MOLECULAR GENETICS OF PLANT RESISTANCE TO FUNGAL PATHOGENS

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 1010660
• Project Start Date: Oct 1, 2016
• Project End Date: Sep 30, 2021
• Program Code: [(N/A)]- (N/A)

Recipient Organization
PURDUE UNIVERSITY
(N/A)
WEST LAFAYETTE,IN 47907

Performing Department
Botany & Plant Pathology

Non Technical Summary
Fungal pathogens are major causes of plant diseases. A thorough understanding of the genes that control disease resistance is required for improvement of fungal resistance in diverse crop plants. Early blight caused by Alternaria solani and gray mold disease caused by B. cinerea are two important horticultural diseases. Tomato is a major horticultural crop in the US and globally that also suffers from major diseases such as early blight both in Indiana and other US states. This research attempts to generate the knowledge base that will support improvement in disease resistance.

Animal Health Component

30%

Research Effort Categories

Basic

70%

Applied

30%

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
212	2420	1040	50%
206	1460	1080	50%

Knowledge Area
212 - Pathogens and Nematodes Affecting Plants; 206 - Basic Plant Biology;

Subject Of Investigation
1460 - Tomato; 2420 - Noncrop plant research;

Field Of Science
1040 - Molecular biology; 1080 - Genetics;

Keywords

fungal resistance

arabidopsis

tomato

molecular genetics

Goals / Objectives
Genetic, molecular and biochemical characterization of Arabidopsis and tomato HISTONE METHYL TRANSFERASES.Identify and characterize targets of HISTONE METHYL TRANSFERASES contributing to fungal resistance

