National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China.
National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, Hubei 430070, PR China; Department of Botany, University of Malakand, Chakdara Dir Lower 18800, Khyber Pakhtunkhwa, Pakistan.
Plant Physiol Biochem. 2021 May;162:468-475. doi: 10.1016/j.plaphy.2021.03.018. Epub 2021 Mar 12.
Expansins are nonenzymatic cell wall proteins that play significant role in plant development as well as stress responses. Hereby, an expansin-like gene, GhEXLB2 was isolated from a cotton (Gossypium hirsutum L.) protoplast with suppression subtractive hybridization to characterize and study its responses against abiotic stresses. GhEXLB2 is the cell-wall localized protein. The expression of GhEXLB2 level was significantly high under polyethylene glycol and salt treatments. GhEXLB2 was further characterized in vitro by cloning and transformation into cotton. Cotton plants overexpressing GhEXLB2 showed enhanced drought tolerance at germination, seedling and flowering stages. After polyethylene glycol (PEG) treatment at germination stage, the length of main root and hypocotyl of overexpressing lines was significantly longer than YZ1 (wild type) and RNAi lines. In addition, HO and malondialdehyde (MDA) contents were lower, while superoxide dismutase (SOD) and peroxidase (POD) activity was detected higher in overexpressing seedlings. On the other hand, higher SOD and POD activity was detected in overexpressing lines than WT plants in soil. In addition, water use efficiency (WUE), soluble sugar, and chlorophyll contents were also significantly greater in overexpressing plants. The present study revealed that GhEXLB2 play crucial role in enhancing drought resistivity in cotton.
扩展蛋白是一种非酶细胞壁蛋白，在植物发育和应激反应中起着重要作用。本研究采用抑制差减杂交技术从棉花原生质体中分离出一个扩展蛋白类似基因 GhEXLB2，对其进行鉴定并研究其对非生物胁迫的响应。GhEXLB2 是一种定位于细胞壁的蛋白。GhEXLB2 的表达水平在聚乙二醇和盐处理下显著升高。通过克隆和转化到棉花中进一步对 GhEXLB2 进行了体外表征。过表达 GhEXLB2 的棉花植株在萌发、幼苗和开花阶段表现出增强的耐旱性。在萌发阶段用聚乙二醇（PEG）处理后，过表达系的主根和下胚轴长度明显长于 YZ1（野生型）和 RNAi 系。此外，过表达幼苗中的 HO 和丙二醛（MDA）含量较低，而超氧化物歧化酶（SOD）和过氧化物酶（POD）活性较高。另一方面，过表达系中的 SOD 和 POD 活性高于 WT 植株在土壤中的活性。此外，过表达植株的水分利用效率（WUE）、可溶性糖和叶绿素含量也显著增加。本研究表明，GhEXLB2 在增强棉花抗旱性方面发挥着关键作用。
