The Presence of Regions Homologous to hrp Cluster in Pseudomonas fluorescens PfG32R

Abstract

Pseudomonas fluorescens PfG32R, which was shown to be able to suppress the occurrence of bacterial wilt of tomato (BWT), conserves the regions homologous to hrpRS and hrpF of P. syringae pv. phaseolicola and also to hrpC and hrpD of P. s. pv. tabaci but at lower degree. Infiltration of PfG32R into leaves of tobacco or of bean at a high concentration (10⁸cfu/ml) was shown to increase the specific activity of phenylalanine ammonia lyase (PAL) in these plants. Furthermore, when PfG32R was inoculated into leaves of tobacco or of bean with a low bacterial concentration, the level of population increased in the first day from 2×10³ to 1.8×10⁴cfu/leaf disk and it was maintained at a slightly lower level thereafter. This population level was higher comparing to the case of inoculation of plant-unrelated bacterium (Escherichia coli MV118), though it was slightly lower than the level of population in the cases of inoculation of plant pathogenic bacteria, P. s. pv. glycinea and P. solanacearum.