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Mehterov N, Balazadeh S, Hille J, Toneva V, Mueller-Roeber B, Gechev T. Oxidative stress provokes distinct transcriptional responses in the stress-tolerant atr7 and stress-sensitive loh2 Arabidopsis thaliana mutants as revealed by multi-parallel quantitative real-time PCR analysis of ROS marker and antioxidant genes. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2012; 59:20-9. [PMID: 22710144 DOI: 10.1016/j.plaphy.2012.05.024] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Accepted: 05/27/2012] [Indexed: 05/05/2023]
Abstract
The Arabidopsis thaliana atr7 mutant is tolerant to oxidative stress induced by paraquat (PQ) or the catalase inhibitor aminotriazole (AT), while its original background loh2 and wild-type plants are sensitive. Both, AT and PQ, which stimulate the intracellular formation of H₂O₂ or superoxide anions, respectively, trigger cell death in loh2 but do not lead to visible damage in atr7. To study gene expression during oxidative stress and ROS-induced programmed cell death, two platforms for multi-parallel quantitative real-time PCR (qRT-PCR) analysis of 217 antioxidant and 180 ROS marker genes were employed. The qRT-PCR analyses revealed AT- and PQ-induced expression of many ROS-responsive genes mainly in loh2, confirming that an oxidative burst plays a role in the activation of the cell death in this mutant. Some of the genes were specifically regulated by either AT or PQ, serving as markers for particular types of ROS. Genes significantly induced by both AT and PQ in loh2 included transcription factors (ANAC042/JUB1, ANAC102, DREB19, HSFA2, RRTF1, ZAT10, ZAT12, ethylene-responsive factors), signaling compounds, ferritins, alternative oxidases, and antioxidant enzymes. Many of these genes were upregulated in atr7 compared to loh2 under non-stress conditions at the first time point, indicating that higher basal levels of ROS and higher antioxidant capacity in atr7 are responsible for the enhanced tolerance to oxidative stress and suggesting a possible tolerance against multiple stresses of this mutant.
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Affiliation(s)
- Nikolay Mehterov
- Department of Plant Physiology and Plant Molecular Biology, University of Plovdiv, 24 Tsar Assen Str., Plovdiv 4000, Bulgaria
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Mechoud MA, Juarez GE, de Valdez GF, Rodriguez AV. Lactobacillus reuteri CRL 1098 and Lactobacillus acidophilus CRL 1014 differently reduce in vitro immunotoxic effect induced by Ochratoxin A. Food Chem Toxicol 2012; 50:4310-5. [PMID: 22975144 DOI: 10.1016/j.fct.2012.07.070] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 07/13/2012] [Accepted: 07/16/2012] [Indexed: 10/27/2022]
Abstract
Ochratoxin A (OTA) is a widespread mycotoxin contaminating several food products which causes detrimental health effects. The ability of Lactobacillus reuteri CRL 1098 and Lactobacillus acidophilus CRL 1014 to prevent OTA effects on TNF-α and IL-10 production and apoptosis induction in human peripheral blood mononuclear cells (PBMC) was investigated. Membrane rafts participation in these responses was also evaluated. L. reuteri reduced by 29% the OTA inhibition of TNF-α production whereas L. acidophilus increased 8 times the TNF-α production by OTA treated-PBMC. Also, both bacteria reversed apoptosis induced by OTA by 32%. However, neither of the bacteria reversed the OTA inhibition on IL-10 production. On the other hand, the lactobacilli were less effective to reverse OTA effects on disrupted-rafts PBMC. This study shows that two lactobacilli strains can reduce some negative OTA effects, being membrane rafts integrity necessary to obtain better results. Also, the results highlight the potential capacity of some lactobacilli strains usually included in natural dietary components in milk-derived products and cereals feed, to reduce OTA toxicity once ingested by humans or animals.
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Affiliation(s)
- Mónica A Mechoud
- Centro de Referencia para Lactobacilos (CERELA-CONICET), Chacabuco 145, T4000ILC Tucumán, Argentina.
