采后热空气处理对枇杷果实抗病性的诱导

Induction of Disease Resistances in Loquat Fruit by Postharvest Hot Air Treatment

研究热空气处理对枇杷果实腐烂和抗病相关酶活性及基因表达的影响。枇杷果实先用43℃热空气处理3 h,然后接种炭疽病菌,接种后的果实置于20℃条件下贮藏8 d。结果表明,热空气处理有效降低了枇杷果实的自然发病率,显著抑制了接种枇杷果实病斑直径的扩展,诱导了果实中几丁质酶、β-1,3-葡聚糖酶、苯丙氨酸解氨酶(PAL)和多酚氧化酶(PPO)等抗病相关酶活性的增强。热空气处理还可显著诱导接种枇杷果实PAL、PPO、过氧化物酶和热激蛋白基因的表达。同时,热空气处理对枇杷果实的硬度、可滴定酸和可溶性固形物含量等品质指标没有显著影响,但促进了类胡萝卜素的积累。以上结果表明,热空气处理可通过诱导抗病相关基因的表达和抗病相关酶活性的上升,提高枇杷果实的抗病能力。

The effects of hot air treatment on fruit decay and the activities and gene expression of defense-related enzymes in postharvest loquat fruit were investigated. Freshly harvested loquat fruits were treated with hot air at 43 ℃ for 3 h, challenged by being inoculated with Colletotrichum acutatum, and then stored at 20 ℃ for 8 d. The results showed that the fruit treated with hot air had significantly lower natural disease incidence and smaller lesion diameter than the control fruit did. The hot air treatment remarkably enhanced the activities of phenylalanine ammonia-lyase(PAL), chitinase, β-1,3-glucanase and polyphenol oxidase(PPO). This hot air treatment also induced the expression of defense-related genes encoding PAL, PPO, peroxidase(POD) and heat shock protein(HSP) 70. Meanwhile, this treatment did not significantly affect fruit firmness, titratable acidity and total soluble solids, but enhanced the accumulation of carotenoids. These results suggest that hot air treatment can enhance disease resistance of loquat fruit by inducing the activity and gene expression of defense-related enzymes.