Authors: Miho Tatsuki Hiroko Hayama Yuri Nakamura
Publish Date: 2009/05/30
Volume: 230, Issue: 2, Pages: 407-417
Abstract
Ethylene plays a crucial role in apple fruit ripening Ethylene receptors have been identified and are known to be negative regulators of ethylene signalling We examined ethylene receptors MdERS1 and MdERS2 in 1MCPtreated and untreated fruit and leaves of cultivar ‘Orin’ and ‘Fuji’ apples MdERS1 and MdERS2 transcription increased rapidly after harvest in control fruit but in 1MCPtreated fruit increases were delayed for 30 days However MdERS1 and MdERS2 protein levels behaved differently MdERS1 decreased gradually in both the control and 1MCP treatments MdERS2 however increased gradually in control ‘Fuji’ and remained steady in 1MCPtreated ‘Fuji’ but remained low in ‘Orin’ Exogenous ethylene treatment of fruit increased MdERS1 and MdERS2 expression with slightly decreased protein levels The ratios of proteins to mRNAs were much lower in ‘Orin’ fruit and they decreased with ethylene treatment in both cultivars However protein to transcript ratio was higher in ‘Fuji’ ethylene treated fruit than in air and ethylenetreated ‘Orin’ fruit MdERS1 and MdERS2 transcript levels were increased by exogenous ethylene treatment in air pretreated leaves but MdERS1 and MdERS2 protein levels did not change or decrease with ethylene treatment and the ratio of protein to mRNA was lower in ethylenetreated leaves Differences between transcription and protein levels may be due to receptor turnover differences in the presence or absence of ethylene Furthermore MdERS1 and MdERS2 protein stabilities in the presence of ethylene were different in the two cvs ‘Orin’ and ‘Fuji’
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