Wang Yingfeng, Lei Bin, Deng Huabing, Liu Xiong, Dong Yating, Chen Wenjuan, Lu Xuedan, Chen Guihua, Zhang Guilian, Tang Wenbang, Xiao Yunhua
Hunan Provincial Key Laboratory of Rice and Rapeseed Breeding for Disease Resistance, College of Agronomy, Hunan Agricultural University, Changsha 410128, China.
State Key Laboratory of Hybrid Rice, Hunan Hybrid Rice Research Center, Changsha 410125, China.
Antioxidants (Basel). 2023 Jul 9;12(7):1404. doi: 10.3390/antiox12071404.
Heat stress (HS) has become one of the major abiotic stresses that severely constrain rice growth. Abscisic acid (ABA) plays an important role in plant development and stress response. However, the effect of different concentrations of exogenous ABA on HS tolerance in rice still needs to be further elucidated. Here, we found that high concentrations of exogenous ABA increased HS damage in seedlings, whereas 10 M ABA treatment increased fresh and dry weight under HS relative to mock seedlings. Our further data showed that, in response to HS, 10 M, ABA-treated seedlings exhibited a lower chlorophyll content, as well as transcript levels of chlorophyll biosynthesis and antioxidant genes, and increased the accumulation of reactive oxygen species (ROS). In addition, the transcript abundance of some heat-, defense-, and ABA-related genes was downregulated on 10 M ABA-treated seedlings under HS. In conclusion, high concentrations of exogenous ABA reduced the HS tolerance of rice seedlings, and this negative effect could be achieved by regulating the accumulation of ROS, chlorophyll biosynthesis, and the transcription levels of key genes in seedlings under HS.
热胁迫（HS）已成为严重制约水稻生长的主要非生物胁迫之一。脱落酸（ABA）在植物发育和胁迫响应中起重要作用。然而，不同浓度外源ABA对水稻耐热性的影响仍需进一步阐明。在此，我们发现高浓度外源ABA会增加幼苗的热胁迫损伤，而10 μM ABA处理相对于模拟处理的幼苗在热胁迫下增加了鲜重和干重。我们的进一步数据表明，响应热胁迫时，10 μM ABA处理的幼苗叶绿素含量较低，叶绿素生物合成和抗氧化基因的转录水平也较低，并且活性氧（ROS）积累增加。此外，在热胁迫下，10 μM ABA处理的幼苗中一些与热、防御和ABA相关基因的转录丰度下调。总之，高浓度外源ABA降低了水稻幼苗的耐热性，这种负面影响可通过调节热胁迫下幼苗中ROS的积累、叶绿素生物合成以及关键基因的转录水平来实现。
