The fourth exon confers antagonistic activity of OsMFT1 and OsMFT2 in rice pre-harvest sprouting

• Published in: The Crop journal 2025-01
• Main Authors: Zhang, Jialing, Liu, Fei, Kuang, Yang, Luo, Ming, Chu, Chengcai, Xu, Fan
• Format: Article
• Language: English
• Subjects: MFT; PEBP; Pre-harvest sprouting; Rice
• ISSN: 2214-5141; 2214-5141
• DOI: 10.1016/j.cj.2024.12.008

Pre-harvest sprouting (PHS) describes the germination of physiologically mature grains in spikes prior to harvest in cereal crops. PHS could seriously decrease grain yield and quality, which makes it a major constraint to cereal production worldwide. A number of PHS-associated genes in cereals have been reported; however, the molecular mechanisms underlying PHS remain largely elusive. Here, we report a CRISPR-Cas9 mutant with severe PHS in a paddy field. The mutated gene OsMFT2 encodes a phosphatidylethanolamine-binding protein (PEBP). Intriguingly, the OsMFT1, in the same PEBP family, had the opposite effect in controlling rice PHS as does OsMFT2. Germination tests of seeds of chimeric protein-expressing plants revealed that the fourth exon conferred the antagonistic activity of OsMFT1 and OsMFT2 in rice PHS. Additionally, two lines of these plants showed elevated grain numbers per panicle, implying that chimeric protein has potential to significantly increase yield. Moreover, transcriptome analysis and genetic studies indicated that OsMFT1 and OsMFT2 performed opposing functions in rice PHS owing to three co-regulated genes that being contrastingly affected by OsMFT1 and OsMFT2. Overall, it seemed that the proper combination of PEBP family members could obtain optimal PHS resistance and high yield.