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Shlezinger N, Goldfinger N, Sharon A. Apoptotic-like programed cell death in fungi: the benefits in filamentous species. Front Oncol 2012; 2:97. [PMID: 22891165 PMCID: PMC3412994 DOI: 10.3389/fonc.2012.00097] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2012] [Accepted: 07/23/2012] [Indexed: 11/13/2022] Open
Abstract
Studies conducted in the early 1990s showed for the first time that Saccharomyces cerevisiae can undergo cell death with hallmarks of animal apoptosis. These findings came as a surprise, since suicide machinery was unexpected in unicellular organisms. Today, apoptosis in yeast is well-documented. Apoptotic death of yeast cells has been described under various conditions and S. cerevisiae homologs of human apoptotic genes have been identified and characterized. These studies also revealed fundamental differences between yeast and animal apoptosis; in S. cerevisiae apoptosis is mainly associated with aging and stress adaptation, unlike animal apoptosis, which is essential for proper development. Further, many apoptosis regulatory genes are either missing, or highly divergent in S. cerevisiae. Therefore, in this review we will use the term apoptosis-like programed cell death (PCD) instead of apoptosis. Despite these significant differences, S. cerevisiae has been instrumental in promoting the study of heterologous apoptotic proteins, particularly from human. Work in fungi other than S. cerevisiae revealed differences in the manifestation of PCD in single cell (yeasts) and multicellular (filamentous) species. Such differences may reflect the higher complexity level of filamentous species, and hence the involvement of PCD in a wider range of processes and life styles. It is also expected that differences might be found in the apoptosis apparatus of yeast and filamentous species. In this review we focus on aspects of PCD that are unique or can be better studied in filamentous species. We will highlight the similarities and differences of the PCD machinery between yeast and filamentous species and show the value of using S. cerevisiae along with filamentous species to study apoptosis.
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Affiliation(s)
- Neta Shlezinger
- Department of Molecular Biology and Ecology of Plants, Tel Aviv University,Tel Aviv, Israel
| | - Nir Goldfinger
- Department of Molecular Biology and Ecology of Plants, Tel Aviv University,Tel Aviv, Israel
| | - Amir Sharon
- Department of Molecular Biology and Ecology of Plants, Tel Aviv University,Tel Aviv, Israel
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Mase K, Mizuno T, Ishihama N, Fujii T, Mori H, Kodama M, Yoshioka H. Ethylene signaling pathway and MAPK cascades are required for AAL toxin-induced programmed cell death. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2012; 25:1015-25. [PMID: 22512379 DOI: 10.1094/mpmi-02-12-0036-r] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Programmed cell death (PCD), known as hypersensitive response cell death, has an important role in plant defense response. The signaling pathway of PCD remains unknown. We employed AAL toxin and Nicotiana umbratica to analysis plant PCD. AAL toxin is a pathogenicity factor of the necrotrophic pathogen Alternaria alternata f. sp. lycopersici. N. umbratica is sensitive to AAL toxin, susceptible to pathogens, and effective in Tobacco rattle virus-based virus-induced gene silencing (VIGS). VIGS analyses indicated that AAL toxin-triggered cell death (ACD) is dependent upon the mitogen-activated protein (MAP) kinase kinase MEK2, which is upstream of both salicylic acid-induced protein kinase (SIPK) and wound-induced protein kinase (WIPK) responsible for ethylene (ET) synthesis. ET treatment of MEK2-silenced N. umbratica re-established ACD. In SIPK- and WIPK-silenced N. umbratica, ACD was compromised and ET accumulation was not observed. However, in contrast to the case of MEK2-silenced plants, ET treatment did not induce cell death in SIPK- and WIPK-silenced plants. This work showed that ET-dependent pathway and MAP kinase cascades are required in ACD. Our results suggested that MEK2-SIPK/WIPK cascades have roles in ET biosynthesis; however, SIPK and WIPK have other roles in ET signaling or another pathway leading to cell death by AAL toxin.
