Molecular genetics of race-specific resistance of cowpea to Striga gesnerioides (Willd.)

• Published in: Pest management science Vol. 65; no. 5; pp. 520 - 527
• Main Authors: Li, Jianxiong, Lis, Karolina E, Timko, Michael P
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.05.2009; Wiley; Wiley Subscription Services, Inc
• Subjects: Africa, Sub-Saharan; Alectra; Alectra vogelii; Biological and medical sciences; biological resistance; Central Africa; chromosome mapping; cowpea; cowpeas; Disease resistance; Fabaceae; Fabaceae - genetics; Fabaceae - physiology; field crops; Flowers & plants; Fundamental and applied biological sciences. Psychology; gene expression; Gene Expression Regulation, Plant; genes; Genetic diversity; genetic improvement; Genetic markers; genetic resistance; genetic variation; Genetics; host plants; Host-Parasite Interactions; Legumes; linkage groups; metabolism; molecular markers; molecular sequence data; Molecules; nucleotide sequences; parasitic plant; Parasitic plants; Parasitic plants. Weeds; Parasitism; parasitology; phenotype; Phenotypes; physiology; Phytopathology. Animal pests. Plant and forest protection; plant breeding; Plant Diseases; Plant Diseases - genetics; Plant Diseases - parasitology; plant hormones; Plant Proteins; Plant Proteins - genetics; Plant Proteins - metabolism; Plant reproduction; Plant resistance; races; roots; salicylic acid; sequence-confirmed amplified regions; Signal transduction; Species Specificity; Stover; Striga; Striga - physiology; Striga gesnerioides; Subsistence agriculture; Tropical environments; tropics; Vigna unguiculata; Western Africa; Western Africa; Central Africa; Sub-Saharan Africa; West Africa; Africa, Sub-Saharan; Vigna unguiculata; Cowpea; Molecular marker; Striga gesnerioides; Grain legume; Disease resistance; Leguminosae; Dicotyledones; Angiospermae; Scrophulariaceae; Genetics; Spermatophyta; Molecular biology; molecular markers; Parasitic plant; Specific resistance
• ISSN: 1526-498X; 1526-4998; 1526-4998
• DOI: 10.1002/ps.1722

Cowpea, Vigna unguiculata (L.) Walp., is an important warm-season legume grown primarily in the semi-arid tropics. The majority of cowpea is grown by subsistence farmers in West and Central sub-Saharan Africa, where its grain and leaves are valued as human food and its stover is used for animal forage. Like all crop plants, cowpea is subject to yield losses resulting from a variety of biotic and abiotic stresses. Among the important biotic constraints to cowpea production is parasitism by the root hemiparasitic weeds Striga gesnerioides (Willd.) [witchweed] and Alectra vogelii (Benth.). At least seven races of S. gesnerioides have been identified within the cowpea-growing regions of West Africa, based on host differential response and genetic diversity analysis. Several race-specific resistance genes have been identified and located to one of two linkage groups (LG1 and LG6) of the current cowpea genetic map. Molecular markers associated with race-specific resistance genes have been identified, and several sequence-confirmed amplified regions (SCARs) have been developed for use in marker-assisted selection and breeding strategies for rapid cowpea improvement. The mechanism of race-specific resistance in the cowpea-Striga interaction has also been examined, with several genes involved in phytohormone and general disease resistance signaling transduction observed to be differentially expressed in resistant and susceptible phenotypes. Results suggest that PR5 expression may be a useful marker of Striga infection, and that salicylic acid signaling appears to play a role in the cowpea-Striga interaction.