A Pseudomonas viridiflava-related bacterium causes a dark-reddish spot disease in Glycine max

Abstract

A virulent Pseudomonas viridiflava-related bacterium has been identified as a new pathogen of soybean, one of the most important crops worldwide. The bacterium was recovered from forage soybean leaves with dark-reddish spots, and damage on petioles and pods was also observed. In contrast, common bean was not affected.

Fig 1

Phylogenetic consensus tree of the soybean Pseudomonas strains based on the nucleotide sequences of the 16S rRNA, rpoD, gyrB, and gltA genes. The scale bar represents the number of substitutions per site. The number shown next to each node indicates the percent bootstrap values of 1,000 replicates. Sequences from Erwinia amylovora were treated as the outgroup. The topological characteristics of the phylogenetic trees produced for individual genes were almost identical (data not shown). P.s., P. syringae.

Fig 2

PFGE and RAPD analysis of soybean strains. (A) PFGE using PmeI and SwaI. Lane 1, Pseudomonas syringae pv. syringae CECT 4429; lane 2, LPPA 221; lane 3, LPPA 222; lane 4, LPPA 223; lane 5, Pseudomonas viridiflava CECT 458; lane S, Salmonella enterica serovar Braenderup H9812 digested with XbaI; lane L, lambda ladder PFG marker (New England BioLabs); the last two are used as size standards. (B) RAPD analysis performed with the indicated primers. Lane M, 50- to 2,000-bp BioMarker EXT size marker (Bioventures Inc., Murfreesboro, TN); lane 1, Pseudomonas syringae pv. syringae CECT 4429; lane 2, LPPA 221; lane 3, LPPA 222; lane 4, LPPA 223; lane 5, Pseudomonas viridiflava CECT 458.

Fig 3

Bacterial dark-reddish spot disease in soybean. Healthy leaves inoculated with sterile water (A) and damage in leaves (B), petioles (C), or pods (D) caused by strain LPPA 223 are shown.