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Wu Y, Sexton WK, Zhang Q, Bloodgood D, Wu Y, Hooks C, Coker F, Vasquez A, Wei CI, Xiao S. Leaf abaxial immunity to powdery mildew in Arabidopsis is conferred by multiple defense mechanisms. J Exp Bot 2024; 75:1465-1478. [PMID: 37952108 DOI: 10.1093/jxb/erad450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Accepted: 11/09/2023] [Indexed: 11/14/2023]
Abstract
Powdery mildew fungi are obligate biotrophic pathogens that only invade plant epidermal cells. There are two epidermal surfaces in every plant leaf: the adaxial (upper) side and the abaxial (lower) side. While both leaf surfaces can be susceptible to adapted powdery mildew fungi in many plant species, there have been observations of leaf abaxial immunity in some plant species including Arabidopsis. The genetic basis of such leaf abaxial immunity remains unknown. In this study, we tested a series of Arabidopsis mutants defective in one or more known defense pathways with the adapted powdery mildew isolate Golovinomyces cichoracearum UCSC1. We found that leaf abaxial immunity was significantly compromised in mutants impaired for both the EDS1/PAD4- and PEN2/PEN3-dependent defenses. Consistently, expression of EDS1-yellow fluorescent protein and PEN2-green fluorescent protein fusions from their respective native promoters in the respective eds1-2 and pen2-1 mutant backgrounds was higher in the abaxial epidermal cells than in the adaxial epidermal cells. Altogether, our results indicate that leaf abaxial immunity against powdery mildew in Arabidopsis is at least partially due to enhanced EDS1/PAD4- and PEN2/PEN3-dependent defenses. Such transcriptionally pre-programmed defense mechanisms may underlie leaf abaxial immunity in other plant species such as hemp and may be exploited for engineering adaxial immunity against powdery mildew fungi in crop plants.
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Affiliation(s)
- Ying Wu
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA
| | - W Kyle Sexton
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA
| | - Qiong Zhang
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA
| | - David Bloodgood
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA
| | - Yan Wu
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA
| | - Caroline Hooks
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA
| | - Frank Coker
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA
| | - Andrea Vasquez
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA
| | - Cheng-I Wei
- Department of Nutrition and Food Science, University of Maryland College Park, MD 20742, USA
| | - Shunyuan Xiao
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD 20850, USA
- Department of Plant Sciences and Landscape Architecture, University of Maryland College Park, MD 20742, USA
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Wu Y, Sexton W, Yang B, Xiao S. Genetic approaches to dissect plant nonhost resistance mechanisms. Mol Plant Pathol 2023; 24:272-283. [PMID: 36617319 PMCID: PMC9923397 DOI: 10.1111/mpp.13290] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/11/2022] [Revised: 10/17/2022] [Accepted: 12/01/2022] [Indexed: 06/17/2023]
Abstract
Nonhost resistance (NHR) refers to the immunity of most tested genotypes of a plant species to most tested variants of a pathogen species. Thus, NHR is broad spectrum and durable in nature and constitutes a major safety barrier against invasion of a myriad of potentially pathogenic microbes in any plants including domesticated crops. Genetic study of NHR is generally more difficult compared to host resistance mainly because NHR is genetically more complicated and often lacks intraspecific polymorphisms. Nevertheless, substantial progress has been made towards the understanding of the molecular basis of NHR in the past two decades using various approaches. Not surprisingly, molecular mechanisms of NHR revealed so far encompasses pathogen-associated molecular pattern-triggered immunity and effector-triggered immunity. In this review, we briefly discuss the inherent difficulty in genetic studies of NHR and summarize the main approaches that have been taken to identify genes contributing to NHR. We also discuss new enabling strategies for dissecting multilayered NHR in model plants with a focus on NHR against filamentous pathogens, especially biotrophic pathogens such as powdery mildew and rust fungi.
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Affiliation(s)
- Ying Wu
- Institute for Bioscience and Biotechnology ResearchUniversity of Maryland College ParkRockvilleMarylandUSA
| | - William Sexton
- Institute for Bioscience and Biotechnology ResearchUniversity of Maryland College ParkRockvilleMarylandUSA
| | - Bing Yang
- Division of Plant Science and Technology, Bond Life Sciences CenterUniversity of MissouriColumbiaMissouriUSA
- Donald Danforth Plant Science CenterSt. LouisMissouriUSA
| | - Shunyuan Xiao
- Institute for Bioscience and Biotechnology ResearchUniversity of Maryland College ParkRockvilleMarylandUSA
- Department of Plant Science and Landscape ArchitectureUniversity of MarylandCollege ParkMarylandUSA
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Zhang Q, Berkey R, Blakeslee JJ, Lin J, Ma X, King H, Liddle A, Guo L, Munnik T, Wang X, Xiao S. Arabidopsis phospholipase Dα1 and Dδ oppositely modulate EDS1- and SA-independent basal resistance against adapted powdery mildew. J Exp Bot 2018; 69:3675-3688. [PMID: 29912376 PMCID: PMC6022666 DOI: 10.1093/jxb/ery146] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 04/10/2018] [Indexed: 05/04/2023]
Abstract
Plants use a tightly regulated immune system to fight off various pathogens. Phospholipase D (PLD) and its product, phosphatidic acid, have been shown to influence plant immunity; however, the underlying mechanisms remain unclear. Here, we show that the Arabidopsis mutants pldα1 and pldδ, respectively, exhibited enhanced resistance and enhanced susceptibility to both well-adapted and poorly adapted powdery mildew pathogens, and a virulent oomycete pathogen, indicating that PLDα1 negatively while PLDδ positively modulates post-penetration resistance. The pldα1δ double mutant showed a similar infection phenotype to pldα1, genetically placing PLDα1 downstream of PLDδ. Detailed genetic analyses of pldδ with mutations in genes for salicylic acid (SA) synthesis (SID2) and/or signaling (EDS1 and PAD4), measurement of SA and jasmonic acid (JA) levels, and expression of their respective reporter genes indicate that PLDδ contributes to basal resistance independent of EDS1/PAD4, SA, and JAsignaling. Interestingly, while PLDα1-enhanced green fluorescent protein (eGFP) was mainly found in the tonoplast before and after haustorium invasion, PLDδ-eGFP's focal accumulation to the plasma membrane around the fungal penetration site appeared to be suppressed by adapted powdery mildew. Together, our results demonstrate that PLDα1 and PLDδ oppositely modulate basal, post-penetration resistance against powdery mildew through a non-canonical mechanism that is independent of EDS1/PAD4, SA, and JA.
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Affiliation(s)
- Qiong Zhang
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD, USA
| | - Robert Berkey
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD, USA
| | - Joshua J Blakeslee
- Department of Horticulture and Crop Science, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, OH, USA
| | - Jinshan Lin
- Department of Horticulture and Crop Science, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, OH, USA
| | - Xianfeng Ma
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD, USA
| | - Harlan King
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD, USA
| | - Anna Liddle
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD, USA
| | - Liang Guo
- National Key Laboratory of Crop Genetic Improvement, College of Plant Sciences, Huazhong Agricultural University, Wuhan, China
| | - Teun Munnik
- Section of Plant Physiology, Swammerdam Institute for Life Sciences, University of Amsterdam, The Netherlands
| | - Xuemin Wang
- Department of Biology, University of Missouri, St. Louis, MO, USA
- Donald Danforth Plant Science Center, St. Louis, MO, USA
| | - Shunyuan Xiao
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD, USA
- Department of Plant Sciences and Landscape Architecture, University of Maryland, Rockville, MD, USA
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