Arabidopsis thaliana: A source of candidate disease-resistance genes for Brassica napus

Genome ◽  
2000 ◽  
Vol 43 (3) ◽  
pp. 452-460 ◽  
Author(s):  
D Sillito ◽  
I AP Parkin ◽  
R Mayerhofer ◽  
D J Lydiate ◽  
A G Good
Keyword(s):  
Arabidopsis Thaliana ◽  
Disease Resistance ◽  
Brassica Napus ◽  
Resistance Genes ◽  
Plant Disease Resistance ◽  
Disease Resistance Genes ◽  
R Gene ◽  
R Genes ◽  
Rapid Divergence ◽  
Genomic Regions

Common structural and amino acid motifs among cloned plant disease-resistance genes (R genes), have made it possible to identify putative disease-resistance sequences based on DNA sequence identity. Mapping of such R-gene homologues will identify candidate disease-resistance loci to expedite map-based cloning strategies in complex crop genomes. Arabidopsis thaliana expressed sequence tags (ESTs) with homology to cloned plant R genes (R-ESTs), were mapped in both A. thaliana and Brassica napus to identify candidate R-gene loci and investigate intergenomic collinearity. Brassica R-gene homologous sequences were also mapped in B. napus. In total, 103 R-EST loci and 36 Brassica R-gene homologous loci were positioned on the N-fo-61-9 B. napus genetic map, and 48 R-EST loci positioned on the Columbia × Landsberg A. thaliana map. The mapped loci identified collinear regions between Arabidopsis and Brassica which had been observed in previous comparative mapping studies; the detection of syntenic genomic regions indicated that there was no apparent rapid divergence of the identified genomic regions housing the R-EST loci.Key words: RFLP mapping, candidate R genes, R-gene homologues, genomic collinearity, Arabidopsis ESTs.

Arabidopsis thaliana: A source of candidate disease-resistance genes for Brassica napus

Genome ◽  
2000 ◽  
Vol 43 (3) ◽  
pp. 452-460 ◽  
Author(s):  
D. Sillito ◽  
I.A.P. Parkin ◽  
R. Mayerhofer ◽  
D.J. Lydiate ◽  
A.G. Good
Keyword(s):  
Arabidopsis Thaliana ◽  
Disease Resistance ◽  
Brassica Napus ◽  
Resistance Genes ◽  
Disease Resistance Genes

Organization, Expression and Evolution of a Disease Resistance Gene Cluster in Soybean

Genetics ◽  
2002 ◽  
Vol 162 (4) ◽  
pp. 1961-1977
Author(s):  
Michelle A Graham ◽  
Laura Fredrick Marek ◽  
Randy C Shoemaker
Keyword(s):  
Disease Resistance ◽  
Resistance Gene ◽  
Resistance Genes ◽  
Developmental Stages ◽  
Gene Evolution ◽  
Pcr Amplification ◽  
Disease Resistance Genes ◽  
Disease Resistance Gene ◽  
R Genes ◽  
Specific Primers

Abstract PCR amplification was previously used to identify a cluster of resistance gene analogues (RGAs) on soybean linkage group J. Resistance to powdery mildew (Rmd-c), Phytophthora stem and root rot (Rps2), and an ineffective nodulation gene (Rj2) map within this cluster. BAC fingerprinting and RGA-specific primers were used to develop a contig of BAC clones spanning this region in cultivar “Williams 82” [rps2, Rmd (adult onset), rj2]. Two cDNAs with homology to the TIR/NBD/LRR family of R-genes have also been mapped to opposite ends of a BAC in the contig Gm_Isb001_091F11 (BAC 91F11). Sequence analyses of BAC 91F11 identified 16 different resistance-like gene (RLG) sequences with homology to the TIR/NBD/LRR family of disease resistance genes. Four of these RLGs represent two potentially novel classes of disease resistance genes: TIR/NBD domains fused inframe to a putative defense-related protein (NtPRp27-like) and TIR domains fused inframe to soybean calmodulin Ca2+-binding domains. RT-PCR analyses using gene-specific primers allowed us to monitor the expression of individual genes in different tissues and developmental stages. Three genes appeared to be constitutively expressed, while three were differentially expressed. Analyses of the R-genes within this BAC suggest that R-gene evolution in soybean is a complex and dynamic process.

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