拮抗细菌XM2的鉴定及其对梨采后黑斑病的生防作用

Identification of Pantoea agglomeran XM2 with biocontrol activity against postharvest pear black spot

摘要:

摘要:【目的】对从西梅(Prunus domestica L.)果实表面分离到拮抗细菌XM2进行鉴定，研究其对链格孢(Alternaria alternata)引起的梨采后黑斑病的生防作用。【方法】根据形态特征、理化性质及16S rDNA 序列比对分析，鉴定XM2的种类;在梨果伤口上进行活体(in vivo)的抑菌试验;在显微镜下观察XM2对病原菌丝的影响。【结果】XM2 鉴定为成团泛菌(Pantoea agglomeran);XM2各种处理液对梨黑斑病防效均显著好于对照，效果由强到弱依次是:菌悬液、发酵液、过滤液和热杀死液，其中，菌悬液防效达97.73% ;XM2使用浓度越大、病原菌接种浓度越低，防效越好;XM2接种时间相对早的处理防效显著优于相对时间晚的处理，即预防效果优于治疗效果。菌株XM2可以较好的定殖于梨果伤口;显微镜观察发现，XM2可使病原菌丝部分断裂，细胞内含物外溢，扭曲变形。【结论】本文首次报道成团泛菌菌株XM2，其活菌体和代谢产物对梨采后黑斑病均有生防作用。

Abstract:

Abstract:［Objective］We isolated the bacterial strain XM2 from prunes (Prunus domestica L.) fruit surface．XM2 was identified and tested as an antagonist for postharvest biological control of black spot disease (Alternaria alternata) on pear fruits.［Methods］Strain XM2 was identified according to its morphological，physiological and biochemical characteristics and 16S rDNA sequence analysis．Inhibition tests were performed in wounds of pear fruits using different types of XM2 inocula，different concentration and inoculation time of XM2 and A．alternata．Effect of XM2 on mycelia morphology of A．alternata was observed under microscope.［Results］Strain XM2 was identified as Pantoea agglomeran．Biological control of XM2 against black spot disease was significantly better than the control，and the best inhibitory was observed when inoculated with suspension (97.73% of control effect)． Higher XM2 concentration and lower A．alternata concentration showed better inhibitory effect．Similarly，the earlier inoculation of XM2 than A． Alternata，the better inhibitory effect on disease development．Microscopic observation found that XM2 broke part of the mycelia，making cell contents spilled and hyphae distorted.［Conclusion］Pantoea agglomeran XM2 has the potential as an effective antagonist against postharvest pear blank spot disease.