24-表油菜素内酯调控苯丙烷代谢增强杏果实抗病性的研究

24-Epibrassinolide Enhances Disease Resistance in Apricot Fruits via Regulation of Phenylpropanoid Metabolism

摘要:

为了探究24-表油菜素内酯（24-epibrassinolide，24-EBR)对杏果实抗病性及苯丙烷代谢的影响。以新疆“赛买提”杏为试材，于0.05 MPa的压力下，用0.9 mg/L的24-表油菜素内酯对绿熟期的杏果实进行减压渗透处理，以蒸馏水处理为对照，处理后的杏果实放置24 h后损伤接种链格孢菌(Alternaria alternata)，置于温度为4 ℃，相对湿度为90%~95%条件下贮藏，定期测定苯丙氨酸解氨酶（PAL）、肉桂酸-4-羟化酶（C4H）、4-香豆酰-辅酶A连接酶（4-CL）的活性及木质素、总酚和类黄酮含量，并统计果实的发病率及病斑直径。结果表明：24-表油菜素内酯处理能显著提高杏果实PAL、C4H、4-CL的活性和木质素、总酚的含量，在贮藏后期增加类黄酮含量，降低杏果实损伤接种的病害发生率及病斑直径。说明24-表油菜素内酯有可能通过诱导杏果实苯丙烷代谢增强来提高果实的抗病性。

Abstract:

The effects of 24-epibrassinolide (24-EBR) treatment on disease resistance and phenylpropanoid metabolism in apricot fruits were investigated. Mature-green Xinjiang ‘Saimaiti’ apricot fruits were processed by vacuum osmotic treatment with 0.9 mg/L 24-EBR, or distilled water as a control, at a pressure of 0.05 MPa. Twenty-four hours after treatment, the apricot fruits were inoculated with Alternaria alternata and stored at a temperature of 4 ℃ and a relative humidity of 90%~95%. The phenylalanine ammonia lyase (PAL), cinnamic acid hydroxylase (C4H), and 4-p-coumaric acyl coenzyme A ligase (4-CL) activities and lignin, total phenolic, and flavonoid content of the apricot fruits were measured periodically. The disease incidence and lesion diameters of the apricot fruits were also recorded. The results showed that 24-EBR treatment significantly increased the activities of PAL, C4H, and 4-CL and the lignin and total phenolic content, increased the flavonoid content towards the end of the storage period, and decreased the disease incidence and lesion diameter of apricot fruits. These results indicate that 24-EBR treatment can enhance the resistance of fruits to postharvest disease by inducing phenylpropanoid metabolism.