MaGA20ox2f, an OsSD1 homolog, regulates flowering time and fruit yield in banana.

Unlabelled: Previous studies illustrated that two banana GA20 oxidase2 (MaGA20ox2) genes, and , are implicated in controlling banana growth and development; however, the biological function of each gene remains unknown. Ma04g15900 protein (termed MaGA20ox2f in this article) is the closest homolog to the Rice SD1 (encoded by 'green revolution gene', ) in the banana genome. The expression of is confined to leaves, peduncles, fruit peels, and pulp. Knockout of by CRISPR/Cas9 led to late flowering and low-yielding phenotypes. The flowering time of #1 and #2 lines was delayed approximately by 61 and 58 days, respectively, while fruit yield decreased by 81.13% and 76.23% compared to wild type under normal conditions. The endogenous levels of downstream products of GA20 oxidase, GA15 and GA20, were significantly reduced in mutant shoots and fruits, but bioactive GA1 was only significantly reduced in the mutant fruits. Quantitative proteomics analysis identified 118 up-regulated proteins and 309 down-regulated proteins in both #1 and #2 lines, compared to wild type, with the down-regulated proteins primarily associated with photosynthesis, porphyrin and chlorophyll metabolism. The decreased chlorophyll contents in #1 and #2 lines corroborated the findings of the proteomics data. We propose that photosynthesis inhibition caused by lower chlorophyll contents in mutant leaves and GA1 deficiency in mutant fruits may be the two critical reasons contributing to the late flowering and low-yielding phenotypes of mutants.

Supplementary Information: The online version contains supplementary material available at 10.1007/s11032-024-01523-3.