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Ercolano MR, Sanseverino W, Carli P, Ferriello F, Frusciante L. Genetic and genomic approaches for R-gene mediated disease resistance in tomato: retrospects and prospects. PLANT CELL REPORTS 2012; 31:973-85. [PMID: 22350316 PMCID: PMC3351601 DOI: 10.1007/s00299-012-1234-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 01/27/2012] [Accepted: 01/27/2012] [Indexed: 05/22/2023]
Abstract
Tomato (Solanum lycopersicum) is one of the world's most important vegetable crops. Managing the health of this crop can be particularly challenging; crop resistance may be overcome by new pathogen races while new pathogens have been introduced by global agricultural markets. Tomato is extensively used as a model plant for resistance studies and much has been attained through both genetic and biotechnological approaches. In this paper, we illustrate genomic methods currently employed to preserve resistant germplasm and to facilitate the study and transfer of resistance genes, and we describe the genomic organization of R-genes. Patterns of gene activation during disease resistance response, identified through functional approaches, are depicted. We also describe the opportunities offered by the use of new genomic technologies, including high-throughput DNA sequencing, large-scale expression data production and the comparative hybridization technique, whilst reporting multifaceted approaches to achieve genetic tomato disease control. Future strategies combining the huge amount of genomic and genetic data will be able to accelerate development of novel resistance varieties sustainably on a worldwide basis. Such strategies are discussed in the context of the latest insights obtained in this field.
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Affiliation(s)
- M R Ercolano
- Department of Soil, Plant, Environmental and Animal Production Sciences, University of Naples 'Federico II', Via Università 100, 80055 Portici, Italy.
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Epstein S, Castillon GA, Qin Y, Riezman H. An essential function of sphingolipids in yeast cell division. Mol Microbiol 2012; 84:1018-32. [DOI: 10.1111/j.1365-2958.2012.08087.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Berkey R, Bendigeri D, Xiao S. Sphingolipids and plant defense/disease: the "death" connection and beyond. FRONTIERS IN PLANT SCIENCE 2012; 3:68. [PMID: 22639658 PMCID: PMC3355615 DOI: 10.3389/fpls.2012.00068] [Citation(s) in RCA: 123] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Accepted: 03/22/2012] [Indexed: 05/19/2023]
Abstract
Sphingolipids comprise a major class of structural materials and lipid signaling molecules in all eukaryotic cells. Over the past two decades, there has been a phenomenal growth in the study of sphingolipids (i.e., sphingobiology) at an average rate of ∼1000 research articles per year. Sphingolipid studies in plants, though accounting for only a small fraction (∼6%) of the total number of publications, have also enjoyed proportionally rapid growth in the past decade. Concomitant with the growth of sphingobiology, there has also been tremendous progress in our understanding of the molecular mechanisms of plant innate immunity. In this review, we (i) cross examine and analyze the major findings that establish and strengthen the intimate connections between sphingolipid metabolism and plant programmed cell death (PCD) associated with plant defense or disease; (ii) highlight and compare key bioactive sphingolipids involved in the regulation of plant PCD and possibly defense; (iii) discuss the potential role of sphingolipids in polarized membrane/protein trafficking and formation of lipid rafts as subdomains of cell membranes in relation to plant defense; and (iv) where possible, attempt to identify potential parallels for immunity-related mechanisms involving sphingolipids across kingdoms.
