MULTI-SPECIES BACILLUS INOCULANT AND ITS EFFECT ON POTATO GROWTH AND CONTROL OF POTATO (SOLANUM TUBEROSUM L.) BLACKLEG DISEASE

Abstract

Potato blackleg disease (PBD) is a common bacterial disease of potato, causing serious losses in potato (Solanum tuberosum L.) production. Using a probiotic biofertilizer that improves the structure of rhizosphere microbiota may be an effective way to prevent the disease. To develop a mixed Bacillus-based inoculant that would control PBD, active strains resistant to PBD were screened by the plates, and the fertilizer effect of the multi-species Bacillus inoculant on potato was tested in field experiment; the abundance of rhizosphere bacteria, actinomycetes, ammonifying bacteria, and nitrogen-fixing bacteria, and enzyme activities in potato leaves and rhizosphere were analyzed in the pot experiment. Our results showed that Bacillus licheniformis exhibited the most antagonistic effect on the PBD pathogen, followed by Bacillus pumilus and Bacillus megaterium. The highest yield of potato tubers was 2.05 kg/plant with the application of the multi-species Bacillus alternated with Gexi Tianzhuang fertilizer. The amendment also effectively improved the activity of defense enzymes in potato rhizosphere and leaves, and significantly changed the composition of potato rhizosphere microbiota. These results showed the multi-species Bacillus inoculant could effectively improve potato yield and had the potential to resist PBD.