Overexpression of BnNAC19 in Brassica napus enhances resistance to Leptosphaeria maculans, the blackleg pathogen of canola

Abstract

Leptosphaeria maculans is a fungal pathogen that causes blackleg disease in canola (Brassica napus), resulting in significant yield and economic losses in Canada and many parts of the world. Plant NAC transcription factors play critical roles in plant development and response to biotic or abiotic stress. In this study, we identified and characterized a BnNAC19 gene from Brassica napus. The overexpression of BnNAC19 in transgenic canola plants contributed to the improvement of seedling resistance against L. maculans. The mycelial growth of a green fluorescent protein‐tagged strain of L. maculans and production of pycnidiospores were shown to be inhibited in the transgenic canola plants overexpressing BnNAC19. In addition, the canola transgenic line overexpressing BnNAC19 showed increased disease resistance in the adult plant, which was determined by quantitative resistance. Both increased seedling and adult plant resistance in transgenic canola plants overexpressing BnNAC19 indicate that the BnNAC19 gene plays a positive role against L. maculans. The expression pattern of genes BnNAC19 upstream and downstream of BnNAC19 that participate in plant defence pathways were investigated to elucidate the B. napus resistance mechanisms to L. maculans infection, and hence to aid the long‐term blackleg disease‐resistant breeding programmes.

Functional genomics of Brassica napus: Progress, challenges, and perspectives

“…Except for S. sclerotiorum and clubroot disease, resistance genes associated with pests and other diseases have been less studied. For example, only a few related genes have been reported for blackleg and verticillium wilt disease (Pröbsting et al, 2020;Zou et al, 2021;Haddadi et al, 2022;Zou and Fernando, 2023). Here, we focus on an overview of S. sclerotiorum and clubroot disease resistance genes in B. napus.…”

“…There are numerous traits involved in the process of plant architecture improvement, but fewer related functional gene studies have been reported. Meanwhile, studies related to waterlogging, diseases and insects, silique shattering resistance, leaf color and efficient nutrient utilization in B. napus have mostly remained at the QTL level, with a few related genes being reported (Li et al, 2014;Zhang et al, 2017b;Hu et al, 2018;Feng et al, 2020;Guo et al, 2022;Li et al, 2022b;Zou and Fernando, 2023;Yang et al, 2023a;Li et al, 2023d).…”