L-谷氨酸对樱桃番茄果实病程相关蛋白的影响

为研究L-谷氨酸(谷氨酸)对果实采后病害的抗性机制,以樱桃番茄为对象,将其浸泡于100 mg/L谷氨酸溶液10 min,经不同诱导时间(0、12、24、36 h)处理后接种Alternaria alternata,定期测定果实的发病率,同时研究谷氨酸对果实病程相关蛋白(pathogenesis-related proteins,PRs)及其编码基因的影响。在体外条件下,观察谷氨酸对病原菌生长状态的影响。结果表明:谷氨酸诱导时间在24 h及以上时,番茄发病率显著下降;体外试验中,谷氨酸对病原菌的孢子萌发率和生长无明显影响;谷氨酸可迅速提高果实β-1,3-葡聚糖酶、几丁质酶(chitinases,CHI)和过氧化物酶(peroxidase,POD)的活力,且诱导LePR1、LePR5、LeCHI3、LeCHI9和LePOD上调表达。综上,谷氨酸对Alternaria alternata的作用机制可能与其诱导了果实体内的病程相关蛋白有关。

Effect of L-glutamate on Pathogenesis-related Proteins in Cherry Tomato Fruit

To decipher the mechanism of L-glutamate on postharvest diseases of fruit, cherry tomatoes were treated with L-glutamate solutions at the concentration of 100 mg/L for 10 min and then incubated for various time (0, 12, 24, 36 h). After inoculating with Alternaria alternata, disease incidence of tomato was measured. The effect of L-glutamate on pathogenesis-related proteins (PRs) and its coding gene were investigated. Moreover, the growth of Alternaria alternata in the presence of L-glutamate was observed in vitro. The results suggested that disease incidence decreased significantly when the time interval between treatment and inoculation increased to 24 h. L-glutamate showed no effect on the spore germination and the survival of pathogen in vitro. Meanwhile, L-glutamate could increase the activity of β-1, 3-glucanase, chitinase (CHI) and peroxidase (POD), and induce the expression of LePR1, LePR5, LeCHI3, LeCHI9 and LePOD. In conclusion, the activation of pathogenesis-related proteins might be related to resistance mechanism underpinning L-glutamate induced fruit immunity.