Molecular Mapping and Microscopic analysis of Faba Bean- Uromyces viciae-fabae Host-Pathogen Interaction

Abstract

This investigation covered characterisation of various faba bean rust isolates by identifying a differential set in the host; identification of molecular markers linked with rust resistance genes Uvf-2 in Doza#12034 and Uvf-3 in Ac1655 and their validation across diverse backgrounds; and elucidation of the host-pathogen interactions of Uromyces viciae-fabae with faba bean, field pea (Pisum sativum), lentil (Lens culinaris), chickpea (Cicer arietinum), lupin (Lupinus albus and Lupinus angustifolius) and mungbean (Vigna radiata). The differential pathogenicity in the interaction of Vicia faba × Uromyces viciae-fabae led to the identification of nine faba bean rust pathotypes, characterised by the set of twelve genotypes (regarded as differential), and named 0-10, 0-46, 40-31, 40-55, 24-40, 63-53, 63-49, 55-63 and 63-63. This information will help faba bean breeders to carefully deploy rust resistance gene(s) which can effectively insight resistance against pathotypes of targeted environment. Genetic analysis, using pathotype 24-40, revealed monogenic inheritance of rust resistance in faba bean genotypes Doza#12034 and Ac1655, respectively. After genotyping Fiord/Doza#12034 and Fiord/Ac1655 RILs, two closely linked KASP markers KASP_Vf_0703 and KASP_Ac×F165 were mapped on chromosome III and V with Uvf-2 and Uvf-3, respectively and validated successfully in a set of local/exotic faba bean genotypes. These closely linked markers will allow breeders to implement markers assisted selection for both resistance genes. The histopathology of Australian U. viciae-fabae revealed a host range: both faba bean and field pea were competent hosts showing varietal differences to pathogen responses, with differential expression in resistance; lentil showed complete hypersensitive resistance by expressing cell death; and chickpea, lupin and mungbean appeared as non-hosts.