Overexpression of jasmonate-responsive OsbHLH034 in rice results in the induction of bacterial blight resistance via an increase in lignin biosynthesis

• Published in: Plant cell reports 2020-09, Vol.39 (9), p.1175-1184
• Main Authors: Onohata, Tomonori, Gomi, Kenji
• Format: Article
• Language: English
• Subjects: Bacteria; Biomedical and Life Sciences; Biosynthesis; Biotechnology; Blight; Cell Biology; Cyclopentanes - metabolism; Cyclopentanes - pharmacology; Disease resistance; Disease Resistance - genetics; Gene Expression Regulation, Plant - drug effects; Gene regulation; Jasmonic acid; Life Sciences; Lignin; Lignin - biosynthesis; Original Article; Oryza - drug effects; Oryza - physiology; Oxylipins - metabolism; Oxylipins - pharmacology; Peroxidase; Phenotypes; Plant Biochemistry; Plant cells; Plant Diseases - genetics; Plant Diseases - microbiology; Plant hormones; Plant Proteins - genetics; Plant Proteins - metabolism; Plant Sciences; Plants, Genetically Modified - genetics; Rice; Signaling; Transcription factors; Transcription Factors - genetics; Transcription Factors - metabolism; Transgenic plants; Xanthomonas - pathogenicity; Yeasts
• ISSN: 0721-7714; 1432-203X
• DOI: 10.1007/s00299-020-02555-7

Key message OsbHLH034 acts as a positive regulator in jasmonate signaling in rice. Jasmonic acid (JA) is a plant hormone under strict regulation by various transcription factors (TFs) that acts as a signaling compound in the regulation of plant defense responses and development. Here, we report that a basic helix–loop–helix (bHLH)-type TF, OsbHLH034, plays an important role in the JA-mediated resistance response against rice bacterial blight caused by Xanthomonas oryzae pv. oryzae . The expression of OsbHLH034 was upregulated at a late phase after JA treatment. OsbHLH034 interacted with a Jasmonate ZIM-domain (JAZ) protein, OsJAZ9, in both plant and yeast cells. Transgenic rice plants overexpressing OsbHLH034 exhibited a JA-hypersensitive phenotype and increased resistance against rice bacterial blight. Conversely, OsbHLH034 -overexpressing plants exhibited high sensitivity to salt stress. The expression of some JA-responsive secretory-type peroxidase genes was upregulated in the OsbHLH034 -overexpressing rice plants. Concomitantly, the lignin content significantly increased in these transgenic plants compared to that in the wild-type. These results indicate that OsbHLH034 acts as a positive regulator of the JA-mediated defense response in rice.