Race-specificity in interactions betweenCucumis melogermplasm andPseudoperonospora cubensis

2017 ◽  
pp. 203-210 ◽  
Author(s):  
A. Lebeda ◽  
E. Křístková ◽  
B. Sedláková ◽  
J. Stěpánková ◽  
M.P. Widrlechner
Keyword(s):  
2005 ◽  
Vol 18 (3) ◽  
pp. 220-228 ◽  
Author(s):  
Shavannor M. Smith ◽  
Scot H. Hulbert

Genes at the maize Rpl rust resistance complex often mispair in meiosis, which allows genes to recombine unequally, creating recombinant haplotypes. Four recombinant haplotypes were identified from progeny of an Rpl-D/Rpl-I heterozygote that conferred a nonparental resistance specificity designated Rpl-I*. Sequence comparisons of paralogs in the recombinant and parental haplotypes demonstrated that all four recombinants were derived from intergenic (between gene) recombination events. The sequence of paralogs in the HRpl-I parental haplotype indicated this haplotype includes 41 or more rpl genes, at least 31 of which are transcribed. The results indicate that most of the novel resistance specificities that have arisen spontaneously at Rp1 are the result of reassortment of existing Rpl genes.


Author(s):  
DALLICE MILLS ◽  
CARLOS F. GONZALEZ
Keyword(s):  

2005 ◽  
Vol 18 (12) ◽  
pp. 1306-1317 ◽  
Author(s):  
Adriana Castañeda ◽  
Joseph D. Reddy ◽  
Basma El-Yacoubi ◽  
Dean W. Gabriel

Suppression subtractive hybridization (SSH) was used to identify genes present in the systemic crucifer black rot pathogen Xanthomonas campestris pv. campestris 528T but missing from the nonsystemic crucifer leaf spot pathogen, X. campestris pv. armoraciae 417. Among the DNA fragments unique to 528T was Xcc2109, one of eight putative avr genes identified in the published 528T genome (NC_003902). Individual and sequential deletion, insertion mutations, or both of all eight 528T avr gene loci were made, but no change in pathogenicity was observed with any combination of avr mutations, including a strain with all eight avr genes deleted. However, insertion or deletion mutants affecting the Xcc2109 locus lost avirulence (i.e., became virulent) on Florida Mustard, an X. campestris pv. campestris race-determining, differential host. The Xcc2109 open reading frame as annotated was cloned and found to be nonfunctional. A longer gene, encompassing Xcc2109 and here designated avrXccFM, was cloned and found to complement the Xcc2109 mutants and to confer avirulence to two additional wild-type X. campestris pv. campestris strains, thereby changing their races. Resistance in Florida Mustard to 528T strains carrying avrXccFM occurred without a typical hypersensitive response (HR) on leaves, although a vascular HR was observed in seedlings.


Souls ◽  
2006 ◽  
Vol 8 (2) ◽  
pp. 55-76
Author(s):  
Lorenzo Morris ◽  
Donn G. Davis

Euphytica ◽  
1988 ◽  
Vol 39 (2) ◽  
pp. 167-174 ◽  
Author(s):  
M. J. Havey ◽  
J. C. Faria ◽  
D. P. Maxwell ◽  
D. J. Hagedorn

2015 ◽  
Vol 105 (8) ◽  
pp. 1104-1113 ◽  
Author(s):  
Angela Feechan ◽  
Marianna Kocsis ◽  
Summaira Riaz ◽  
Wei Zhang ◽  
David M. Gadoury ◽  
...  

The Toll/interleukin-1 receptor nucleotide-binding site leucine-rich repeat gene, “resistance to Uncinula necator 1” (RUN1), from Vitis rotundifolia was recently identified and confirmed to confer resistance to the grapevine powdery mildew fungus Erysiphe necator (syn. U. necator) in transgenic V. vinifera cultivars. However, sporulating powdery mildew colonies and cleistothecia of the heterothallic pathogen have been found on introgression lines containing the RUN1 locus growing in New York (NY). Two E. necator isolates collected from RUN1 vines were designated NY1-131 and NY1-137 and were used in this study to inform a strategy for durable RUN1 deployment. In order to achieve this, fitness parameters of NY1-131 and NY1-137 were quantified relative to powdery mildew isolates collected from V. rotundifolia and V. vinifera on vines containing alleles of the powdery mildew resistance genes RUN1, RUN2, or REN2. The results clearly demonstrate the race specificity of RUN1, RUN2, and REN2 resistance alleles, all of which exhibit programmed cell death (PCD)-mediated resistance. The NY1 isolates investigated were found to have an intermediate virulence on RUN1 vines, although this may be allele specific, while the Musc4 isolate collected from V. rotundifolia was virulent on all RUN1 vines. Another powdery mildew resistance locus, RUN2, was previously mapped in different V. rotundifolia genotypes, and two alleles (RUN2.1 and RUN2.2) were identified. The RUN2.1 allele was found to provide PCD-mediated resistance to both an NY1 isolate and Musc4. Importantly, REN2 vines were resistant to the NY1 isolates and RUN1REN2 vines combining both genes displayed additional resistance. Based on these results, RUN1-mediated resistance in grapevine may be enhanced by pyramiding with RUN2.1 or REN2; however, naturally occurring isolates in North America display some virulence on vines with these resistance genes. The characterization of additional resistance sources is needed to identify resistance gene combinations that will further enhance durability. For the resistance gene combinations currently available, we recommend using complementary management strategies, including fungicide application, to reduce populations of virulent isolates.


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