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Affiliation(s)
- Robert Berkey
- Institute for Bioscience and Biotechnology Research, University of MarylandRockville, MD, USA
- Department of Plant Sciences and Landscape Architecture, University of MarylandCollege Park, MD, USA
| | - Dipti Bendigeri
- Institute for Bioscience and Biotechnology Research, University of MarylandRockville, MD, USA
- Department of Plant Sciences and Landscape Architecture, University of MarylandCollege Park, MD, USA
| | - Shunyuan Xiao
- Institute for Bioscience and Biotechnology Research, University of MarylandRockville, MD, USA
- Department of Plant Sciences and Landscape Architecture, University of MarylandCollege Park, MD, USA
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Abstract
Plants inhabit environments crowded with infectious microbes that pose constant threats to their survival. Necrotrophic pathogens are notorious for their aggressive and wide-ranging virulence strategies that promote host cell death and acquire nutrients for growth and reproduction from dead cells. This lifestyle constitutes the axis of their pathogenesis and virulence strategies and marks contrasting immune responses to biotrophic pathogens. The diversity of virulence strategies in necrotrophic species corresponds to multifaceted host immune response mechanisms. When effective, the plant immune system disarms the infectious necrotroph of its pathogenic arsenal or attenuates its effect, restricting further ingress and disease symptom development. Simply inherited resistance traits confer protection against host-specific necrotrophs (HSNs), whereas resistance to broad host-range necrotrophs (BHNs) is complex. Components of host genetic networks, as well as the molecular and cellular processes that mediate host immune responses to necrotrophs, are being identified. In this review, recent advances in our understanding of plant immune responses to necrotrophs and comparison with responses to biotrophic pathogens are summarized, highlighting common and contrasting mechanisms.
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Affiliation(s)
- Tesfaye Mengiste
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907, USA.
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59
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Ternes P, Feussner K, Werner S, Lerche J, Iven T, Heilmann I, Riezman H, Feussner I. Disruption of the ceramide synthase LOH1 causes spontaneous cell death in Arabidopsis thaliana. THE NEW PHYTOLOGIST 2011; 192:841-854. [PMID: 21883234 DOI: 10.1111/j.1469-8137.2011.03852.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The bioactive lipid ceramide is produced by the enzyme ceramide synthase, which exists in several isoforms in most eukaryotic organisms. Here, we investigated functional differences between the three ceramide synthase isoforms in Arabidopsis thaliana. The biochemical properties of the three ceramide synthases were investigated by comparing lipid profiles of yeast strains expressing LOH1, LOH2 or LOH3 with those of wild-type and loh1, loh2 and loh3 knockout plants. Expression profiles of the ceramide synthases and of the pathogenesis-related gene PR-1 were investigated by real-time PCR. Each ceramide synthase isoform showed a characteristic preference regarding acyl-CoA chain length as well as sphingoid base hydroxylation, which matches the pattern of ceramide and glucosylceramide species found in leaves. After extended culture under short-day conditions, loh1 plants showed spontaneous cell death accompanied by enhanced expression of PR-1. The levels of free trihydroxy sphingoid bases as well as ceramide and glucosylceramide species with C(16) fatty acid were significantly elevated while species with C(20) -C(28) fatty acids were reduced. These data suggest that spontaneous cell death in the loh1 line is triggered either by the accumulation of free trihydroxy sphingoid bases or ceramide species with C(16) fatty acid.
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Affiliation(s)
- Philipp Ternes
- Department of Plant Biochemistry, Albrecht von Haller Institute for Plant Sciences, Georg August University, D-37077 Göttingen, Germany
- Present address: metanomics GmbH, Tegeler Weg 33, D-10589 Berlin, Germany
| | - Kirstin Feussner
- Department of Plant Biochemistry, Albrecht von Haller Institute for Plant Sciences, Georg August University, D-37077 Göttingen, Germany
- Department of Molecular Microbiology and Genetics, Institute for Microbiology and Genetics, Georg August University, D-37077 Göttingen, Germany
| | - Stephanie Werner
- Department of Plant Biochemistry, Albrecht von Haller Institute for Plant Sciences, Georg August University, D-37077 Göttingen, Germany
| | - Jennifer Lerche
- Department of Plant Biochemistry, Albrecht von Haller Institute for Plant Sciences, Georg August University, D-37077 Göttingen, Germany
| | - Tim Iven
- Department of Plant Biochemistry, Albrecht von Haller Institute for Plant Sciences, Georg August University, D-37077 Göttingen, Germany
| | - Ingo Heilmann
- Department of Plant Biochemistry, Albrecht von Haller Institute for Plant Sciences, Georg August University, D-37077 Göttingen, Germany
| | - Howard Riezman
