Molecular mapping of soybean rust (Phakopsora pachyrhizi) resistance genes: discovery of a novel locus and alleles.
Soybean production in South and North America has recently been threatened by the widespread dissemination of soybean rust (SBR) caused by the fungus Phakopsora pachyrhizi. Currently, chemical spray containing fungicides is the only effective method to control the disease. This strategy increases production costs and exposes the environment to higher levels of fungicides. As a first step towards the development of SBR resistant cultivars, we studied the genetic basis of SBR resistance in five F2 populations derived from crossing the Brazilian-adapted susceptible cultivar CD 208 to each of five different plant introductions (PI 200487, PI 200526, PI 230970, PI 459025, PI 471904) carrying SBR-resistant genes (Rpp). Molecular mapping of SBR-resistance genes was performed in three of these PIs (PI 459025, PI 200526, PI 471904), and also in two other PIs (PI 200456 and 224270). The strategy mapped two genes present in PI 230970 and PI 459025, the original sources of Rpp2 and Rpp4, to linkage groups (LG) J and G, respectively. A new SBR resistance locus, rpp5 was mapped in the LG-N. Together, the genetic and molecular analysis suggested multiple alleles or closely linked genes that govern SBR resistance in soybean.
Garcia
Alexandre
A
State University of Londrina (UEL), Rod. Celso Garcia Cid Km 380, Cx. Postal 6001, CEP 86051-990 Londrina, PR, Brazil.
Calvo
Eberson Sanches
ES
de Souza Kiihl
Romeu Afonso
RA
Harada
Arlindo
A
Hiromoto
Dario Minoru
DM
Vieira
Luiz Gonzaga Esteves
LG
D000483:Alleles; D001487:Basidiomycota / Q000472:pathogenicity*; D002874:Chromosome Mapping; D017343:Genes, Plant; D006824:Hybridization, Genetic; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology*; D013025:Glycine max / Q000235:genetics* / Q000382:microbiology*