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Alvarez S, Hicks LM, Pandey S. ABA-dependent and -independent G-protein signaling in Arabidopsis roots revealed through an iTRAQ proteomics approach. J Proteome Res 2011; 10:3107-22. [PMID: 21545083 DOI: 10.1021/pr2001786] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Heterotrimeric G-proteins are important signal transducers in all eukaryotes. The plant hormone abscisic acid (ABA) has emerged as a key regulator of G-protein-mediated signaling pathways in plants. ABA-regulation of G-protein signaling involves both conventional and novel mechanisms. We have utilized the null mutant of the Arabidopsis G-protein α subunit gpa1 to evaluate to what extent ABA-dependent changes in the proteome are regulated by G-proteins. We used Arabidopsis root tissue as both ABA and G-proteins, individually and in combination, affect root growth and development. We identified 720 proteins, of which 42 showed GPA1-dependent and 74 showed ABA-dependent abundance changes. A majority of ABA-regulated proteins were also GPA1-dependent. Our data provide insight into how tissue specificity might be achieved in ABA-regulated G-protein signaling. A number of proteins related to ER body formation and intracellular trafficking were altered in gpa1 mutant, suggesting a novel role for GPA1 in these pathways. A potential link between ABA metabolism and ABA signaling was also revealed. The comparison of protein abundance changes in the absence of ABA offers clues to the role of GPA1 in ABA-independent signaling pathways, for example, regulation of cell division. These findings substantially contribute to our knowledge of G-protein signaling mechanisms in plants.
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Affiliation(s)
- Sophie Alvarez
- Donald Danforth Plant Science Center, 975 North Warson Road, St. Louis, Missouri 63132, USA
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202
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Ando S, Sato Y, Shigemori H, Shimizu T, Okada K, Yamane H, Jikumaru Y, Kamiya Y, Yamada K, Akimoto-Tomiyama C, Tanabe S, Nishizawa Y, Minami E. Identification and characterization of 2'-deoxyuridine from the supernatant of conidial suspensions of rice blast fungus as an infection-promoting factor in rice plants. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2011; 24:519-532. [PMID: 21171893 DOI: 10.1094/mpmi-07-10-0172] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We previously detected infection-promoting activity in the supernatant of the conidial suspension (SCS) of the rice blast fungus. In the present study, a molecule carrying the activity was purified and identified as 2'-deoxyuridine (dU). The infection-promoting activity of dU was strictly dependent on its chemical structure and displayed characteristics consistent with those of the SCS. Notably, the activity of dU was exclusively detected during interactions between rice and virulent isolates of the fungus, the number of susceptible lesions in leaf blades was increased by dU, and nonhost resistance in rice plants was not affected by treatment with dU. In addition, the expression of pathogensis-related genes, accumulation of H(2)O(2), and production of phytoalexins in rice in response to inoculation with virulent fungal isolates was not suppressed by dU. The infection-promoting activity of dU was not accompanied by elevated levels of endogenous abscissic acid, which is known to modify plant-pathogen interactions, and was not detected in interactions between oat plants and a virulent oat blast fungus isolate. Taken together, these results demonstrate that dU is a novel infection-promoting factor that acts specifically during compatible interactions between rice plants and rice blast fungus in a mode distinct from that of toxins and suppressors.
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Affiliation(s)
- Sugihiro Ando
- Division of Plant Sciences, National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, Ibaraki 305-8602, Japan
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203
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Aubert Y, Leba LJ, Cheval C, Ranty B, Vavasseur A, Aldon D, Galaud JP. Involvement of RD20, a member of caleosin family, in ABA-mediated regulation of germination in Arabidopsis thaliana. PLANT SIGNALING & BEHAVIOR 2011; 6:538-40. [PMID: 21673513 PMCID: PMC3142386 DOI: 10.4161/psb.6.4.14836] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The RD20 gene encodes a member of the caleosin family, which is primarily known to function in the mobilization of seed storage lipids during germination. In contrast to other caleosins, RD20 expression is early-induced by water deficit conditions and we recently provided genetic evidence for its positive role in drought tolerance in Arabidopsis. RD20 is also responsive to pathogen infection and is constitutively expressed in diverse tissues and organs during development suggesting additional roles for this caleosin. This addendum describes further exploration of phenotypic alterations in T-DNA insertional rd20 mutant and knock-out complemented transgenic plants in the context of early development and susceptibility to a phytopathogenic bacteria. We show that the RD20 gene is involved in ABA-mediated inhibition of germination and does not play a significant role in plant defense against Pseudomonas syringae.
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Affiliation(s)
- Yann Aubert
- Laboratoire Surfaces Cellulaires et Signalisation chez les Végétaux; UMR 5546; CNRS-Université de Toulouse; Castanet-Tolosan, France
| | - Louis-Jérome Leba
- Laboratoire Surfaces Cellulaires et Signalisation chez les Végétaux; UMR 5546; CNRS-Université de Toulouse; Castanet-Tolosan, France
| | - Cécilia Cheval
- Laboratoire Surfaces Cellulaires et Signalisation chez les Végétaux; UMR 5546; CNRS-Université de Toulouse; Castanet-Tolosan, France
| | - Benoit Ranty
- Laboratoire Surfaces Cellulaires et Signalisation chez les Végétaux; UMR 5546; CNRS-Université de Toulouse; Castanet-Tolosan, France
| | - Alain Vavasseur
- Laboratoires des Echanges Membranaires et Signalisation; UMR 6191; CNRS-CEA-Université Aix-Marseille II; Commissariat à l'Energie Atomique-Cadarache Bat 156; Saint-Paul-lez-Durance, France
| | - Didier Aldon
- Laboratoire Surfaces Cellulaires et Signalisation chez les Végétaux; UMR 5546; CNRS-Université de Toulouse; Castanet-Tolosan, France
| | - Jean-Philippe Galaud
- Laboratoire Surfaces Cellulaires et Signalisation chez les Végétaux; UMR 5546; CNRS-Université de Toulouse; Castanet-Tolosan, France
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204
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Seo YS, Chern M, Bartley LE, Han M, Jung KH, Lee I, Walia H, Richter T, Xu X, Cao P, Bai W, Ramanan R, Amonpant F, Arul L, Canlas PE, Ruan R, Park CJ, Chen X, Hwang S, Jeon JS, Ronald PC. Towards establishment of a rice stress response interactome. PLoS Genet 2011; 7:e1002020. [PMID: 21533176 PMCID: PMC3077385 DOI: 10.1371/journal.pgen.1002020] [Citation(s) in RCA: 145] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2010] [Accepted: 01/20/2011] [Indexed: 01/01/2023] Open
Abstract
Rice (Oryza sativa) is a staple food for more than half the world and a model for studies of monocotyledonous species, which include cereal crops and candidate bioenergy grasses. A major limitation of crop production is imposed by a suite of abiotic and biotic stresses resulting in 30%-60% yield losses globally each year. To elucidate stress response signaling networks, we constructed an interactome of 100 proteins by yeast two-hybrid (Y2H) assays around key regulators of the rice biotic and abiotic stress responses. We validated the interactome using protein-protein interaction (PPI) assays, co-expression of transcripts, and phenotypic analyses. Using this interactome-guided prediction and phenotype validation, we identified ten novel regulators of stress tolerance, including two from protein classes not previously known to function in stress responses. Several lines of evidence support cross-talk between biotic and abiotic stress responses. The combination of focused interactome and systems analyses described here represents significant progress toward elucidating the molecular basis of traits of agronomic importance.
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Affiliation(s)
- Young-Su Seo
- Department of Plant Pathology, University of California Davis, Davis, California, United States of America
| | - Mawsheng Chern
- Department of Plant Pathology, University of California Davis, Davis, California, United States of America
- The Joint Bioenergy Institute, Emeryville, California, United States of America
| | - Laura E. Bartley
- Department of Plant Pathology, University of California Davis, Davis, California, United States of America
- The Joint Bioenergy Institute, Emeryville, California, United States of America
| | - Muho Han
- Plant Metabolism Research Center and Graduate School of Biotechnology, Kyung Hee University, Yongin, Korea
| | - Ki-Hong Jung
- Department of Plant Pathology, University of California Davis, Davis, California, United States of America
- The Joint Bioenergy Institute, Emeryville, California, United States of America
- Department of Plant Molecular Systems Biotechnology and Crop Biotech Institute, Kyung Hee University, Yongin, Korea
| | - Insuk Lee
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
| | - Harkamal Walia
- Department of Plant Pathology, University of California Davis, Davis, California, United States of America
| | - Todd Richter
- Department of Plant Pathology, University of California Davis, Davis, California, United States of America
| | - Xia Xu
- Department of Plant Pathology, University of California Davis, Davis, California, United States of America
| | - Peijian Cao
- Department of Plant Pathology, University of California Davis, Davis, California, United States of America
| | - Wei Bai
- Department of Plant Pathology, University of California Davis, Davis, California, United States of America
| | - Rajeshwari Ramanan
- Department of Plant Pathology, University of California Davis, Davis, California, United States of America
- Plant Sciences, Centre for Cellular and Molecular Biology, Hyderabad, India
| | - Fawn Amonpant
- Department of Plant Pathology, University of California Davis, Davis, California, United States of America
| | - Loganathan Arul
- Department of Plant Pathology, University of California Davis, Davis, California, United States of America
| | - Patrick E. Canlas
- Department of Plant Pathology, University of California Davis, Davis, California, United States of America
| | - Randy Ruan
- Department of Plant Pathology, University of California Davis, Davis, California, United States of America
| | - Chang-Jin Park
- Department of Plant Pathology, University of California Davis, Davis, California, United States of America
| | - Xuewei Chen
- Department of Plant Pathology, University of California Davis, Davis, California, United States of America
| | - Sohyun Hwang
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
| | - Jong-Seong Jeon
- Plant Metabolism Research Center and Graduate School of Biotechnology, Kyung Hee University, Yongin, Korea
| | - Pamela C. Ronald
- Department of Plant Pathology, University of California Davis, Davis, California, United States of America
- The Joint Bioenergy Institute, Emeryville, California, United States of America
- Plant Metabolism Research Center and Graduate School of Biotechnology, Kyung Hee University, Yongin, Korea
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205
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Jin YM, Jung J, Jeon H, Won SY, Feng Y, Kang JS, Lee SY, Cheong JJ, Koiwa H, Kim M. AtCPL5, a novel Ser-2-specific RNA polymerase II C-terminal domain phosphatase, positively regulates ABA and drought responses in Arabidopsis. THE NEW PHYTOLOGIST 2011; 190:57-74. [PMID: 21231936 DOI: 10.1111/j.1469-8137.2010.03601.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Arabidopsis RNA polymerase II (RNAPII) C-terminal domain (CTD) phosphatases regulate stress-responsive gene expression and plant development via the dephosphorylation of serine (Ser) residues of the CTD. Some of these phosphatases (CTD phosphatase-like 1 (CPL1) to CPL3) negatively regulate ABA and stress responses. Here, we isolated AtCPL5, a cDNA encoding a protein containing two CTD phosphatase domains (CPDs). To characterize AtCPL5, we analyzed the gene expression patterns and subcellular protein localization, investigated various phenotypes of AtCPL5-overexpressors and knockout mutants involved in ABA and drought responses, performed microarray and RNA hybridization analyses using AtCPL5-overexpressors, and assessed the CTD phosphatase activities of the purified AtCPL5 and each CPD of the protein. Transcripts of the nucleus-localized AtCPL5 were induced by ABA and drought. AtCPL5-overexpressors exhibited ABA-hypersensitive phenotypes (increased inhibition of seed germination, seedling growth, and stomatal aperture), lower transpiration rates upon dehydration, and enhanced drought tolerance, while the knockout mutants showed weak ABA hyposensitivity. AtCPL5 overexpression changed the expression of numerous genes, including those involved in ABA-mediated responses. In contrast to Ser-5-specific phosphatase activity of the negative stress response regulators, purified AtCPL5 and each CPD of the protein specifically dephosphorylated Ser-2 in RNAPII CTD. We conclude that AtCPL5 is a unique CPL family protein that positively regulates ABA-mediated development and drought responses in Arabidopsis.