- Department of Biochemistry, Sciences II, University of Geneva, CH-1211 Geneva 4, Switzerland
| | - Ivo Feussner
- Department of Plant Biochemistry, Albrecht von Haller Institute for Plant Sciences, Georg August University, D-37077 Göttingen, Germany
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60
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Zhang L, Jia C, Liu L, Zhang Z, Li C, Wang Q. The involvement of jasmonates and ethylene in Alternaria alternata f. sp. lycopersici toxin-induced tomato cell death. JOURNAL OF EXPERIMENTAL BOTANY 2011; 62:5405-18. [PMID: 21865178 PMCID: PMC3223041 DOI: 10.1093/jxb/err217] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Revised: 05/30/2011] [Accepted: 06/08/2011] [Indexed: 05/19/2023]
Abstract
Previous studies have shown that an ethylene (ET)-dependent pathway is involved in the cell death signalling triggered by Alternaria alternata f. sp. lycopersici (AAL) toxin in detached tomato (Solanum lycopersicum) leaves. In this study, the role of jasmonic acid (JA) signalling in programmed cell death (PCD) induced by AAL toxin was analysed using a 35S::prosystemin transgenic line (35S::prosys), a JA-deficient mutant spr2, and a JA-insensitive mutant jai1. The results indicated that JA biosynthesis and signalling play a positive role in the AAL toxin-induced PCD process. In addition, treatment with the exogenous ET action inhibitor silver thiosulphate (STS) greatly suppressed necrotic lesions in 35S::prosys leaves, although 35S::prosys leaflets co-treated with AAL toxin and STS still have a significant high relative conductivity. Application of 1-aminocyclopropane-1-carboxylic acid (ACC) markedly enhanced the sensitivity of spr2 and jai1 mutants to the toxin. However, compared with AAL toxin treatment alone, exogenous application of JA to the ET-insensitive mutant Never ripe (Nr) did not alter AAL toxin-induced cell death. In addition, the reduced ET-mediated gene expression in jai1 leaves was restored by co-treatment with ACC and AAL toxin. Furthermore, JA treatment restored the decreased expression of ET biosynthetic genes but not ET-responsive genes in the Nr mutant compared with the toxin treatment alone. Based on these results, it is proposed that both JA and ET promote the AAL toxin-induced cell death alone, and the JAI1 receptor-dependent JA pathway also acts upstream of ET biosynthesis in AAL toxin-triggered PCD.
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Affiliation(s)
- Liping Zhang
- Key Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Ministry of Agriculture, Department of Horticulture, Zhejiang University, Hangzhou 310058, China
| | - Chengguo Jia
- Key Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Ministry of Agriculture, Department of Horticulture, Zhejiang University, Hangzhou 310058, China
| | - Lihong Liu
- Key Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Ministry of Agriculture, Department of Horticulture, Zhejiang University, Hangzhou 310058, China
| | - Zhiming Zhang
- Key Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Ministry of Agriculture, Department of Horticulture, Zhejiang University, Hangzhou 310058, China
| | - Chuanyou Li
- State Key Laboratory of Plant Genomics, National Centre for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Qiaomei Wang
- Key Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Ministry of Agriculture, Department of Horticulture, Zhejiang University, Hangzhou 310058, China
- To whom correspondence should be addressed. E-mail:
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Chivasa S, Slabas AR. Plant extracellular ATP signalling: new insight from proteomics. MOLECULAR BIOSYSTEMS 2011; 8:445-52. [PMID: 21979580 DOI: 10.1039/c1mb05278k] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Complex signalling systems have evolved in multicellular organisms to enable cell-to-cell communication during growth and development. In plants, cell communication via the extracellular matrix (apoplast) controls many processes vital for plant survival. Secretion of ATP into the extracellular matrix is now recognised as a previously unknown stimulus for cell signalling with a role in many aspects of plant physiology. In the last decade, the secondary messenger molecules in extracellular ATP signalling were identified, but the downstream gene and protein networks that underpin plant responses to extracellular ATP are only beginning to be characterised. Here we review the current status of our knowledge of plant extracellular signalling and demonstrate how applying state-of-the art proteomic technologies is rapidly bringing new discoveries in extracellular ATP research. We discuss how monitoring of the global proteomic profile during responses to modulation of extracellular ATP signalling has led to novel insight into pathogen defence systems and plant programmed cell death regulation. On the basis of extensive proteomic, pharmacological, and reverse genetics data, extracellular ATP has been confirmed to constitute an important molecular switch that tightly controls organellar energy metabolism, reprogramming of primary metabolic pathways, and redirection of resources to protein networks that support adaptation of plants to stress.
