摘要
以中华猕猴桃（ActinidiachinensisPlanch．）果实为试材，木葡聚糖内糖基转移酶（XET）cDNA为探针，研究果实成熟进程中XETmRNA的变化规律，探讨XET在果实后熟软化过程的作用。结果表明，20℃下外源乙烯处理可促进XETmRNA的积累，且这种效应因乙烯处理时间的加长而加强，进而加速了果实软化；0℃处理可抑制XETmRNA的增加，延缓果实软化，但当果实转入20℃后熟时，果实硬度迅速下降，而XETmRNA水平变化不明显。认为XET可能只是一种诱导酶，由它引起的细胞壁解聚并非是猕猴桃果实后熟软化的关键因子。
To explore the role of xyoglucan endotransglycosytase (XET) in the softening of kiwi fruit (Actinidia chinensis Planch. ) fruit during fruit ripening, the expression pattern of XET gene in relation to fruit softening was investigated. Northem analysis showed that XET mRNA was in very low level in the fruit at harvest time; treatment with 100 uL/L ethyene induced mRNA accumulation, the longer the ethylene treatment, the higher the mRNA level, thus promoted fruit softening. The mRNA level reached the highest at 24 h after ethylene treatment and had no significant change during ethytene climacteric as the ripening fruit stored at 20 ℃ . A trace of mRNA level was determined in the fruit stored at 0 ℃ while fruit firmnss did not chang significantly. There was no marked change of mRNA level in the fruit when it was transferred to 20 ℃ after storing for 168 h at 0 ℃, however, the fruit softened quickly. It is proposed that XET might be a kind of inductase leading to xyloglucan depolymerization in the fruit cell wall and not play a key role of softening of kiwi fruit after ripening.
基金
国家自然科学基金!39670523
浙江省自然科学基金!395066
农业部"九五"重点项目!95-17-01-14
关键词
猕猴桃
果实
软化
木葡聚糖内糖基
转移酶
MRNA
Actinidia chinensis, Fruit, Softening, Xyloglucan endotransglycosylase, Gene, Expression
