Transcriptional regulation of the CRK/DUF26 group of Receptor-like protein kinases by ozone and plant hormones in Arabidopsis

Abstract

BackgroundPlant Receptor-like/Pelle kinases (RLK) are a group of conserved signalling components that regulate developmental programs and responses to biotic and abiotic stresses. One of the largest RLK groups is formed by the Domain of Unknown Function 26 (DUF26) RLKs, also called Cysteine-rich Receptor-like Kinases (CRKs), which have been suggested to play important roles in the regulation of pathogen defence and programmed cell death. Despite the vast number of RLKs present in plants, however, only a few of them have been functionally characterized.ResultsWe examined the transcriptional regulation of all Arabidopsis CRKs by ozone (O3), high light and pathogen/elicitor treatment - conditions known to induce the production of reactive oxygen species (ROS) in various subcellular compartments. Several CRKs were transcriptionally induced by exposure to O3 but not by light stress. O3 induces an extracellular oxidative burst, whilst light stress leads to ROS production in chloroplasts. Analysis of publicly available microarray data revealed that the transcriptional responses of the CRKs to O3 were very similar to responses to microbes or pathogen-associated molecular patterns (PAMPs). Several mutants altered in hormone biosynthesis or signalling showed changes in basal and O3-induced transcriptional responses.ConclusionsCombining expression analysis from multiple treatments with mutants altered in hormone biosynthesis or signalling suggest a model in which O3 and salicylic acid (SA) activate separate signaling pathways that exhibit negative crosstalk. Although O3 is classified as an abiotic stress to plants, transcriptional profiling of CRKs showed strong similarities between the O3 and biotic stress responses.

Reactive oxygen species generation and signaling in plants

“…Several mutants altered in hormone biosynthesis or signalling showed also changes in ozone-induced transcriptional responses. 134 Gauthier et al 135 have identified two members of the cysteine-rich receptor-like kinase gene family and a leucine-rich repeat (LRR-RLK) protein in Arabidopsis which are transcriptionally induced after ozone treatment, and thus they could sense ROS through redox modifications of their extracellular domain. Corresponding knock-out lines lead to sensitivity to extracellular ROS resulting in subtle lesion formation upon ozone treatment indicating their involvement in ROS signaling.…”

A Key Role for Apoplastic H2O2 in Norway Spruce Phenolic Metabolism

“…8D). CRK expression has been shown to be modulated in response to ROS-and cellular redox state-related stresses (Lehti-Shiu et al, 2009;Wrzaczek et al, 2010;Bourdais et al, 2015). Moreover, CRKs are thought to be involved in cellular redox and apoplastic ROS sensing by the presence of conserved Cys residues in their apoplastic domain.…”

Transcriptomics of induced defense responses to greenbug aphid feeding in near isogenic wheat lines

“…Cysteine-rich Receptor Kinases (CRKs) belonging to DUF26 class proteins are known to mediate biotic and abiotic stress responses by activating ABA, SA, and JA hormone signaling [52,53]. Six transcripts related to Domain of Unknown Function 26 (DUF26) RLKs were also altered in a comparison between RB and SB after greenbug infestation (Fig.…”

“…4A). The receptor kinases including LRR and CRKs are shown to activate downstream signals by inducing production of ROS [52].…”