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Affiliation(s)
- Stephen Chivasa
- School of Biological & Biomedical Sciences, Durham University, Durham, United Kingdom.
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62
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Baldwin T, Riley R, Zitomer N, Voss K, Coulombe Jr. R, Pestka J, Williams D, Glenn A. The current state of mycotoxin biomarker development in humans and animals and the potential for application to plant systems. WORLD MYCOTOXIN J 2011. [DOI: 10.3920/wmj2011.1292] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Filamentous fungi that contaminate livestock feeds and human food supply often produce toxigenic secondary metabolites known as mycotoxins. Among the hundreds of known mycotoxins, aflatoxins, deoxynivalenol, fumonisins, ochratoxin A and zearalenone are considered the most commercially important. Intense research on these mycotoxins, especially aflatoxin, has resulted in the development of 'biomarkers' used to link exposure to disease risk. In the case of aflatoxin this effort has led to the discovery of both exposure and mechanism-based biomarkers, which have proven essential for understanding aflatoxin's potential for causing disease in humans, including subtle effects on growth and immune response. Fumonisin biomarkers have also been used extensively in farm and laboratory animals to study the fumonisin-induced disruption of cellular and systemic physiology which leads to disease. This review summarises the status of mycotoxin biomarker development in humans and animals for the commercially important mycotoxins. Since the fungi responsible for the production of these mycotoxins are often endophytes that infect and colonise living plant tissues, accumulation of mycotoxins in the plant tissues may at times be associated with development of plant disease symptoms. The presence of mycotoxins, even in the absence of disease symptoms, may still have subtle biological effects on the physiology of plants. This review examines the question of whether or not the knowledge gained from mechanistic studies and development of biomarkers in animal and human systems is transferable to the study of mycotoxin effects on plant systems. Thus far, fumonisin has proven amenable to development of mechanism-based biomarkers to study maize seedling disease caused by the fumonisin producer, Fusarium verticillioides. Expanding our knowledge of mechanisms of toxicity and the overt and subtle effects on animal, human, and plant systems through the identification and validation of biomarkers will further our ability to monitor and limit the damage and economic impact of mycotoxins.
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Affiliation(s)
- T. Baldwin
- Toxicology and Mycotoxin Research Unit, USDA, ARS, 950 College Station Road, Athens GA 30605, USA
- Department of Plant Pathology, University of Georgia, 2105 Miller Plant Science Building, Athens GA 30602-7274, USA
| | - R. Riley
- Toxicology and Mycotoxin Research Unit, USDA, ARS, 950 College Station Road, Athens GA 30605, USA
| | - N. Zitomer
- Toxicology and Mycotoxin Research Unit, USDA, ARS, 950 College Station Road, Athens GA 30605, USA
| | - K. Voss
- Toxicology and Mycotoxin Research Unit, USDA, ARS, 950 College Station Road, Athens GA 30605, USA
| | - R. Coulombe Jr.
