Liu Enliang, Xu Linli, Luo Zhengqian, Li Zhiqiang, Zhou Guohui, Gao Haifeng, Fang Furong, Tang Jun, Zhao Yue, Zhou Zhilin, Jin Ping
Grain Crops Institute, Xinjiang Academy of Agricultural Sciences, Urumqi, China.
Comprehensive Proving Ground, Xinjiang Academy of Agricultural Sciences, Urumqi, China.
Front Plant Sci. 2023 Mar 16;14:1136709. doi: 10.3389/fpls.2023.1136709. eCollection 2023.
Drought is a common environmental stress with great negative impacts on plant growth, development and geographical distribution as well as agriculture and food production. Sweet potato is characterized by starchy, fresh and pigmented tuber, and is regarded as the seventh most important food crop. However, there has been no comprehensive study of the drought tolerance mechanism of different sweet potato cultivars to date. Here, we studied the mechanism for drought response of seven sweet potato drought-tolerant cultivars using the drought coefficients, physiological indicators and transcriptome sequencing. The seven sweet potato cultivars were classified into four groups of drought tolerance performance. A large number of new genes and transcripts were identified, with an average of about 8000 new genes per sample. Alternative splicing events in sweet potato, which were dominated by first exon and last exon alternative splicing, were not conserved among different cultivars and not significantly affected by drought stress. Furthermore, different drought-tolerance mechanisms were revealed through differentially expressed gene analysis and functional annotation. Two drought-sensitive cultivars, Shangshu-9 and Xushu-22, mainly resisted drought stress by up-regulating plant signal transduction. The other drought-sensitive cultivar Jishu-26 responded to drought stress by down-regulating isoquinoline alkaloid biosynthesis and nitrogen/carbohydrate metabolism. In addition, the drought-tolerant cultivar Chaoshu-1 and drought-preferred cultivar Z15-1 only shared 9% of differentially expressed genes, as well as many opposite metabolic pathways in response to drought. They mainly regulated flavonoid and carbohydrate biosynthesis/metabolism in response to drought, while Z15-1 increased photosynthesis and carbon fixation capacity. The other drought-tolerant cultivar Xushu-18 responded to drought stress by regulating the isoquinoline alkaloid biosynthesis and nitrogen/carbohydrate metabolism. The extremely drought-tolerant cultivar Xuzi-8 was almost unaffected by drought stress and responded to drought environment only by regulating the cell wall. These findings provide important information for the selection of sweet potatoes for specific purposes.
干旱是一种常见的环境胁迫，对植物的生长、发育、地理分布以及农业和粮食生产都有极大的负面影响。甘薯以其富含淀粉、口感新鲜且带有色素的块茎为特征，被视为第七大重要粮食作物。然而，迄今为止，尚未有对不同甘薯品种耐旱机制的全面研究。在此，我们利用干旱系数、生理指标和转录组测序，研究了七个耐旱甘薯品种的干旱响应机制。这七个甘薯品种被分为四组耐旱表现类型。鉴定出了大量新基因和转录本，每个样本平均约有8000个新基因。甘薯中的可变剪接事件主要由首个外显子和最后一个外显子的可变剪接主导，在不同品种间并不保守，且不受干旱胁迫的显著影响。此外，通过差异表达基因分析和功能注释揭示了不同的耐旱机制。两个干旱敏感品种商薯9号和徐薯22号，主要通过上调植物信号转导来抵抗干旱胁迫。另一个干旱敏感品种济薯26号通过下调异喹啉生物碱生物合成以及氮/碳水化合物代谢来响应干旱胁迫。此外，耐旱品种潮薯1号和偏耐旱品种Z15 - 1仅共享9%的差异表达基因，以及许多应对干旱的相反代谢途径。它们主要通过调节类黄酮和碳水化合物的生物合成/代谢来响应干旱，而Z15 - 1提高了光合作用和碳固定能力。另一个耐旱品种徐薯18号通过调节异喹啉生物碱生物合成以及氮/碳水化合物代谢来响应干旱胁迫。极度耐旱品种徐紫8号几乎不受干旱胁迫影响，仅通过调节细胞壁来响应干旱环境。这些发现为特定用途甘薯的选择提供了重要信息。
