Characterization of endophytic bacteria isolated from various cultivated plants and determination of their antagonistic effects on plant pathogenic bacteria

Abstract

This study aims to characterize endophytic bacteria (EB) isolated from various cultivated plants and to identify isolates that have an antagonistic effect against some plant pathogenic bacteria. For this purpose, 191 endophyte bacteria (EB) were isolated from root, stem, shoot, and leaf tissues, which were subjected to intensive surface sterilization of samples taken from seedling and the vegetative period from some cultivated plants widely grown in Van province and its vicinity. In-vitro characterizations of these isolates were made in terms of nitrogen fixation ability, phosphate solubility ability, aminocyclopropane-1-carboxylate deaminase (ACC-d) production ability, indole-3-acetic acid (IAA) production ability and siderophore production ability which are PGPR markers. It was determined that 58.9% of the isolates were gram (-), and 41.1% were gram (+). It was revealed that EB isolates with codes V33K1, V35Y1, V34G1, V17G2, V30Y3, V38K1, V17K1, and V36Y2 showed activity in all other categories besides nitrogen fixation. Twenty-five isolates were active in 3 different categories, 59 isolates were in 2 different categories, and 67 isolates were active in only one category. In contrast, 21 isolates were not active in any category. It was also determined that isolate V30Y3 and V30G2 had an antagonistic effect against seven different plant pathogenic bacterial isolates. The 16s rDNA sequence analysis of the isolates selected according to weighted grading scores and antagonistic effects identified the isolates with codes V40K2, V30Y3, V30G2, V31Y4, V33K2 as Bacillus velezensis (MN186863), Bacillus megaterium (MN187955), Pseudomonas caspiana (MN128080), Pantoea sp. (MT249279) and Bacillus sp. (MT249109), respectively.