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(新疆农业大学食品科学与药学学院,新疆乌鲁木齐 830052)

链格孢侵染对甜瓜病程相关蛋白活性及基因表达的影响

张培岭,黄伟,马玲,冯作山,白羽嘉*

(新疆农业大学食品科学与药学学院,新疆乌鲁木齐830052)

以抗病能力强的伽师瓜和抗病能力较弱的86-1甜瓜作为实验材料,研究甜瓜果实应答链格孢侵染过程中对几丁质酶(CHT)、β-1,3-葡聚糖酶(GLU)活力变化的影响及基因表达规律。伽师瓜和86-1甜瓜接种浓度为1×106个/mLA.alternata孢子悬浮液20 μL,置于6～8 ℃冷库贮藏,测定病斑大小,几丁质酶和β-1,3-葡聚糖酶活力及基因相对表达量。结果表明:损伤接种A.alternata后,伽师瓜和86-1甜瓜均在15 d发病,贮藏过程中伽师瓜果实的发病率及病斑大小均低于86-1甜瓜;甜瓜应答侵染过程中,几丁质酶和β-1,3-葡聚糖酶活力呈现先升高后下降的趋势,分别于21 d,18 d达到酶活高峰,且接种伽师瓜酶活力显著高于86-1甜瓜(p<0.05),伽师瓜通过增强病程相关酶活力来抵御链格孢的侵染;伽师瓜CHT1、CHT2、GLU基因表达量显著高于86-1甜瓜,分别在贮藏18、18、15 d表达量最大;贮藏0～21 d病程相关蛋白活力及基因相对表达量与病斑直径呈正相关,说明病程相关蛋白在植物抵御病原微生物侵染早期与中期中起到了关键作用,并且在侵染中期作用显著。

甜瓜,链格孢,病程相关蛋白,基因表达

Abstract:Jiashi muskmelon and 86-1 muskmelon species with the characteristics of disease resistance were used as experiment material. This study was aimed to the activities of CHT,GLU and the gene expression rules for CHT and GLU in muskmelon fruits inoculated withA.alternatawere analyzed. Jiashi muskmelon and 86-1 muskmelon were inoculated with 20 μLA.alternataspore suspension,inoculation with 20 μL of sterile water as a blank control,the materials were transferred to cold storage at 6～8 ℃,determination of lesion size,the activities of CHT,GLU and the gene expression ofCHTandGLU. The results showed that the incidence and the lesion size of Jiashi muskmelon were lower than that of 86-1 muskmelon during the inoculated withA.alternataafter 15 days. During the infection period,the activities of CHT,GLU was significantly increased with a trend from rise to decline. The peak of activities for CHT,GLU revealed of 21 d,18 d. The activities of CHT,GLU in Jiashi melon significantly higher than 86-1 muskmelon Jiashi muskmelon to resist the infection ofA.alternariaby enhancing the activity of protease and maintaining the enzyme activity at a higher level. The relative expressions forCHT1,CHT2,GLUwere higher in Jiashi muskmelon than 86-1 muskmelon during the whole infection period. The expression levels ofCHT1,CHT2 andGLUwere significantly higher than 86-1 melon,and the expression level ofCHT1,CHT2 andGLUwas the highest in storage at 18,18 and 15 days. The relative expression of protein-related protein and gene expression were positively correlated with lesion diameter for 0～21 d. These results suggest that the pathogenesis related proteins play a key role in the early and middle stage of plant pathogen resistance.

Keywords:muskmelon;Alternariaalternata;pathogenesis-related proteins;gene expression

甜瓜在田间种植、采后运输过程中始终遭受到病原微生物的持续侵染,因此甜瓜内源性抵御病原菌侵染的能力是关键。果实采后病程相关蛋白的研究可从抗病防卫基因调控及其所编码的蛋白生物活性等方面揭示果实采后抗病性的机制[1]。病程相关蛋白的诱导主要通过病原侵染、生理因素、化学诱导剂、物理因素产生[2],病程相关蛋白可以直接对病原菌起到抵御的作用。研究发现在诱导产生SAR的植物体中没有受到侵染的部位几丁质酶、β-1,3-葡聚糖酶活性也显著升高[3-4]。目前,果实采后病程相关蛋白的研究主要集中于苹果、芒果、番茄、葡萄[5-8]等,对伽师瓜病程相关蛋白的研究报道较少。……