Role of bacterial cyanide production in differential reaction of plant cultivars to deleterious rhizosphere pseudomonads

Abstract

Lettuce and wheat cultivars, differing in reaction to root inoculation with plant growth-inhibitory bacteria, were tested for sensitivity to (i) gaseous metabolites produced by deleterious, cyanogenic isolates of Pseudomonasfluorescens, and to (ii) pure cyanide. Reactions were read as shoot and/or root elongation after exposure of seedlings to the volatiles in vitro. Lettuce cultivar Salad Bowl was significantly less sensitive than cv. Montana, both to bacterial volatiles and to pure cyanide, and a similar difference between these cultivars was also obtained in greenhouse experiments where bacteria were inoculated directly on the roots. Cultivar differences were, however, not recorded, either in vitro or in the greenhouse, when the bacteria were grown on a medium which did not support cyanide production. In wheat, a difference in sensitivity to bacteria-produced volatiles was recorded between two cultivars (Drabant and Besso) differing in reaction to bacterial inoculation, but in contrast to lettuce cultivars, the wheat cultivars tested did not react differentially to pure cyanide. The results suggest that in lettuce differential sensitivity to cyanide is one factor behind cultivar differences in reaction to the bacteria tested, even though bacterial metabolites other than cyanide may contribute to the plant growth inhibition recorded. In wheat, however, differential cultivar responses to these bacteria could not be shown to be related to cyanide. Phytopathology 72, 111-115.Voisard C, Keel C, Haas D and D6fago G 1989 Cyanide production by Pseudomonas fluorescens helps suppress black root rot of tobacco under gnotobiotic conditions. EMBO J 8, 351-358.

Evaluation of environmental bacterial communities as a factor affecting the growth of duckweed Lemna minor

“…Cyanide production is virtually the only proposed mechanism with enough supporting data [40, 41], whereas other studies have suggested the benefit of hydrogen cyanide based on antifungal activity [42]. The current study did not show a significant correlation between cyanide production and plant growth.…”

Χαρακτηριστικά βιοελέγχου των στελεχών Pseudomonas chlororaphis ToZa7, Serratia rubidaea S55, Serratia marcescens PiHa5II και Bacillus cereus S76, από ελληνικά αγρο-οικοσυστήματα

“…Είναι πιθανό η παραγωγή του υδροκυανίου να έχει διαφορετική επίδραση ανάλογα με τον ξενιστή. Για τα φυτά καπνού για παράδειγμα, η επίδραση είναι εμφανώς θετική (Voisard et al, 1989) ενώ όπως προαναφέρθηκε, σε φυτά πατάτας, μαρουλιού και φασολιάς, η αύξηση φαίνεται ότι αναστέλλεται (Bakker & Schippers, 1987;Bakker et al, 1989;Åström & Burns, 1989).…”