Mapping EST-derived SSRs and ESTs involved in resistance to bacterial blight in Manihot esculenta.
Cassava (Manihot esculenta Crantz) is a major root crop widely grown in the tropics. Cassava bacterial blight, caused by Xanthomonas axonopodis pv. manihotis (Xam), is an important disease in Latin America and Africa resulting in significant losses. The preferred control method is the use of resistant genotypes. Mapping expressed sequence tags (ESTs) and determining their co-localization with quantitative trait loci (QTLs) may give additional evidence of the role of the corresponding genes in resistance or defense. Twenty-one EST-derived simple sequence repeats (SSRs) were mapped in 16 linkage groups. ESTs showing similarities with candidate resistance genes or defense genes were also mapped using strategies such as restriction fragment length polymorphisms, cleaved amplified polymorphic sequences, and allele-specific primers. In total, 10 defense-related genes and 2 bacterial artificial chromosomes (BACs) containing resistance gene candidates (RGCs) were mapped in 11 linkage groups. Two new QTLs associated with resistance to Xam strains CIO121 and CIO151 were detected in linkage groups A and U, respectively. The QTL in linkage group U explained 61.6% of the phenotypic variance and was associated with an RGC-containing BAC. No correlation was found between the new EST-derived SSRs or other mapped ESTs and the new or previously reported QTLs.
López
Camilo E
CE
Laboratoire Génome et Développement des Plantes, UMR 5096, Institut de recherche pour le développement /CNRS / Université de Perpignan, Centre IRD, 911, avenue Agropolis BP 64501, 34394 Montpellier cedex 5, France.
Quesada-Ocampo
Lina M
LM
Bohórquez
Adriana
A
Duque
Myriam Cristina
MC
Vargas
Jaime
J
Tohme
Joe
J
Verdier
Valérie
V
D000483:Alleles; D001483:Base Sequence; D015415:Biomarkers; D002874:Chromosome Mapping; D020224:Expressed Sequence Tags; D017343:Genes, Plant; D005838:Genotype; D002365:Manihot / Q000235:genetics* / Q000382:microbiology; D018598:Minisatellite Repeats; D010935:Plant Diseases / Q000235:genetics / Q000276:immunology*; D012150:Polymorphism, Restriction Fragment Length; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D040641:Quantitative Trait Loci; D019655:Quantitative Trait, Heritable; D014974:Xanthomonas
D015415:Biomarkers