柿采后丙烯和1–甲基环丙烯处理对两个扩展蛋白基因表达的影响

为进一步了解扩展蛋白（Expansin，EXP）在柿果实采后软化过程中的作用，以丙烯和1–甲基环丙烯（1-methylcyclopropene，1-MCP）处理‘富平尖柿’采后果实，采用实时荧光定量PCR技术检测果实中EXP基因表达量的变化。结果显示，丙烯促进柿果实成熟软化，使乙烯释放高峰升高并提前到来，提高ACC合成酶（ACS）、ACC氧化酶（ACO）活性；1-MCP减缓柿果实的成熟软化，推迟并降低乙烯释放高峰，抑制ACS和ACO活性。随着贮藏时间的延长，柿果实逐渐软化，对照果实DkEXP3和DkEXP4的相对表达量均表现为先上升后下降的趋势。丙烯处理促进了DkEXP3和DkEXP4的表达，使表达高峰升高且提早到来；1-MCP处理抑制了DkEXP3和DkEXP4的表达，推迟且降低了表达高峰。对照和1-MCP处理的果实的DkEXP3和DkEXP4的相对表达量高峰均较乙烯释放高峰早。DkEXP3和DkEXP4在果皮、果肉、果心中表达水平不同。本结果说明EXP可能在采后柿果实成熟软化前期起作用，其表达有组织特异性，且受到乙烯的调控。

Effects of Propylene and 1-methylcyclopropene on Expression of Two EXP Genes in Persimmon Fruits

In order to further explore the function of expansins（EXP）in the postharvest softening progress of persimmon fruits，‘Fuping Jianshi’was treated with 1-MCP and propylene，respectively. Real- time fluorescent quantitative PCR technology was used to detect the relative expression level of EXP genes in persimmon fruits. The results showed that propylene treatment promoted the softening of persimmon fruits，increased ethylene production and advanced the onset of climactic of ethylene production and accelerated the enzymatic activity of ACS and ACO. However，1-MCP treatment delayed the softening of persimmon fruits，retarded and reduced the peak of ethylene production，inhibited the enzymatic activity of ACS and ACO. Accompanying with fruit ripening，the expression levels of DkEXP3 and DkEXP4 inincreased sharply to maximum within the first 9 d of storage，followed by a control fruit steady decline until the end of storage. Treatment with propylene promoted the expression of DkEXP3 and DkEXP4，increased and advanced the peak of their expression；Treatment with 1-MCP showed a suppression of DkEXP3 and DkEXP4 expression in persimmon fruit，delayed and reduced the peak intensity. The peak expression levels of DkEXP3 and DkEXP4 in，pericarp and core. The results indicated that EXP might play a role in the early stage of postharvest persimmon fruit ripening and softening progress. The expression of EXP genes is tissue-specific and regulated by ethylene. control fruits and 1-MCP treatment fruits appeared earlier than those of the peak of ethylene production rate. The expression levels of EXP genes were different in sarcocarp