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MESH Headings
- Abscisic Acid/pharmacology
- Amino Acid Sequence
- Arabidopsis/drug effects
- Arabidopsis/enzymology
- Arabidopsis/genetics
- Arabidopsis/physiology
- Arabidopsis Proteins/chemistry
- Arabidopsis Proteins/genetics
- Arabidopsis Proteins/metabolism
- Cell Nucleus/drug effects
- Cell Nucleus/metabolism
- Cloning, Molecular
- DNA, Complementary/genetics
- Droughts
- Gene Expression Regulation, Plant/drug effects
- Gene Knockout Techniques
- Genes, Plant
- Glucuronidase/metabolism
- Molecular Sequence Data
- Phosphoserine/metabolism
- Phylogeny
- Plant Stomata/drug effects
- Plants, Genetically Modified
- Protein Structure, Tertiary
- RNA Polymerase II/chemistry
- RNA Polymerase II/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Real-Time Polymerase Chain Reaction
- Stress, Physiological/drug effects
- Stress, Physiological/genetics
- Subcellular Fractions/drug effects
- Subcellular Fractions/metabolism
- Up-Regulation/drug effects
- Up-Regulation/genetics
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Affiliation(s)
- Yong-Mei Jin
- Department of Agricultural Biotechnology, Center for Agricultural Biomaterials, Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, 151-921, Republic of Korea
| | - Jinwook Jung
- Department of Agricultural Biotechnology, Center for Agricultural Biomaterials, Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, 151-921, Republic of Korea
| | - Hyesung Jeon
- Department of Agricultural Biotechnology, Center for Agricultural Biomaterials, Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, 151-921, Republic of Korea
| | - So Youn Won
- Department of Agricultural Biotechnology, Center for Agricultural Biomaterials, Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, 151-921, Republic of Korea
- Rural Development Administration, Suwon, 441-707, Republic of Korea
| | - Yue Feng
- Faculty of Molecular and Environmental Plant Science, Vegetable and Fruit Improvement Center, Department of Horticultural Sciences, Texas A&M University, College Station, TX 77843-2133, USA
| | - Jae-Sook Kang
- Division of Applied Life Science (BK21 Program), Gyeongsang National University, Jinju, 660-701, Republic of Korea
| | - Sang Yeol Lee
- Division of Applied Life Science (BK21 Program), Gyeongsang National University, Jinju, 660-701, Republic of Korea
| | - Jong-Joo Cheong
- Department of Agricultural Biotechnology, Center for Agricultural Biomaterials, Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, 151-921, Republic of Korea
| | - Hisashi Koiwa
- Faculty of Molecular and Environmental Plant Science, Vegetable and Fruit Improvement Center, Department of Horticultural Sciences, Texas A&M University, College Station, TX 77843-2133, USA
| | - Minkyun Kim
- Department of Agricultural Biotechnology, Center for Agricultural Biomaterials, Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, 151-921, Republic of Korea
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206
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Luna E, Pastor V, Robert J, Flors V, Mauch-Mani B, Ton J. Callose deposition: a multifaceted plant defense response. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2011; 24:183-93. [PMID: 20955078 DOI: 10.1094/mpmi-07-10-0149] [Citation(s) in RCA: 406] [Impact Index Per Article: 31.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Callose deposition in Arabidopsis has emerged as a popular model system to quantify activity of plant immunity. However, there has been a noticeable rise in contradicting reports about the regulation of pathogen-induced callose. To address this controversy, we have examined the robustness of callose deposition under different growth conditions and in response to two different pathogen-associated molecular patterns, the flagellin epitope Flg22 and the polysaccharide chitosan. Based on a commonly used hydroponic culture system, we found that variations in growth conditions have a major impact on the plant's overall capacity to deposit callose. This environmental variability correlated with levels of hydrogen peroxide (H₂O₂) production. Depending on the growth conditions, pretreatment with abscissic acid stimulated or repressed callose deposition. Despite a similar effect of growth conditions on Flg22- and chitosan-induced callose, both responses showed differences in timing, tissue responsiveness, and colocalization with H₂O₂. Furthermore, mutant analysis revealed that Flg22- and chitosan-induced callose differ in the requirement for the NADPH oxidase RBOHD, the glucosinolate regulatory enzymes VTC1 and PEN2, and the callose synthase PMR4. Our study demonstrates that callose is a multifaceted defense response that is controlled by distinct signaling pathways, depending on the environmental conditions and the challenging pathogen-associated molecular pattern.
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Affiliation(s)
- Estrella Luna
- Department of Biological Chemistry, Rothamsted Research, Harpenden AL5 2JQ UK
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207
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Beattie GA. Water relations in the interaction of foliar bacterial pathogens with plants. ANNUAL REVIEW OF PHYTOPATHOLOGY 2011; 49:533-55. [PMID: 21438680 DOI: 10.1146/annurev-phyto-073009-114436] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
This review examines the many ways in which water influences the relations between foliar bacterial pathogens and plants. As a limited resource in aerial plant tissues, water is subject to manipulation by both plants and pathogens. A model is emerging that suggests that plants actively promote localized desiccation at the infection site and thus restrict pathogen growth as one component of defense. Similarly, many foliar pathogens manipulate water relations as one component of pathogenesis. Nonvascular pathogens do this using effectors and other molecules to alter hormonal responses and enhance intercellular watersoaking, whereas vascular pathogens use many mechanisms to cause wilt. Because of water limitations on phyllosphere surfaces, bacterial colonists, including pathogens, benefit from the protective effects of cellular aggregation, synthesis of hygroscopic polymers, and uptake and production of osmoprotective compounds. Moreover, these bacteria employ tactics for scavenging and distributing water to overcome water-driven barriers to nutrient acquisition, movement, and signal exchange on plant surfaces.
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Affiliation(s)
- Gwyn A Beattie
- Department of Plant Pathology and Microbiology, Iowa State University, Ames, Iowa 50011-3211, USA.
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208
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Chen H, Lai Z, Shi J, Xiao Y, Chen Z, Xu X. Roles of arabidopsis WRKY18, WRKY40 and WRKY60 transcription factors in plant responses to abscisic acid and abiotic stress. BMC PLANT BIOLOGY 2010; 10:281. [PMID: 21167067 PMCID: PMC3023790 DOI: 10.1186/1471-2229-10-281] [Citation(s) in RCA: 302] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2009] [Accepted: 12/19/2010] [Indexed: 05/17/2023]
Abstract
BACKGROUND WRKY transcription factors are involved in plant responses to both biotic and abiotic stresses. Arabidopsis WRKY18, WRKY40, and WRKY60 transcription factors interact both physically and functionally in plant defense responses. However, their role in plant abiotic stress response has not been directly analyzed. RESULTS We report that the three WRKYs are involved in plant responses to abscisic acid (ABA) and abiotic stress. Through analysis of single, double, and triple mutants and overexpression lines for the WRKY genes, we have shown that WRKY18 and WRKY60 have a positive effect on plant ABA sensitivity for inhibition of seed germination and root growth. The same two WRKY genes also enhance plant sensitivity to salt and osmotic stress. WRKY40, on the other hand, antagonizes WRKY18 and WRKY60 in the effect on plant sensitivity to ABA and abiotic stress in germination and growth assays. Both WRKY18 and WRKY40 are rapidly induced by ABA, while induction of WRKY60 by ABA is delayed. ABA-inducible expression of WRKY60 is almost completely abolished in the wrky18 and wrky40 mutants. WRKY18 and WRKY40 recognize a cluster of W-box sequences in the WRKY60 promoter and activate WRKY60 expression in protoplasts. Thus, WRKY60 might be a direct target gene of WRKY18 and WRKY40 in ABA signaling. Using a stable transgenic reporter/effector system, we have shown that both WRKY18 and WRKY60 act as weak transcriptional activators while WRKY40 is a transcriptional repressor in plant cells. CONCLUSIONS We propose that the three related WRKY transcription factors form a highly interacting regulatory network that modulates gene expression in both plant defense and stress responses by acting as either transcription activator or repressor.
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Affiliation(s)
- Han Chen
- State Key Laboratory of Biocontrol and Key Laboratory of Gene Engineering of the Ministry of Education, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Zhibing Lai
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907-2054, USA
| | - Junwei Shi
- State Key Laboratory of Biocontrol and Key Laboratory of Gene Engineering of the Ministry of Education, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Yong Xiao
- State Key Laboratory of Biocontrol and Key Laboratory of Gene Engineering of the Ministry of Education, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Zhixiang Chen
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907-2054, USA
| | - Xinping Xu
- State Key Laboratory of Biocontrol and Key Laboratory of Gene Engineering of the Ministry of Education, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
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209
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Orellana S, Yañez M, Espinoza A, Verdugo I, González E, Ruiz-Lara S, Casaretto JA. The transcription factor SlAREB1 confers drought, salt stress tolerance and regulates biotic and abiotic stress-related genes in tomato. PLANT, CELL & ENVIRONMENT 2010; 33:2191-208. [PMID: 20807374 DOI: 10.1111/j.1365-3040.2010.02220.x] [Citation(s) in RCA: 127] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Members of the abscisic acid-responsive element binding protein (AREB)/abscisic acid-responsive element binding factor (ABF) subfamily of basic leucine zipper (bZIP) transcription factors have been implicated in abscisic acid (ABA) and abiotic stress responses in plants. Here we describe two members identified in cultivated tomato (Solanum lycopersicum), named SlAREB1 and SlAREB2. Expression of SlAREB1 and SlAREB2 is induced by drought and salinity in both leaves and root tissues, although that of SlAREB1 was more affected. In stress assays, SlAREB1-overexpressing transgenic tomato plants showed increased tolerance to salt and water stress compared to wild-type and SlAREB1-down-regulating transgenic plants, as assessed by physiological parameters such as relative water content (RWC), chlorophyll fluorescence and damage by lipoperoxidation. In order to identify SlAREB1 target genes responsible for the enhanced tolerance, microarray and cDNA-amplified fragment length polymorphism (AFLP) analyses were performed. Genes encoding oxidative stress-related proteins, lipid transfer proteins (LTPs), transcription regulators and late embryogenesis abundant proteins were found among the up-regulated genes in SlAREB1-overexpressing lines, especially in aerial tissue. Notably, several genes encoding defence proteins associated with responses to biotic stress (e.g. pathogenesis-related proteins, protease inhibitors, and catabolic enzymes) were also up-regulated by SlAREB1 overexpression, suggesting that this bZIP transcription factor is involved in ABA signals that participate in abiotic stress and possibly in response to pathogens.
