scholarly journals Tryptophan-derived metabolites and BAK1 separately contribute to Arabidopsis postinvasive immunity against Alternaria brassicicola

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ayumi Kosaka ◽  
Marta Pastorczyk ◽  
Mariola Piślewska-Bednarek ◽  
Takumi Nishiuchi ◽  
Erika Ono ◽  
...  
Keyword(s):  
Gene Expression ◽  
Arabidopsis Thaliana ◽  
Alternaria Brassicicola ◽  
Nonhost Resistance ◽  
Antimicrobial Proteins ◽  
Basal Resistance ◽  
Pathogen Invasion ◽  
Gene Expression Analyses ◽  
Colletotrichum Tropicale ◽  
Immune Pathway

AbstractNonhost resistance of Arabidopsis thaliana against the hemibiotrophic fungus Colletotrichum tropicale requires PEN2-dependent preinvasive resistance and CYP71A12 and CYP71A13-dependent postinvasive resistance, which both rely on tryptophan (Trp) metabolism. We here revealed that CYP71A12, CYP71A13 and PAD3 are critical for Arabidopsis’ postinvasive basal resistance toward the necrotrophic Alternaria brassicicola. Consistent with this, gene expression and metabolite analyses suggested that the invasion by A. brassicicola triggered the CYP71A12-dependent production of indole-3-carboxylic acid derivatives and the PAD3 and CYP71A13-dependent production of camalexin. We next addressed the activation of the CYP71A12 and PAD3-dependent postinvasive resistance. We found that bak1-5 mutation significantly reduced postinvasive resistance against A. brassicicola, indicating that pattern recognition contributes to activation of this second defense-layer. However, the bak1-5 mutation had no detectable effects on the Trp-metabolism triggered by the fungal penetration. Together with this, further comparative gene expression analyses suggested that pathogen invasion in Arabidopsis activates (1) CYP71A12 and PAD3-related antifungal metabolism that is not hampered by bak1-5, and (2) a bak1-5 sensitive immune pathway that activates the expression of antimicrobial proteins.

scholarly journals bak1-5 mutation uncouples tryptophan-dependent and independent postinvasive immune pathways triggered in Arabidopsis by multiple fungal pathogens

2020 ◽  
Author(s):  
Ayumi Kosaka ◽  
Marta Pastorczyk ◽  
Mariola Piślewska-Bednarek ◽  
Takumi Nishiuchi ◽  
Haruka Suemoto ◽  
...  
Keyword(s):  
Pattern Recognition ◽  
Fungal Pathogens ◽  
Alternaria Brassicicola ◽  
Antimicrobial Proteins ◽  
Pathogen Invasion ◽  
Gene Expression Analyses ◽  
Colletotrichum Tropicale ◽  
Immune Pathway ◽  
Dose Dependent ◽  
Recognition Receptor

ABSTRACTRobust nonhost resistance of Arabidopsis thaliana against the nonadapted hemibiotrophic fungus Colletotrichum tropicale requires PEN2-dependent preinvasive and CYP71A12/CYP71A13-dependent postinvasive resistance, which both rely on tryptophan (Trp) metabolism. Here we report that CYP71A12 and CYP71A13 are critical for Arabidopsis’ postinvasive resistance toward both the necrotrophic Alternaria brassicicola and the adapted hemibiotrophic C. higginsianum fungi. Metabolite analyses suggest that the production of indole-3-carboxylic acid derivatives (ICAs) and camalexin is induced upon pathogen invasion, while phenotypic comparison of cyp79B2 cyp79B3 and pen2 cyp71A12 cyp71A13 plants indicates that the contribution of ICAs to postinvasive resistance is dose-dependent. We also found that the disruption of intact pattern recognition receptor complex caused by bak1–5 mutation significantly reduced postinvasive resistance against C. tropicale and A. brassicicola, indicating that pattern recognition commonly contributes to this second defense-layer against pathogens with distinct infection strategies. However, the bak1–5 mutation had no detectable effects on Trp-metabolite accumulation triggered by pathogen invasion. Together with this, further comparative gene expression analyses suggested that pathogen invasion in Arabidopsis activates (i) bak1–5 insensitive Trp-metabolism that leads to antimicrobial secondary metabolites, and (ii) a bak1–5 sensitive immune pathway that activates the expression of antimicrobial proteins.

scholarly journals Alternative splicing landscapes in Arabidopsis thaliana across tissues and stress conditions highlight major functional differences with animals

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Guiomar Martín ◽  
Yamile Márquez ◽  
Federica Mantica ◽  
Paula Duque ◽  
Manuel Irimia
Keyword(s):  
Gene Expression ◽  
Arabidopsis Thaliana ◽  
Alternative Splicing ◽  
Stress Responses ◽  
Target Genes ◽  
Intron Retention ◽  
Single Gene ◽  
Exon Skipping ◽  
Environmental Response ◽  
Biotic Stresses

Abstract Background Alternative splicing (AS) is a widespread regulatory mechanism in multicellular organisms. Numerous transcriptomic and single-gene studies in plants have investigated AS in response to specific conditions, especially environmental stress, unveiling substantial amounts of intron retention that modulate gene expression. However, a comprehensive study contrasting stress-response and tissue-specific AS patterns and directly comparing them with those of animal models is still missing. Results We generate a massive resource for Arabidopsis thaliana, PastDB, comprising AS and gene expression quantifications across tissues, development and environmental conditions, including abiotic and biotic stresses. Harmonized analysis of these datasets reveals that A. thaliana shows high levels of AS, similar to fruitflies, and that, compared to animals, disproportionately uses AS for stress responses. We identify core sets of genes regulated specifically by either AS or transcription upon stresses or among tissues, a regulatory specialization that is tightly mirrored by the genomic features of these genes. Unexpectedly, non-intron retention events, including exon skipping, are overrepresented across regulated AS sets in A. thaliana, being also largely involved in modulating gene expression through NMD and uORF inclusion. Conclusions Non-intron retention events have likely been functionally underrated in plants. AS constitutes a distinct regulatory layer controlling gene expression upon internal and external stimuli whose target genes and master regulators are hardwired at the genomic level to specifically undergo post-transcriptional regulation. Given the higher relevance of AS in the response to different stresses when compared to animals, this molecular hardwiring is likely required for a proper environmental response in A. thaliana.

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