Project Methods
Objective 1. Genetic, molecular and biochemical characterization of Arabidopsis and tomato HISTONE METHYL TRANSFERASES.Arabidopsis histone methyl transferases (HMTs) that are required for plant immune responses were identified from a reverse genetic screen. The hmt1 and hmt2 mutant plants easily succumb to infection by fungal and bacterial pathogens with a concomitant decrease in immune response gene expression. We will focus on these two HMTs which encode SET DOMAIN GROUP (SDG) proteins characteristic of many histone lysine methyl transferases (Pontvianne et al., 2010).1.1. Phenotypic, molecular and genetic characterization of HMT1 and HMT2 genes:The molecular, genetic and biochemical characterization of histone lysine methyl transferase mutants will be completed. In addition, specificities in biological functions of HMT1 and HMT2 will be analyzed. First, we will characterize the two mutants for activation of defense and hormone response genes after infection, pathogen derived signals, or treatment with hormones, and PAMP molecules to determine the relationship between the two pathways. Mutant and wild type plants challenged with various defense activators and hormones will be used to study spatial and temporal immune response genes expression in infected and systemic tissues. Second, pathogen, environmental and developmental cues that regulate HMT1 and HMT2 gene expression and enzymatic activities will be analyzed. HMT gene expression in systemic and infected tissues in response to various pathogens, defense activators, and plant hormones will be studied to link gene expression patterns and function in systemic and local resistance. In addition, gene expression and histone methylation levels at chromatin of hormone and defense response genes will be analyzed using QRT-PCR and ChIP-qPCR in hmt1 and hmt2 mutants. The HMT1 and HMT2 protein levels and their enzymatic activity will be studied after elicitation with pathogen derived signals. 1.2. Biochemical characterization of HMT1 and HMT2: We will determine the substrate specificity of HMT1 and HMT2 through biochemical analysis of the recombinant proteins and the Arabidopsis hmt1 and hmt2 single and double mutants. The specificity towards histone lysine H3K4, H3K9, H3K27, H3K36 and the levels of methylation (mono-, di-, tri-methylation) will be analyzed. To determine genome wide or gene specific changes in histone lysine methylation, commercially available antibodies specific to mono-, di-, and tri-methylations of histone H3 (K4, K9, K27, K36) residues will be used to probe a western blot or conduct ChIP experiments. The various antibodies will be used to probe a western blot from wild type, hmt1, hmt2 single and double mutant plants exposed to mock treatment, PTI elicitors (flg22, pep1) or immune response suppressors (selected bacterial effectors, fungal toxins) to quantify impacts of HMT1 and HMT2 on global H3 methylation levels. Changes in histone methylation levels in the presence or absence of immune response elicitors or suppressors will help us establish connection to resistance or susceptibility responses.1.3. Genetic and molecular characterization of tomato Histone lysine methyl transferasesThe goal here is characterization of tomato SDG HISTONE METHYL TRANSFERASES (SlSDGs) through genetic, molecular and biochemical studies to determine their contribution in fungal resistance. HMTs are major regulators of various plant processes through their function in histone lysine modifications but little is known about the functions of tomato HMTs. The proposed experiments will lay the foundation for future studies in the contribution of histone lysine methylation in tomato disease resistance. Two genes, SlSDG33 and SlSDG20 encoding tomato SET domain histone lysine methyl transferases (SlSDGs) were identified as significant players in tomato resistance to Alternaria solani, the causal agent of early blight in tomato, and are targets of detailed functional analysis proposed here.2. Identify and characterize targets of Arabidopsis HISTONE METHYL TRANSFERASES HMT1 and HMT2.2.1 RNA-seq analysis to determine global impact of HMTs on gene expression and identify direct and indirect targets of histone lysine methylation: RNA will be extracted from mock, flg22 or pep1 treated hmt1, hmt2 and hmt1hmt2 plants. The RNA-seq experiment will be conducted with three biological replicates to generate a statistically robust dataset. The paired-end sequencing strategy, in which short sequences are determined from both ends of a DNA fragment, alleviates potential problems of mapping sequences to the reference Arabidopsis genome. We are aiming at a minimum of 30 million read pairs per sample using three biological replicates (Cloonan et al., 2008). The Purdue bioinformatics core facility will guide the statistical analysis of the RNA-seq data to determine the extent of HMT1 and HMT2 regulatory impact and identify genes and processes regulated by the two enzymes.The differentially expressed genes based on fold changes (FDR≤0.05) will be categorized into functional groups based on Gene Ontology. We will determine whether a specific set of functionally groups are preferentially affected by the hmt mutations. Differential expression (DE) analysis across different conditions between different treatments (genotype, flg22/pep1/mock treatment) will be carried out using 'R' (Version 2.15.1) and different methods of limma package (Smyth, 2005 ; Anders and Huber, 2010; Robinson et al., 2010).2.2. Determine genome wide H3 histone methylation landscape during immune responses: Genome wide histone methylation sites in pep1 or flg22 elicited plants will be examined using chromatin immunoprecipitation (ChIP) and deep sequencing (ChIP-Seq) (Park, 2009; Pepke et al., 2009). In general, ChIP is performed by enrichment of cross-linked DNA-protein complexes using specific antibodies. The DNA bound to the target protein are isolated and used as input DNA for library generation and sequencing. First, the histone methylation antibodies for ChIP will be selected based on the substrate specificity of HMT1 and HMT2. Once the specific substrate lysine residues are known, we will conduct the ChIP experiments in hmt1, hmt2 and hmt1 hmt2 double mutants and compare them to ChIP data from wild type plants. The data will be analyzed to decipher the extent of pep1 or flagellin induced enrichment of methylated histones, distribution of methylated histones at transcriptionally active genes, regulatory or transcribed regions of genes, and whether it is biased to certain functional categories such as plant immune response genes. The data will be compared to published histone methylation profiles performed in the context of plant development to decipher those specific to immune pathways (Bernatavichute et al., 2008; Zhang et al., 2009; Roudier et al., 2011).2.3. Determine targets of recruitment of HMT1 and HMT2 in elicited plants through ChIP-seq: Here we will analyze PAMP (flg22, pep1) induced global histone methylation and HMT1 and HMT2 recruitment sites using ChIP-sequencing. flg22 or pep1 treated HMT1-HA and HMT2-FLAG plants will be used to determine HMT1 and HMT2 direct targets using antibodies specific to the tags. Genes that are directly targeted by HMT1 and HMT2 will be selected by comparing the RNA-seq data above to HMT1 and HMT2 specific and global methylation ChIP-seq data. The direct targets will be used to study the molecular basis for the selective regulation of gene expression by histone methylation. Recruitment of HMT1-HA and HMT2-FLAG to target sites will be analyzed in elicited, non-elicited and immune response suppressed plants.2.4 Characterize the role of HMT1 and HMT2 target gene in plant immunity: Once target genes are identified from RNA-seq and ChIP-seq, we will select core target genes to analyze how they are regulated by histone methylation and their role in plant defense.

