拮抗酵母控制樱桃番茄采后病害及其机制研究

Control Efficacy of Antagonistic Yeast against Postharvest Disease of Cherry Tomatoand the Mechanisms Involved

通过体外和体内试验,从实验室保存的酵母菌中筛选对樱桃番茄采后黑斑病具有控制作用的拮抗酵母,考察所筛选的拮抗酵母对樱桃番茄自然腐烂的防治效果及对果实品质的影响。通过拮抗酵母对黑斑病病原菌链格孢孢子萌发、芽管伸长和菌丝结构的影响,在樱桃番茄伤口处和表面的生长动态,探讨其对病原菌的直接和间接抑制作用。采用RT-qPCR技术测定拮抗酵母对樱桃番茄抗性相关基因表达水平的影响,分析其对樱桃番茄果实抗病性的影响。结果表明,试验菌株中,卡利比克毕赤酵母对樱桃番茄采后黑斑病的控制效果最好,该处理组果实发病率仅为16.25%,显著低于对照组(68.76%),并且该拮抗酵母还可显著降低樱桃番茄采后自然腐烂,缓减果实品质劣变。卡利比克毕赤酵母通过抑制链格孢孢子萌发、菌丝伸长以及寄生于菌丝上直接抑制病原菌生长,还在樱桃番茄伤口处和表面与链格孢竞争营养和空间而间接抑制病原菌生长。卡利比克毕赤酵母还能诱导樱桃番茄抗氧化基因(SOD,CAT和APX)以及病程相关基因(PR基因)(GLU和CHI)的表达。卡利比克毕赤酵母可以显著控制樱桃番茄采后黑斑病和自然腐烂,对果实品质无显著不良影响。该拮抗酵母可以通过抑制病原菌生长和提高樱桃番茄抗性基因的表达控制果实采后病害。

In this study,antagonistic yeast for controlling black spot of postharvest cherry tomato was to be screened by in vitro and in vivo test,and the biocontrol efficacy of this antagonistic yeast against the natural decay of cherry tomato and its effects on the quality of fruits were then investigated.The direct and indirect inhibition of this yeast on Alternaria alternata was explored through its effects on spore germination,germ tube elongation and hyphae structure of this pathogen,and its growth dynamics on wound and surface of cherry tomato,respectively.Then,the effects of antagonistic yeast on the expression levels of resistance-related genes in cherry tomato were determined by RT-qPCR technology to analyze the effect of antagonistic yeast on the disease resistance of the fruits.Results indicated that Pichia caribbica showed the best control efficacy against postharvest black spot of cherry tomato,and the disease incidence of yeast-treated fruits was only 16.25%which was significantly lower than that of the control(68.76%).This antagonistic yeast could also significantly reduce the natural decay of postharvest cherry tomato and slow down the deterioration of quality.P.caribbica could directly inhibit the growth of A.alternata by inhibiting the spore germination and mycelial elongation as well as parasitic on mycelia of A.alternata.It also could indirectly inhibit the growth of A.alternata by competing with the pathogen for nutrition and space on the wound and surface of cherry tomato.P.caribbica could induce the expression levels of antioxidant genes(SOD,CAT and APX)and pathogenesis-related genes(PR genes)(GLU and CHI)in cherry tomato.P.caribbica showed biocontrol efficacy against postharvest black spot and natural rot of cherry tomato,and had no significant adverse effects on fruit quality.It alleviated postharvest diseases of cherry tomato by inhibiting the growth of pathogen and increasing the expression of resistance-related genes.