The regulation mode of RIN transcription factor involved in ethylene biosynthesis in tomato fruit

Abstract

LE-RIN encodes the RIN (Ripening Inhibitor) transcription factor belonging to the MADS (Mcm1, Agamous, Deficiens, Srf) box family and regulates tomato ripening. The RIN transcription factor plays an indispensable role in ethylene biosynthesis. In the study, we respectively evaluated gene expressions and enzymatic activities of 1-aminocyclopropane-1-carboxylic acid (ACC) synthase (ACS) and ACC oxidase (ACO) and ethylene production to understand the transcriptional regulation of RIN transcription factor in ethylene biosynthesis. RIN transcription factor generates strong or weak induction of the expression of LE-ACS2, LE-ACS4 and LE-ACO1 associated with ethylene biosynthesis. Exogenous ethylene could positively affect gene expression of mature green AC tomato fruit compared with the control, including LE-ACS2, LE-ACO1 and LE-ACO4. However, LE-ACS6 expression was negatively affected by RIN transcription factor and high ethylene production. Accordingly, the activities of ACC synthase and ACC oxidase and ethylene production were also changed. RIN transcription factor has an impact upon ethylene biosynthesis via regulating transcription of LE-ACS2, LE-ACS4, LE-ACO1 and LE-ACS6. These results will help to further clarify the mechanism of tomato fruit development and ripening, and to maintain quality and prolong shelf life of tomato fruit.