一株水稻内生菠萝泛菌的分离及防病促生效果评价

Identification of an endophytic Pantoea ananatis strain XP-1 with antagonistic effect to Xanthomonas oryzae pv.oryzicola and growth-promoting effect on rice seedlings

由稻黄单胞菌稻生致病变种(Xanthomonas oryzae pv.oryzicola,Xoc)引起的水稻条斑病是水稻的主要细菌性病害之一,严重影响水稻的产量和质量。开发安全、高效的生防资源对该病害的防控至关重要。本研究利用点接法和牛津杯法,筛选获得了1个对Xoc拮抗效果较好的水稻内生菌菌株XP-1,其发酵液抑菌圈直径为(56.1±0.1)mm。XP-1对烟草青枯病菌(Ralstonia solanacearum)、水稻白叶枯病菌(Xanthomonas oryzae pv.oryzae)、烟草青枯病菌(Ralstonia solanacearum)、白菜软腐病菌(Pectobacterium carotovorum subsp.carotovorum)、草莓角斑病菌(Xanthomonas fragariae)和甘蓝黑腐病菌(Xanthomonas campestris pv.campestris)等5种常见植物病原细菌均有较好的抑制作用。XP-1菌株具有产IAA、铁载体和解无机磷的能力,无固氮和解钾能力。室内浸种和盆栽试验结果表明:XP-1菌株的稀释发酵液能够促进水稻种子萌发及幼苗生长,对3个水稻品种(日本晴、IR24、滇禾优615)的病斑抑制率高达63.72%~94.47%。根据形态特征、生理生化特性和分子生物学鉴定结果,XP-1菌株为菠萝泛菌(Pantoea ananatis)。XP-1菌株抑菌谱较广,是一株有益的水稻内生菌,对水稻具有较好的防病促生效果。本研究为水稻细菌性条斑病生防资源的开发奠定了基础。

Rice bacterial leaf streak,the main bacterial disease caused by Xanthomonas oryzae pv.oryzicola(Xoc),seriously affects rice production.Exploring safe and efficient biological resources is very important for the control of the disease.In this study,an endophytic bacterial strain XP-1 was obtained from rice leaves by confronting incubation method,with an inhibition zone diameter of(56.1±0.1)mm against Xoc.XP-1 also exhibited good antagonistic activity against 5 common bacterial phytopathogens(Ralstonia solanacearum,Xanthomonas oryzae pv.oryzae,Ralstonia solanacearum,Pectobacterium carotovorum subsp.carotovorum,Xanthomonas fragariae and Xanthomonas campestris pv.campestris).Physiological and biochemical test showed that XP-1 strain can produce IAA and siderophore,and solubilize phosphate but cannot solubilize potassium and fix nitrogen.Through indoor seed soaking test and greenhouse pot experiment,it was showed that the diluted fermentation broth of XP-1 could promote seed germination and seedling growth of rice plants,and inhibit leaf lesion on 3 rice varieties,with an inhibition rate of 63.72%-94.47%.The beneficial endophytic XP-1 strain,which has a wide antimicrobial spectrum,was identified as Pantoea ananatis based on morphological characteristics,physiological and biochemical properties and molecular identification results.This study provides the foundation for further exploration of biological resources for rice bacterial leaf streak control.