Ethylene is required for both the initiation and progression of softening in pear (Pyrus communis L.) fruit
Ethylene is required for both the initiation and progression of softening in pear (Pyrus communis L.) fruit
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DOI：
10.1093/jxb/erg073
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发表时间：
2003-02-01
影响因子：
6.9
通讯作者：
Kubo, Y
中科院分区：
文献类型：
--
作者：
Hiwasa, K;Kinugasa, Y;Kubo, Y
为了研究乙烯在软化起始和随后进行中的生理作用，梨果实用丙烯、乙烯的类似物或1-甲基环丙烯（1-MCP）处理，1-MCP是乙烯作用的气体抑制剂。成熟前期的丙烯处理促进了乙烯释放和果肉软化，而同一时期的1-MCP处理显著延迟了成熟相关事件的开始。此外，1-MCP处理后开始成熟显着抑制随后的果肉软化和乙烯的产生。这些结果清楚地表明，乙烯不仅是一种副产品，但在启动和维持调节软化过程中成熟起着至关重要的作用。观察结果还表明，乙烯在成熟的调节完全在自催化的方式。梨多聚半乳糖醛酸酶（PG）基因PC-PG 1和PC-PG 2的mRNA积累与果实软化的模式在丙烯和1-MCP处理。然而，梨内切-1，4-β-D-葡聚糖酶（EGase）基因，PC-EG 1和PC-EG 2的表达模式，在这两个处理中没有受到影响。结果表明，即使在成熟后期，PG的表达也需要乙烯，但EGases的表达则不需要乙烯。
In order to investigate the physiological role of ethylene in the initiation and subsequent progression of softening, pear fruit were treated with propylene, an analogue of ethylene or 1-methylcyclopropene (1-MCP), a gaseous inhibitor of ethylene action at the preclimacteric or ripening stages. The propylene treatment at the pre-ripe stage stimulated ethylene production and flesh softening while the 1-MCP treatment at the same stage markedly retarded the initiation of the ripening-related events. Moreover, 1-MCP treatment after the initiation of ripening markedly suppressed the subsequent flesh softening and ethylene production. These results clearly indicate that ethylene is not merely a by-product, but plays a crucial role in both the initiation and maintenance of regulating the softening process during ripening. The observations also suggest that ethylene in ripening is regulated entirely in an autocatalytic manner. The mRNA accumulation of pear polygalacturonases (PG) genes, PC-PG1 and PC-PG2, was in parallel with the pattern of fruit softening in both propylene and 1-MCP treatments. However, the expression pattern of pear endo-1,4-beta-D-glucanases (EGase) genes, PC-EG1 and PC-EG2, was not affected in both treatments. The results suggest that ethylene is required for PGs expression even in the late ripening stage, but not for EGases.