Ethylene Response Factor MaERF012 Modulates Fruit Ripening by Regulating Chlorophyll Degradation and Softening in Banana

Ethylene response factors (ERFs) are one of largest plant-specific transcription factor families involved in fruit ripening. However, the regulatory mechanism by which ERFs modulate fruit yellowing and softening remains unknown in banana. We previously found that the transcription of MaERF012 was closely related to 'Fenjiao' banana fruit ripening. Herein, we found that MaERF012 was differentially expressed in the fruit pulp and peel and was closely related to fruit ripening. MaERF012 activated the promoter activity of one chlorophyll degradation gene (MaSGR1), two starch degradation genes (MaGWD1 and MaAMY3), and three cell wall degradation genes (MaPL8, MaEXP-A8, and MaXYL23-like), which were tested by EMSA, Y1H, and DLR. Transient overexpression of MaERF012 accelerates fruit ripening by promoting fruit yellowing and softening by up-regulating the transcription of chlorophyll, starch, and cell wall degradation genes. Over-expression of MaERF012 alters the transcriptome profiles of the fruit peel and pulp, and the differentially expressed genes were mainly enriched in starch and sucrose metabolism, plant hormone signal transduction, biosynthesis of secondary metabolism, and fructose and mannose metabolism. Overall, the data showed that MaERF012 acts as a transcriptional activator by regulating fruit ripening by activating the transcription of chlorophyll, starch, and cell wall degradation genes.

Automated summary

In this study, researchers identified a transcription factor called MaERF012 that plays a crucial role in regulating fruit yellowing and softening in bananas. They found that MaERF012 activates the transcription of genes involved in chlorophyll degradation, starch degradation, and cell wall degradation, thereby promoting fruit ripening. The overexpression of MaERF012 also altered the transcriptome profiles of the fruit peel and pulp, affecting genes related to starch and sucrose metabolism, plant hormone signal transduction, and secondary metabolism. These findings provide new insights into the molecular mechanisms underlying banana fruit ripening.