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Effects of avirulent bacteriocin‐producing strains of Pseudomonas solanacearum on the control of bacterial wilt of tobacco
Author(s) -
CHEN W. Y.,
ECHANDI E.
Publication year - 1984
Publication title -
plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.928
H-Index - 85
eISSN - 1365-3059
pISSN - 0032-0862
DOI - 10.1111/j.1365-3059.1984.tb02646.x
Subject(s) - bacterial wilt , rhizosphere , biology , inoculation , pseudomonas , microbiology and biotechnology , bacteria , population , virulence , sowing , strain (injury) , horticulture , biochemistry , genetics , demography , anatomy , sociology , gene
Root systems of tobacco dipped in suspensions containing 2 × 10 9 colony forming units (CFU)/ml of avirulent bacteriocin‐producing strains (ABPS) of Pseudomonas solanacearum and assayed immediately after planting in steam‐sterilized soil had 8 × 10 6 CFU/root system of ABPS. The bacterial population declined to an average of 5·3 × 10 5 CFU/root system after 30 days. Roots of seedlings dipped in bacterial suspensions of ABPS were more effectively protected against wilt caused by P. solanacearum than those dipped in suspensions of an avirulent nonbacteriocin‐producing strain (ANBPS). Lipopolysaccharide (LPS) isolated from one ABPS (121) inhibited the attachment of bacteria on roots by 70% but had no effect on the reduction of wilt, whereas bacterial cells significantly reduced the disease severity as compared to LPS or water treatment. In steam‐sterilized soil containing a 1:1 mixture (5 × 10 5 CFU/g of oven‐dried soil) of ABPS 121 or 237 and the virulent strain K‐60, ABPS 121 reduced multiplication of the virulent strain in soil and in the rhizosphere of seedlings. When roots of seedlings were dipped in a suspension of 2 × 10 9 CFU/ml of ABPS before planting, root colonization by the virulent strain added to steam‐sterilized soil at 2 × 10 6 CFU/g of oven‐dried soil was significantly reduced. When roots were dipped in a suspension of ABPS and assayed 20 days after planting, 98% of the bacterial population was found in the original zone of inoculation and only 2% was detected in new growths of the root system. Plants which were grown in soil infested with ABPS 121 or K‐60 had both strains present at variable populations along all sections of roots.