Systematic analysis of xanthomonads (Xanthomonas spp.) associated with pepper and tomato lesions.

Abstract

The taxonomy and evolutionary relationships among members of the genus Xanthomonas associated with tomato and pepper have been a matter of considerable controversy since their original description in 1921. These bacteria, which are a major affliction of tomato and pepper crops in warm and humid regions, were originally described as a single species, but subsequent research has shown the existence of at least two genetic groups differentiated by physiological, biochemical and pathological characteristics. This work synthesizes the findings from several approaches, including pathogenicity tests, enzymic activity, restriction fragment analysis of the entire genome, DNA-DNA hybridization and RNA sequence comparisons based on a 2097 base sequence comprising the 16S rRNA gene, the intergenic spacer located between the 16S and 23S rRNA genes and a small region of the 23S rRNA gene. Within the group of xanthomonads pathogenic on pepper and tomato four distinct phenotypic groups exist, of which three form distinct genomic species. These include Xanthomonas axonopodis pv. vesicatoria (A and C group), Xanthomonas vesicatoria (B group) and Xanthomonas gardneri (D group). On the basis of phenotypic and genotypic differences between A-and C-group strains, the C strains should be considered as a subspecies within Xanthomonas axonopodis pv. vesicatoria.

Herança da resistência à mancha-bacteriana em tomateiro

“…Divisão esta, não aceita por Schaad et al (2000), Young et al (1996), que propuseram a classificação de X. campestris pv. vesicatoria para o grupo A e X. exitiosa (Valterin et al, 1995) para o grupo B. Recentemente, Jones et al(2000), após realizar estudos, incluindo testes de patogenicidade atividade enzimática, marcadores genéticos, hibridização DNA-DNA e comparação de seqüências de RNA, concluiu que dentro do grupo das Xanthomonas patogênicas ao tomate e pimentão existem quatro grupos fenotípicos distintos, os quais apresentam três espécies genéticas diferentes, a saber: X. axonopodis pv. vesicatoria (grupos A e C), X. vesicatoria (grupo B -raça T2) e X. gardneri (ex Sutic 1957) Jones et al 2000, sp.…”

A genetic screen to isolate type III effectors translocated into pepper cells during Xanthomonas infection

“…Xcv 75-3 and Xcv 81-18 are closely related to Xcv 85-10, because all three strains are pepper race 2, tomato race 1, and serovar A. Xcv 81-23, Xcv 81-18, Xcv 597, and Xcv 82-8 are also serovar A strains, but they are different pepper or tomato races. Xcv 71-4 and Xcv 81-6 are both in serovar B, Xv 938 in serovar C, and Xv 444 in serovar D (38). X. axonopodis pv.…”

“…Xanthomonas spp. have been grouped according to the following traits: phenotype on different plant cultivars (36), amylolitic activity designated as serovars A-D (37), and 16S rRNA nucleotide homology (38). Xcv 75-3 and Xcv 81-18 are closely related to Xcv 85-10, because all three strains are pepper race 2, tomato race 1, and serovar A. Xcv 81-23, Xcv 81-18, Xcv 597, and Xcv 82-8 are also serovar A strains, but they are different pepper or tomato races.…”

PM 7/110 (1) Xanthomonas spp. (Xanthomonas euvesicatoria, Xanthomonas gardneri, Xanthomonas perforans, Xanthomonas vesicatoria) causing bacterial spot of tomato and sweet pepper

“…Groups A and C were briefly transferred to Xanthomonas axonopodis pv. vesicatoria, largely on the basis of DNA homology among a large but incomplete collection of xanthomonads (Vauterin et al, 1995;Jones et al, 2000) while group B was clearly separated at species level as X. vesicatoria. Group D strains, originally identified in the former Yugoslavia ( Sutic, 1957) and including identical strains from Costa Rica, maintained species status as X. gardneri (Jones et al, 2004).…”