Transcriptome analysis of the Brassica napus–Leptosphaeria maculans pathosystem identifies receptor, signaling and structural genes underlying plant resistance

Abstract

The hemibiotrophic fungal pathogen Leptosphaeria maculans is the causal agent of blackleg disease in Brassica napus (canola, oilseed rape) and causes significant loss of yield worldwide. While genetic resistance has been used to mitigate the disease by means of traditional breeding strategies, there is little knowledge about the genes that contribute to blackleg resistance. RNA sequencing and a streamlined bioinformatics pipeline identified unique genes and plant defense pathways specific to plant resistance in the B. napus-L. maculans LepR1-AvrLepR1 interaction over time. We complemented our temporal analyses by monitoring gene activity directly at the infection site using laser microdissection coupled to quantitative PCR. Finally, we characterized genes involved in plant resistance to blackleg in the Arabidopsis-L. maculans model pathosystem. Data reveal an accelerated activation of the plant transcriptome in resistant host cotyledons associated with transcripts coding for extracellular receptors and phytohormone signaling molecules. Functional characterization provides direct support for transcriptome data and positively identifies resistance regulators in the Brassicaceae. Spatial gradients of gene activity were identified in response to L. maculans proximal to the site of infection. This dataset provides unprecedented spatial and temporal resolution of the genes required for blackleg resistance and serves as a valuable resource for those interested in host-pathogen interactions.

Progress and prospects of glucosinolate pathogen resistance in some brassica plants

“…(Voorrips, 1995 pathosystem was unclear at the time. Considering that IGSLs promote the production of callose that likely prevents L. maculans colonization and reproduction in apoplastic spaces within cotyledons thereby confering resistance on B. napus (Becker et al 2017). This agrees with Aist and Bushnell (1991), who proposed that callose deposition is a conserved defense response in plants that is controlled by GSL metabolism through acting as a physical barrier in the cell wall.…”

SeqEnrich: A tool to predict transcription factor networks from co-expressed Arabidopsis and Brassica napus gene sets

“…napus RNA-seq co-expressed gene lists: i) a tissue-specific dataset of 684 genes activated within the vasculature of the B . napus funiculus [35] (Fig 4A); and ii) a defense response dataset of 3,234 genes activated specifically in cotyledons resistant to the fungal pathogen Leptosphaeria maculans [36] (Fig 4B–4C). These datasets were selected because of i) the differences in the size of the query list, ii) the tissue type from where RNA sequencing was performed, and iii) the environmental conditions in which the plants were reared based on their cellular response.…”

Global RNA sequencing reveals enhanced photosynthetic activity and auxin response inBrassica napustreated withPseudomonas chlororaphisPA23

“…Raw sequencing reads were trimmed, quality checked, and aligned according to the methods described in Becker et al 2017 [25]. Data clustering was performed on averaged raw counts with the PVClust package of R-Studio.…”