The sweetpotato β-amylase gene IbBAM1.1 enhances drought and salt stress resistance by regulating ROS homeostasis and osmotic balance

• Published in: Plant physiology and biochemistry 2021-11, Vol.168, p.167-176
• Main Authors: Zhu, Hong, Yang, Xue, Wang, Xia, Li, Qiyan, Guo, Jiayu, Ma, Tao, Zhao, Chunmei, Tang, Yanyan, Qiao, Lixian, Wang, Jingshan, Sui, Jiongming
• Format: Article
• Language: English
• Subjects: beta-Amylase - genetics; Drought and salt resistance; Droughts; Gene Expression Regulation, Plant; Homeostasis; Hydrogen Peroxide - metabolism; IbBAM1.1; Ipomoea batatas - genetics; Ipomoea batatas - metabolism; Osmotic balance; Plant Proteins - genetics; Plant Proteins - metabolism; Plants, Genetically Modified - metabolism; Reactive Oxygen Species - metabolism; ROS homeostasis; Salt Stress; Salt Tolerance - genetics; Stress, Physiological - genetics; Sweetpotato; β-amylase
• ISSN: 0981-9428; 1873-2690
• DOI: 10.1016/j.plaphy.2021.09.034

Abiotic stressors, such as drought and high salinity, seriously affect plant growth, productivity, and quality. Maintaining reactive oxygen species (ROS) homeostasis and osmotic balance plays a crucial role in abiotic stress tolerance. β-amylase (BAM) hydrolyzes α-1,4-glycosidic bonds by releasing maltose from starch in the regulation of soluble sugars. However, the function and mechanism of BAMs related to abiotic stress resistance remain unclear in sweetpotato (Ipomoea batatas (L.) Lam.). In this study, we isolated a novel β-amylase gene IbBAM1.1, which was strongly induced by PEG6000, NaCl, and maltose treatments in sweetpotato variety Yanshu25. Overexpression of IbBAM1.1 conferred enhanced tolerance to the drought and high salinity stressors in Arabidopsis thaliana. The activity of β-amylase and the degradation of starch were promoted under drought or salt stress. Accordingly, the contents of osmoprotectants, including maltose and proline were significantly higher in the transgenic lines than those in wild type (WT) plants. Less ROS, such as H2O2 and O2−, accumulated in the overexpressing lines than in WT plants. Superoxide dismutase activity was strongly enhanced and the level of malondialdehyde was lower under the drought or salt treatment in transgenic plants. Taken together, these results demonstrate that IbBAM1.1 acted as a positive regulator, at least in part, by regulating the level of osmoprotectants to balance the osmotic pressure and activate the scavenging system to maintain ROS homeostasis in the plants. •IbBAM1.1 is induced by drought, high salinity and maltose treatments in sweetpotato.•Overexpression of IbBAM1.1 enhances drought and salt tolerance in transgenic plants.•IbBAM1.1 regulates ROS homeostasis and osmotic balance to enhance abiotic resistance.