采前喷施洋葱伯克霍尔德菌Burkholderia contaminans对草莓采后腐烂和品质的影响
Effects of preharvest spraying of Burkholderia contaminans on postharvest decay and quality of strawberry

为明确采前喷施洋葱伯克霍尔德菌Burkholderia contaminans B-1对草莓采后贮藏期的腐烂和品质的影响，采用洋葱伯克霍尔德菌菌悬液喷施草莓植株，检测草莓采后腐烂率及硬度、色泽、可滴定酸、抗坏血酸及失重率等指标，并统计草莓表面菌落生长情况。结果表明，采前喷施浓度为1×1010 CFU/mL的洋葱伯克霍尔德菌B-1菌悬液，可显著降低草莓采后腐烂的发生，而且喷施3次贮藏效果优于喷施1次。在16℃下贮藏7 d，喷施3次处理在接种灰葡萄孢菌和自然条件下的抑制率分别达到67.33%和58.45%。采前喷施洋葱伯克霍尔德菌菌悬液可有效提升草莓品质，延缓果实硬度、可溶性固形物、可滴定酸，降低Vc含量，一定程度上可保持果实亮度。洋葱伯克霍尔德菌可在果实表面定殖，且抑制果实表面病原菌的生长。菌悬液喷施3次，16℃贮藏7 d后，果实表面拮抗菌数量达到贮藏前的4.79×104倍，同时，病原菌在果实表面的菌落数也大大减少。洋葱伯克霍尔德菌可引起灰葡萄孢菌菌丝畸形，内含物外渗。此外，洋葱伯克霍尔德菌对草莓植株白粉病有抑制作用，并促进植株生长，株高、单株鲜重和单株叶片分别比对照增加19.39%、28.13%和36.04%。研究表明该菌株在草莓生产和贮藏领域具有较大潜力。
To find out the effects of preharvest application of Burkholderia contaminans on postharvest decay and quality of strawberry fruits, the strawberry plants were sprayed with B. contaminans B-1 suspension, and the parameters of strawberry fruits such as hardness, color, titratable acidity, ascorbic acid and weight loss were evaluated, and statistical analysis of the colony growth on the fruit surface was conducted in this study. After separately stored at 16℃ for seven days and at 6℃ for 15 days, the trial results showed that the postharvest disease occurrence could be significantly reduced when spraying 1×1010 CFU/mL B-1 before harvest, and spraying three times could bring better results than spraying only one time. When the strawberries were stored at 16℃ for seven days, the inhibition rate on the fruits inoculated with Botrytis cinerea was 67.33% when applying B-1 three times, while the value under natural conditions was 58.45%. Preharvest application of B. contaminans could greatly improve the quality of strawberry fruits, help keep the hardness, SSC, titratable acid and Vc content for longer time, and maintain the fruit brightness to some extent. The antagonistic bacteria B-1 could effectively colonize on the fruit surface, and inhibit the pathogen growth. With the strawberry being sprayed with B-1 suspension three times, the number of antagonistic bacteria on the fruits stored at 16℃ for seven days reached 4.79×104 times of the prestorage number, while the number of pathogenic fungi was greatly reduced. B-1 could cause hyphal malformation, rupture and inclusion extravasation. In addition, B. contaminans had an inhibitory effect on the powdery mildew, and could also promote the growth of strawberry plants. After spraying three times, the plant height, plant fresh weight and leaf number per plant increased by 19.39%, 28.13% and 36.04%, respectively, compared with those of the control. The results suggested that B-1 bacterial strain had great potential for strawberry production and storage application.