A review of angular leaf spot resistance in common bean

Authors: NAY, MICHELLE - Eth Zurich; SOUZA, THIAGO - Embrapa; RAATZ, BODO - International Center For Tropical Agriculture (CIAT); MUKANKUSI, CLARE - International Center For Tropical Agriculture (CIAT); GONCALVES-VIDIGAL, MARIA - Universidade Estadual De Maringá; Pastor Corrales, Marcial

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/11/2019
Publication Date: 6/4/2019
Citation: Nay, M.M., Souza, T., Raatz, B., Mukankusi, C.M., Goncalves-Vidigal, M.C., Pastor Corrales, M.A. 2019. A review of angular leaf spot resistance in common bean. Crop Science. 59:1376-1391. https://doi.org/10.2135/cropsci2018.09.0596.
DOI: https://doi.org/10.2135/cropsci2018.09.0596

Interpretive Summary: Angular leaf spot (ALS) is major disease that reduces yield and seed quality of common bean in the Americas and Africa. Common bean varieties with resistance to ALS represent the most cost-effective strategy to manage this disease. However, developing varieties with effective ALS resistance is difficult due to the changing virulence of the pathogen. When new virulent strains have appeared, previously resistant varieties have become susceptible. An effective and durable strategy requires multi-layered knowledge of the pathogen, of the common bean host, and of the host-pathogen interactions. We examine here the components of a durable strategy for ALS resistance. This review includes an assessment of the extensive virulence diversity of the ALS pathogen in the Americas and Africa, of the existing genes conferring resistance to ALS, and of the DNA markers linked to these genes for use in resistance breeding. We also consider how new DNA technologies could facilitate and accelerate ALS resistance breeding. This information is of high value to government, commercial, and university scientists working in breeding programs aiming to develop common bean cultivars with durable ALS resistance.

Technical Abstract: Angular leaf spot (ALS), caused by Pseudocercospora griseola, is one of the most devastating diseases of common bean in tropical and subtropical production areas. Breeding for ALS resistance is difficult due to the extensive virulence diversity of P. griseola and the recurrent appearance of new virulent races. Five major loci, Phg-1 to Phg-5, conferring ALS resistance have been named and tightly linked markers reported. Quantitative trait loci (QTL) have also been reported, but the validation of some QTLs is still pending. The Phg-1, Phg-4, and Phg-5 loci are from the Andean gene pool whereas Phg-2 and Phg-3 are from the Mesoamerican gene pool. The reference genome of common bean and high-throughput sequencing technologies are enabling the development of molecular markers tightly linked to the Phg loci, more accurate mapping of the resistance loci, and the comparison of their genomic positions. The objective of this report is to provide a comprehensive review of ALS resistance in common bean. We are also reporting three case studies of ALS resistance breeding in Latin America and Africa. This review will serve as a reference for future resistance mapping studies and as a guide for the selection of resistance loci in breeding programs aiming to develop common bean cultivars with durable ALS resistance.