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Affiliation(s)
- Sandra Orellana
- Instituto de Biología Vegetal y Biotecnología, Universidad de Talca,Talca, Chile
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210
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Bechtold U, Lawson T, Mejia-Carranza J, Meyer RC, Brown IR, Altmann T, Ton J, Mullineaux PM. Constitutive salicylic acid defences do not compromise seed yield, drought tolerance and water productivity in the Arabidopsis accession C24. PLANT, CELL & ENVIRONMENT 2010; 33:1959-73. [PMID: 20573051 DOI: 10.1111/j.1365-3040.2010.02198.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Plants that constitutively express otherwise inducible disease resistance traits often suffer a depressed seed yield in the absence of a challenge by pathogens. This has led to the view that inducible disease resistance is indispensable, ensuring that minimal resources are diverted from growth, reproduction and abiotic stress tolerance. The Arabidopsis genotype C24 has enhanced basal resistance, which was shown to be caused by permanent expression of normally inducible salicylic acid (SA)-regulated defences. However, the seed yield of C24 was greatly enhanced in comparison to disease-resistant mutants that display identical expression of SA defences. Under both water-replete and -limited conditions, C24 showed no difference and increased seed yield, respectively, in comparison with pathogen-susceptible genotypes. C24 was the most drought-tolerant genotype and showed elevated water productivity, defined as seed yield per plant per millilitre water consumed, and achieved this by displaying adjustments to both its development and transpiration efficiency (TE). Therefore, constitutive high levels of disease resistance in C24 do not affect drought tolerance, seed yield and seed viability. This study demonstrates that it will be possible to combine traits that elevate basal disease resistance and improve water productivity in crop species, and such traits need not be mutually exclusive.
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Affiliation(s)
- Ulrike Bechtold
- Department of Biological Sciences, University of Essex, Colchester CO43SQ, UK.
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211
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Mhamdi A, Queval G, Chaouch S, Vanderauwera S, Van Breusegem F, Noctor G. Catalase function in plants: a focus on Arabidopsis mutants as stress-mimic models. JOURNAL OF EXPERIMENTAL BOTANY 2010; 61:4197-220. [PMID: 20876333 DOI: 10.1093/jxb/erq282] [Citation(s) in RCA: 455] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Hydrogen peroxide (H(2)O(2)) is an important signal molecule involved in plant development and environmental responses. Changes in H(2)O(2) availability can result from increased production or decreased metabolism. While plants contain several types of H(2)O(2)-metabolizing proteins, catalases are highly active enzymes that do not require cellular reductants as they primarily catalyse a dismutase reaction. This review provides an update on plant catalase genes, function, and subcellular localization, with a focus on recent information generated from studies on Arabidopsis. Original data are presented on Arabidopsis catalase single and double mutants, and the use of some of these lines as model systems to investigate the outcome of increases in intracellular H(2)O(2) are discussed. Particular attention is paid to interactions with cell thiol-disulphide status; the use of catalase-deficient plants to probe the apparent redundancy of reductive H(2)O(2)-metabolizing pathways; the importance of irradiance and growth daylength in determining the outcomes of catalase deficiency; and the induction of pathogenesis-related responses in catalase-deficient lines. Within the context of strategies aimed at understanding and engineering plant stress responses, the review also considers whether changes in catalase activities in wild-type plants are likely to be a significant part of plant responses to changes in environmental conditions or biotic challenge.
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Affiliation(s)
- Amna Mhamdi
- Institut de Biologie des Plantes, UMR CNRS 8618, Université de Paris sud, F-91405 Orsay cedex, France
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212
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Curvers K, Seifi H, Mouille G, de Rycke R, Asselbergh B, Van Hecke A, Vanderschaeghe D, Höfte H, Callewaert N, Van Breusegem F, Höfte M. Abscisic acid deficiency causes changes in cuticle permeability and pectin composition that influence tomato resistance to Botrytis cinerea. PLANT PHYSIOLOGY 2010; 154:847-60. [PMID: 20709830 PMCID: PMC2949027 DOI: 10.1104/pp.110.158972] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Accepted: 08/08/2010] [Indexed: 05/19/2023]
Abstract
A mutant of tomato (Solanum lycopersicum) with reduced abscisic acid (ABA) production (sitiens) exhibits increased resistance to the necrotrophic fungus Botrytis cinerea. This resistance is correlated with a rapid and strong hydrogen peroxide-driven cell wall fortification response in epidermis cells that is absent in tomato with normal ABA production. Moreover, basal expression of defense genes is higher in the mutant compared with the wild-type tomato. Given the importance of this fast response in sitiens resistance, we investigated cell wall and cuticle properties of the mutant at the chemical, histological, and ultrastructural levels. We demonstrate that ABA deficiency in the mutant leads to increased cuticle permeability, which is positively correlated with disease resistance. Furthermore, perturbation of ABA levels affects pectin composition. sitiens plants have a relatively higher degree of pectin methylesterification and release different oligosaccharides upon inoculation with B. cinerea. These results show that endogenous plant ABA levels affect the composition of the tomato cuticle and cell wall and demonstrate the importance of cuticle and cell wall chemistry in shaping the outcome of this plant-fungus interaction.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Monica Höfte
- Laboratory of Phytopathology (K.C., H.S., B.A., M.H.) and Department of Plant Biotechnology and Genetics (K.C., R.d.R., F.V.B.), Ghent University, B–9000 Ghent, Belgium; Department of Plant Systems Biology (K.C., R.d.R., F.V.B.) and Department for Molecular Biomedical Research (A.V.H., D.V., N.C.), VIB, B–9052 Ghent, Belgium; Plate-forme de Chimie du Végétal, Institut Jean-Pierre Bourgin, UMR1318, Institut National de la Recherche Agronomique, 78026 Versailles cedex, France (G.M., H.H.); Department of Molecular Genetics, Flanders Institute for Biotechnology, B–2660 Wilrijk, Belgium (B.A.)
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213
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Miao W, Wang X, Song C, Wang Y, Ren Y, Wang J. Transcriptome analysis of Hpa1Xoo transformed cotton revealed constitutive expression of genes in multiple signalling pathways related to disease resistance. JOURNAL OF EXPERIMENTAL BOTANY 2010; 61:4263-75. [PMID: 20667962 PMCID: PMC2955741 DOI: 10.1093/jxb/erq227] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Revised: 07/05/2010] [Accepted: 07/06/2010] [Indexed: 05/20/2023]
Abstract
The transcriptome profile in leaves and roots of the transgenic cotton line T-34 expressing hpa1(Xoo) from Xanthomonas oryzae pv. oryzae was analysed using a customized 12k cotton cDNA microarray. A total of 530 cDNA transcripts involved in 34 pathways were differentially expressed in the transgenic line T-34, in which 123 differentially expressed genes were related to the cotton defence responses including the hypersensitive reaction, defence responses associated with the recognition of pathogen-derived elicitors, and defence signalling pathways mediated by salicylic acid, jasmonic acid, ethylene, auxin, abscicic acid, and Ca(2+). Furthermore, transcripts encoding various leucine-rich protein kinases and mitogen-activated protein kinases were up-regulated in the transgenic line T-34 and expression of transcripts related to the energy producing and consuming pathway was also increased, which suggested that the enhanced metabolism related to the host defence response in the transgenic line T-34 imposed an increased energy demand on the transgenic plant.
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Affiliation(s)
- Weiguo Miao
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
- Department of Environment and Plant Protection, Hainan University, Haikou 570228, China
| | - Xiben Wang
- Cereal Research Centre, Agriculture and Agri-Food Canada, Winnipeg, Manitoba, Canada R3T 2N9
| | - Congfeng Song
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | - Yu Wang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | | | - Jinsheng Wang
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
- To whom correspondence should be addressed: E-mail:
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214
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Dileo MV, Pye MF, Roubtsova TV, Duniway JM, Macdonald JD, Rizzo DM, Bostock RM. Abscisic acid in salt stress predisposition to phytophthora root and crown rot in tomato and chrysanthemum. PHYTOPATHOLOGY 2010; 100:871-9. [PMID: 20701484 DOI: 10.1094/phyto-100-9-0871] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Plants respond to changes in the environment with complex signaling networks, often under control of phytohormones that generate positive and negative crosstalk among downstream effectors of the response. Accordingly, brief dehydration stresses such as salinity and water deficit, which induce a rapid and transient systemic increase in levels of abscisic acid (ABA), can influence disease response pathways. ABA has been associated with susceptibility of plants to bacteria, fungi, and oomycetes but relatively little attention has been directed at its role in abiotic stress predisposition to root pathogens. This study examines the impact of brief salinity stress on infection of tomato and chrysanthemum roots by Phytophthora spp. Roots of plants in hydroponic culture exposed to a brief episode of salt (sodium chloride) stress prior to or after inoculation were severely diseased relative to nonstressed plants. Tomato roots remained in a predisposed state up to 24 h following removal from the stress. An increase in root ABA levels in tomato preceded or temporally paralleled the onset of stress-induced susceptibility, with levels declining in roots prior to recovery from the predisposed state. Exogenous ABA could substitute for salt stress and significantly enhanced pathogen colonization and disease development. ABA-deficient tomato mutants lacked the predisposition response, which could be restored by complementation of the mutant with exogenous ABA. In contrast, ethylene, which exacerbates disease symptoms in some host-parasite interactions, did not appear to contribute to the predisposition response. Thus, several lines of evidence support ABA as a critical and dominant factor in the salinity-induced predisposition to Phytophthora spp. infection.
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Affiliation(s)
- Matthew V Dileo
- Department of Plant Pathology, University of California, One Shields Ave., Davis, CA 95616, USA
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215
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Laluk K, Mengiste T. Necrotroph attacks on plants: wanton destruction or covert extortion? THE ARABIDOPSIS BOOK 2010; 8:e0136. [PMID: 22303261 PMCID: PMC3244965 DOI: 10.1199/tab.0136] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Necrotrophic pathogens cause major pre- and post-harvest diseases in numerous agronomic and horticultural crops inflicting significant economic losses. In contrast to biotrophs, obligate plant parasites that infect and feed on living cells, necrotrophs promote the destruction of host cells to feed on their contents. This difference underpins the divergent pathogenesis strategies and plant immune responses to biotrophic and necrotrophic infections. This chapter focuses on Arabidopsis immunity to necrotrophic pathogens. The strategies of infection, virulence and suppression of host defenses recruited by necrotrophs and the variation in host resistance mechanisms are highlighted. The multiplicity of intraspecific virulence factors and species diversity in necrotrophic organisms corresponds to variations in host resistance strategies. Resistance to host-specific necrotophs is monogenic whereas defense against broad host necrotrophs is complex, requiring the involvement of many genes and pathways for full resistance. Mechanisms and components of immunity such as the role of plant hormones, secondary metabolites, and pathogenesis proteins are presented. We will discuss the current state of knowledge of Arabidopsis immune responses to necrotrophic pathogens, the interactions of these responses with other defense pathways, and contemplate on the directions of future research.
