DIVERSITY OFRALSTONIA SOLANACEARUMPOPULATIONS AFFECTING TOBACCO CROPS IN NORTH CAROLINA

Abstract

One hundred eighty four strains of Ralstonia solanacearum isolated in 2007 and 2008 from 11 tobacco fields in North Carolina were evaluated for genotypic diversity and aggressiveness. All strains were race 1, biovar 1, and belonged to phylotype II. Genetic diversity of the strains was assessed with the use of repetitive sequence-based polymerase chain reaction. DNA primers (REP, ERIC, and BOX) were used to generate genomic fingerprints. Both REP and BOX revealed 3 patterns: A r , C r , and D r and A b , C b , and D b , respectively. Five patterns were identified with ERIC-PCR. Pattern A e was found in 80% of the strains collected. Pattern B e was in 4%, pattern C e in 13%, pattern D e in 2%, and pattern E e in 1% of the strains collected. Cluster analyses showed that the strains were 88% similar and constitute a rather homogeneous group. Aggressiveness of strains was evaluated on 3 tobacco cultivars with different levels of resistance to bacterial wilt. Overall, aggressiveness depended on the field from which the strains were collected. Within a field there was a significant difference (P , 0.0001) in aggressiveness among strains. Differences in aggressiveness were significantly associated (P , 0.0001) to genotypic patterns. In fields where patterns A and C were found, strains of pattern A were the most aggressive, whereas in fields with patterns B, C, and E, strains of pattern E were the most aggressive.

Effect of temperature and resistance of tobacco cultivars to the progression of bacterial wilt, caused by Ralstonia solanacearum

“…Bocsanczy et al (2012) found R. solanacearum strains from tomato that were able to produce wilt symptoms at 18°C in Florida. Our growth chamber study indicated that a minimum temperature of 15°C is required for BW symptom development in tobacco cultivars with R. solanacearum strains of phylotype II collected from North Carolina (Katawczik et al 2016). Thus R. solanacearum strains may exhibit variable level of infection efficacy based on the location of isolation and other geographic factors that determine adaptability as suggested by Bocsanczy et al (2012).…”

“…Bacterial strains and inoculum preparation R. solanacearum strains 4, 7, 25, and 46 previously characterized as race 1 biovar 1 phylotype II (Katawczik et al 2016;Katawczik and Mila 2012), were used. All strains were collected in North Carolina in 2007 from stems of diseased tobacco plants by isolating on tetrazolium chloride medium (TZC) (Kelman 1954) and stored in 20 % glycerol at −80°C.…”

“…Strains 25 and 46 were isolated from cultivars K346 and K394, respectively, in Johnston County. Strains were selected for their varying levels of virulence (Katawczik et al 2016). For the histological studies, strain AW1-gfp38, which expresses a modified green fluorescent protein (GFP-mut2), was used (Liu et al 2001).…”

Genetic diversity and aggressiveness of Erwinia psidii on Eucalyptus spp. in Brazil

“…Among them, repetitive element sequence (rep)-based PCR, based on repetitive extragenic palindromic sequences (REP-PCR), enterobacterial repetitive intergenic consensus sequences (ERIC-PCR) and BOX elements (BOX-PCR) use primers to amplify conserved repetitive DNA sequences present in Gram-negative bacteria. In addition to unveiling interspecific diversity, these repetitive elements are useful for elucidating relationships within bacterial species because their fingerprints are conserved at the pathovar and strain intraspecific levels (Katawczik et al, 2016;Zulperi et al, 2016).…”

A Practical Guide to Visualization and Statistical Analysis of R. solanacearum Infection Data Using R

“…I will limit myself to analysis which can be derived from the one definition of the Disease Index (see Material and Methods), however, different definitions have been used in the literature. For example, Katawczik et al (2016) use a weighted measurement of disease incidence and perform an analysis in a generalized linear framework.…”