New Bacillus strains as potentials growth promoters and biocontrol agents in wheat (Triticum aestivum)

GAIDO, J.; BARENGO, PAMELA B.; OLIVELLA, LAURA; PIZARRO, DOLORES M.; GIZZI, F.; ESPARIZ, MARTIN; DAURELIO, LUCAS D.

Congreso; Congreso conjunto SAMIGE-SAIB; 2020

SAMIGE-SAIB

Wheat is one of the most produced cereal in our country and is the main wintry crop. However, its yield is affected by both biotic and abiotic stress, which involves the use of harmful agrochemicals to the environment in order to maintain crop yields. Thus, it is necessary to develop low environmental impact formulations, as those based on biological products. Plant growth promoting rizhobacteria (PGPR) are bacteria with the ability to promote plant growth and stimulate its defense mechanisms against pathogen agents. In the present work, the objective was to determinate PGPR and biocontrol ability over wheat from four new Bacillus strains (ZAV_W127, ZAV_W133, ZAV_W35 y ZAV_W102). In order to evaluate PGPR ability a short term assay in growth chamber was performed. Mercurio Klein wheat seeds were inoculated with suspensions from the new strains and a culture media dilution used as a control. Each strain was tested by triplicated and 15 days after seeding, biometric parameters (fresh and dry biomass, root and leaves length and root diameter) were measured. It was found that all of the strains showed augmented parameters in at least one repetition, although one of them (ZAV_W35) stood out above the others. For the biocontrol analysis over pathogen fungi, assays were conducted in Petri dishes containing APD media. A group of inoculated and previously disinfected seeds was challenged with Fusarium graminearum by seeding a conidia suspension in the center of the dish. Other group of inoculated seeds was sown without being disinfected, in order to analyze biocontrol over storage fungi. In both cases, controls in identical conditions were performed, using seeds inoculated with culture media. After 7 days of incubation in growth chamber, seeds infection with F. graminearum and storage fungi development were detected. One of the strains (ZAV_W35) evidenced biocontrol capability over F. graminearum, whereas another one (ZAV_W102) was shown to be effective avoiding the spread of storage fungi over seeds. These results suggest that two of the four tested strains exhibit potential biocontrol and PGPR ability, making them promising to be used as future inoculants.