Progress 10/01/16 to 09/30/21

Outputs
Target Audience:The project targetsaudiences include the scientific community especially people in plant sciences, plant pathology, crop protection areas. Also, peer scientist in tomato pathology, genetics and epigenetics will be interested in our results. Further, other stake holders interested in the application of research findings and translating observations into potential products are possible audiences for our project. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The project provided training for undergraduate students, graduate students and mentoring of postdoctoral scientists. How have the results been disseminated to communities of interest?The results were disseminated through peer reviewed journal articles that are widely accessible to the scientific community. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Plants are constantly exposed to biotic and abiotic factors throughout their developmental stages which threaten their growth and productivity. Environmental stresses limit crop productivity and are likely to increase in severity due to the drastic and rapid changes in global climate. In this project, we studied the genetic factors that contribute to plant adaption to pathogens and other environmental factors in tomato. Plant responses to environmental cues are underpinned by rapid and extensive transcriptional reprogramming. Post translational modification of histones orchestrate these reprogramming and cellular responses by altering chromatin structure and establishing permissive or repressive states. Histone lysine methylation (HLM) is a principal modification of chromatin that affects various cellular processes. HLM is mediated by histone methyltransferases (HMTs) that deposit methyl groups to specific lysine residues on n-terminal histones tails. Although it is known that chromatin modifications occur in response to environmental cues, the mechanisms by which this is achieved, and the biological functions of HMTs are poorly understood. The function of tomato histone methyltransferases Set Domain Group (SDG)33 and SDG34 in biotic and abiotic stress responses were studied using tomato mutants generated through CRISPR/cas9 genome editing. SDG33 and SDG34 genes were induced by pathogens, drought stress, the plant hormones methyl jasmonate, salicylate and abscisic acid. The sdg33 and sdg34 mutants display altered global HLMs. SDG34 is required for global H3K36 and H3K4 mono, di- and tri-methylation while SDG33 is primarily responsible for di- and tri- H3K36 and H3K4 methylation. Tomato SDG33 and SDG34 are orthologues of the Arabidopsis SDG8, an H3K4 and H3K36 methyl transferase previously implicated in plant immunity and plant growth through epigenetic control of Carotenoid 16 Isomerase (CCR2) and other target genes. However, the tomato sdg33 or sdg34 single mutants showed no altered responses to fungal and bacterial pathogens likely due to functional redundancy of the tomato SDG33 and SDG34 genes consistent with their overlapping biochemical activities. Interestingly, tomato SDG33 or SDG34 genes rescued the disease susceptibility and early flowering phenotypes of Arabidopsis sdg8 mutant. Expression of CCR2 gene is completely inhibited in Arabidopsis sdg8 mutant attributed to loss of H3K36 di- and tri methylation at CCR2 chromatin. CCR2 gene expression was partially restored by transgenic expression of tomato SDG33 or SDG34 genes in Arabidopsis sdg8. In tomato, the single CCR2 gene is expressed independent of SDG33 or SDG33 genes suggesting that the genomic targets of the tomato HMTs are different. Unexpectedly, sdg33 and sdg34 plants were more tolerant to osmotic stress, maintain a higher water status during drought which translated to better survival after drought. Tolerance of sdg33 and sdg34 to drought stress is accompanied by higher expression of drought responsive genes. Collectively, our data demonstrate the critical role of tomato HLM in pathogen and stress tolerance likely through the regulation of gene expression. Finally, we studied tomato Receptor like cytoplasmic kinases (RLCKs). Plants perceive the presence of pathogens through Pattern Recognition Receptors (PRR) which are predominantly RLKs, and subsequently recruit RLCKs to signal to downstream regulators of defense responses. Many RLCKs were characterized from Arabidopsis for their role in signaling of responses to bacterial infection. An example of RLCKs is Arabidopsis BIK1 which is implicated in signal transmission of pathogen recognition event at the cell surface. The tomato genome encodes 647 RLK/RLCKs comprising about 2% of its predicted genes. The functions of most of these predicted tomato RLCKs and RLKs have not been determined. Previously, our lab characterized the Arabidopsis BIK1 and tomato TPK1b RLCKs for fungal resistance. Here, we conducted a reverse genetic screen focused on BIK1 and TPK1b related tomato RLCKs to identify a subset with defense functions. Virus induced gene silencing and pathogen assays conducted on 15 RLCKs identified four RLCK genes with potential role in plant immunity. Then, tomato knock out mutants were generated for four RLCK genes through CRISPR/cas9 genome editing to validate the VIGS data. Subsequently, we demonstrated that TPK07, TPK09, TPK011 and TRK04 are required for resistance to B. cinerea. The data are supported by the pathogen induced expression of these genes. Furthermore, trk04 seedlings are impaired in seedling growth responses to Jasmonic acid. Our study establishes that tomato TPK07, TPK09, TPK011 and TRK04 contribute to defense against B. cinerea but their mechanism of function needs to be elucidated in future studies.

