Utililization of root-colonizing bacteria to protect hot- pepper againts tobacco mosaic virus

Abstract

Tobacco Mosaic Tobamovirus (TMV) is one of important constraint 9 infecting Solanaceous plants including hot pepper in Indonesia. To accomplish and 10 improve the effectiveness of virus management, we used root-colonizing bacteria (rhizobacteria) 11 which isolated from healthy hot pepper. Eight rhizobacteria isolates were selected and 12 were evaluated their capacity in enhancing plant growth and induce systemic resistance (ISR) 13 against TMV in greenhouse trials. The rhizobacteria was applied as seed treatment and soil 14 drench. Bacterized-seedling showed better growth vigor, fitness and milder 15 symptom than non-bacterized control plants. It suggested that the effect of growth promotion 16 and protection of rhizobacteria against TMV. The protection effect of rhizobacteria 17 was more pronounced after challenged inoculation by TMV, especially for plant treated 18 by isolates I-6, I-16 and I-35. However, the viral accumulation was slightly affected 19 by bacterial treatment. The rhizobacteria treatment elicited ISR might 20 be by increasing peroxidase enzyme activity or not depends on the species. Based on 21 whole results, isolate I-35 was the potential plant growth promotion rhizobacteria 22 (PGPR). The I-35 was identified as Bacillus cereus based on morphological 23 characteristics and nucleotide sequences of 16S r-RNA.