Insights into genomic and phenotypic comparative analysis of Xanthomonas vesicatoria native strains that cause bacterial spot with different aggressiveness degree on tomato

BIANCO, MI; PONSO, A; GARITA-CAMBRONERO J; CUBERO, J; CONFORTE, VP; DUNGER, G; MORALES, G; VOJNOV, AA; ROMERO, AM; YARYURA, PM

Florida

Conferencia; 7th Xanthomonas genomics conference; 2022

Xanthomonas vesicatoria (Xv) is a member of a complex of species that causes bacterial spot on tomato (Solanum lycopersicum). This disease is generally controlled using copper-based agrochemicals, which contaminate the environment and have led to the emergence ofcopper-resistant Xanthomonas spp. strains. Therefore, to develop sustainable alternative control strategies for bacterial spot, it is essential to understand the pathogenic mechanisms used by these bacteria to infect their hosts. In Argentina, bacterial spot is found in all tomato-producing areas, being Xv one of the main species detected in the fields. Currently, little is known about several virulence factors of Xv. Previously, we isolated three native strains of Xv (BNM208, BNM214 and BNM216) from diseased tomato plants and observed that the most aggressive strain, BNM208, formed a homogeneous, compact and well-structured biofilm and produced a significantly more viscous xanthan than BNM214 and BNM216. Therefore, to elucidate the causes of these differences, we sequenced genomes of the three strains, compared them with each other and with 12 other Xv genomes, and analysis groups of genes encoding virulence factors in other phytopathogenic Xanthomonas spp., focusing our studies on xanthan and T4P. We did not find a difference among thethree strains in the gene cluster encoding xanthan production; however, the microscopicallyobservations of the respective xanthans showed that BNM208 produced molecules longer than BNM214 and BNM216. This could be related to the higher expression of GumC (protein involved in xanthan polymerization) in BNM208 than in BNM214 and BNM216. Moreover, the three strains moved by twitching and contain in their genomes Xac3805-like and XC_3823-like genes (encoding pilins in other Xanthomonas spp.). Interestingly, only BNM208 contains a Xac3241-like gene. Therefore, we suggest it is probably Xac3805-like or XC_3823-like gene could encode the major pilin in Xv, but to confirm this, further studies are required.