Systems-level nutrient stress analysis of soil grown Brassica napus shoots and roots by quantitative proteomics

Appropriate soil nutrient management is critical for modern Canola (Brassica napus L.) varieties and hybrids to meet their yield potentials. Canola fields are typically supplemented by the application of nitrogen, phosphorus, sulphur, and to a lesser extent, potassium fertilizers to maximize yield, while deficiency in these key macronutrients can result in severe growth phenotypes and significant yield losses. To date, our understanding of canola nutrient deficiency responses is disparate, encompassing a large number of varieties using a variety of technologies and assessment criteria, with seminal understanding of the overlaps between nutrient deficiencies responses, having not yet been defined, placing limitations on our ability to increase the nutrient efficiency of this critical oil seed. To address this, we performed a comparative quantitative proteomics analysis of both shoot and root tissue harvested from soil-grown Canola plants experiencing either nitrogen, phosphorus, potassium, or sulphur deficiency. Our results show intriguing similarities in plant responses to deficiency in multiple nutrients. We also find very distinct proteome-level changes between shoot and root tissue of plants experiencing nutrient stress, suggesting the presence of highly organ-specific responses to nutrient deficiency. Our results pave the way for a more comprehensive understanding of the shared and distinct response mechanisms of plants to multiple essential nutrients.