Dynamic regulation of Pep-induced immunity through post-translational control of defence transcript splicing

Dressano, Keini; Weckwerth, Philipp; Poretsky, Elly; Takahashi, Yohei; Villarreal, Carleen; Shen, Zhouxin; Schroeder, Julian; Briggs, Steven P.; Huffaker, Alisa

doi:10.1038/s41477-020-0724-1

Cited by 49 publications

(53 citation statements)

References 70 publications

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“…Upon liberation from their precursors, AtPeps interact with two leucine‐rich receptor kinases, PEP RECEPTOR1 and ‐2 (AtPEPR1 and AtPEPR2), which activate downstream signaling in complex with SOMATIC EMBRYO RECEPTOR KINASE (SERK) co‐receptors and the membrane‐associated cytoplasmic kinases BOTRYTIS‐INDUCED KINASE 1 (BIK1) and BRASSINOSTEROID‐SIGNALING KINASE 5 (BSK5) (Yamaguchi et al ., 2006, 2010; Krol et al ., 2010; Lu et al ., 2010; Postel et al ., 2010; Roux et al ., 2011; Liu et al ., 2013; Majhi et al ., 2019). Upon activation of the receptor complex, signaling occurs through the mitogen‐activated protein (MAP) kinases MPK3/6/4/11, production of the phytohormones jasmonic acid (JA), ethylene (ET) and salicylic acid (SA) and of ROS generated by NADPH oxidase enzymes (Huffaker and Ryan, 2007; Bartels et al ., 2013; Huffaker et al ., 2013; Tintor et al ., 2013; Dressano et al ., 2019). This is accompanied by modulation of ion channels and transporters that increases calcium levels in the cytoplasm and reduces the export of protons to the apoplast (Huffaker et al ., 2006; Ma et al ., 2014).…”

Section: Introductionmentioning

confidence: 99%

Differential activities of maize plant elicitor peptides as mediators of immune signaling and herbivore resistance

et al. 2020

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Plant elicitor peptides (Peps) are conserved regulators of defense responses and models for the study of damage-associated molecular pattern-induced immunity. Although present as multigene families in most species, the functional relevance of these multigene families remains largely undefined. While Arabidopsis Peps appear largely redundant in function, previous work examining Pep-induced responses in maize (Zm) implied specificity of function. To better define the function of individual ZmPeps and their cognate receptors (ZmPEPRs), activities were examined by assessing changes in defense-associated phytohormones, specialized metabolites and global gene expression patterns, in combination with heterologous expression assays and analyses of CRISPR/Cas9-generated knockout plants. Beyond simply delineating individual ZmPep and ZmPEPR activities, these experiments led to a number of new insights into Pep signaling mechanisms. ZmPROPEP and other poaceous precursors were found to contain multiple active Peps, a phenomenon not previously observed for this family. In all, seven new ZmPeps were identified and the peptides were found to have specific activities defined by the relative magnitude of their response output rather than by uniqueness. A striking correlation was observed between individual ZmPep-elicited changes in levels of jasmonic acid and ethylene and the magnitude of induced defense responses, indicating that ZmPeps may collectively regulate immune output through rheostat-like tuning of phytohormone levels. Peptide structure-function studies and ligand-receptor modeling revealed structural features critical to the function of ZmPeps and led to the identification of ZmPep5a as a potential antagonist peptide able to competitively inhibit the activity of other ZmPeps, a regulatory mechanism not previously observed for this family.

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Section: Introductionmentioning

confidence: 99%

Differential activities of maize plant elicitor peptides as mediators of immune signaling and herbivore resistance

et al. 2020

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“…In order to buffer these attenuation mechanisms the plant would need to adopt a safeguard against sustained activation of CPK28. Recent work has demonstrated that following cell stimulation with AtPep1 (85) or the bacterial flagellin immunogenic epitope flg22 (86), alternative CPK28 transcripts are produced that generate a truncated isoform that lacks the C-terminal EF-hand lobe. This CPK28 variant could act to outcompete Ca 2+ “competent” proteins for downstream substrates, alleviating immune attenuation (87).…”

Section: Discussionmentioning

confidence: 99%

Phosphorylation-dependent sub-functionalization of the calcium-dependent protein kinase CPK28

