Jasmonate-induced biosynthesis of steroidal glycoalkaloids depends on COI1 proteins in tomato

• Published in: Biochemical and biophysical research communications 2017-07, Vol.489 (2), p.206-210
• Main Authors: Abdelkareem, Ayman, Thagun, Chonprakun, Nakayasu, Masaru, Mizutani, Masaharu, Hashimoto, Takashi, Shoji, Tsubasa
• Format: Article
• Language: English
• Subjects: Alkaloids - biosynthesis; Alkaloids - chemistry; COI1; Cyclopentanes - administration & dosage; Cyclopentanes - pharmacology; Jasmonate; Lycopersicon esculentum - drug effects; Lycopersicon esculentum - metabolism; Oxylipins - administration & dosage; Oxylipins - pharmacology; Phytosterols - biosynthesis; Phytosterols - chemistry; Plant Proteins - genetics; Plant Proteins - metabolism; Steroidal glycoalkaloid; Tomato; α-tomatine
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2017.05.132

In tomato, perception of jasmonates by a receptor complex, which includes the F-box protein CORONATINE INSENSITIVE 1 (COI1), elicits biosynthesis of defensive steroidal glycoalkaloids (SGAs) via a jasmonate-responsive ERF transcription factor, JRE4/GAME9. Although JRE4 is upregulated by jasmonate and induces the expression of many metabolic genes involved in SGA biosynthesis, it is not known whether JRE4 alone is sufficient for increased SGA biosynthesis upon activation of jasmonate signaling. Here, we show that application of methyl jasmonate induces the expression of JRE4 and SGA biosynthesis genes in leaves and hairy roots of wild-type tomato, but not in jasmonic acid insensitive 1 (jai1), a loss-of-function mutant allele of the tomato COI1 gene. Induced overexpression of JRE4 increased the expression of SGA biosynthesis genes in transgenic hairy roots of both wild-type tomato and the jai1 mutant, suggesting that JRE4 is the primary transcription factor that functions downstream of the jasmonate signaling pathway. •JAs elicit SGA biosynthesis via a transcription factor JRE4 in tomato.•COI1-mediated perception of JA is a critical requirement for SGA formation.•JRE4 alone is sufficient for increased SGA biosynthesis upon activation of JA signaling.•COI1-dependent mechanisms not relying on transcriptional activation of JRE4 exist.