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Affiliation(s)
- Kristin Laluk
- Purdue University, Department of Botany and Plant Pathology, 915 W. State Street, West Lafayette, IN 47907
- Address correspondence to
and
| | - Tesfaye Mengiste
- Purdue University, Department of Botany and Plant Pathology, 915 W. State Street, West Lafayette, IN 47907
- Address correspondence to
and
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216
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Coca M, San Segundo B. AtCPK1 calcium-dependent protein kinase mediates pathogen resistance in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2010; 63:526-40. [PMID: 20497373 DOI: 10.1111/j.1365-313x.2010.04255.x] [Citation(s) in RCA: 134] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
In mammals, lipid bodies play a key role during pathological and infectious diseases. However, our knowledge on the function of plant lipid bodies, apart from their role as the major site of lipid storage in seed tissues, remains limited. Here, we provide evidence that a calcium-dependent protein kinase (CPK) mediates pathogen resistance in Arabidopsis. AtCPK1 expression is rapidly induced by fungal elicitors. Loss-of-function mutants of AtCPK1 exhibit higher susceptibility to pathogen infection compared to wild-type plants. Conversely, over-expression of AtCPK1 leads to accumulation of salicylic acid (SA) and constitutive expression of SA-regulated defence and disease resistance genes, which, in turn, results in broad-spectrum protection against pathogen infection. Expression studies in mutants affected in SA-mediated defence responses revealed an interlocked feedback loop governing AtCPK1 expression and components of the SA-dependent signalling pathway. Moreover, we demonstrate the dual localization of AtCPK1 in lipid bodies and peroxisomes. Overall, our findings identify AtCPK1 as a component of the innate immune system of Arabidopsis plants.
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Affiliation(s)
- María Coca
- Department of Molecular Genetics, Centre for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB, Jordi Girona 18, 08034 Barcelona, Spain
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217
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Kathiria P, Sidler C, Golubov A, Kalischuk M, Kawchuk LM, Kovalchuk I. Tobacco mosaic virus infection results in an increase in recombination frequency and resistance to viral, bacterial, and fungal pathogens in the progeny of infected tobacco plants. PLANT PHYSIOLOGY 2010; 153:1859-70. [PMID: 20498336 PMCID: PMC2923882 DOI: 10.1104/pp.110.157263] [Citation(s) in RCA: 117] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2010] [Accepted: 05/20/2010] [Indexed: 05/18/2023]
Abstract
Our previous experiments showed that infection of tobacco (Nicotiana tabacum) plants with Tobacco mosaic virus (TMV) leads to an increase in homologous recombination frequency (HRF). The progeny of infected plants also had an increased rate of rearrangements in resistance gene-like loci. Here, we report that tobacco plants infected with TMV exhibited an increase in HRF in two consecutive generations. Analysis of global genome methylation showed the hypermethylated genome in both generations of plants, whereas analysis of methylation via 5-methyl cytosine antibodies demonstrated both hypomethylation and hypermethylation. Analysis of the response of the progeny of infected plants to TMV, Pseudomonas syringae, or Phytophthora nicotianae revealed a significant delay in symptom development. Infection of these plants with TMV or P. syringae showed higher levels of induction of PATHOGENESIS-RELATED GENE1 gene expression and higher levels of callose deposition. Our experiments suggest that viral infection triggers specific changes in progeny that promote higher levels of HRF at the transgene and higher resistance to stress as compared with the progeny of unstressed plants. However, data reported in these studies do not establish evidence of a link between recombination frequency and stress resistance.
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Affiliation(s)
| | | | | | | | | | - Igor Kovalchuk
- Department of Biological Sciences, University of Lethbridge, Lethbridge, Alberta, Canada T1K 3M4 (P.K., C.S., A.G., M.K., I.K.); Lethbridge Research Centre, Agriculture and Agri-Food Canada, Lethbridge, Alberta, Canada T1J 4B1 (L.M.K.)
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218
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Petanović R, Kielkiewicz M. Plant-eriophyoid mite interactions: cellular biochemistry and metabolic responses induced in mite-injured plants. Part I. EXPERIMENTAL & APPLIED ACAROLOGY 2010; 51:61-80. [PMID: 20229098 DOI: 10.1007/s10493-010-9351-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Accepted: 02/26/2010] [Indexed: 05/08/2023]
Abstract
This review is a comprehensive study of recent advances related to cytological, biochemical and physiological changes induced in plants in response to eriophyoid mite attack. It has been shown that responses of host plants to eriophyoids are variable. Most of the variability is due to individual eriophyoid mite-plant interactions. Usually, the direction and intensity of changes in eriophyoid-infested plant organs depend on mite genotype, density, or the feeding period, and are strongly differentiated relative to host plant species, cultivar, age and location. Although the mechanisms of changes elicited by eriophyoid mites within plants are not fully understood, in many cases the qualitative and quantitative biochemical status of mite-infested plants are known to affect the performance of consecutive herbivorous arthropods. In future, elucidation of the pathways from eriophyoid mite damage to plant gene activation will be necessary to clarify plant responses and to explain variation in plant tissue damage at the feeding and adjacent sites.
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Affiliation(s)
- Radmila Petanović
- Department of Entomology and Agricultural Zoology, Faculty of Agriculture, University of Belgrade, Nemanjina 6, Belgrade-Zemun 11081, Serbia.
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219
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Jensen MK, Kjaersgaard T, Petersen K, Skriver K. NAC genes: time-specific regulators of hormonal signaling in Arabidopsis. PLANT SIGNALING & BEHAVIOR 2010; 5:907-10. [PMID: 20484991 PMCID: PMC3014545 DOI: 10.4161/psb.5.7.12099] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Accepted: 04/15/2010] [Indexed: 05/19/2023]
Abstract
Environmental stresses on both animals and plants impose massive transcriptional perturbations. Successful adaptations to such stresses are being orchestrated by both activating and repressing effects of transcription factors on specific target genes. We have recently published a systematic characterization of members of the large NAC gene transcription factor family in the model weed Arabidopsis thaliana. Our analysis revealed interesting sub-groupings of the Arabidopsis NAC genes, relating structure and function. Here we present a meta-analysis revealing distinct temporal expression profiles of NAC genes upon stimuli with seven phytohormones. Our analysis could be a first indication of NAC-centered transcriptional networks, which coordinate timely hormonal signaling in plants.
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Affiliation(s)
- Michael Krogh Jensen
- Molecular Genetics Department, Centre for Research in Agricultural Genomics, CSICIRTA- UAB, Barcelona, Spain
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220
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Sahu PP, Rai NK, Chakraborty S, Singh M, Chandrappa PH, Ramesh B, Chattopadhyay D, Prasad M. Tomato cultivar tolerant to Tomato leaf curl New Delhi virus infection induces virus-specific short interfering RNA accumulation and defence-associated host gene expression. MOLECULAR PLANT PATHOLOGY 2010; 11:531-44. [PMID: 20618710 PMCID: PMC6640424 DOI: 10.1111/j.1364-3703.2010.00630.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Tomato leaf curl New Delhi virus (ToLCNDV) infection causes significant yield loss in tomato. The availability of a conventional tolerance source against this virus is limited in tomato. To understand the molecular mechanism of virus tolerance in tomato, the abundance of viral genomic replicative intermediate molecules and virus-directed short interfering RNAs (siRNAs) by the host plant in a naturally tolerant cultivar H-88-78-1 and a susceptible cultivar Punjab Chhuhara at different time points after agroinfection was studied. We report that less abundance of viral replicative intermediate in the tolerant cultivar may have a correlation with a relatively higher accumulation of virus-specific siRNAs. To study defence-related host gene expression in response to ToLCNDV infection, the suppression subtractive hybridization technique was used. A library was prepared from tolerant cultivar H-88-78-1 between ToLCNDV-inoculated and Agrobacterium mock-inoculated plants of this cultivar at 21 days post-inoculation (dpi). A total of 106 nonredundant transcripts was identified and classified into 12 different categories according to their putative functions. By reverse Northern analysis and quantitative real-time polymerase chain reaction (qRT-PCR), we identified the differential expression pattern of 106 transcripts, 34 of which were up-regulated (>2.5-fold induction). Of these, eight transcripts showed more than four fold induction. qRT-PCR analysis was carried out to obtain comparative expression profiling of these eight transcripts between Punjab Chhuhara and H-88-78-1 on ToLCNDV infection. The expression patterns of these transcripts showed a significant increase in differential expression in the tolerant cultivar, mostly at 14 and 21 dpi, in comparison with that in the susceptible cultivar, as analysed by qRT-PCR. The probable direct and indirect relationship of siRNA accumulation and up-regulated transcripts with the ToLCNDV tolerance mechanism is discussed.
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Affiliation(s)
- Pranav Pankaj Sahu
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi-110067, India
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221
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Jiang CJ, Shimono M, Sugano S, Kojima M, Yazawa K, Yoshida R, Inoue H, Hayashi N, Sakakibara H, Takatsuji H. Abscisic acid interacts antagonistically with salicylic acid signaling pathway in rice-Magnaporthe grisea interaction. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2010; 23:791-8. [PMID: 20459318 DOI: 10.1094/mpmi-23-6-0791] [Citation(s) in RCA: 172] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Plant hormones play pivotal signaling roles in plant-pathogen interactions. Here, we report characterization of an antagonistic interaction of abscisic acid (ABA) with salicylic acid (SA) signaling pathways in the rice-Magnaporthe grisea interaction. Exogenous application of ABA drastically compromised the rice resistance to both compatible and incompatible M. grisea strains, indicating that ABA negatively regulates both basal and resistance gene-mediated blast resistance. ABA markedly suppressed the transcriptional upregulation of WRKY45 and OsNPR1, the two key components of the SA signaling pathway in rice, induced by SA or benzothiadiazole or by blast infection. Overexpression of OsNPR1 or WRKY45 largely negated the enhancement of blast susceptibility by ABA, suggesting that ABA acts upstream of WRKY45 and OsNPR1 in the rice SA pathway. ABA-responsive genes were induced during blast infection in a pattern reciprocal to those of WRKY45 and OsPR1b in the compatible rice-blast interaction but only marginally in the incompatible one. These results suggest that the balance of SA and ABA signaling is an important determinant for the outcome of the rice-M. grisea interaction. ABA was detected in hyphae and conidia of M. grisea as well as in culture media, implying that blast-fungus-derived ABA could play a role in triggering ABA signaling at host infection sites.
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Affiliation(s)
- Chang-Jie Jiang
- Plant Disease Resistance Research Unit, National Institute of Agrobiological Sciences, Kannondai 2-1-2, Tsukuba, 305-8602 Japan
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222
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Fujisawa M, Harada H, Kenmoku H, Mizutani S, Misawa N. Cloning and characterization of a novel gene that encodes (S)-beta-bisabolene synthase from ginger, Zingiber officinale. PLANTA 2010; 232:121-30. [PMID: 20229191 DOI: 10.1007/s00425-010-1137-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2009] [Accepted: 02/22/2010] [Indexed: 05/28/2023]
Abstract
Ginger, Zingiber officinale Roscoe, contains a fragrant oil mainly composed of sesquiterpenes and monoterpenes. We isolated a cDNA that codes for a sesquiterpene synthase from young rhizomes of ginger, Z. officinale Roscoe, Japanese cultivar "Kintoki". The cDNA, designated ZoTps1, potentially encoded a protein that comprised 550 amino acid residues and exhibited 49-53% identity with those of the sesquiterpene synthases already isolated from the genus Zingiber. Recombinant Escherichia coli cells, in which ZoTps1 was coexpressed along with genes for D-mevalonate utilization, resulted in the production of a sesquiterpene (S)-beta-bisabolene exclusively with a D-mevalonolactone supplement. This result indicated that ZoTps1 was the (S)-beta-bisabolene synthase gene in ginger. ZoTPS1 was suggested to catalyze (S)-beta-bisabolene formation with the conversion of farnesyl diphosphate to nerolidyl diphosphate followed by the cyclization between position 1 and 6 carbons. The ZoTps1 transcript was detected in young rhizomes, but not in leaves, roots and mature rhizomes of the ginger "Kintoki".
