Bitki Koruma Bülteni, cilt.59, sa.3, ss.59-69, 2019 (Hakemli Dergi)
Pseudomonas syringae pv. phaseolicola (Psp) is a seed-borne bacterium which causeshalo blight disease in common bean. This study aimed the determination of plantgrowth-promoting traits (such as IAA, phosphate solubilization) and antagonisticpotentials (such as siderophore and ammonia productions) of endophytic plant growthpromotingbacteria (PGPB) from healthy bean plants growing in different regionsagainst Psp in vitro conditions. A total of 131 bacteria were primarily characterizedas putative PGPB and tested for antagonist activity against Psp in dual culture tests.Seventy-one bacterial isolates demonstrated antagonistic activities against Psp isolatein varying ratios. Among these 71 isolates, 30 representative bacterial isolates from thedifferent regions/fields were selected. On the basis of morphological, physiological,biochemical characteristics and confirmation by MALDI-TOF analyses, 30 endophyticantagonist isolates were identified as belonging to 10 genera, 24 different species.According to results obtained, 10 isolates belong to Bacillus spp., 6 isolates belongto Pseudomonas spp., 4 isolates belong to Rhizobium radiobacter, 2 isolates belongto Arthrobacter spp., 2 isolates belong to Achromobacter spanius, 2 isolates belong toSerratia liquefaciens, 1 isolate belongs to Acinetobacter calcoaceticus, Exiguobacteriumsp., Microbacterium hydrocarbonoxydans, and Ochrobactrum anthropi. The largest andlowest inhibition zone was produced by endophytic bacterial isolates Pseudomonasgessardii (4.85) and Bacillus licheniformis (1.35). Among the tested antagonist bacterialisolates, 10 isolates were positive for the production of α-amylase, 7 isolates positivefor phosphate solubilization, 29 isolates positive for siderophore production, 11isolates positive for protease production. All selected bacterial isolates produced IAAand ammonia in relatively varying amounts. P. gessardii produced a relatively largeamount of extracellular siderophore (5.83), Exiguobacterium sp. produced a relativelylarge amount of extracellular protease (5.25), P. gessardii and O. anthropi produceda relatively large amount of extracellular IAA (161.39 μg/ml) and Acinetobactercalcoaceticus produced a relatively large amount of phosphatase (2.63). This is thefirst study reporting bean plants harbor endophytes having plant growth promotingactivities with antagonistic potential against Psp.