荧光假单胞杆菌对板栗疫病的控制效果

Biological Control of Chestnut Dlight by Fluorescent Pseudomonas spp.

利用荧光假单胞杆菌(Pseudomonas fluorescens)WCS374r、WCS417r、Q2-87、2-79和CHA0r,恶臭假单胞杆菌(P.putida)WCS358r菌株及其转基因菌株WCS358∷phl和WCS358∷phz,以及绿脓假单胞杆菌(P.aerug-inosa)7NSK2及其相应的嗜铁素突变体,采用预先接种和混合接种两种方法开展了板栗疫病的生物防治试验。在对板栗疫病菌的拮抗活性测定中,所用生防菌对其孢子萌发和菌丝的生长有不同程度的抑制作用,其中以能产生嗜铁素的WCS358r等菌株,优于其嗜铁素缺失突变体,说明嗜铁素是抑制板栗疫病菌孢子萌发的有效因子。在生物防治试验中,WCS358r对板栗疫病有较好的防治效果,其嗜铁素缺失突变体JM218却没有效果,其转基因菌株WCS358∷phl的发病率与WCS358r接近,说明细菌产生的嗜铁素有一定的防治作用,而细菌产生的抗生素DAPG没有防治效果。混合接种比预先接种防治效果提高了10%左右。

Bioassays were developed to study the biological control of Cryphonectria parasitica by Pseudomonas fluorescens WCS374r, WCS417r,Q2 -87,2 -79 and CHAOr,P. put/da WCS358r and its genetically modified strains WCS358 ：：phi and WCS358 ：：phz,and P. aeruginosa 7NSK2 and its siderophore - minus mutants. The gemination of spores and growth of mycelia in C. parasitica were inhibited or reduced in in vitro antagonism by all Pseudomonas strains. Among the strains tested, all the siderophore producing strains, i. e. WCS358r, WCS374r, WCS417r and 7NSK2 had stronger suppressive effects than their related siderophore - minus mutants, demonstrating that siderophore is the main suppressive bacterial determinant. In bioassays with direct suppression, strain WSC358r had the best control effects. The siderophore - minus mutant JM218 have no control effects at all,indicating that sidcrophore is a promising bacterial determinant to control chestnut blight caused by C. parasitica. WCS358 ：：phl had no enhanced control effect on this disease compared with its wild - type strain WCS358r. Inoculation of with mixture of biological strains and spores of pathogen had better control effects than the approach in which biocontrol strains were applied to wounds prior to inoculation of pathogen, with a lower incidence of 10% than the latter.