Phytopathogenic Curtobacterium flaccumfaciens Strains Circulating on Leguminous Plants, Alternative Hosts and Weeds in Russia

Abstract

Many bacterial plant pathogens have a broad host range important for their life cycle. Alternate hosts from plant families other than the main (primary) host support the survival and dissemination of the pathogen population even in absence of main host plants. Metabolic peculiarities of main and alternative host plants can affect genetic diversity within and between the pathogen populations isolated from those plants. Strains of Gram-positive bacterium Curtobacterium flaccumfaciens were identified as being causal agents of bacterial spot and wilt diseases on leguminous plants, and other crop and weed plants, collected in different regions of Russia. Their biochemical properties and susceptibility to copper compounds have been found to be relatively uniform. According to conventional PCR assays, all of the isolates studied were categorised as pathovar Curtobacterim flaccumfaciens pv. flaccumfaciens, a pathogen of legumes. However, the strains demonstrated a substantial diversity in terms of virulence on several tested host plants and different phylogenetic relationships were revealed by BOX-PCR and alanine synthase gene (alaS) sequencing.

First Report of Curtobacterium flaccumfaciens in Bulgaria

“…The role of such alternative and alternate host plants as natural reservoirs of this coryneform bacterium is considered of great importance and has recently been the subject of serious investigation. Among them, tomato, bell pepper, eggplant, sunflower, wheat, etc., could be mentioned [ 22 , 23 , 24 ]. In this regard, clarifying the ability of the pathogenic bacteria to persist and survive in various uncommon habitats sheds light on the probability that they will exert their pathogenic potential and expand their host range.…”

“…Over the past few decades, knowledge about the composition of C. flaccumfaciens has accumulated, demonstrating that it is a complex species. In most of the cases, the identification at the species level has been conducted via polyphase approaches based on the comparison of the sequences of 16S rDNA [ 25 , 26 , 27 , 28 , 29 , 30 ], MALDI-ToF MS [ 17 , 28 , 29 ] and PCR methods [ 22 , 23 , 30 ]. The most applied PCR protocols are usually based on amplification with pathovar-specific primers specifically targeting C. flaccumfaciens pv.…”