Endophytic Bacterial Induction of Defence Enzymes against Bacterial Blight of Cotton

Abstract

Bacterial blight of cotton caused by Xanthomonas axonopodis pv. malvacearum (Xam) is a major yield constraint in cotton crops. The effect of inducing systemic resistance against Xam in cotton with a talc-based bioformulation of the endophytic Bacillus strains EPCO 102 and EPCO 16 and Pseudomonas fluorescens strain Pf1, with or without the addition of chitin, was tested under greenhouse conditions. The bioformulation, applied through seed, soil or foliar spray, significantly reduced disease incidence. The addition of chitin to the formulation reduced disease incidence still further. EPCO 102 with chitin led to the lowest bacterial blight incidence. The bacterial strains also caused higher levels of chitinase, peroxidase, polyphenol oxidase, phenylalanine ammonia-lyase and phenol in cotton, besides reduction of blight incidence. In addition, the endophytic Bacillus strains increased cotton yield under greenhouse conditions.