SlWRKY80 recruits SlHDA1 to regulates the tomato fruit ripening and color transformation

Abstract

AbstractFruit ripening involves key transcription factors (TF). Despite the established importance of WRKY TFs in plant development, the involvement of WRKY and its underlying mechanism in the regulation of fruit ripening and color transformation remain unclear. Here, we discovered a phenomenon where SlWRKY80 is involved in the ripening and color transformation of tomato. Overexpression ofSlWRKY80shortened the color transition cycle of tomato fruit, whereas loss-of-function mutation inSlWRKY80delays this process. On the 7thday after the color breakdown (Break+7), the fruit color was bright red inSlWRKY80-overexpression lines. SlWRKY80 could bind to downstream promoters ofSlSGR1andSlPSY1, thereby exerting a positive regulatory effect on the expression levels ofSlSGR1andSlPSY1. This regulatory activity led to the facilitation of chlorophyll a decomposition and carotenoid synthesis during the transition of fruit color, ultimately accelerating fruit ripening and color change. TheSlWRKY80knockout lines (slwrky80cr-3 andslwrky80cr-4) showed light red. Thr (The 69thamino acid) mutated to Ser of SlWRKY80 (slwrky80cr-46), SlHDA1 was recruited as a regulatory factor to enhance the regulation of downstreamSlPSY1bySlWRKY80, and inhibited theSlSGR1expression bySlWRKY80which maybe the reason why theslwrky80cr-46 knockout lines exhibited brown color. In conclusion, SlWRKY80 regulates the expression ofSlSGR1andSlPSY1by recruiting SlHDA1, thereby regulating chlorophyll decomposition and carotenoid synthesis, and further participating in fruit maturation and related fruit color formation. This research has important guiding significance for breeding tomato germplasm with excellent commercial traits.