In vitro antagonism of endophytic endospore-forming bacteria against Moniliophthora roreri H.C Evans et al.

Abstract

The aim of this work was to determine the antagonistic effect of the endophytic endospore-forming bacteria against M. roreri, as well as its identification. The trial was carried out by dual culture method on Petri dishes containing Potato Dextrose Agar culture medium (PDA). The bacterial inoculum was placed in the center of the plate, and discs of the pathogenic fungus were placed on both sides of the plate. M. roreri colony growth was measured and the radial growth inhibition percentage (RGIP) was calculated at 15 days. A completely randomized design was used with five replicates per treatment (isolate from endophytic bacteria) and control (M. roreri). Besides, bacteria were characterized from the cultural, morphological and physiological point of view according to methodologies collected in the scientific literature. In the antagonism test, 23 isolates of the bacteria (51.1 %) showed a RGIP in the pathogen ranging from 53.8 to 73.8 %; while 22 isolates (48.9 %) registered a RGIP between 2.8 and 47.2 %, at 15 days of incubation in the interaction. The description of the bacterial isolates based on their cultural and morpho-physiological characteristics confirmed their taxonomic location in the group of the aerobic endospore-forming bacteria, class Bacilli. It is demonstrated the high potential of new strains of Bacillus spp. as promising candidates for the biological control of M. roreri, which is the causal agent of frosty pod rot.