Influences of propylene treatment on fruit softening and ethylene biosynthesis of persimmon genotype, 'Hiratanenashi' were investigated. The treatment with propylene could accelerate the softening and enhance ethylene biosynthesis, with higher sensitivity of immature fruit to the propylene was consistent with mRNA increase derived from transcription of ACS and ACO genes. Furthermore, ethylene synthesis increase in immature fruits was controlled and regulated mainly by DK-ACS1, DK-ACS2, DK-ACO1 and DK-ACO2, but regulated only by DK-ACS1 and DK-ACO1 in mature fruits.
The regulation of postharvest treatment with propylene and 1-MCP on ethylene release rate and expressions of 1- aminocyclopropane-l-carboxylic acid synthase （ACS） and 1-aminocyclopropane-1-carboxylic acid oxidase （ACO） genes in Fuping Janshi persimmon （Diospyros kaki L.） fruit were investigated. Fruits were treated with propylene and 1-MCP, then stored at 20℃, ethylene release rate of the treated fruits was measured at regular intervals and RNA was extracted for Northern blotting analysis. The results suggested that treatment with propylene accelerated the expressions of ACS and ACO genes and then enhanced the ethylene biosynthesis, while treatment with 1-MCP inhibited the expressions of two genes and their ethylene biosynthesis. Furthermore, different effects on expressions caused by treatments with propylene and 1-MCP existed in various fruit tissues, the inhibitory effect on ACS and ACO genes by 1-MCP was the strongest in pericarp, followed by pulp and core tissues, in the area near fruit stalk, the inhibitory effect was the weakest. While the enhanced effect on ACS and ACO genes by propylene increased from pulp, core, and pericarp to the area near fruit stalk. Expression of each member of ACS and ACO families in various tissues was also completely different, in control and propylene treatment, DKACS3 gene just expressed in the area near fruit stalk and did not express in other tissues, but DKACS2 gene expressed in four tissues by treatment with propylene.
LIU Le, RAO Jing-ping, CHANG Xiao-xiao and YI Shun-chao College of Horticulture, Northwest Agricultural and Forest University/Key Laboratory of Northwest Horticultural Plants Germplasm and Genetic Improvement, Ministry of Agriculture, Yangling 712100, P.R.China
