Thesis: Mining novel resistance genes against Blackleg (Leptosphaeria maculans) in diverse Brassica germplasm
Blackleg, caused by Leptosphaeria maculans, is one of the most devastating fungal diseases affecting global canola (Brassica napus) production. In severe cases, yield reduction due to this pathogen can reach up to 90%, which translates to significant economic loss. Planting resistant varieties has been employed as a sustainable management option to circumvent such damage in canola production. However, the continuous deployment of the same resistance genes in cultivated varieties has led to the pathogen developing virulence mechanisms to overcome these resistance genes. The monitoring of blackleg populations indicates a breakdown of resistance in the genes Rlm1, Rlm2, Rlm3, Rlm4, and Rlm9, which are present in current Australian varieties. These resistance-breakdown events will have a negative impact in the canola industry if not immediately addressed. Hence, there is an urgent need to identify new sources of resistance to sustainably protect the canola industry from this devastating disease. In this project, we aim to identify novel qualitative and quantitative resistance in a wide array of plant materials previously described to express resistance, which include B. napus introgression lines, wild relatives, advanced and elite breeding lines. Approaches involving genomics and bioinformatics will be undertaken to subsequently identify, characterize, and verify new gene(s) for blackleg resistance. With the identification of these new gene(s), we hope to dissect further the complex mechanisms involved in blackleg resistance and reinforce breeding efforts to accelerate the development of resistant varieties.
Why my research is important
The million-dollar canola industry is under threat from blackleg disease. While major resistance genes are known to completely protect canola plants from the pathogen, recent reports indicate that they are becoming ineffective. Hence, this project will explore natural variations in diverse brassica germplasm to discover novel qualitative and quantitative resistance; the ultimate goal of which is to sustainably protect the industry from this devastating disease through the utilization of durable and readily available sources of resistance.