Li Guangyan, Zhang Caixia, Zhang Guangheng, Fu Weimeng, Feng Baohua, Chen Tingting, Peng Shaobing, Tao Longxing, Fu Guanfu
National Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, 310006, Zhejiang, China.
Crop Production and Physiology Center (CPPC), College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China.
Rice (N Y). 2020 Mar 13;13(1):18. doi: 10.1186/s12284-020-00379-3.
Abscisic acid (ABA) acts as a signaling hormone in plants against abiotic stress, but its function in energy homeostasis under heat stress is unclear.
Two rice genotypes, Nipponbare (wild-type, WT) with flat leaves and its mutant high temperature susceptibility (hts) plant with semi-rolled leaves, were subjected to heat stress. We found significantly higher tissue temperature, respiration rate, and ABA and HO contents in leaves as well as a lower transpiration rate and stomatal conductance in hts than WT plants. Additionally, increased expression of HSP71.1 and HSP24.1 as well as greater increases in carbohydrate content, ATP, NAD (H), and dry matter weight, were detected in WT than hts plants under heat stress. More importantly, exogenous ABA significantly decreased heat tolerance of hts plants, but clearly enhanced heat resistance of WT plants. The increases in carbohydrates, ATP, NAD (H), and heat shock proteins in WT plants were enhanced by ABA under heat stress, whereas these increases were reduced in hts plants.
It was concluded that ABA is a negative regulator of heat tolerance in hts plants with semi-rolled leaves by modulating energy homeostasis.
脱落酸（ABA）作为植物中抵御非生物胁迫的信号激素，但其在热胁迫下能量稳态中的作用尚不清楚。
对两种水稻基因型进行热胁迫处理，一种是叶片扁平的日本晴（野生型，WT），另一种是叶片半卷曲的突变体高温敏感型（hts）植株。我们发现，与WT植株相比，hts植株叶片中的组织温度、呼吸速率、ABA和过氧化氢含量显著更高，而蒸腾速率和气孔导度更低。此外，在热胁迫下，WT植株中检测到HSP71.1和HSP24.1的表达增加，以及碳水化合物含量、ATP、NAD（H）和干物质重量的增加幅度大于hts植株。更重要的是，外源ABA显著降低了hts植株的耐热性，但明显增强了WT植株的耐热性。热胁迫下，ABA增强了WT植株中碳水化合物、ATP、NAD（H）和热激蛋白的增加，而在hts植株中这些增加有所减少。
得出结论，ABA通过调节能量稳态，是叶片半卷曲的hts植株耐热性的负调节因子。
