Journal Article

GWAS provides biological insights into mechanisms of the parasitic plant (Striga) resistance in sorghum

Runo, Steven, Kibet, Willy, Kavuluko, Jacinta, Masanga, Joel, Wamalwa, Mark, Odeny, Damaris, Kibe, Magdaline, Magomere, Titus, Sugut, Irine, Mutinda, Sylvia

2021

Overview

Background Sorghum yields in sub-Saharan Africa (SSA) are greatly reduced by parasitic plants of the genus Striga (witchweed). Vast global sorghum genetic diversity collections, as well as the availability of modern sequencing technologies, can be potentially harnessed to effectively manage the parasite. Results We used laboratory assays – rhizotrons to screen a global sorghum diversity panel to identify new sources of resistance to Striga ; determine mechanisms of resistance, and elucidate genetic loci underlying the resistance using genome-wide association studies (GWAS). New Striga resistant sorghum determined by the number, size and biomass of parasite attachments were identified. Resistance was by; i) mechanical barriers that blocked parasite entry, ii) elicitation of a hypersensitive reaction that interfered with parasite development, and iii) the inability of the parasite to develop vascular connections with hosts. Resistance genes underpinning the resistance corresponded with the resistance mechanisms and included pleiotropic drug resistance proteins that transport resistance molecules; xylanase inhibitors involved in cell wall fortification and hormonal regulators of resistance response, Ethylene Response Factors. Conclusions Our findings are of fundamental importance to developing durable and broad-spectrum resistance against Striga and have far-reaching applications in many SSA countries where Striga threatens the livelihoods of millions of smallholder farmers that rely on sorghum as a food staple.

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: Agriculture / Barriers / Biomass / Biomedical and Life Sciences / Cell walls / Crop yield / Drug resistance / ethylene / Evaluation / Gene loci / Genetic aspects / Genetic diversity / genetic variation / Genome-wide association studies / Genome-wide association studies (GWAS) / Genomes / Genotype & phenotype / genus / Geography / hypersensitive response / Influence / Life Sciences / Parasite resistance / Parasites / Parasitic plants / Plant Sciences / Plant-biotic interactions / Protein transport / Research Article / Resistance factors / S. hermonthica (Striga) / Small farms / Sorghum / Sorghum diversity panel / Striga / Striga resistance / Sub-Saharan Africa / Tree Biology / Xylanase / xylanases