Effect of K+ and Mn2+on lycopene content and related gene expression pattern in tomato fruit

WANG Yan; TIAN Hongmei; ZHANG Jian; WANG Mingxia; JIA Li; FANG Ling

doi:10.3969/j.issn.1673-2871.2016.08.003

Abstract：The aim of this study was to evaluate the effect of exogenous substances on the mechanism of lycopene accumula?tion. High generation and inbred tomato materials were used, and the gene expression levels of lycopene and related genes were detected at different veraison stage of fruit after treating with K+and Mn2+. The results showed that lycopene accumulat?ed rapidly at half ripening stage in the treatment of K+. The lycopene content was obviously higher than control when fruits at ripe stage. The expression levels of various enzyme genes were consistent with the dynamic accumulation of lycopene. The expression of phytoene synthase(PSY1 and PSY2), phytoene desaturase(PDS)and ζ-carotene desaturase(ZDS)genes could be enhanced by K+solution to increase the lycopene quickly during firm ripening stage to ripe stage. On the contrary, the lycopene content was lower than control when fruits were treated with Mn2+solution, and the fast accumulation period of lycopene was from firm ripening stage to ripe stage. The gene expression levels of PDS and ZDS were obviously lower at five turning stages when the fruits were treated with Mn2+solution, suggesting that the expression of ZDS and PDS was inhibited by Mn2+, as a result, leading to the reduction of lycopene accumulation. Our study illustrated that the expression of PSY1 and PSY2 genes could be successfully improved and the lycopene accumulation increased extensively under the treatment of K+solution from firm ripening stage to ripe stage. The lycopene content in tomato fruit can be regulated by using exogenous sub?stances.