Bi Baodi, Tang Jingliang, Han Shuang, Guo Jinggong, Miao Yuchen
Institute of Plant Stress Biology, State Key Laboratory of Cotton Biology, Department of Biology, Henan University, 85 Minglun Street, Kaifeng, 475001, China.
BMC Plant Biol. 2017 Jun 6;17(1):99. doi: 10.1186/s12870-017-1048-9.
Sinapic acid and its esters have broad functions in different stages of seed germination and plant development and are thought to play a role in protecting against ultraviolet irradiation. To better understand the interactions between sinapic acid esters and seed germination processes in response to various stresses, we analyzed the role of the plant hormone abscisic acid (ABA) in the regulation of sinapic acid esters involved in seed germination and early seedling growth.
We found that exogenous sinapic acid promotes seed germination in a dose-dependent manner in Arabidopsis thaliana. High-performance liquid chromatography mass spectrometry analysis showed that exogenous sinapic acid increased the sinapoylcholine content of imbibed seeds. Furthermore, sinapic acid affected ABA catabolism, resulting in reduced ABA levels and increased levels of the ABA-glucose ester. Using mutants deficient in the synthesis of sinapate esters, we showed that the germination of mutant sinapoylglucose accumulator 2 (sng2) and bright trichomes 1 (brt1) seeds was more sensitive to ABA than the wild-type. Moreover, Arabidopsis mutants deficient in either abscisic acid deficient 2 (ABA2) or abscisic acid insensitive 3 (ABI3) displayed increased expression of the sinapoylglucose:choline sinapoyltransferase (SCT) and sinapoylcholine esterase (SCE) genes with sinapic acid treatment. This treatment also affected the accumulation of sinapoylcholine and free choline during seed germination.
We demonstrated that sinapoylcholine, which constitutes the major phenolic component in seeds among various minor sinapate esters, affected ABA homeostasis during seed germination and early seedling growth in Arabidopsis. Our findings provide insights into the role of sinapic acid and its esters in regulating ABA-mediated inhibition of Arabidopsis seed germination in response to drought stress.
芥子酸及其酯类在种子萌发和植物发育的不同阶段具有广泛功能，被认为在抵御紫外线辐射方面发挥作用。为了更好地理解芥子酸酯与种子萌发过程在应对各种胁迫时的相互作用，我们分析了植物激素脱落酸（ABA）在调节参与种子萌发和幼苗早期生长的芥子酸酯中的作用。
我们发现外源芥子酸以剂量依赖的方式促进拟南芥种子萌发。高效液相色谱 - 质谱分析表明，外源芥子酸增加了吸胀种子中芥子酰胆碱的含量。此外，芥子酸影响ABA分解代谢，导致ABA水平降低和ABA - 葡萄糖酯水平升高。利用芥子酸酯合成缺陷型突变体，我们发现突变体芥子酰葡萄糖积累突变体2（sng2）和亮毛状体1（brt1）种子的萌发对ABA比野生型更敏感。此外，脱落酸缺陷2（ABA2）或脱落酸不敏感3（ABI3）缺陷的拟南芥突变体在芥子酸处理下，芥子酰葡萄糖：胆碱芥子酰转移酶（SCT）和芥子酰胆碱酯酶（SCE）基因的表达增加。这种处理还影响了种子萌发过程中芥子酰胆碱和游离胆碱的积累。
我们证明，在各种次要芥子酸酯中构成种子主要酚类成分的芥子酰胆碱，在拟南芥种子萌发和幼苗早期生长过程中影响ABA稳态。我们的研究结果为芥子酸及其酯类在调节ABA介导的拟南芥种子萌发对干旱胁迫抑制中的作用提供了见解。