- Department of Veterinary Sciences, Utah State University, 4815 Old Main Hill, Logan UT 84322-4620, USA
| | - J. Pestka
- Department of Food Science and Human Nutrition, Michigan State University, 234 GM Trout Building, East Lansing MI 48824-1224, USA
| | - D. Williams
- Department of Environmental and Molecular Toxicology, Oregon State University, 1007 Agriculture & Life Sciences Building, Corvallis, OR 97331, USA
| | - A. Glenn
- Toxicology and Mycotoxin Research Unit, USDA, ARS, 950 College Station Road, Athens GA 30605, USA
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Markham JE, Molino D, Gissot L, Bellec Y, Hématy K, Marion J, Belcram K, Palauqui JC, Satiat-JeuneMaître B, Faure JD. Sphingolipids containing very-long-chain fatty acids define a secretory pathway for specific polar plasma membrane protein targeting in Arabidopsis. THE PLANT CELL 2011; 23:2362-78. [PMID: 21666002 PMCID: PMC3160045 DOI: 10.1105/tpc.110.080473] [Citation(s) in RCA: 176] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2010] [Revised: 04/15/2011] [Accepted: 05/20/2011] [Indexed: 05/18/2023]
Abstract
Sphingolipids are a class of structural membrane lipids involved in membrane trafficking and cell polarity. Functional analysis of the ceramide synthase family in Arabidopsis thaliana demonstrates the existence of two activities selective for the length of the acyl chains. Very-long-acyl-chain (C > 18 carbons) but not long-chain sphingolipids are essential for plant development. Reduction of very-long-chain fatty acid sphingolipid levels leads in particular to auxin-dependent inhibition of lateral root emergence that is associated with selective aggregation of the plasma membrane auxin carriers AUX1 and PIN1 in the cytosol. Defective targeting of polar auxin carriers is characterized by specific aggregation of Rab-A2(a)- and Rab-A1(e)-labeled early endosomes along the secretory pathway. These aggregates correlate with the accumulation of membrane structures and vesicle fragmentation in the cytosol. In conclusion, sphingolipids with very long acyl chains define a trafficking pathway with specific endomembrane compartments and polar auxin transport protein cargoes.
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Affiliation(s)
| | - Diana Molino
- Institut Jean-Pierre Bourgin, Unité Mixte de Recherche 1318, Institut National de la Recherche Agronomique–AgroParisTech, Centre de Versailles-Grignon, 78000 Versailles, France
| | - Lionel Gissot
- Institut Jean-Pierre Bourgin, Unité Mixte de Recherche 1318, Institut National de la Recherche Agronomique–AgroParisTech, Centre de Versailles-Grignon, 78000 Versailles, France
| | - Yannick Bellec
- Institut Jean-Pierre Bourgin, Unité Mixte de Recherche 1318, Institut National de la Recherche Agronomique–AgroParisTech, Centre de Versailles-Grignon, 78000 Versailles, France
| | - Kian Hématy
- Institut Jean-Pierre Bourgin, Unité Mixte de Recherche 1318, Institut National de la Recherche Agronomique–AgroParisTech, Centre de Versailles-Grignon, 78000 Versailles, France
| | - Jessica Marion
- Institut des Sciences du Végétal, Centre National de la Recherche Scientifique, F-91198 Gif-sur-Yvette Cedex, France
| | - Katia Belcram
- Institut Jean-Pierre Bourgin, Unité Mixte de Recherche 1318, Institut National de la Recherche Agronomique–AgroParisTech, Centre de Versailles-Grignon, 78000 Versailles, France
| | - Jean-Christophe Palauqui
- Institut Jean-Pierre Bourgin, Unité Mixte de Recherche 1318, Institut National de la Recherche Agronomique–AgroParisTech, Centre de Versailles-Grignon, 78000 Versailles, France
| | - Béatrice Satiat-JeuneMaître
- Institut des Sciences du Végétal, Centre National de la Recherche Scientifique, F-91198 Gif-sur-Yvette Cedex, France
| | - Jean-Denis Faure
- Institut Jean-Pierre Bourgin, Unité Mixte de Recherche 1318, Institut National de la Recherche Agronomique–AgroParisTech, Centre de Versailles-Grignon, 78000 Versailles, France
- Address correspondence to
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64
