Banana MaBZR1/2 associate with MaMPK14 to modulate cell wall modifying genes during fruit ripening
Banana MaBZR1/2 interact with MaMPK14 to enhance the transcriptional inhibition of cell wall modifying genes including MaEXP2, MaPL2 and MaXET5.
Fruit ripening and softening, the major attributes to perishability in fleshy fruits, are modulated by various plant hormones and gene expression. Banana MaBZR1/2, the central transcription factors of brassinosteroid (BR) signaling, mediate fruit ripening through regulation of ethylene biosynthesis, but their possible roles in fruit softening as well as the underlying mechanisms remain to be determined. In this work, we found that MaBZR1/2 directly bound to and repressed the promoters of several cell wall modifying genes such as MaEXP2, MaPL2 and MaXET5, whose transcripts were elevated concomitant with fruit ripening. Moreover, yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assays indicated that MaBZR1/2 physically interacted with a mitogen-activated protein kinase MaMPK14, and this interaction strengthened the MaBZR1/2-mediated transcriptional inhibitory abilities. Collectively, our study provides insight into the mechanism of MaBZR1/2 contributing to fruit ripening and softening, which may have potential for banana molecular improvement.
KeywordsBanana fruit BZR Cell wall modification Protein–protein interaction Transcriptional regulation
BRI1-associated receptor kinase 1
Brassinosteroid Insensitive 1-EMS-Suppressor 1
Bimolecular fluorescence complementation
Brassinosteroid insensitive 2
Brassinosteroid insensitive 1
Brassinazole resistant 1
Electrophoretic mobility shift assay
Mitogen-activated protein kinase
Mitogen-activated protein kinase kinase
Mitogen-activated protein kinase kinase kinase
Polymerase chain reaction
This work was funded by the National Natural Science Foundation of China (Grant no. 31401922, 31772021), Guangdong Special Support Program (Grant no. 2017TQ04N512), China Agriculture Research System (Grant no. CARS-31-11), and Guangdong Provincial Special Fund For Modern Agriculture Industry Technology Innovation Teams.
Author contribution statement
JK and XS conceived and designed the research. WS and YG carried out most of the experiments. WW performed some of the experiments. JC, WL, and DY analyzed the data. JK, XS, JC and WL wrote the manuscript. All the authors read and approved the manuscript.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interests.
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