Isolation, conventional and molecular identification of Fusarium proliferatum responsible to bulb rot of garlic and potential biological control by new bacterial strains

Abstract

The purpose of the present study was to isolate and identify Fusarium proliferatum from infected garlic bulbs, using conventional and molecular identification techniques, as well as to evaluate the in vitro effect of new bacterial strains on the mycelial growth of F. proliferatum. Infected garlic bulb samples were collected and the phytopathogenic fungi isolated and identified using standardised conventional and molecular methods. The effect of the bacterial strains isolated from the different substrates and the filtrates of their liquid culture on the mycelial growth of F. proliferatum was studied using the direct confrontation method between F. proliferatum and the microorganism or the filtrate that may be antagonistic. The results obtained showed a precise identification of F. proliferatum responsible for garlic bulb rot and the deposit of the nucleotide sequence in the NCBI database under accession number OP820542. Three bacterial isolates with a significant inhibitory effect on the growth of F. proliferatum were isolated and selected. These isolates were identified as Bacillus subtilis (Isolat A4), Bacillus tequilensis (Isolat A11) and Pseudomonas sp. (Isolat A12) which exhibited inhibition percentages of 54.00 ± 1.00 %, 59.00 ± 1.00 %, 67.33 ± 1.70 % respectively in comparison with fluconazole 59.17 ± 0.76 %. The current study will contribute to the understanding of garlic bulb rot and to the exploration of new methods of biological control of this disease, as part of a strategy of sustainability and pesticide reduction.