Postharvest behavior of Sechium edule and expression of ACS4, ETR1 and MAPK4 in fruits of different developmental stages

Abstract

Mexico has a high phenotypic diversity of chayote (Sechium edule), which is grouped into approximately 11 varietal groups, of which, the Smooth green, Cambray and Negro Xalapa chayotes, are the most commercialized in the center of Veracruz. It is important to identify the varietal groups with outstanding characteristics during postharvest, and to analyze the expression of genes during the physiological development of the fruits. The loss of fresh weight, germination and percentage of diseased fruits in the three varietal groups was determined during postharvest. In Smooth green chayote, the expression of ACS1, ACS4, ETR1 and MAPK4 genes was evaluated in fruits of different ages. There was no significant difference in fresh weight loss among the three varietal groups, Negro Xalapa was the one that germinated with greater speed, and Smooth green presented higher percentage of diseased fruits. MAPK4 and ETR1 were expressed in low level in all analyzed fruits. However, MAPK4 expression levels increased in fruits of younger age. ETR1 expression levels increased in fruits of one and 2.5 weeks postanthesis, and a low expression level was observed in fruits of 1.5 and 4 weeks postanthesis. ACS1 was not expressed in the fruits analyzed, and ACS4 was only expressed in diseased fruits.