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Affiliation(s)
- Masaki Fujisawa
- Central Laboratories for Frontier Technology, Kirin Holdings Co. Ltd., i-BIRD, Nonoichi, Ishikawa, Japan
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223
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Chen L, Zhang L, Yu D. Wounding-induced WRKY8 is involved in basal defense in Arabidopsis. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2010; 23:558-65. [PMID: 20367464 DOI: 10.1094/mpmi-23-5-0558] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The WRKY family of plant transcription factors controls several types of plant stress responses. Arabidopsis WRKY8, localized to the nucleus, is mainly induced by abscissic acid, H(2)O(2), wounding, Pseudomonas syringae and Botrytis cinerea infection, and aphid and maggot feeding. To determine its biological functions, we isolated loss-of-function T-DNA insertion mutants and generated gain-of-function overexpressing WRKY8 transgenic plants in Arabidopsis. Plants expressing the mutated WRKY8 gene showed increased resistance to P. syringae but slightly decreased resistance to B. cinerea. In contrast, transgenic plants overexpressing WRKY8 were more susceptible to P. syringae infection but more resistant to B. cinerea infection. The contrasting responses to the two pathogens were correlated with opposite effects on pathogen-induced expression of two genes; salicylic acid-regulated PATHOGENESIS-RELATED1 (PR1) and jasmonic acid-regulated PDF1.2. Therefore, our results suggest that WRKY8 is a negative regulator of basal resistance to P. syringae and positive regulator to B. cinerea.
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Affiliation(s)
- Ligang Chen
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan, China
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224
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Hayes MA, Feechan A, Dry IB. Involvement of abscisic acid in the coordinated regulation of a stress-inducible hexose transporter (VvHT5) and a cell wall invertase in grapevine in response to biotrophic fungal infection. PLANT PHYSIOLOGY 2010; 153:211-21. [PMID: 20348211 PMCID: PMC2862438 DOI: 10.1104/pp.110.154765] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2010] [Accepted: 03/21/2010] [Indexed: 05/18/2023]
Abstract
Biotrophic fungal and oomycete pathogens alter carbohydrate metabolism in infected host tissues. Symptoms such as elevated soluble carbohydrate concentrations and increased invertase activity suggest that a pathogen-induced carbohydrate sink is established. To identify pathogen-induced regulators of carbohydrate sink strength, quantitative real-time polymerase chain reaction was used to measure transcript levels of invertase and hexose transporter genes in biotrophic pathogen-infected grapevine (Vitis vinifera) leaves. The hexose transporter VvHT5 was highly induced in coordination with the cell wall invertase gene VvcwINV by powdery and downy mildew infection. However, similar responses were also observed in response to wounding, suggesting that this is a generalized response to stress. Analysis of the VvHT5 promoter region indicated the presence of multiple abscisic acid (ABA) response elements, suggesting a role for ABA in the transition from source to sink under stress conditions. ABA treatment of grape leaves was found to reproduce the same gene-specific transcriptional changes as observed under biotic and abiotic stress conditions. Furthermore, the key regulatory ABA biosynthetic gene, VvNCED1, was activated under these same stress conditions. VvHT5 promoter::beta-glucuronidase-directed expression in transgenic Arabidopsis (Arabidopsis thaliana) was activated by infection with powdery mildew and by ABA treatment, and the expression was closely associated with vascular tissue adjacent to infected regions. Unlike VvHT1 and VvHT3, which appear to be predominantly involved in hexose transport in developing leaves and berries, VvHT5 appears to have a specific role in enhancing sink strength under stress conditions, and this is controlled through ABA. Our data suggest a central role for ABA in the regulation of VvcwINV and VvHT5 expression during the transition from source to sink in response to infection by biotrophic pathogens.
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Affiliation(s)
| | | | - Ian B. Dry
- Commonwealth Scientific and Industrial Research Organization Plant Industry, Glen Osmond, South Australia 5064, Australia
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225
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De Vleesschauwer D, Yang Y, Vera Cruz C, Höfte M. Abscisic acid-induced resistance against the brown spot pathogen Cochliobolus miyabeanus in rice involves MAP kinase-mediated repression of ethylene signaling. PLANT PHYSIOLOGY 2010; 152:2036-52. [PMID: 20130100 PMCID: PMC2850001 DOI: 10.1104/pp.109.152702] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Accepted: 01/23/2010] [Indexed: 05/17/2023]
Abstract
The plant hormone abscisic acid (ABA) is involved in an array of plant processes, including the regulation of gene expression during adaptive responses to various environmental cues. Apart from its well-established role in abiotic stress adaptation, emerging evidence indicates that ABA is also prominently involved in the regulation and integration of pathogen defense responses. Here, we demonstrate that exogenously administered ABA enhances basal resistance of rice (Oryza sativa) against the brown spot-causing ascomycete Cochliobolus miyabeanus. Microscopic analysis of early infection events in control and ABA-treated plants revealed that this ABA-inducible resistance (ABA-IR) is based on restriction of fungal progression in the mesophyll. We also show that ABA-IR does not rely on boosted expression of salicylic acid-, jasmonic acid -, or callose-dependent resistance mechanisms but, instead, requires a functional Galpha-protein. In addition, several lines of evidence are presented suggesting that ABA steers its positive effect on brown spot resistance through antagonistic cross talk with the ethylene (ET) response pathway. Exogenous ethephon application enhances susceptibility, whereas genetic disruption of ET signaling renders plants less vulnerable to C. miyabeanus attack, thereby inducing a level of resistance similar to that observed on ABA-treated wild-type plants. Moreover, ABA treatment alleviates C. miyabeanus-induced activation of the ET reporter gene EBP89, while derepression of pathogen-triggered EBP89 transcription via RNA interference-mediated knockdown of OsMPK5, an ABA-primed mitogen-activated protein kinase gene, compromises ABA-IR. Collectively, these data favor a model whereby exogenous ABA enhances resistance against C. miyabeanus at least in part by suppressing pathogen-induced ET action in an OsMPK5-dependent manner.
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Affiliation(s)
| | | | | | - Monica Höfte
- Laboratory of Phytopathology, Faculty of Bioscience Engineering, Ghent University, B–9000 Ghent, Belgium (D.D.V., M.H.); Department of Plant Pathology and Huck Institutes of Life Sciences, Pennsylvania State University, University Park, Pennsylvania 16802 (Y.Y.); and Plant Breeding, Genetics, and Biotechnology Division, International Rice Research Institute, 1099 Manila, Philippines (C.V.C.)
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226
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Hirayama T, Shinozaki K. Research on plant abiotic stress responses in the post-genome era: past, present and future. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2010; 61:1041-52. [PMID: 20409277 DOI: 10.1111/j.1365-313x.2010.04124.x] [Citation(s) in RCA: 598] [Impact Index Per Article: 42.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Understanding abiotic stress responses in plants is an important and challenging topic in plant research. Physiological and molecular biological analyses have allowed us to draw a picture of abiotic stress responses in various plants, and determination of the Arabidopsis genome sequence has had a great impact on this research field. The availability of the complete genome sequence has facilitated access to essential information for all genes, e.g. gene products and their function, transcript levels, putative cis-regulatory elements, and alternative splicing patterns. These data have been obtained from comprehensive transcriptome analyses and studies using full-length cDNA collections and T-DNA- or transposon-tagged mutant lines, which were also enhanced by genome sequence information. Moreover, studies on novel regulatory mechanisms involving use of small RNA molecules, chromatin modulation and genomic DNA modification have enabled us to recognize that plants have evolved complicated and sophisticated systems in response to complex abiotic stresses. Integrated data obtained with various 'omics' approaches have provided a more comprehensive picture of abiotic stress responses. In addition, research on stress responses in various plant species other than Arabidopsis has increased our knowledge regarding the mechanisms of plant stress tolerance in nature. Based on this progress, improvements in crop stress tolerance have been attempted by means of gene transfer and marker-assisted breeding. In this review, we summarize recent progress in abiotic stress studies, especially in the post-genomic era, and offer new perspectives on research directions for the next decade.
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You MK, Shin HY, Kim YJ, Ok SH, Cho SK, Jeung JU, Yoo SD, Kim JK, Shin JS. Novel bifunctional nucleases, OmBBD and AtBBD1, are involved in abscisic acid-mediated callose deposition in Arabidopsis. PLANT PHYSIOLOGY 2010; 152:1015-29. [PMID: 20018603 PMCID: PMC2815893 DOI: 10.1104/pp.109.147645] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2009] [Accepted: 12/08/2009] [Indexed: 05/23/2023]
Abstract
Screening of the expressed sequence tag library of the wild rice species Oryza minuta revealed an unknown gene that was rapidly and strongly induced in response to attack by a rice fungal pathogen (Magnaporthe oryzae) and an insect (Nilaparvata lugens) and by wounding, abscisic acid (ABA), and methyl jasmonate treatments. Its recombinant protein was identified as a bifunctional nuclease with both RNase and DNase activities in vitro. This gene was designated OmBBD (for O. minuta bifunctional nuclease in basal defense response). Overexpression of OmBBD in an Arabidopsis (Arabidopsis thaliana) model system caused the constitutive expression of the PDF1.2, ABA1, and AtSAC1 genes, which are involved in priming ABA-mediated callose deposition. This activation of defense responses led to an increased resistance against Botrytis cinerea. atbbd1, the knockout mutant of the Arabidopsis ortholog AtBBD1, was susceptible to attack by B. cinerea and had deficient callose deposition. Overexpression of either OmBBD or AtBBD1 in atbbd1 plants complemented the susceptible phenotype of atbbd1 against B. cinerea as well as the deficiency of callose deposition. We suggest that OmBBD and AtBBD1 have a novel regulatory role in ABA-mediated callose deposition.
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El Oirdi M, Trapani A, Bouarab K. The nature of tobacco resistance against Botrytis cinerea depends on the infection structures of the pathogen. Environ Microbiol 2010; 12:239-53. [PMID: 19799622 DOI: 10.1111/j.1462-2920.2009.02063.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
To protect themselves, plants have evolved an armoury of defences in response to pathogens and other stress situations. These include the production of pathogenesis-related (PR) proteins and the accumulation of antimicrobial molecules such as phytoalexins. Here we report that resistance of tobacco to Botrytis cinerea is cultivar specific. Nicotiana tabacum cv. Petit Havana but not N. tabacum cv. Xanthi or cv. samsun is resistant to B. cinerea. This resistance is correlated with the accumulation of the phytoalexin scopoletin and PR proteins. We also show that this resistance depends on the type of B. cinerea stage. Nicotiana tabacum cv. Petit Havana is more resistant to spores than to mycelium of B. cinerea. This reduced resistance of N. tabacum cv. Petit Havana to the mycelium compared with spores is correlated with the suppression of PR proteins accumulation and the capacity of the mycelium, not the spores, to metabolize scopoletin. These data present an important advance in understanding the strategies used by B. cinerea to establish its disease on tobacco plants.
