SUPPRESSION OF SEPTORIA-TRITICI BLOTCH AND LEAF RUST OF WHEAT BY RECOMBINANT CYANIDE-PRODUCING STRAINS OF PSEUDOMONAS-PUTIDA

Pseudomonas putida strain BK8661, which produces siderophore(s), antib iotic(s), and low levels of hydrogen cyanide (HCN), suppresses growth of Septoria tritici and Puccinia recondita f. sp. tritici in vitro and on wheat leaves, Pleiotropic mutants of strain BK8661 deficient in si derophore and antibiotic synthesis were significantly less effective i n suppressing symptoms than was the wild type, HCN overproducing deriv atives of the pleiotropic mutants were constructed by the integration of the hcnABC gene cluster from Pseudomons fluorescens CHA0, In the ab sence of siderophore(s) and antibiotic(s), HCN production by the overp roducing bacterial strains resulted in a small but statistically signi ficant increase in the suppression of symptoms caused by S. tritici an d P. recondita f. sp. tritici on wheat seedling leaves.