Effect of Bacillus methylotrophicus AL7 against Cotton Verticillium Wilt and Its Colonization in Rhizosphere of Cotton
The control effects of Bacillus methylotrophicus AL7 on cotton Verticillium wilt were investigated by pot experiments and its colonization ability in cotton root and rhizosphere soil was evaluated by transforming tetracycline resistance plasmid pGFP78 into AL7 and then observing by tetracycline resistance plate medium and confocal laser scanning microscope (CLSM).The results indicated that the control efficacy of strain AL7 on cotton verticillium wilt was 77.1%,with motility and the ability to produce biofilm.After transformed into strain AL7,tetracycline resistance plasmid pGFP78 has no significant negative influence on the growth of AL7.The colonization detection results showed that AL7 could colonize in cotton rhizosphere soil.Colonization peak reaches 6 × 106 cfu/g soil at five days after inoculation with AL7,and the colonization quantity reaches 2 × 106 cfu/g soil at eighty days after treatment.Strain AL7 also could colonize in cotton root organization.The colonization quantity reaches 6 × 104 cfu/g root.CLSM observation showed that the strain AL7 could also colonize into cotton root tissue with a large number at seven days after inoculation.