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Affiliation(s)
- Mohamed El Oirdi
- Centre de Recherche en Amélioration Végétale, Faculté des Sciences, Université de Sherbrooke, 2500 Boulevard de l'Université, Sherbrooke, Québec, J1K2R1, Canada
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Uncoupling of sustained MAMP receptor signaling from early outputs in an Arabidopsis endoplasmic reticulum glucosidase II allele. Proc Natl Acad Sci U S A 2009; 106:22522-7. [PMID: 20007779 DOI: 10.1073/pnas.0907711106] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Recognition of microbe-associated molecular patterns (MAMPs), conserved structures typical of a microbial class, triggers immune responses in eukaryotes. This is accompanied by a diverse set of physiological responses that are thought to enhance defense activity in plants. However, the extent and mechanisms by which MAMP-induced events contribute to host immunity are poorly understood. Here we reveal Arabidopsis priority in sweet life4 (psl4) and psl5 mutants that are insensitive to the bacterial elongation factor (EF)-Tu epitope elf18 but responsive to flagellin epitope flg22. PSL4 and PSL5, respectively, identify beta- and alpha-subunits of endoplasmic reticulum-resident glucosidase II, which is essential for stable accumulation and quality control of the elf18 receptor EFR but not the flg22 receptor FLS2. We notice that EFR signaling is partially and differentially impaired without a significant decrease of the receptor steady-state levels in 2 weakly dysfunctional gIIalpha alleles, designated psl5-1 and rsw3. Remarkably, rsw3 plants exhibit marked supersusceptibility against a virulent bacterial phytopathogen despite nearly intact coactivation of MAPKs, reactive oxygen species, ethylene biosynthesis, and callose deposition in response to elf18, demonstrating that these signaling outputs alone are insufficient to mount effective immunity. However, rsw3 plants fail to maintain high transcript levels of defense-promoting WRKY, PR1, and PR2 genes at late time points (4 to 24 h) after elf18 elicitation. This points to an unexpected separation between initial and sustained activation of EFR-mediated signaling in the absence of proper glucosidase II-mediated endoplasmic reticulum quality control. Our findings strongly suggest the importance of sustained MAMP receptor signaling as a key step in the establishment of robust immunity.
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232
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SIEMENS DAVIDH, HAUGEN RISTON, MATZNER STEVEN, VANASMA NICHOLAS. Plant chemical defence allocation constrains evolution of local range. Mol Ecol 2009; 18:4974-83. [DOI: 10.1111/j.1365-294x.2009.04389.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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233
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Hao G, Du X, Zhao F, Ji H. Fungal endophytes-induced abscisic acid is required for flavonoid accumulation in suspension cells of Ginkgo biloba. Biotechnol Lett 2009; 32:305-14. [PMID: 19821072 DOI: 10.1007/s10529-009-0139-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Accepted: 09/09/2009] [Indexed: 11/26/2022]
Abstract
Treatment of suspension cells of Ginkgo biloba with fungal endophytes resulted in accumulation of flavonoids, increased abscisic acid (ABA) production and activation of phenylalanine ammonia-lyase (PAL). Fluridone, an inhibitor of ABA biosynthesis, was effective in inhibiting fungal endophytes-induced ABA biosynthesis, increase of PAL activity and flavonoids accumulation. Moreover, exogenous application of ABA enhanced PAL activity and increased accumulation of flavonoids in G. biloba cells with or without fungal endophytes elicitor. These finding suggest a causal relationship between ABA release and both PAL activity and flavonoid accumulation under fungal endophytes treatment and that ABA is involved in fungal endophytes-induced flavonoids accumulation in this plant.
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Affiliation(s)
- Gangping Hao
- Department of Biochemistry, Taishan Medical University, 271000 Tai'an, People's Republic of China.
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234
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Nishimura N, Okamoto M, Narusaka M, Yasuda M, Nakashita H, Shinozaki K, Narusaka Y, Hirayama T. ABA Hypersensitive Germination2-1 Causes the Activation of Both Abscisic Acid and Salicylic Acid Responses in Arabidopsis. ACTA ACUST UNITED AC 2009; 50:2112-22. [DOI: 10.1093/pcp/pcp146] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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235
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Bouwmeester K, Govers F. Arabidopsis L-type lectin receptor kinases: phylogeny, classification, and expression profiles. JOURNAL OF EXPERIMENTAL BOTANY 2009; 60:4383-96. [PMID: 19773388 DOI: 10.1093/jxb/erp277] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
In plants, lectin receptor kinases are considered to play crucial roles during development and in the adaptive response to various stimuli. Arabidopsis lectin receptor kinases can be divided into three type-classes based on sequence similarity of their extracellular lectin motifs. The current study focuses on the legume-like lectin receptor kinases (LecRKs), which are regarded as ideal candidates for monitoring cell wall integrity and are possibly functional in adaptive responses. An inventory of the Arabidopsis LecRK gene family is presented here. It consists of 45 members including three that were recently identified; two encode N-terminal truncated variants one of which has two in tandem kinase domains. Phylogenetic trees derived from full-length amino acid sequence alignments were highly concordant to phylograms that were purely based on lectin motifs or kinase domains. The phylograms allowed reclassification of the LecRK genes and hence a new proposal for gene nomenclature was suggested. In addition, a comprehensive expression analysis was executed by exploring public repositories. This revealed that several LecRK genes are differentially expressed during plant growth and development. Moreover, multiple LecRKs appear to be induced upon treatment with elicitors and pathogen infection. Variation in gene expression was also analysed in seedlings of diverse Arabidopsis accessions. Taken together, this study provides a genome-wide overview of the LecRK gene family and an up-to-date classification using a novel and systematic gene nomenclature.
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Affiliation(s)
- Klaas Bouwmeester
- Laboratory of Phytopathology, Wageningen University, Wageningen and Graduate School Experimental Plant Sciences, The Netherlands
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236
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Saijo Y, Tintor N, Lu X, Rauf P, Pajerowska-Mukhtar K, Häweker H, Dong X, Robatzek S, Schulze-Lefert P. Receptor quality control in the endoplasmic reticulum for plant innate immunity. EMBO J 2009; 28:3439-49. [PMID: 19763087 DOI: 10.1038/emboj.2009.263] [Citation(s) in RCA: 191] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2009] [Accepted: 08/06/2009] [Indexed: 11/09/2022] Open
Abstract
Pattern recognition receptors in eukaryotes initiate defence responses on detection of microbe-associated molecular patterns shared by many microbe species. The Leu-rich repeat receptor-like kinases FLS2 and EFR recognize the bacterial epitopes flg22 and elf18, derived from flagellin and elongation factor-Tu, respectively. We describe Arabidopsis 'priority in sweet life' (psl) mutants that show de-repressed anthocyanin accumulation in the presence of elf18. EFR accumulation and signalling, but not of FLS2, are impaired in psl1, psl2, and stt3a plants. PSL1 and PSL2, respectively, encode calreticulin3 (CRT3) and UDP-glucose:glycoprotein glycosyltransferase that act in concert with STT3A-containing oligosaccharyltransferase complex in an N-glycosylation pathway in the endoplasmic reticulum. However, EFR-signalling function is impaired in weak psl1 alleles despite its normal accumulation, thereby uncoupling EFR abundance control from quality control. Furthermore, salicylic acid-induced, but EFR-independent defence is weakened in psl2 and stt3a plants, indicating the existence of another client protein than EFR for this immune response. Our findings suggest a critical and selective function of N-glycosylation for different layers of plant immunity, likely through quality control of membrane-localized regulators.
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Affiliation(s)
- Yusuke Saijo
- Department of Plant Microbe Interactions, Max Planck Institute für Züchtungforschung, Köln, Germany.
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237
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Roubtsova TV, Bostock RM. Episodic Abiotic Stress as a Potential Contributing Factor to Onset and Severity of Disease Caused by Phytophthora ramorum in Rhododendron and Viburnum. PLANT DISEASE 2009; 93:912-918. [PMID: 30754535 DOI: 10.1094/pdis-93-9-0912] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Phytophthora ramorum attacks many forest and nursery species, primarily causing trunk or stem cankers, foliar blight, and dieback, and in some species root infection has been demonstrated. However, the abiotic and edaphic factors that influence infection and disease development are unresolved. Root infection by P. ramorum and the potential for mild abiotic stress in disease predisposition was examined with Rhododendron hybrid Cunningham's White and Viburnum tinus cv. Spring Bouquet. To impose water stress in a uniform and synchronous manner, osmotic stress induced with 0.2 M NaCl was selected. Roots were exposed to NaCl for 16 to 24 h in modified hydroponic culture or standard potting soil, removed from the NaCl, and then inoculated with zoospores. In the hydroponic regime, disease symptoms developed in Rhododendron and V. tinus plants within 1 week after inoculation of salt-stressed roots, whereas symptom development was delayed in nonstressed, inoculated plants. Microscopic examination of roots from both species revealed that their apices were covered with sporangia of P. ramorum. On potted Rhododendron plants inoculated by applying zoospores directly to the soil, stem lesions developed rapidly in salt-stressed plants, with death of the plant occurring within 4 weeks after inoculation. Nonstressed plants survived for 6 to 8 weeks before succumbing to disease, and symptom development in these plants was delayed by 1 to 2 weeks relative to the inoculated, salt-stressed plants. A postinfection episode of salt stress to inoculated roots in the hydroponic regime resulted in significantly faster development of stem lesions in Rhododendron relative to nonstressed, inoculated plants.
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Affiliation(s)
- Tatiana V Roubtsova
- Department of Plant Pathology, University of California, One Shields Ave., Davis, CA 95616
| | - Richard M Bostock
- Department of Plant Pathology, University of California, One Shields Ave., Davis, CA 95616
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238
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Schäfer P, Pfiffi S, Voll LM, Zajic D, Chandler PM, Waller F, Scholz U, Pons-Kühnemann J, Sonnewald S, Sonnewald U, Kogel KH. Manipulation of plant innate immunity and gibberellin as factor of compatibility in the mutualistic association of barley roots with Piriformospora indica. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2009; 59:461-74. [PMID: 19392709 DOI: 10.1111/j.1365-313x.2009.03887.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Fungi of the order Sebacinales (Basidiomycota) are involved in a wide spectrum of mutualistic symbioses with various plants, thereby exhibiting unique potential for biocontrol strategies. Piriformospora indica, a model organism of this fungal order, is able to increase the biomass and grain yield of crop plants, and induces local and systemic resistance to fungal diseases and tolerance to abiotic stress. To elucidate the molecular basis for root colonization, we characterized the interaction of P. indica with barley roots by combining global gene expression profiling, metabolic profiling, and genetic studies. At the metabolic level, we show that fungal colonization reduces the availability of free sugars and amino acids to the root tip. At the transcriptional level, consecutive interaction stages covering pre-penetration-associated events and progressing through to root colonization showed differential regulation of signal perception and transduction components, secondary metabolism, and genes associated with membrane transport. Moreover, we observed stage-specific up-regulation of genes involved in phytohormone metabolism, mainly encompassing gibberellin, auxin and abscisic acid, but salicylic acid-associated gene expression was suppressed. The changes in hormone homoeostasis were accompanied with a general suppression of the plant innate immune system. Further genetic studies showed reduced fungal colonization in mutants that are impaired in gibberellin synthesis as well as perception, and implicate gibberellin as a modulator of the root's basal defence. Our data further reveal the complexity of compatibility mechanisms in host-microbe interactions, and identify gibberellin signaling as potential target for successful fungi.
