Rhizobacteria with potential antagonist in vitro to Mycosphaerella fijiensis Morelet

Abstract

The use of biocontrollers in agriculture benefits the physiological aspects in plants, unlike the constant application of pesticides in the cultivation of banana has caused the loss of sensitivity in M. fijiensis, reducing soil microbiota. The objective was to characterize the antagonistic potential of PGPR in inhibition of ascospore germination and mycelial development of M. fijiensis. Monosporic cultures of M. fijiensis and identified by PCR were performed. The cellular extracts of Pseudomonas putida PB3-6, Klebsiella variicola BO3-4, Enterobacter asburiae BA4-19, Serratia marcescens PM3-8, Enterobacter asburiae PM3-14, Pseudomonas protegens CHA0, Pseudomonas fluorescens WCS417, Pseudomonas veronii R4 and Bacillus subtilis ATCC 5540 were evaluated for its antagonistic evaluations: a) Inhibition of the germination tube of the ascospores at 2% and b) Mycelial development at (2 and 10%). The PCR used in the identification of M. fijiensis confirms the amplification product of 1018 bp. The antagonistic factor of the cellular extracts at 2% of PM3-14 and CHA0 inhibits over 80% the development of germ tubes. The inhibition to the mycelial development of the cellular extract to 2%, of CHA0 achieved an effectiveness of 54% and the strains (PM3-8, PM3-14 and BA4-19) with (32, 26 and 26%). 10% of the extract of strain PM3-8 inhibited mycelial development with turbidity levels of 0.47 (OD600_nm). The use of these bio-controllers in agriculture will offer an alternative to benefit in reducing the use of agrochemicals