Publications

• Type: Journal Articles Status: Published Year Published: 2021 Citation: Li, W., Liao, CJ., Bluhm, B.H. et al. A Maize (Zea mays L.) BIK1-Like Receptor-Like Cytoplasmic Kinase Contributes to Disease Resistance. Plant Mol Biol Rep (2021). https://doi.org/10.1007/s11105-021-01299-2.
• Type: Journal Articles Status: Published Year Published: 2021 Citation: Nida H, Lee S, and Mengiste T. 2021. Transcriptome analysis of early stages of sorghum grain mold disease reveals defense regulators and metabolic pathways associated with resistance. BMC Genomics 2021 Apr 22;22(1):295. doi: 10.1186/s12864-021-07609-y.
• Type: Journal Articles Status: Published Year Published: 2021 Citation: Nida H, Girma G, Mekonen M, Tirfessa A, Seyoum A, Bejiga T, Birhanu C, Dessalegn K, Senbetay T, Ayana G, Tesso T, Ejeta G, Mengiste T. 2021. Genome-wide association analysis reveals seed protein loci as determinants of variations in grain mold resistance in sorghum. Theor Appl Genet. 2021 Apr;134(4):1167-1184. doi: 10.1007/s00122-020-03762-2.
• Type: Journal Articles Status: Published Year Published: 2021 Citation: Jaiswal N, Liao CJ, Mengesha B, Han H, Lee S, Sharon A, Zhou Y, and Mengiste T. 2021. Regulation of plant immunity and growth by tomato receptor-like cytoplasmic kinase. New Phytol. doi: 10.1111/nph.17801.
• Type: Journal Articles Status: Published Year Published: 2021 Citation: Dessalegn, K., Lule, D., Nida, H. et al. Evaluation of selected Ethiopian sorghum genotypes for resistance to anthracnose. Eur J Plant Pathol (2021). https://doi.org/10.1007/s10658-021-02386-6

Progress 10/01/19 to 09/30/20

Outputs
Target Audience:The target audience includes students, the scientific community, and extension agents with a need for information Changes/Problems:The major challenge has been the reduced activities of the research labs due to the COVID-19 pandemic that caused delays in finalizing some of the projects. What opportunities for training and professional development has the project provided?The project provided training for graduate students in plant molecular biology, plant pathology, and genetics of plant disease resistance. How have the results been disseminated to communities of interest?The results were presented in the from of seminars at different meetiongs. What do you plan to do during the next reporting period to accomplish the goals?Publication of at least two peer reviewed publications on this project. These will be on tomato genes required for quantitative resistance to fungal pathogens.

Impacts
What was accomplished under these goals? The molecular mechanisms and genetic of quantitative resistance (QR) to fungal pathogens and their relationships with plant growth pathways are poorly understood. In this project we studied two classes of tomato enzymes, protein kinases and histone modifying enzymes for their function in fungal resistance. We identified histone epigenetic marks that change during responses to pathogens. Identified genes encoding histone modifying enzymes including a histone methyl transferases and demethylase Generated tomato CRISPR lines and characterized for their responses to fungal pathogens. We demonstrate that genetic improvement of crops through modification of histone epigenetic marks provides avenues for improvement of crops for disease resistance. In parallel, we identified tomato receptor-like cytoplasmic kinases which complex with upstream RLKs that are likely receptors for pathogen derived molecules. A series of loss of function tomato mutants were generated and their role in fungal resistance deciphered. Most of these are required for resistance to pathogens. Subsequently transcription factors that are downstream targets of RLCKs were isolated and their regulatory relationship determined. Signaling components from pathogen perception to defense response activation that limit fungal growth and disease symptom in infected plants were identified. Overall, further studies are required to finalize the observations and generate peer reviewed publications.