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Affiliation(s)
- Patrick Schäfer
- Research Centre for Biosystems, Land Use and Nutrition, Justus Liebig University, Giessen, Germany.
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239
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Allègre M, Héloir MC, Trouvelot S, Daire X, Pugin A, Wendehenne D, Adrian M. Are grapevine stomata involved in the elicitor-induced protection against downy mildew? MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2009; 22:977-86. [PMID: 19589073 DOI: 10.1094/mpmi-22-8-0977] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Stomata, natural pores bordered by guard cells, regulate transpiration and gas exchanges between plant leaves and the atmosphere. These natural openings also constitute a way of penetration for microorganisms. In plants, the perception of potentially pathogenic microorganisms or elicitors of defense reactions induces a cascade of events, including H(2)O(2) production, that allows the activation of defense genes, leading to defense reactions. Similar signaling events occur in guard cells in response to the perception of abscisic acid (ABA), leading to stomatal closure. Moreover, few elicitors were reported to induce stomatal closure in Arabidopsis and Vicia faba leaves. Because responses to ABA and elicitors share common signaling events, it led us to question whether stomatal movements and H(2)O(2) production in guard cells could play a key role in elicitor-induced protection against pathogens that use stomata for infection. This study was performed using the grapevine-Plasmopara viticola pathosystem. Using epidermal peels, we showed that, as for ABA, the elicitor-induced stomatal closure is mediated by reactive oxygen species (ROS) production in guard cells. In plants, we observed that the protection against downy mildew induced by some elicitors is probably not due only to effects on stomatal movements or to a guard-cell-specific activation of ROS production.
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Affiliation(s)
- Mathilde Allègre
- Unité Mixte de Recherche INRA 1088/CNRS 5184/ Université de Bourgogne Plante-Microbe-Environnement, 17 rue Sully, BP 86510, 21065 Dijon cedex, France
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240
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Sánchez-Rodríguez C, Estévez JM, Llorente F, Hernández-Blanco C, Jordá L, Pagán I, Berrocal M, Marco Y, Somerville S, Molina A. The ERECTA Receptor-Like Kinase Regulates Cell Wall-Mediated Resistance to Pathogens in Arabidopsis thaliana. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2009; 22:953-63. [PMID: 19589071 DOI: 10.1094/mpmi-22-8-0953] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Some receptor-like kinases (RLK) control plant development while others regulate immunity. The Arabidopsis ERECTA (ER) RLK regulates both biological processes. To discover specific components of ER-mediated immunity, a genetic screen was conducted to identify suppressors of erecta (ser) susceptibility to Plectosphaerella cucumerina fungus. The ser1 and ser2 mutations restored disease resistance to this pathogen to wild-type levels in the er-1 background but failed to suppress er-associated developmental phenotypes. The deposition of callose upon P. cucumerina inoculation, which was impaired in the er-1 plants, was also restored to near wild-type levels in the ser er-1 mutants. Analyses of er cell walls revealed that total neutral sugars were reduced and uronic acids increased relative to those of wild-type walls. Interestingly, in the ser er-1 walls, neutral sugars were elevated and uronic acids were reduced relative to both er-1 and wild-type plants. The cell-wall changes found in er-1 and the ser er-1 mutants are unlikely to contribute to their developmental alterations. However, they may influence disease resistance, as a positive correlation was found between uronic acids content and resistance to P. cucumerina. We propose a specific function for ER in regulating cell wall-mediated disease resistance that is distinct from its role in development.
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Affiliation(s)
- Clara Sánchez-Rodríguez
- Centro de Biotecnología y Genómica de Plantas (UPM-INIA), Departamento Biotecnología, Campus Montegancedo Universidad Politécnica de Madrid, E-28223-Pozuelo de Alarcón (Madrid), Spain
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241
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Fan J, Hill L, Crooks C, Doerner P, Lamb C. Abscisic acid has a key role in modulating diverse plant-pathogen interactions. PLANT PHYSIOLOGY 2009; 150:1750-61. [PMID: 19571312 PMCID: PMC2719142 DOI: 10.1104/pp.109.137943] [Citation(s) in RCA: 220] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2009] [Accepted: 06/25/2009] [Indexed: 05/18/2023]
Abstract
We isolated an activation-tagged Arabidopsis (Arabidopsis thaliana) line, constitutive disease susceptibility2-1D (cds2-1D), that showed enhanced bacterial growth when challenged with various Pseudomonas syringae strains. Systemic acquired resistance and systemic PATHOGENESIS-RELATED GENE1 induction were also compromised in cds2-1D. The T-DNA insertion adjacent to NINE-CIS-EPOXYCAROTENOID DIOXYGENASE5 (NCED5), one of six genes encoding the abscisic acid (ABA) biosynthetic enzyme NCED, caused a massive increase in transcript level and enhanced ABA levels >2-fold. Overexpression of NCED genes recreated the enhanced disease susceptibility phenotype. NCED2, NCED3, and NCED5 were induced, and ABA accumulated strongly following compatible P. syringae infection. The ABA biosynthetic mutant aba3-1 showed reduced susceptibility to virulent P. syringae, and ABA, whether through exogenous application or endogenous accumulation in response to mild water stress, resulted in increased bacterial growth following challenge with virulent P. syringae, indicating that ABA suppresses resistance to P. syringae. Likewise ABA accumulation also compromised resistance to the biotrophic oomycete Hyaloperonospora arabidopsis, whereas resistance to the fungus Alternaria brassicicola was enhanced in cds2-1D plants and compromised in aba3-1 plants, indicating that ABA promotes resistance to this necrotroph. Comparison of the accumulation of salicylic acid and jasmonic acid in the wild type, cds2-1D, and aba3-1 plants challenged with P. syringae showed that ABA promotes jasmonic acid accumulation and exhibits a complex antagonistic relationship with salicylic acid. Our findings provide genetic evidence that the abiotic stress signal ABA also has profound roles in modulating diverse plant-pathogen interactions mediated at least in part by cross talk with the jasmonic acid and salicylic acid biotic stress signal pathways.
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Affiliation(s)
- Jun Fan
- Department of Disease and Stress Biology , John Innes Centre, Norwich NR4 7UH, United Kingdom
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242
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Jia F, Gampala SS, Mittal A, Luo Q, Rock CD. Cre-lox univector acceptor vectors for functional screening in protoplasts: analysis of Arabidopsis donor cDNAs encoding ABSCISIC ACID INSENSITIVE1-like protein phosphatases. PLANT MOLECULAR BIOLOGY 2009; 70:693-708. [PMID: 19499346 PMCID: PMC2755202 DOI: 10.1007/s11103-009-9502-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2009] [Accepted: 05/15/2009] [Indexed: 05/27/2023]
Abstract
The 14,200 available full length Arabidopsis thaliana cDNAs in the universal plasmid system (UPS) donor vector pUNI51 should be applied broadly and efficiently to leverage a "functional map-space" of homologous plant genes. We have engineered Cre-lox UPS host acceptor vectors (pCR701- 705) with N-terminal epitope tags in frame with the loxH site and downstream from the maize Ubiquitin promoter for use in transient protoplast expression assays and particle bombardment transformation of monocots. As an example of the utility of these vectors, we recombined them with several Arabidopsis cDNAs encoding Ser/Thr protein phosphatase type 2C (PP2Cs) known from genetic studies or predicted by hierarchical clustering meta-analysis to be involved in ABA and stress responses. Our functional results in Zea mays mesophyll protoplasts on ABA-inducible expression effects on the Late Embryogenesis Abundant promoter ProEm:GUS reporter were consistent with predictions and resulted in identification of novel activities of some PP2Cs. Deployment of these vectors can facilitate functional genomics and proteomics and identification of novel gene activities.
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Affiliation(s)
- Fan Jia
- Department of Biological Sciences, Texas Tech University. Lubbock TX, U. S. A. 79409-3131
| | | | - Amandeep Mittal
- Department of Biological Sciences, Texas Tech University. Lubbock TX, U. S. A. 79409-3131
| | - Qingjun Luo
- Department of Biological Sciences, Texas Tech University. Lubbock TX, U. S. A. 79409-3131
| | - Christopher D. Rock
- Department of Biological Sciences, Texas Tech University. Lubbock TX, U. S. A. 79409-3131
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Mialoundama AS, Heintz D, Debayle D, Rahier A, Camara B, Bouvier F. Abscisic acid negatively regulates elicitor-induced synthesis of capsidiol in wild tobacco. PLANT PHYSIOLOGY 2009; 150:1556-66. [PMID: 19420326 PMCID: PMC2705044 DOI: 10.1104/pp.109.138420] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2009] [Accepted: 05/01/2009] [Indexed: 05/04/2023]
Abstract
In the Solanaceae, biotic and abiotic elicitors induce de novo synthesis of sesquiterpenoid stress metabolites known as phytoalexins. Because plant hormones play critical roles in the induction of defense-responsive genes, we have explored the effect of abscisic acid (ABA) on the synthesis of capsidiol, the major wild tobacco (Nicotiana plumbaginifolia) sesquiterpenoid phytoalexin, using wild-type plants versus nonallelic mutants Npaba2 and Npaba1 that are deficient in ABA synthesis. Npaba2 and Npaba1 mutants exhibited a 2-fold higher synthesis of capsidiol than wild-type plants when elicited with either cellulase or arachidonic acid or when infected by Botrytis cinerea. The same trend was observed for the expression of the capsidiol biosynthetic genes 5-epi-aristolochene synthase and 5-epi-aristolochene hydroxylase. Treatment of wild-type plants with fluridone, an inhibitor of the upstream ABA pathway, recapitulated the behavior of Npaba2 and Npaba1 mutants, while the application of exogenous ABA reversed the enhanced synthesis of capsidiol in Npaba2 and Npaba1 mutants. Concomitant with the production of capsidiol, we observed the induction of ABA 8'-hydroxylase in elicited plants. In wild-type plants, the induction of ABA 8'-hydroxylase coincided with a decrease in ABA content and with the accumulation of ABA catabolic products such as phaseic acid and dihydrophaseic acid, suggesting a negative regulation exerted by ABA on capsidiol synthesis. Collectively, our data indicate that ABA is not required per se for the induction of capsidiol synthesis but is essentially implicated in a stress-response checkpoint to fine-tune the amplification of capsidiol synthesis in challenged plants.
