting drought tolerance to Dinanath grass leaves. These findings collectively contribute to an enhanced understanding of candidate genes and key metabolites relevant to drought response in Dinanath grass. Furthermore, they establish a groundwork for the creation of a transcriptome database aimed at developing abiotic stress-tolerant grasses and major crop varieties through both transgenic and genome editing approaches.
沿阶草（Pennisetum pedicellatum Trin.）是一种广泛种植的牧草，以其显著的耐旱性而闻名。为了全面掌握沿阶草在应对缺水条件下的适应机制，本研究采用转录组学和代谢组学方法研究了暴露于两种不同干旱强度（48 小时和 96 小时）下的沿阶草叶片。转录组学分析表明，在 48 小时和 96 小时干旱条件下，沿阶草叶片分别有 218 个和 704 个基因差异表达。在 48 小时干旱胁迫下，差异表达基因（DEGs）和积累的代谢物主要富集在次生代谢物生物合成途径中，特别是酚类和类黄酮。相反，在 96 小时干旱条件下，富集的途径主要涉及脂质代谢，特别是甾醇脂质。特别是苯丙氨酸途径和油菜素内酯信号转导在 48 小时和 96 小时水分亏缺条件下的抗旱反应中起着关键作用。这种对干旱的不同反应表明，沿阶草的适应机制高度依赖于干旱胁迫的强度。此外，与苯丙烷和脂肪酸生物合成以及信号转导途径相关的不同基因，如苯丙氨酸解氨酶、腐胺羟基肉桂酰转移酶、脱落酸 8'-羟化酶 2、 syntaxin-61、脂氧合酶 5、钙依赖性蛋白激酶和磷脂酶 D alpha one，正向调节耐旱性。转录组学和代谢组学联合分析突出了与次生细胞壁增厚和木质素生物合成相关的调控途径在赋予沿阶草叶片耐旱性方面的卓越作用。这些发现共同有助于增强对沿阶草中与干旱反应相关的候选基因和关键代谢物的理解。此外，它们为通过转基因和基因组编辑方法创建一个旨在开发非生物胁迫耐受草和主要作物品种的转录组数据库奠定了基础。
