|VALENTINI, GISELI - Universidade Estadual De Maringá|
|GONCALVES-VIDIGAL, MARIA CELESTE - Universidade Estadual De Maringá|
|CREGAN, PERRY - Retired ARS Employee|
|Pastor Corrales, Marcial - Talo|
Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/4/2017
Publication Date: 5/30/2017
Citation: Valentini, G., Goncalves-Vidigal, M., Cregan, P., Song, Q., Pastor Corrales, M.A. 2017. High-resolution mapping reveals linkage between genes in common bean cultivar Ouro Negro conferring resistance to the rust, anthracnose, and angular leaf spot diseases. Theoretical and Applied Genetics. doi: 10.1007/s00122-017-2920-6.
Interpretive Summary: Rust, Anthracnose, and angular leaf spot are among the most devastating diseases of common bean in the world and most particularly in the Americas and Africa, which are the largest common bean production regions of the world. The black-seeded Ouro Negro dry bean cultivar is unique because it is resistant to all three diseases. We have conducted studies showing that the resistance in Ouro Negro to the rust, anthracnose and angular leaf spot diseases is conferred by three different single and dominant genes. Our studies also showed that these genes provide effective resistance to numerous strains of the highly variable fungal pathogens that cause these diseases. In a recent study, we used conventional and next generation sequencing technologies to show that these genes are located very close to each other in the fourth chromosome of the common bean. Moreover, these technologies made it possible to map the location of these genes in the genome of common bean. Our study showed that these genes are inherited together. We then developed molecular markers to tag each of these genes. The results from these studies showed that the newly discovered DNA markers are closely associated with each of the three genes, indicating that they can be very effective for transferring all three genes into cultivars grown in farmer’s fields. Common bean breeders will also benefit from these results.
Technical Abstract: Rust, Anthracnose, and angular leaf spot are major diseases of common bean in the world and most particularly in the Americas and Africa, which are the largest common bean production regions of the world. The Mesoamerican black-seeded cultivar Ouro Negro is unusual in that it has resistance to all three diseases. Ouro Negro has the Ur-14 gene that confers broad spectrum resistance to rust and it has the gene cluster Co-34/Phg-3 which contains two tightly linked genes with resistance to ANT and ALS, respectively. In this study, we demonstrate the genetic linkage between Ur-14 and Co-34/Phg-3. A co-segregation analysis of 105 F2:3 families from a cross of Rudá (susceptible) × Ouro Negro (resistant), phenotyped separately for their reactions to the rust and anthracnose pathogens, showed that the single and dominant Ur-14 and Co-34 genes in Ouro Negro conferred resistance to rust and anthracnose and that Ur-14 and Co-34/Phg-3 were closely linked. Genotyping the 105 F2:3 families first with 5399 single nucleotide polymorphism markers on the Illumina BeadChip BARCBEAN6K_3 and then with 18 single sequence repeat (SSR) markers specifically designed for the candidate region containing Ur-14 and Co-34/Phg-3, revealed that Ur-14 was positioned at 0.5 cM from Co-34/Phg-3 at the end of chromosome Pv04 in the common bean genome. The close proximity of six SSR markers to the Ur-14 gene and eight SSR markers to the Co-34/Phg-3 cluster, illustrate the great potential utility of these markers for the development of cultivars with resistance to three very destructive diseases of common.