猕猴桃果实成熟衰老进程中乙烯受体基因家族成员的表达研究

Five ethylene receptor gene family members were cloned from kiwifruit EST database. Real-time and endpoint PCR were used to analyze gene expression patterns during development and post-harvest ripening and senescence. During fruit development, levels of transcripts of AdERS1a and AdETR3 decreased, whereas those of AdERS1b and AdETR2 peaked at 97 days after full bloom (DAFB). In ripening kiwifruit, there was a diverse response of the ethylene receptor family to internal and external ethylene. AdERS1a, AdETR2 and AdETR3 expression increased at the climacteric stage and transcripts were induced by external ethylene treatment, while AdERS1b showed no response to ethylene. AdETR1 was negative regulated by internal and external ethylene in ripening fruit, a result not found previously in this receptor family in ripening fruit. 1-MCP treatment prevented the ethylene response of all ethylene receptor genes, but transient down-regulation was only found in AdETR2. The differential ethylene response of the receptors suggests different sensitivities and ethylene binding amongst the family members in co-operating the first stages of the ethylene signal transduction pathway.