多菌灵对荧光假单胞杆菌的正向调控作用及其应用

POSITIVE REGULATIONS OF PSEUDOMONAS FLUORESCENS BY CARBENDAZIM AND ITS APPLICATION IN CONTROLLING COTTON VERTICILLIUM WILT

报道了多菌灵对荧光假单胞杆菌P32(Pseudomonas fluorescens P32)的正向调控作用。多菌灵和P32均能在一定程度上防治棉花黄萎病,但单独使用的效果不理想。试验表明,P32在培养条件下对多菌灵不敏感,而多菌灵可以提高P32在棉花根际及土壤中的定殖存活量。用于土壤处理时,多菌灵最多可以分别使土壤和根际的P32群体提高到12.6和13.8倍,用于种子处理时,则对土壤中P32的群体影响较小,但仍能显著地提高根际P32的群体数量。多菌灵能显著提高P32在天然未灭菌的土壤中对棉花黄萎病的防治效果,当土壤中多菌灵的浓度为10μg/g时,P32的防治效果为82.2％,当土壤中不含多菌灵时,防治效果仅为40.4％;在蒸汽灭菌的土壤中,多菌灵的促进作用消失,多菌灵浓度为10μg/g时,防治效果为66.6％,不含多菌灵时,防治效果为63.7％。用多菌灵和P32的混剂进行种子处理,发现同样的结果。混剂的防治效果为72.7％,P32的防治效果为50.6％,多菌灵的防治效果为42.3％。说明多菌灵对P32防治棉花黄萎病的效果有明显的增效作用,其增效机制可能是多菌灵抑制了土壤中与P32有竞争作用的微生物的活力,使P32的群体数量增加。此外,多菌灵还能提高土著荧光假单胞杆菌的群体数量,从而提高了对黄萎病的防治效果。

This article reports the positive regulations of Pseudomonas fluorescent strian P32 by carbendazim. Both carbendazim and P32 can reduce the Verticillium wilt of cotton singly, though no distinct control effect can be obtained. Pseudomonas fluorescent strian P32 is not sensitive to carbendazim on medium plate. Carbendazim can enhance the colonization and population both in rhizosphere and soils. When added to soils, carbendazim can enhance the population both in soil and rhizosphere by as much as 11. 6 times and 12. 8 times, respectively. When combined with P32, carbendazim can also influence the population of P32 sharply, though influence on population of P32 in soil is much less. Carbendazim can improve the control efficacy of P32 against Verticillium wilt of cotton in natural soils infested by Verticillim dahliae, when carbendazim is added to soils at 10ug/g, P32 (seed treatment) can reduce the disease rate by 82. 2%, otherwise only reduce by 40. 4%. In steamed soils, the enhancement by carbendazim can not be obtained. When there exsits carbendazim, P32 reduce the disease rate by 66. 6%, otherwise by 63. 7%. Seed treatment with carbendazim-P32 complex can reduce the disease rate by 72. 7%, single P32 reduce disease rate by 50. 6%, carbendazim reduce that by 42. 3%. This indicates that carbendazim improved the control efficacy of P32 against Verticillium wilt of cotton significantly, possibly by weakening or eliminating some of microorganisms competitive to P32, and P32 thus establishes a large and active population which is the prerequisite in biological control. Carbendazim also enhances the population of native fluorescent pseudomonads.