Publications

• Type: Journal Articles Status: Published Year Published: 2020 Citation: Fuyou Fu, Gezahegn Girma & Tesfaye Mengiste. 2020. Global mRNA and microRNA expression dynamics in response to anthracnose infection in sorghum. BMC Genomics 21, 760. https://doi.org/10.1186/s12864-020-07138-0

Progress 10/01/18 to 09/30/19

Outputs
Target Audience:The target audiance has been the scientific community. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The project is part of a series of studies aimed to detetrmine the fucntions of diverse tomato genes in fungal resistance. It provided an avenue to train graduate students and post doctoral fellows. How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals?We identified novelgenes and pathways that regulate fungal resistance in tomato. These will be studied in detail in te followiong years.

Impacts
What was accomplished under these goals? Endogenous peptides regulate plant immunity and growth. Systemin, a peptide specific to the Solanaceae, is known for its functions in plant responses to insect herbivory and pathogen infections. Here, we describe the identification of the tomato (Solanum lycopersicum) PEPR1/2 ORTHOLOG RECEPTOR-LIKE KINASE1 (PORK1) as the TOMATO PROTEIN KINASE1b (TPK1b) interacting protein and demonstrate its biological functions in systemin signaling and tomato immune responses. Tomato PORK1 RNA interference (RNAi) plants with significantly reduced PORK1 expression showed increased susceptibility to tobacco hornworm (Manduca sexta), reduced seedling growth sensitivity to the systemin peptide, and compromised systemin-mediated resistance to Botrytis cinerea. Systemin-induced expression of Proteinase Inhibitor II (PI-II), a classical marker for systemin signaling, was abrogated in PORK1 RNAi plants. Similarly, in response to systemin and wounding, the expression of jasmonate pathway genes was attenuated in PORK1 RNAi plants. TPK1b, a key regulator of tomato defense against B. cinerea and M. sexta, was phosphorylated by PORK1. Interestingly, wounding- and systemin-induced phosphorylation of TPK1b was attenuated when PORK1 expression was suppressed. Our data suggest that resistance to B. cinerea and M. sexta is dependent on PORK1-mediated responses to systemin and subsequent phosphorylation of TPK1b. Altogether, PORK1 regulates tomato systemin, wounding, and immune responses.

Publications

• Type: Journal Articles Status: Published Year Published: 2018 Citation: Siming Xu, Chao-Jan Liao, Namrata Jaiswal, Sanghun Lee, Dae-Jin Yun, Sang Yeol Lee, Michael Garvey, Ian Kaplan, Tesfaye Mengiste. Tomato PEPR1 ORTHOLOG RECEPTOR-LIKE KINASE1 Regulates Responses to Systemin, Necrotrophic Fungi, and Insect Herbivory. The Plant Cell 30, 2214-2229

Progress 10/01/17 to 09/30/18

Outputs
Target Audience:Our target audience have been the scientific community, in particular scientists in the plant microbe interaction. In addition, industries that are interested in the translational work from discovery to application. Changes/Problems:There were not major changes to the project. What opportunities for training and professional development has the project provided?This project was used as a ground to train studnets at all levels. How have the results been disseminated to communities of interest?Seminars, presentations and posters were made atprofessional societyconferences. What do you plan to do during the next reporting period to accomplish the goals?Weare taking the discoveries we made in the model plant Arabidopsis, test our findiongs in tomayto plants. The idea is to translate our observations into crop plants to ultimately generate disease resistance materials.

