scholarly journals Need for speed: Bacterial effector XopJ2 is associated with increased of dispersal velocity of Xanthomonas perforans

Author(s):  
Anuj Sharma ◽  
Sujan Timilsina ◽  
Peter Abrahamian ◽  
Gerald V. Minsavage ◽  
James Colee ◽  
...  
2016 ◽  
Vol 106 (10) ◽  
pp. 1097-1104 ◽  
Author(s):  
Sujan Timilsina ◽  
Peter Abrahamian ◽  
Neha Potnis ◽  
Gerald V. Minsavage ◽  
Frank F. White ◽  
...  

Bacterial disease management is a challenge for modern agriculture due to rapid changes in pathogen populations. Genome sequences for hosts and pathogens provide detailed information that facilitates effector-based breeding strategies. Tomato genotypes have gene-for-gene resistance to the bacterial spot pathogen Xanthomonas perforans. The bacterial spot populations in Florida shifted from tomato race 3 to 4, such that the corresponding tomato resistance gene no longer recognizes the effector protein AvrXv3. Genome sequencing showed variation in effector profiles among race 4 strains collected in 2006 and 2012 and compared with a race 3 strain collected in 1991. We examined variation in putative targets of resistance among Florida strains of X. perforans collected from 1991 to 2006. Consistent with race change, avrXv3 was present in race 3 strains but nonfunctional in race 4 strains due to multiple independent mutations. Effectors xopJ4 and avrBs2 were unchanged in all strains. The effector avrBsT was absent in race 3 strains collected in the 1990s but present in race 3 strains collected in 2006 and nearly all race 4 strains. These changes in effector profiles suggest that xopJ4 and avrBsT are currently the best targets for resistance breeding against bacterial spot in tomato.


Plant Disease ◽  
2019 ◽  
Vol 103 (1) ◽  
pp. 147-147
Author(s):  
P. Abrahamian ◽  
J. M. Klein ◽  
J. B. Jones ◽  
G. E. Vallad ◽  
R. A. Melanson

2009 ◽  
Vol 99 (9) ◽  
pp. 1037-1044 ◽  
Author(s):  
Matthew D. Robbins ◽  
Audrey Darrigues ◽  
Sung-Chur Sim ◽  
Mohammed Abu Taher Masud ◽  
David M. Francis

Bacterial spot of tomato is caused by four species of Xanthomonas. The accession PI 128216 (Solanum pimpinellifolium) displays a hypersensitive reaction (HR) to race T3 strains (predominately Xanthomonas perforans). We developed an inbred backcross (IBC) population (BC2S5, 178 families) derived from PI 128216 and OH88119 (S. lycopersicum) as the susceptible recurrent parent for simultaneous introgression and genetic analysis of the HR response. These IBC families were evaluated in the greenhouse for HR to race T3 strain Xcv761. The IBC population was genotyped with molecular markers distributed throughout the genome in order to identify candidate loci conferring resistance. We treated the IBC population as a hypothesis forming generation to guide validation in subsequent crosses. Nonparametric analysis identified an association between HR and markers clustered on chromosome 11 (P < 0.05 to 0.0001) and chromosome 6 (0.04 > P > 0.002). Further analysis of the IBC population suggested that markers on chromosome 6 and 11 failed to assort independently, a phenomenon known as gametic phase disequilibrium. Therefore, to validate marker-trait linkages, resistant IBC plants were crossed with OH88119 and BC3F2 progeny were evaluated for HR in the greenhouse. In these subsequent populations, the HR response was associated with the chromosome 11 markers (P < 0.0002) but not with the markers on chromosome 6 (P > 0.25). Independent F2 families were developed by crossing resistant IBC lines to OH8245, OH88119, and OH7530. These populations were genotyped, organized into classes based on chromosome 11 markers, and evaluated for resistance in the field. The PI 128216 locus on chromosome 11 provided resistance that was dependent on gene dosage and genetic background. These results define a single locus, Rx-4, from PI 128216, which provides resistance to bacterial spot race T3, has additive gene action, and is located on chromosome 11.


2019 ◽  
Vol 10 ◽  
Author(s):  
Sujan Timilsina ◽  
Juliana A. Pereira-Martin ◽  
Gerald V. Minsavage ◽  
Fernanda Iruegas-Bocardo ◽  
Peter Abrahamian ◽  
...  

Molecules ◽  
2019 ◽  
Vol 24 (10) ◽  
pp. 1932 ◽  
Author(s):  
Qingchun Liu ◽  
Kang Qiao ◽  
Shouan Zhang

Carvacrol, a plant-derived volatile small molecule, is effective against various agents that can cause damage to humans, the food processing industry, and plants, and is considered a safe substance for human consumption. In this short communication, previous studies on the effectiveness of carvacrol against various agents, particularly plant pathogens and their associated mechanisms are described. In our study, carvacrol was found to be effective on media against several soilborne pathogens and in planta against three foliar pathogens (Xanthomonas perforans, Alternaria tomatophila, and Podosphaeraxanthii) of important vegetable crops in south Florida of the United States. Current research findings indicated that the effectiveness of carvacrol against various plant pathogens tested was associated with its direct bactericidal/fungicidal effect, which was affected greatly by its volatility. Development of new formulations to overcome the volatility and to prolong the effectiveness of carvacrol was also presented. Our studies on carvacrol suggested that, with advanced development of new formulations, carvacrol could be used as a promising tool in the integrated pest management for bacterial, fungal, and viral pathogens of important vegetable crops in Florida, the USA, and the world.


2020 ◽  
Vol 21 (11) ◽  
pp. 4070
Author(s):  
Rui Shi ◽  
Dilip R. Panthee

Bacterial spot (BS) is one of the most devastating foliar bacterial diseases of tomato and is caused by multiple species of Xanthomonas. We performed the RNA sequencing (RNA-Seq) analysis of three tomato lines with different levels of resistance to Xanthomonas perforans race T4 to study the differentially expressed genes (DEGs) and transcript-based sequence variations. Analysis between inoculated and control samples revealed that resistant genotype Solanum pimpinellifolium accession PI 270443 had more DEGs (834), followed by susceptible genotype tomato (S. lycopersicum L) breeding line NC 714 (373), and intermediate genotype tomato breeding line NC 1CELBR (154). Gene ontology (GO) terms revealed that more GO terms (51) were enriched for upregulated DEGs in the resistant genotype PI 270443, and more downregulated DEGs (67) were enriched in the susceptible genotype NC 714. DEGs in the biotic stress pathway showed more upregulated biotic stress pathway DEGs (67) for PI 270443 compared to more downregulated DEGs (125) for the susceptible NC 714 genotype. Resistant genotype PI 270443 has three upregulated DEGs for pathogenesis-related (PR) proteins, and susceptible genotype NC 714 has one downregulated R gene. Sequence variations called from RNA-Seq reads against the reference genome of susceptible Heinz 1706 showed that chr11, which has multiple reported resistance quantitative trait loci (QTLs) to BS race T4, is identical between two resistant lines, PI 270443 and NC 1CELBR, suggesting that these two lines share the same resistance QTLs on this chromosome. Several loci for PR resistance proteins with sequence variation between the resistant and susceptible tomato lines were near the known Rx4 resistance gene on chr11, and additional biotic stress associated DEGs near to the known Rx4 resistance gene were also identified from the susceptible NC 714 line.


2015 ◽  
Vol 143 (3) ◽  
pp. 543-548 ◽  
Author(s):  
Edivânio R. Araújo ◽  
Josineide R. Costa ◽  
Nadson C. Pontes ◽  
Alice Maria Quezado-Duval

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