The Membrane-Anchored BOTRYTIS-INDUCED KINASE1 Plays Distinct Roles in Arabidopsis Resistance to Necrotrophic and Biotrophic Pathogens

Abstract

Plant resistance to disease is controlled by the combination of defense response pathways that are activated depending on the nature of the pathogen. We identified the Arabidopsis thaliana BOTRYTIS-INDUCED KINASE1 (BIK1) gene that is transcriptionally regulated by Botrytis cinerea infection. Inactivation of BIK1 causes severe susceptibility to necrotrophic fungal pathogens but enhances resistance to a virulent strain of the bacterial pathogen Pseudomonas syringae pv tomato. The response to an avirulent bacterial strain is unchanged, limiting the role of BIK1 to basal defense rather than race-specific resistance. The jasmonate-and ethylene-regulated defense response, generally associated with resistance to necrotrophic fungi, is attenuated in the bik1 mutant based on the expression of the plant defensin PDF1.2 gene. bik1 mutants show altered root growth, producing more and longer root hairs, demonstrating that BIK1 is also required for normal plant growth and development. Whereas the pathogen responses of bik1 are mostly dependent on salicylic acid (SA) levels, the nondefense responses are independent of SA. BIK1 is membrane-localized, suggesting possible involvement in early stages of the recognition or transduction of pathogen response. Our data suggest that BIK1 modulates the signaling of cellular factors required for defense responses to pathogen infection and normal root hair growth, linking defense response regulation with that of growth and development.

The novel elicitor AsES triggers a defense response against Botrytis cinerea in Arabidopsis thaliana

“…7). Similar cross-talk events have been described for the B. cinerea-induced protein kinase mutant bik1, that shows inhibition of PDF1.2 but increased SA-induced defense responses [45] and for the activator of SA and repressor of JA-responsive genes, the transcription factor WRKY70 [46,47]. More work would be required to determine the exact localization of these cross-talks in relation to pathogen invasion to determine their relevance.…”

CAST AWAY, a Membrane-Associated Receptor-Like Kinase, Inhibits Organ Abscission in Arabidopsis

“…4C), as previously shown for the PBS1, MLPK, and BIK1 class VII RLCKs (Warren et al, 1999;Boisson et al, 2003;Murase et al, 2004;Veronese et al, 2006;Kakita et al, 2007). Palmitoylation of N-terminal Cys residues is also predicted to allow reversible membrane association for CST and many other class VII RLCKs ( Fig.…”

“…Although receptor-like cytoplasmic kinases (RLCKs) account for at least 125 of the 610 annotated RLKs in Arabidopsis (Arabidopsis thaliana), much remains to be learned about their functions within cell signaling complexes (Shiu and Bleecker, 2001;Goring and Walker, 2004;Shiu et al, 2004;Jurca et al, 2008). Several of the 46 RLCKs assigned to the class VII subfamily have been found to function in pathogen response and developmental signaling pathways (Swiderski and Innes, 2001;Shao et al, 2003;Murase et al, 2004;Muto et al, 2004;Veronese et al, 2006;Ade et al, 2007;Lu et al, 2010;Zhang et al, 2010;Liu et al, 2011).…”

“…The BOTRYTIS-INDUCED KINASE1 (BIK1) RLCK functions in a signaling relay with an activated ligand-binding RLK and its coreceptor. BIK1 was shown to interact with two Leu-rich repeat receptor-like kinases (LRR-RLKs), the ligand-binding FLAGELLIN-SENSITIVE2 (FLS2) and its coreceptor BRI1-ASSOCIATED KINASE1 (BAK1; Veronese et al, 2006;Lu et al, 2010). FLS2 binding of the bacterial flagellin-derived peptide, flg22, triggers the interaction of FLS2 and BAK1 and downstream signaling for pathogen-associated molecular patterns (PAMP)-triggered immunity (Chinchilla et al, 2007;Heese et al, 2007).…”

Botrytis small RNA Bc-siR37 suppresses plant defense genes by cross-kingdom RNAi

“…2B). 21,32 Therefore, we assumed that the reduced transcript levels of predicted Bc-siR37 host targets were due to gene silencing rather than plant cell death caused by the pathogen. Nevertheless, comprehensive transcriptional re-programing is common during stress response in plants, which could explain the reduced transcription levels of the predicted target genes during infection.…”