一氧化氮对番茄果实采后成熟和Le-ETR4基因表达的影响

以破色期的‘卡罗’番茄果实为试材，研究了NO供体硝普钠（SNP）50 μmol · L-1处理30 min对番茄果实采后成熟的作用，并采用Northern杂交技术检测NO对番茄乙烯受体基因Le-ETR4表达的影响。结果表明，50 μmol · L-1 SNP处理降低了番茄果实的乙烯释放速率，抑制了ACC氧化酶（ACC oxidase,ACO）、纤维素酶（Cellulase）和多聚半乳糖醛酸酶（Polygalacturonase,PG）的活性，延缓了果实的色泽变化和软化，同时显著抑制了番茄乙烯受体基因Le-ETR4的表达。以上结果说明NO主要通过抑制番茄乙烯的生物合成和乙烯受体基因表达来控制成熟相关酶的活性，NO可以在生理水平和乙烯受体水平调控番茄果实的成熟。

Effects of Nitric Oxide on Postharvest Ripening and Le-ETR4 Expression of Tomato Fruit

The effects of NO on postharvest ripening of breaking tomato fruit（Lycopersicon esculentum）were investigated using 50 μmol · L-1 SNP treatment for 30 min. Northern hybridization method was taken to detect the expression of Le-ETR4. The results indicated that dipping fruits in 50 μmol · L-1 SNP treatment for 30 min obviously reduced ethylene production rate, inhibited the activities of cellulase, polygalacturonase and ACC oxidase, and delayed color development and fruit softening. NO treatment also significantly repressed the expression of Le-ETR4. These results demonstrate that NO can inhibit activities of ripening-related enzymes through suppressing ethylene synthesis and expression of ethylene receptor gene. The ripening process of tomato can be regulated by NO both on a physiological and ethylene receptor level.