Impacts
What was accomplished under these goals? Our research identified an Arabidopsis protein that is a key global regulator of plant immunity through histone lysine methylation. Post-translational modification of histones modulates gene expression underlying diverse functions. The extent and mechanisms of the regulatory impact of histone lysine methylation (HLM) on plant immunity is poorly understood. We show that Arabidopsis histone methyl transferases SET DOMAIN GROUP (SDG8, SDG25) genes regulate pep1-, flg22-, effector-triggered immunity and systemic acquired resistance. Genome wide basal and induced transcriptome regulated by SDG8 and/or SDG25 was determined through RNA-seq. Two components of SDG-dependent transcriptome, CAROTENOID ISOMERASE2 (CCR2) and ECERIFERUM 3 (CER3), are also required for plant immunity, establishing mechanisms in defense functions of SDG8 and SDG25. CCR2 catalyzes the biosynthesis of carotenoids whereas CER3 is involved in the biosynthesis of cuticular wax. SDG8 and SDG25 affect distinct and overlapping global and locus-specific H3K4 and H3K36 methylations. The loss of immunity in sdg mutants is thus attributed to the altered global, as well as CCR2- and CER3-specific HLMs. Interestingly, loss of immunity in sdg, ccr2 and cer3 mutants is also associated with diminished accumulation of lipids and loss of cuticle integrity. In addition, sdg8 and sdg25 mutants are impaired in H2B ubiquitination (H2Bubn) at CCR2, CER3 and H2Bubn regulated R-gene, SNC1, revealing cross talk between the two histone modifications. In sum, SDG8 and SDG25 contribute to plant immunity directly through HLM or indirectly through H2Bubn and by regulating expression of plant immunity genes, accumulation of lipids, biosynthesis of carotenoids and maintenance of cuticle integrity.

Publications

• Type: Journal Articles Status: Published Year Published: 2016 Citation: Liao CJ, Lai Z, Lee S, Yun DJ, Mengiste T. 2016. Arabidopsis HOOKLESS1 Regulates Responses to Pathogens and Abscisic Acid through Interaction with MED18 and Acetylation of WRKY33 and ABI5 Chromatin. Plant Cell. 2016 Jul;28(7):1662-81

Progress 10/01/16 to 09/30/17

Outputs
Target Audience:The target audiences are the scientific community working in the area of plant microbe interactions, graduate students, and undergraduate students, and the growers with interest in genetic resistance. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The project provided trainingfor one undergraduate studentand two graduate students. Training in molecular techniques, molecular biology, plant pathology and plant-microbe interaction has been provided. How have the results been disseminated to communities of interest?Yes, some of these have been published in peer reviewed journals. What do you plan to do during the next reporting period to accomplish the goals?Primarily focus on the tomato-Botrytis interaction, to demonstrate the function of tomato receptor like kinases, acetyl transferases and methyl transferases and their functional partners in plant resistance to fungal pathogens.

Impacts
What was accomplished under these goals? The project is aimed at understanding mechanisms that underpin immune response gene expression. Towards this, we have been studying the role of chromatin modifications and their regulatory functions in defense gene expression. We have studied the functions of Arabidopsis histone acetyltransferase HOOKLESS1. Additional studies are underway in tomato to determine the real contributions of these clas of proteins in disease resistance in crop plants. HLS1 regulates plant responses to pathogens and abscisic acid (ABA) through histone acetylation at chromatin of target loci. The hls1 mutants show impaired responses to bacterial and fungal infection, accelerated senescence, and impaired responses to ABA. HLS1 modulates the expression of WRKY33 and ABA INSENSITIVE5 (ABI5), known regulators of pathogen and ABA responses, respectively, through direct association with these loci. Histone 3 acetylation (H3Ac), a positive mark of transcription, at WRKY33 and ABI5 requires HLS1 function. ABA treatment and pathogen infection enhance HLS1 recruitment and H3Ac at WRKY33. HLS1 associates with Mediator, a eukaryotic transcription co-regulatory complex, through direct interaction with mediator subunit 18 (MED18) with which it shares multiple functions. HLS1 recruits MED18 to the WRKY33 promoter, boosting WKRY33 expression, suggesting the synergetic action of HLS1 and MED18. By contrast, MED18 recruitment to ABI5 and transcriptional activation are independent of HLS1. ABA-mediated priming of resistance to fungal infection was abrogated in hls1 and wrky33 mutants but correlated with ABA-induced HLS1 accumulation. HLS1 provides a regulatory node in pathogen and hormone response pathways through interaction with the Mediator complex and important transcription factors.

Publications

• Type: Journal Articles Status: Published Year Published: 2016 Citation: Lee S, Fu F, Xu S, Lee SY, Yun DJ, Mengiste T. 2016. Global Regulation of Plant Immunity by Histone Lysine Methyl Transferases. Plant Cell 28(7):1640-61.