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Affiliation(s)
- Alexis Samba Mialoundama
- Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique and Université de Strasbourg, 67084 Strasbourg cedex, France
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Schäfer P, Pfiffi S, Voll LM, Zajic D, Chandler PM, Waller F, Scholz U, Pons-Kühnemann J, Sonnewald S, Sonnewald U, Kogel KH. Phytohormones in plant root-Piriformospora indica mutualism. PLANT SIGNALING & BEHAVIOR 2009; 4:669-71. [PMID: 19820343 PMCID: PMC2710571 DOI: 10.4161/psb.4.7.9038] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2009] [Accepted: 05/18/2009] [Indexed: 05/21/2023]
Abstract
Piriformospora indica is a mutualistic root-colonising basidiomycete that tranfers various benefits to colonized host plants including growth promotion, yield increases as well as abiotic and biotic stress tolerance. The fungus is characterized by a broad host spectrum encompassing various monocots and dicots. Our recent microarray-based studies indicate a general plant defense suppression by P. indica and significant changes in the GA biosynthesis pathway. Furthermore, barley plants impaired in GA synthesis and perception showed a significant reduction in mutualistic colonization, which was associated with an elevated expression of defense-related genes. Here, we discuss the importance of plant hormones for compatibility in plant root-P. indica associations. Our data might provide a first explanation for the colonization success of the fungus in a wide range of higher plants.
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Affiliation(s)
- Patrick Schäfer
- Research Centre for Biosystems, Land Use and Nutrition, Justus Liebig University, Giessen, Germany.
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245
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Schuman MC, Heinzel N, Gaquerel E, Svatos A, Baldwin IT. Polymorphism in jasmonate signaling partially accounts for the variety of volatiles produced by Nicotiana attenuata plants in a native population. THE NEW PHYTOLOGIST 2009; 183:1134-1148. [PMID: 19538549 DOI: 10.1111/j.1469-8137.2009.02894.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Herbivore- and jasmonate-induced volatile organic compounds (VOCs), which mediate indirect defense, must provide reliable information for predators that frequently learn to associate their release with feeding herbivores. Yet little is known about variation of these cues within populations of native plants, on a scale encountered by predators. We examined variation in herbivore-elicited VOC emissions and patterns of herbivore-induced jasmonate signaling from accessions of Nicotiana attenuata co-occurring in a native population. VOC emissions elicited by herbivore oral secretions (OS) and by methyl jasmonate (MJ) were characterized using gas chromatography-mass spectrometry (GC-MS), high-resolution two-dimensional gas chromatography-time-of-flight mass spectrometry (GCxGC-ToF-MS) and micro-hydrolysis and micro-hydrogenation reactions. Accessions varied in emissions of abundant (trans-alpha-bergamotene, alpha-duprezianene, trans-beta-ocimene, and cis-3-hexenol) and total detectable VOCs, as well as the accumulation of jasmonates, the jasmonate antagonist salicylic acid (SA), abscisic acid (ABA) and jasmonate signaling-related transcripts after OS elicitation. Yet MJ treatment exacerbated differences in VOC emission, suggesting that much variation in VOC emission is caused by processes downstream of jasmonate signaling. Co-occurring N. attenuata plants emit different VOCs following simulated herbivore elicitation as a result in part of differences in jasmonate production and responsiveness, which could reduce the effectiveness of induced indirect defense.
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Affiliation(s)
| | | | | | - Ales Svatos
- Department of Mass Spectrometry, Max Planck Institute for Chemical Ecology, Hans-Knöll-Strasse 8, D-07745 Jena, Germany
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246
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Ton J, Flors V, Mauch-Mani B. The multifaceted role of ABA in disease resistance. TRENDS IN PLANT SCIENCE 2009; 14:310-7. [PMID: 19443266 DOI: 10.1016/j.tplants.2009.03.006] [Citation(s) in RCA: 470] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2009] [Revised: 03/20/2009] [Accepted: 03/23/2009] [Indexed: 05/18/2023]
Abstract
Long known only for its role in abiotic stress tolerance, recent evidence shows that abscisic acid (ABA) also has a prominent role in biotic stress. Although it acts as a negative regulator of disease resistance, ABA can also promote plant defense and is involved in a complicated network of synergistic and antagonistic interactions. Its role in disease resistance depends on the type of pathogen, its specific way of entering the host and, hence, the timing of the defense response and the type of affected plant tissue. Here, we discuss the controversial evidence pointing to either a repression or a promotion of resistance by ABA. Furthermore, we propose a model in which both possibilities are integrated.
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Affiliation(s)
- Jurriaan Ton
- Rothamsted Research, West Common, Harpenden, Herts, AL5 2JQ, UK
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247
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Pieterse CMJ, Leon-Reyes A, Van der Ent S, Van Wees SCM. Networking by small-molecule hormones in plant immunity. Nat Chem Biol 2009; 5:308-16. [PMID: 19377457 DOI: 10.1038/nchembio.164] [Citation(s) in RCA: 1227] [Impact Index Per Article: 81.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Plants live in complex environments in which they intimately interact with a broad range of microbial pathogens with different lifestyles and infection strategies. The evolutionary arms race between plants and their attackers provided plants with a highly sophisticated defense system that, like the animal innate immune system, recognizes pathogen molecules and responds by activating specific defenses that are directed against the invader. Recent advances in plant immunity research have provided exciting new insights into the underlying defense signaling network. Diverse small-molecule hormones play pivotal roles in the regulation of this network. Their signaling pathways cross-communicate in an antagonistic or synergistic manner, providing the plant with a powerful capacity to finely regulate its immune response. Pathogens, on the other hand, can manipulate the plant's defense signaling network for their own benefit by affecting phytohormone homeostasis to antagonize the host immune response.
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Affiliation(s)
- Corné M J Pieterse
- Plant-Microbe Interactions, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands.
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248
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Ramírez V, Coego A, López A, Agorio A, Flors V, Vera P. Drought tolerance in Arabidopsis is controlled by the OCP3 disease resistance regulator. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2009; 58:578-91. [PMID: 19175769 DOI: 10.1111/j.1365-313x.2009.03804.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Water scarcity and corresponding abiotic drought stress is one of the most important factors limiting plant performance and yield. In addition, plant productivity is severely compromised worldwide by infection with microbial pathogens. Two of the most prominent pathways responsible for drought tolerance and disease resistance to fungal pathogens in Arabidopsis are those controlled by the phytohormones abscisic acid (ABA) and the oxylipin methyl jasmonate (MeJA), respectively. Here, we report on the functional characterization of OCP3, a transcriptional regulator from the homeodomain (HD) family. The Arabidopsis loss-of-function ocp3 mutant exhibits both drought resistance and enhanced disease resistance to necrotrophic fungal pathogens. Double-mutant analysis revealed that these two resistance phenotypes have different genetic requirements. Whereas drought tolerance in ocp3 is ABA-dependent but MeJA-independent, the opposite holds true for the enhanced disease resistance characteristics. These observations lead us to propose a regulatory role of OCP3 in the adaptive responses to these two stresses, functioning as a modulator of independent and specific aspects of the ABA- and MeJA-mediated signal transduction pathways.
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Affiliation(s)
- Vicente Ramírez
- Instituto de Biología Molecular y Celular de Plantas, Valencia, Spain
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249
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Trusov Y, Sewelam N, Rookes JE, Kunkel M, Nowak E, Schenk PM, Botella JR. Heterotrimeric G proteins-mediated resistance to necrotrophic pathogens includes mechanisms independent of salicylic acid-, jasmonic acid/ethylene- and abscisic acid-mediated defense signaling. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2009; 58:69-81. [PMID: 19054360 DOI: 10.1111/j.1365-313x.2008.03755.x] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Heterotrimeric G proteins are involved in the defense response against necrotrophic fungi in Arabidopsis. In order to elucidate the resistance mechanisms involving heterotrimeric G proteins, we analyzed the effects of the Gβ (subunit deficiency in the mutant agb1-2 on pathogenesis-related gene expression, as well as the genetic interaction between agb1-2 and a number of mutants of established defense pathways. Gβ-mediated signaling suppresses the induction of salicylic acid (SA)-, jasmonic acid (JA)-, ethylene (ET)- and abscisic acid (ABA)-dependent genes during the initial phase of the infection with Fusarium oxysporum (up to 48 h after inoculation). However, at a later phase it enhances JA/ET-dependent genes such as PDF1.2 and PR4. Quantification of the Fusarium wilt symptoms revealed that Gβ- and SA-deficient mutants were more susceptible than wild-type plants, whereas JA- and ET-insensitive and ABA-deficient mutants demonstrated various levels of resistance. Analysis of the double mutants showed that the Gβ-mediated resistance to F. oxysporum and Alternaria brassicicola was mostly independent of all of the previously mentioned pathways. However, the progressive decay of agb1-2 mutants was compensated by coi1-21 and jin1-9 mutations, suggesting that at this stage of F. oxysporum infection Gβ acts upstream of COI1 and ATMYC2 in JA signaling.
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Affiliation(s)
- Yuri Trusov
- School of Integrative Biology, University of Queensland, St. Lucia, Queensland, 4072, Australia
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250
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Leon-Reyes A, Spoel SH, De Lange ES, Abe H, Kobayashi M, Tsuda S, Millenaar FF, Welschen RAM, Ritsema T, Pieterse CMJ. Ethylene modulates the role of NONEXPRESSOR OF PATHOGENESIS-RELATED GENES1 in cross talk between salicylate and jasmonate signaling. PLANT PHYSIOLOGY 2009; 149:1797-809. [PMID: 19176718 PMCID: PMC2663751 DOI: 10.1104/pp.108.133926] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2008] [Accepted: 01/25/2009] [Indexed: 05/18/2023]
Abstract
The plant hormones salicylic acid (SA), jasmonic acid (JA), and ethylene (ET) play crucial roles in the signaling network that regulates induced defense responses against biotic stresses. Antagonism between SA and JA operates as a mechanism to fine-tune defenses that are activated in response to multiple attackers. In Arabidopsis (Arabidopsis thaliana), NONEXPRESSOR OF PATHOGENESIS-RELATED GENES1 (NPR1) was demonstrated to be required for SA-mediated suppression of JA-dependent defenses. Because ET is known to enhance SA/NPR1-dependent defense responses, we investigated the role of ET in the SA-JA signal interaction. Pharmacological experiments with gaseous ET and the ET precursor 1-aminocyclopropane-1-carboxylic acid showed that ET potentiated SA/NPR1-dependent PATHOGENESIS-RELATED1 transcription, while it rendered the antagonistic effect of SA on methyl jasmonate-induced PDF1.2 and VSP2 expression NPR1 independent. This overriding effect of ET on NPR1 function in SA-JA cross talk was absent in the npr1-1/ein2-1 double mutant, demonstrating that it is mediated via ET signaling. Abiotic and biotic induction of the ET response similarly abolished the NPR1 dependency of the SA-JA signal interaction. Furthermore, JA-dependent resistance against biotic attackers was antagonized by SA in an NPR1-dependent fashion only when the plant-attacker combination did not result in the production of high levels of endogenous ET. Hence, the interaction between ET and NPR1 plays an important modulating role in the fine tuning of the defense signaling network that is activated upon pathogen and insect attack. Our results suggest a model in which ET modulates the NPR1 dependency of SA-JA antagonism, possibly to compensate for enhanced allocation of NPR1 to function in SA-dependent activation of PR genes.
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Affiliation(s)
- Antonio Leon-Reyes
- Plant-Microbe Interactions, Department of Biology, Faculty of Science, Utrecht University, 3508 TB Utrecht, The Netherlands
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