嫁接对西瓜果实瓜氨酸含量及合成途径关键酶基因表达的影响  

Effects of grafting on citrulline content and expression of key enzyme genes in watermelon fruits

作　　者：李蒙蒙[1] 路绪强[1] 赵胜杰[1] 何楠[1] 刘文革[1] LI Mengmeng;LU Xuqiang;ZHAO Shengjie;HE Nan;LIU Wenge(Zhengzhou Fruit Research Institute, CAAS, Zhengzhou 450009, Henan, China)

机构地区：[1]中国农业科学院郑州果树研究所

出　　处：《果树学报》2019年第7期857-865,共9页Journal of Fruit Science

基　　金：中国农业科学院科技创新工程(CAAS-ASTIP-2016-ZFRI-07);国家西甜瓜产业技术体系(CARS-25-03);国家自然科学基金(31471893,31672178)

摘　　要：[目的]探讨嫁接前后西瓜果实瓜氨酸含量及其合成途径关键酶表达量的变化,从基因表达水平阐明嫁接影响西瓜果实瓜氨酸含量的机制。[方法]以低瓜氨酸品种‘SBD黑’为接穗,以‘西嫁强生’为砧木,插接法嫁接‘,SBD黑’西瓜实生苗为对照。用分光光度法测定果实发育过程中瓜氨酸含量,通过荧光定量分析果实发育过程中瓜氨酸合成途径关键酶基因的表达量变化。[结果]嫁接可以增加西瓜果实发育过程中瓜氨酸含量,且在西瓜果实发育38d时瓜氨酸增加量最大(63%)。在果实发育后期NAGK、GAT基因表达量在嫁接西瓜与未嫁接西瓜果实中相差较大,嫁接西瓜果实中Arginase基因表达量在整个发育过程中始终高于未嫁接西瓜。[结论]嫁接西瓜果实中瓜氨酸含量的升高可能是由于瓜氨酸合成上游基因NAGK、GAT高表达,下游基因Arginase低表达共同作用的结果。【Objective】In recent years, with the progress of agricultural production conditions and scientific research level as well as the adjustment of agricultural economic policies, watermelon production in China has developed rapidly. Continuous cropping has impeded the agricultural production, resulting in severe soil-borne diseases and thus restricting the sustainable development of cucurbit crops. In practical production, grafting is widely used to solve the above-mentioned problems. Considerable practical experience and researches indicated that watermelon grafting could overcome some continuous cropping obstacles, and grafting onto a suitable rootstock could make watermelon plants grow vigorously, improve the water and fertilizer absorption, enhance resistance to diseases, raise the seedling tolerance to high temperature and salt stress, and increase the yield of watermelon. Previous studies have shown that watermelon fruit is rich in citrulline. On exposure to drought, intensive light and salt stress, citrulline was the primary component (49%) of the amino acids pool, and the citrulline content could accumulate osmotically. It was important to help plants to maintain the osmotic pressure and enhance the ability of stress tolerance. It was suggested that citrulline content could act as a potent scavenger in watermelons by protecting the green tissues from the oxidative stress during drought conditions. Citrulline was identified as the most potent scavenger of hydroxyl radicals than mannitol, proline, and glycine betaine, so some scholars suggested that citrulline can be used as a biomarker to study stress resistance of plants. So far, some studies have shown that grafting can change citrulline contents in watermelon fruits, but the current research is just limited to the determination of citrulline content. There is limited information available about the citrulline synthesis pathway and the mechanism of citrulline accumulation. This study aims to investigate the impact of grafting on citrulline accumulation i

关 键 词：西瓜 嫁接 瓜氨酸 关键酶基因 

分 类 号：S651[农业科学—果树学]