The importance of SlSWEET transporters in fruit and seed development in tomato

Abstract

Sugar is an important energy source during plant development and serve as nutrients to organ development including fruits Tomato is an important economic fruit crop in the world yet the mechanism of sugar supply in fruits is still unclear Studies indicate that SWEET (Sugars Will Eventually be Exported Transporters) sugar transporters regulated seed filling in Arabidopsis and may involve in development of tomato fruits Here by using quantitative PCR we have discovered that SlSWEET12c was specifically highly expressed in 35-day-old fruits and SlSWEET15 was highly expressed 21-day-old fruits Yeast complementation growth assay and radio-tracer uptake assay suggested that SlSWEET12c exhibited weak but specific transport activity to sucrose Localization of SlSWEET12c/15-GFP in yeast and plant cell vacuoles suggested their putative functions in vacuolar sugar accumulation Tissue-specific expression of SlSWEET12c/15-GUS fusion proteins were observed in transgenic tomato plants We discovered that SlSWEET12c/15 proteins were mainly accumulated in seed coat and less in flesh and vascular bundle To confirm its physiological function knockout mutant lines using CRISPR/cas9 system were generated We found that in slsweet15 mutant fruits development and seed filling were inhibited These results imply that SlSWEET15 may function at vacuolar membrane to regulate sucrose in seeds and supply for fruits development

Date of Award	2019
Original language	English
Supervisor	Woei-Jiun Guo (Supervisor)