Oilseed Brassica under threat: viral pathogens and the compounding effects of climate change

• Climate change intensifies virus pressure in Brassica oilseed crops. • TuYV and TuMV cause severe yield losses in Brassica napus. • Elevated CO 2 alters aphid behaviour, increasing virus transmission. • Resistance genes show reduced effectiveness under heat stress. Oilseed crops of the genus Brassica rank third globally in vegetable oil production and contribute substantially to global oil supplies for both food and industrial purposes, including lubricants, biofuels, and cosmetics. Despite advances in high-yielding cultivars and modern agronomic practices, the productivity of oilseed Brassica species remains significantly constrained by a range of pathogens, particularly viral agents such as turnip yellows virus (TuYV), turnip mosaic virus (TuMV), and cauliflower mosaic virus (CaMV). Climate change further exacerbates these challenges by influencing plant physiology, virus biology and vector ecology. Rising temperatures enhance virus-vector interactions and increase the risk of disease outbreaks, while elevated atmospheric CO 2 concentrations can alter plant nutritional profiles, potentially stimulating vector feeding behaviour and promoting virus transmission. Although natural sources of resistance offer partial protection, their effectiveness may be compromised under abiotic stress conditions such as heat stress, highlighting vulnerabilities in plant defence. This mini-review addresses three major challenges to Brassica oilseed production: the impact of principal viral pathogens, climate-driven shifts in host-virus-vector dynamics, and the environmental robustness of genetic resistance. The review also outlines knowledge gaps and research priorities for developing climate-resilient Brassica oilseed genotypes.