A scalable hydroponic-based method for screening isolates of chickpea Fusarium wilt pathogen, Fusarium oxysporum f.sp. ciceris v1

Chickpea is the third most consumed grain legume in the world. It serves as a valuable source of protein and micronutrients, especially for the large vegetarian population in the Indian subcontinent. One of the major constraints in chickpea production is the Fusarium wilt disease caused by the soil-born necrotrophic pathogen Fusarium oxysporum f. sp. ciceris (Foc). The pathogen has been shown to interact with chickpea in a race-specific manner and evolved into multiple races. So far eight races of it have been reported including 0, 1A, 1B/C, 2, 3, 4, 5, and 6. When a pathogenic race and host genotype interact in a race-specific manner, the interaction follows the typical gene-for-gene interaction (R-AVR) hypothesis, where major genes control avirulence/virulence in the pathogen and resistance/susceptibility in the host. However, so far neither any race-specific molecules (AVR) from the Fusarium oxysporum f. sp. ciceris nor the resistance gene (R) from the chickpea have been reported. We are using a forward genetics screen for the identification of avirulence genes by r and t-DNA insertional mutagenesis. Since Fusarium is a soil-born pathogen that infects roots, the usual root dip method used for its screening cannot scale for screening 1000 mutants. Hence, the need arises for a scalable high throughput method to screen numerous mutants. We are in the process of optimizing a hydroponics-based screening method of pathogens. We have tried to optimize many conditions for a highly reproducible method.