陈浩 孙进华 王树军 李焕苓 王果 王家保

摘  要：荔枝霜疫霉病是荔枝生產过程中的主要病害之一，严重影响荔枝品质和产量。本文以霜疫霉病抗病品种‘黑叶和感病品种‘桂味成熟果实为材料，研究霜疫霉悬浮孢子接种后果皮中苯丙烷类代谢通路相关酶活性及代谢产物含量的变化，分析苯丙烷代谢通路与荔枝对霜疫霉侵染抗性的关系。研究结果表明：抗、感病品种接种霜疫霉菌后，其苯丙氨酸解氨酶（PAL）和过氧化物酶（POD）活性均有不同程度的提高，且抗性品种‘黑叶的POD活性高于感病品种‘桂味。与之相反，‘桂味的β-葡萄糖苷酶（BGLU）活性高于‘黑叶。抗性品种‘黑叶的总酚、类黄酮和花色素苷含量高于感病品种‘桂味，而‘桂味的香豆素含量高于‘黑叶。接种霜疫霉菌后，总酚、类黄酮和花色素苷含量随贮藏时间的延长而逐渐下降，香豆素含量则有一定程度的升高。相关分析表明，上述指标与病情指数显著相关，暗示它们与荔枝对霜疫霉侵染的抗性密切相关。

关键词：荔枝霜疫霉病;苯丙烷类代谢;苯丙氨酸解氨酶;过氧化物酶;β-葡萄糖苷酶;香豆素

中图分类号：S436.67.1      文献标识码：A

Effects of Phenylpropanoid Metabolism in Different Litchi Varieties During the Infection of Phytophthora litchii

CHEN Hao1，2， SUN Jinhua1， WANG Shujun1， LI Huanling1， WANG Guo1， WANG Jiabao1

1. Environment and Plant Protection Institute， Chinese Academy of Tropical Agriculture Sciences， Haikou， Hainan 571101， China; 2. College of Plant Sciences and Technology， Huazhong Agricultural University， Wuhan， Hubei 430070， China

Abstract： Litchi downy blight is the most serious disease in litchi， which leads to the yield and quality loss of fruit. In this work， the mature fruits of the disease-resistant variety ‘Heiye and the disease-susceptible variety ‘Guiwei inoculated with Phytophthora litchii infection were used to test the changes of enzymatic activities and metabolisms involved in phenylpropanoid metabolic pathway. The results indicated that the PAL （phenylalanine ammonia lyase） and POD （peroxidase） activity of the resistant and susceptible varieties increased following the infection of P. litchii. The activity of the two enzymes was higher in the resistant variety than that in the susceptible one. In contrast， the BGLU （beta-glucosidase） activity in ‘Guiwei was higher than that in ‘Heiye. The contents of total phenols， flavonoids and anthocyanins in ‘Heiye were higher than that in ‘Guiwei， and the contents of all the three types of metabolites in the two varieties decreased gradually with the extension of storage time. However， the content of coumarin increased in both cultivars. Correlation analysis showed that the enzyme activity and the content of phenylpropanoid metabolites were significantly correlated with the disease index， which suggested that the biosynthesis of phenylpropanoid metabolites is closely related to the resistance of litchi against P. litchii.

Keywords： litchi downy blight; phenylpropanoid metabolism; phenylalanine ammonia lyase; peroxidase; beta-glucosidase; coumarin

DOI： 10.3969/j.issn.1000-2561.2021.06.026

荔枝霜疫霉病（litchi downy blight）由荔枝霜疫霉（Phytophthora litchii）侵染引起，是荔枝（Litchi chinensis Sonn.）主要病害之一，在荔枝生长的各阶段均可发生，主要侵染荔枝的嫩叶、幼茎、花和果实，严重时可导致荔枝减产80%，危害极其严重[1]。近年来，有关研究发现苯丙烷类代谢通路及其代谢产物对植物抵御病原菌的入侵发挥重要作用。植物体在……