Multi-scale phenotyping of senescence-related changes in roots of Rapeseed in response to nitrate limitation.

Abstract

Root senescence remains largely unexplored. In this study, the temporality of the morphological, metabolic, and proteomic changes occurring with root aging were investigated, providing a comprehensive picture of the root senescence program. We found novel senescence-related markers for the characterization of the developmental stage of root tissues. The rapeseed root system is unique in that it consists of the taproot and lateral roots. Our study confirms that the taproot, which transiently accumulates large quantities of starch and proteins, is specifically dedicated to nutrient storage and remobilization, while the lateral roots are mainly dedicated to nutrient uptake. Proteomic data from the taproot and lateral roots highlight the different senescence-related events that control nutrient remobilization and nutrient uptake capacities. Both the proteome and enzyme activities revealed senescence-induced proteases and nucleotide catabolic enzymes that deserve attention as they may play important roles in nutrient remobilization efficiency in rapeseed roots. Taking advantage of publicly available transcriptomic and proteomic data on senescent Arabidopsis leaves, we have highlighted new lists of senescence-related proteins specific or common to root organs and/or leaves.