12-OPDA Reductase and OPC-8:0 CoA Ligase Mediate Jasmonic Acid Synthesis in Lasiodiplodia iranensis

Abstract

Jasmonic acid (JA), a phytohormone with a distinct flavor, is an important fragrance ingredient. The filamentous fungi Lasiodiplodia sp. can produce JA via fermentation. Based on comparative transcriptome analysis of L. iranensis M2017288 in static and shaking culture, 13 differentially expressed genes potentially related to JA synthesis were screened, including g4442 and g8524, annotated as 12-OPDA reductase (LiOPR) and OPC-8:0 CoA ligase (LiOPCL), respectively. Quantitative real-time PCR and RNA interference assays confirmed that g4442 and g8524 expression levels were positively correlated with the JA synthesis. Recombinant LiOPR protein utilized (15Z)-12-oxophyto-10,15-dienoic acid (12-OPDA) to generate (9S,13S,15Z)-12-oxo-10,11-dihydrophyto-15-enoate (OPC8:0). JA was detected in cascade reactions of both recombinant LiOPR and LiOPCL coupled with Saccharomyces cerevisiae. Phylogenetic analyses revealed that LiOPR and LiOPCL belong to a different evolutionary branch from plants, suggesting that they are essential enzymes for fungal JA synthesis, which is worthy of further investigation.