The jasmonic acid‐amino acid conjugates JA‐Val and JA‐Leu are involved in rice resistance to herbivores

• Published in: Plant, cell and environment cell and environment, 2022-01, Vol.45 (1), p.262-272
• Main Authors: Fu, Wenjie, Jin, Gaochen, Jiménez‐Alemán, Guillermo H., Wang, Xinjue, Song, Jiajin, Li, Suhua, Lou, Yonggen, Li, Ran
• Format: Article
• Language: English
• Subjects: Active control; Amino acids; Animals; Cereal crops; Chemical defense; Conjugates; Cyclopentanes - chemistry; Cyclopentanes - metabolism; Cyclopentanes - pharmacology; Damage accumulation; Gene Expression Regulation, Plant - drug effects; Herbivores; Herbivory; Isoleucine; Jasmonic acid; Leucine - chemistry; Moths; Oryza - drug effects; Oryza - metabolism; Oryza - physiology; Oxylipins - chemistry; Oxylipins - metabolism; Oxylipins - pharmacology; Pest resistance; plant defence; Plant growth; Plant hormones; Plant resistance; Plants; Plants, Genetically Modified; Rice; Signal transduction; Valine - chemistry
• ISSN: 0140-7791; 1365-3040
• DOI: 10.1111/pce.14202

The phytohormone jasmonic acid (JA) plays a core role in plant defence against herbivores. When attacked by herbivores, JA and its bioactive derivatives are accumulated at the damage site, and subsequently perceived by the jasmonate co‐receptors COI1 and JAZ proteins. The (+)‐7‐iso‐jasmonoyl‐L‐isoleucine (JA‐Ile) is known to be the main active JA derivative controlling vascular plant responses to herbivores as well as other JA‐regulated processes. However, whether other endogenous JA‐amino acid conjugates (JA‐AAs) are involved in herbivore‐induced defence responses remain unknown. Here, we investigated the role of herbivore‐elicited JA‐AAs in the crop plant rice. The levels of five JA‐AAs were significantly increased under the armyworm, leaf folder and brown planthopper attack. Of the elicited JA derivatives, JA‐Ile, JA‐Val and JA‐Leu could serve as ligands to promote the interaction between rice COI1 and JAZs, inducing OsJAZ4 degradation in vivo. JA‐Val or JA‐Leu treatment increased the expression of JA‐ and defence‐related pathway genes but not JA‐Ile levels, suggesting that these JA‐AAs may directly function in JA signalling. Furthermore, the application of JA‐Val or JA‐Leu resulted in JA‐mediated plant growth inhibition, while enhancing plant resistance to herbivore attack. This study uncovers that JA‐Val and JA‐Leu also play a role in rice defence against herbivores. Herbivore‐elicitation increased the accumulation of several JA‐AAs in rice. In addition to JA‐Ile, JA‐Val and JA‐Leu could also bind to rice jasmonate co‐receptors, degrade OsJAZ4 in vivo and inhibit rice root growth. JA‐Val and JA‐Leu treatments resulted in enhancing rice resistance to herbivores.