Differential expression of seven α-expansin genes during growth and ripening of pear fruit
Differential expression of seven α-expansin genes during growth and ripening of pear fruit
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DOI：
10.1034/j.1399-3054.2003.00064.x
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发表时间：
2003-04-01
影响因子：
6.4
通讯作者：
Kubo, Y
中科院分区：
文献类型：
--
作者：
Hiwasa, K;Rose, JKC;Kubo, Y
7个cDNA，指定PcExp 1至PcExp 7，编码扩展蛋白同源物，从成熟的梨果实中分离和他们的表达谱进行了研究，在成熟的果实和其他组织，并响应乙烯。PcExp 2、PcExp 3、PcExp 5和PcExp 6 mRNA的积累量随果实软化而显著增加，过熟期逐渐下降。在成熟早期阶段用乙烯作用的抑制剂1-甲基环丙烯（MCP）处理果实，抑制乙烯生物合成、果实软化和扩展蛋白mRNA的积累。相反，丙烯处理在preclimacteric阶段诱导积累相同的四个expansin基因，以及乙烯的产生和果实软化。表达模式与果实软化的速率和程度的变化相关。PcExp 1 mRNA的丰度在果实发育的后期扩展阶段增加，并在成熟过程中进一步增加，而PcExp 4 mRNA水平在整个果实生长和成熟过程中是恒定的。MCP和丙烯处理对PcExp 1和PcExp 4的表达影响不大。PcExp 7在幼果中表达，但在成熟果实中不表达。PcExp 4和PcExp 6 mRNA在花中也有表达。PcExp 4、PcExp 5、PcExp 6和PcExp 7 mRNA的积累在年轻生长的组织中更丰富，但在完全扩增的组织中不丰富，表明这些基因在细胞扩增中的作用。这些结果表明，多个expansin基因在梨果实发育过程中表现出差异表达和激素调控，至少有六个expansin在成熟过程中表现出重叠表达。
Seven cDNAs, designated PcExp1 to PcExp7 , encoding expansin homologues, were isolated from mature pear fruit and their expression profiles were investigated in ripening fruit and other tissues, and in response to ethylene. Accumulation of PcExp2 , -3, -5 and -6 mRNA increased markedly with fruit softening and then declined at the over-ripe stage. Treatment of fruit at an early ripening stage with 1-methylcyclopropene (MCP), an inhibitor of ethylene action, suppressed ethylene biosynthesis, fruit softening and the accumulation of the expansin mRNAs. Conversely, propylene treatment at the preclimacteric stage induced accumulation of the same four expansin genes, as well as ethylene production and fruit softening. The expression patterns correlated with alteration in the rate and extent of fruit softening. The abundance of PcExp1 mRNA increased at the late expanding phase of fruit development and further increased during ripening, whereas PcExp4 mRNA levels were constant throughout fruit growth and ripening. The MCP and propylene treatments had little effect on PcExp1 and PcExp4 expression. PcExp7 was expressed in young but not mature fruit. PcExp4 and PcExp6 mRNA was also detected in flowers. The accumulation of PcExp4, -5, -6 and -7 mRNA was more abundant in young growing tissues, but not in fully expanded tissues, suggesting roles for these genes in cell expansion. These results demonstrate that characteristically, multiple expansin genes show differential expression and hormonal regulation during pear fruit development and at least six expansins show overlapping expression during ripening.