Široká Jitka, Ament Anita, Mik Václav, Pospíšil Tomáš, Kralová Michaela, Zhang Chao, Pernisová Markéta, Karady Michal, Nožková Vladimira, Nishizato Yuho, Kaji Takuya, Saito Rina, Htitich Mohamed, Floková Kristýna, Wasternack Claus, Strnad Miroslav, Ueda Minoru, Novák Ondřej, Brunoni Federica
Laboratory of Growth Regulators, Faculty of Science, Palacký University, Šlechtitelů 27, Olomouc CZ-77900, Czech Republic.
Laboratory of Growth Regulators, Institute of Experimental Botany, The Czech Academy of Sciences, Šlechtitelů 27, Olomouc CZ-77900, Czech Republic.
Plant Physiol. 2024 Dec 23;197(1). doi: 10.1093/plphys/kiae636.
Jasmonates are a family of oxylipin phytohormones regulating plant development and growth and mediating "defense versus growth" responses. The upstream JA biosynthetic precursor cis-(+)-12-oxo-phytodienoic acid (cis-OPDA) acts independently of CORONATIVE INSENSITIVE 1-mediated JA signaling in several stress-induced and developmental processes. However, its perception and metabolism are only partially understood. An isoleucine analog of the biologically active JA-Ile, OPDA-Ile, was detected years ago in wounded leaves of flowering plants, opening up the possibility that conjugation of cis-OPDA to amino acids might be a relevant mechanism for cis-OPDA regulation. Here, we extended the analysis of amino acid conjugates of cis-OPDA and identified naturally occurring OPDA-Val, OPDA-Phe, OPDA-Ala, OPDA-Glu, and OPDA-Asp accumulating in response to biotic and abiotic stress in Arabidopsis (Arabidopsis thaliana). The OPDA amino acid conjugates displayed cis-OPDA-related plant responses in a JA-Ile-dependent manner. We also showed that the synthesis and hydrolysis of cis-OPDA amino acid conjugates are mediated by members of the amidosynthetase GRETCHEN HAGEN 3 and the amidohydrolase INDOLE-3-ACETYL-LEUCINE RESISTANT 1/ILR1-like families. Thus, OPDA amino acid conjugates function in the catabolism or temporary storage of cis-OPDA in stress responses instead of acting as chemical signals per se.
茉莉酸酯是一类氧化脂质植物激素，可调节植物的发育和生长，并介导“防御与生长”反应。上游茉莉酸生物合成前体顺式-(+)-12-氧代植物二烯酸（cis-OPDA）在几个应激诱导和发育过程中独立于不敏感冠菌素1介导的茉莉酸信号传导发挥作用。然而，人们对其感知和代谢的了解仅处于部分水平。数年前在开花植物的受伤叶片中检测到了具有生物活性的茉莉酸异亮氨酸（JA-Ile）的异亮氨酸类似物OPDA-Ile，这表明顺式-OPDA与氨基酸的缀合可能是顺式-OPDA调节的一种相关机制。在此，我们扩展了对顺式-OPDA氨基酸缀合物的分析，并鉴定出了在拟南芥中响应生物和非生物胁迫而积累的天然存在的OPDA-缬氨酸、OPDA-苯丙氨酸、OPDA-丙氨酸、OPDA-谷氨酸和OPDA-天冬氨酸。OPDA氨基酸缀合物以依赖茉莉酸异亮氨酸的方式表现出与顺式-OPDA相关的植物反应。我们还表明，顺式-OPDA氨基酸缀合物的合成和水解由酰胺合成酶GRETCHEN HAGEN 3和酰胺水解酶吲哚-3-乙酰亮氨酸抗性1/ILR1样家族的成员介导。因此，OPDA氨基酸缀合物在应激反应中参与顺式-OPDA的分解代谢或临时储存，而不是本身作为化学信号起作用。