Bredow

Bender

Dingee

et al. 2020

Preprint

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Calcium (Ca2+)-dependent protein kinases (CDPKs or CPKs) are a unique family of Ca2+-sensor/kinase-effector proteins with diverse functions in plants. In Arabidopsis thaliana, CPK28 contributes to immune homeostasis by promoting degradation of the key immune signaling receptor-like cytoplasmic kinase BOTRYTIS-INDUCED KINASE 1 (BIK1), and additionally functions in vegetative-to-reproductive stage transition. How CPK28 controls these seemingly disparate pathways is unknown. Here, we identify a single phosphorylation site in the kinase domain of CPK28 (Ser318) that is differentially required for its function in immune homeostasis and stem elongation. We show that CPK28 undergoes intra- and inter-molecular auto-phosphorylation on Ser318 and can additionally be trans-phosphorylated on this residue by BIK1. Analysis of several other phosphorylation sites demonstrates that Ser318 phosphorylation is uniquely required to prime CPK28 for Ca2+ activation at physiological concentrations of Ca2+, possibly through stabilization of the Ca2+-bound active state as indicated by intrinsic fluorescence experiments. Together, our data indicate that phosphorylation of Ser318 is required for the activation of CPK28 at low intracellular [Ca2+ ] to prevent initiation of an immune response in the absence of infection. By comparison, phosphorylation of Ser318 is not required for stem-elongation, indicating pathway specific requirements for phosphorylation-based Ca2+-sensitivity priming. We additionally provide evidence for a conserved function for Ser318 phosphorylation in related group IV CDPKs which holds promise for biotechnological applications by generating CDPK alleles that enhance resistance to microbial pathogens without consequences to yield.

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“…Arabidopsis thaliana plants used in this study were Columbia (Col-0) ecotype. SALK_015201 encodes the irr-1 knock-out allele (also annotated as SALK_015201C and SALKseq_015201) and SALK_066572 encodes the irr-2 knock-out allele which were previously characterized (Dressano et al, 2020; Petrov et al, 2013). Homozygous phyB-9 seed stocks (ABRC stock number CS6217) were also previously characterized (Reed et al, 1994).…”

Section: Methodsmentioning

confidence: 99%

“…RNA-seq reads for twelve individuals comprising Pep-treated and untreated irr-1 mutant and wild-type plants (three biological replicates per genotype per condition) were obtained from the NCBI SRA with IDs SRR11218900 - SRR11218911 (Dressano et al, 2020). The paired-end 150-bp reads were aligned to the TAIR10 reference genome (Lamesch et al, 2012) using the spliced alignment option of the STAR aligner (Dobin et al, 2013).…”

Section: Methodsmentioning

confidence: 99%

“…In this study we performed a reverse genetic screen based on our auxin responsive proteomics data (Clark et al, 2019) and publicly available Arabidopsis T-DNA insertion alleles (O’Malley and Ecker, 2010; Alonso et al, 2003). From this screen we identified a T-DNA line with a long hypocotyl phenotype which we initially called slim shady and was recently published as IMMUNOREGULATORY RNA BINDING PROTEIN (IRR) (Dressano et al, 2020). A long hypocotyl phenotype in SALK_015201 lines had been previously reported (Petrov et al, 2013) but a second T-DNA allele in IRR had a wild-type phenotype, prompting us to reconsider the genetic lesion responsible for the long hypocotyl phenotype.…”

Section: Introductionmentioning

confidence: 99%

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slim shadyis a novel allele of PHYTOCHROME B present in the T-DNA line SALK_015201

Dash

McEwan²,

Montes

et al. 2021

Preprint

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Auxin is a hormone that is required for hypocotyl elongation during seedling development. In response to auxin rapid changes in transcript and protein abundance occur in hypocotyls and some auxin responsive gene expression is linked to hypocotyl growth. To functionally validate proteomic studies, a reverse genetics screen was performed on mutants in auxin-regulated proteins to identify novel regulators of plant growth. This uncovered a long hypocotyl mutant, which we called slim shady, in an annotated insertion line in IMMUNOREGULATORY RNA-BINDING PROTEIN (IRR). Overexpression of the IRR gene failed to rescue the slim shady phenotype and characterization of a second T-DNA allele of IRR found that it had a wild-type hypocotyl length. The slim shady mutant has an elevated expression of numerous genes associated with the brassinosteroid-auxin-phytochrome (BAP) regulatory module compared to wild-type, including transcription factors that regulate brassinosteroid, auxin and phytochrome pathways. Additionally, slim shady seedlings fail to exhibit a strong transcriptional response to auxin. Using whole genome sequence and transcriptomics data for SALK_015201C we determined that a novel single nucleotide polymorphism in PHYTOCHROME B was responsible for the slim shady phenotype. This is predicted to induce a frameshift and premature stop codon at leucine 1125, within the histidine kinase-related domain of the carboxy terminus of PHYB, which is required for phytochrome signaling and function. Genetic complementation analyses with phyb-9 confirmed that slim shady is a mutant allele of PHYB. This study advances our understanding of the molecular mechanisms in seedling development, by furthering our understanding of how light signaling is linked to auxin dependent cell elongation. Furthermore, this study highlights the importance of confirming the genetic identity of research material before attributing phenotypes to known mutations sourced from T-DNA stocks.

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Dynamic regulation of Pep-induced immunity through post-translational control of defence transcript splicing

Cited by 49 publications

References 70 publications

Differential activities of maize plant elicitor peptides as mediators of immune signaling and herbivore resistance

Differential activities of maize plant elicitor peptides as mediators of immune signaling and herbivore resistance

Phosphorylation-dependent sub-functionalization of the calcium-dependent protein kinase CPK28

slim shadyis a novel allele of PHYTOCHROME B present in the T-DNA line SALK_015201

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