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Bi FC, Zhang QF, Liu Z, Fang C, Li J, Su JB, Greenberg JT, Wang HB, Yao N. A conserved cysteine motif is critical for rice ceramide kinase activity and function. PLoS One 2011; 6:e18079. [PMID: 21483860 PMCID: PMC3069040 DOI: 10.1371/journal.pone.0018079] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Accepted: 02/22/2011] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Ceramide kinase (CERK) is a key regulator of cell survival in dicotyledonous plants and animals. Much less is known about the roles of CERK and ceramides in mediating cellular processes in monocot plants. Here, we report the characterization of a ceramide kinase, OsCERK, from rice (Oryza sativa spp. Japonica cv. Nipponbare) and investigate the effects of ceramides on rice cell viability. PRINCIPAL FINDINGS OsCERK can complement the Arabidopsis CERK mutant acd5. Recombinant OsCERK has ceramide kinase activity with Michaelis-Menten kinetics and optimal activity at 7.0 pH and 40°C. Mg2+ activates OsCERK in a concentration-dependent manner. Importantly, a CXXXCXXC motif, conserved in all ceramide kinases and important for the activity of the human enzyme, is critical for OsCERK enzyme activity and in planta function. In a rice protoplast system, inhibition of CERK leads to cell death and the ratio of added ceramide and ceramide-1-phosphate, CERK's substrate and product, respectively, influences cell survival. Ceramide-induced rice cell death has apoptotic features and is an active process that requires both de novo protein synthesis and phosphorylation, respectively. Finally, mitochondria membrane potential loss previously associated with ceramide-induced cell death in Arabidopsis was also found in rice, but it occurred with different timing. CONCLUSIONS OsCERK is a bona fide ceramide kinase with a functionally and evolutionarily conserved Cys-rich motif that plays an important role in modulating cell fate in plants. The vital function of the conserved motif in both human and rice CERKs suggests that the biochemical mechanism of CERKs is similar in animals and plants. Furthermore, ceramides induce cell death with similar features in monocot and dicot plants.
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Affiliation(s)
- Fang-Cheng Bi
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Quan-Fang Zhang
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Zhe Liu
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Ce Fang
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Jian Li
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Jian-Bin Su
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Jean T. Greenberg
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois, United States of America
| | - Hong-Bin Wang
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Nan Yao
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
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65
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Voelzmann A, Bauer R. Ceramide synthases in mammalians, worms, and insects: emerging schemes. Biomol Concepts 2010; 1:411-22. [DOI: 10.1515/bmc.2010.028] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
AbstractThe ceramide synthase (CerS) gene family comprises a group of highly conserved transmembrane proteins, which are found in all studied eukaryotes. The key feature of the CerS proteins is their role in ceramide synthase activity. Therefore, their original name ‘longevity assurance gene (Lass) homologs’, after the founding member, the yeast longevity assurance gene lag1, was altered to ‘CerS’. All CerS have high sequence similarity in a domain called LAG1 motif and a subset of CerS proteins is predicted to contain a Homeobox (Hox) domain. These domains could be the key to the multiple roles CerS have. CerS proteins play a role in diverse biological processes such as proliferation, differentiation, apoptosis, stress response, cancer, and neurodegeneration. In this review, we focus on CerS structure and biological function with emphasis of biological functions in the widely used model systems Caenorhabditis elegans and Drosophila melanogaster. Also, we focus on the accumulating data suggesting a role for CerS in lipid homeostasis.
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Affiliation(s)
- André Voelzmann
- 1LIMES Institute, Program Unit Development and Genetics, Laboratory for Molecular Developmental Biology, University of Bonn, Carl-Troll-Str. 31, D-53115 Bonn, Germany
| | - Reinhard Bauer
- 1LIMES Institute, Program Unit Development and Genetics, Laboratory for Molecular Developmental Biology, University of Bonn, Carl-Troll-Str. 31, D-53115 Bonn, Germany
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66
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Sánchez-Rangel D, Plasencia J. The role of sphinganine analog mycotoxins on the virulence of plant pathogenic fungi. TOXIN REV 2010. [DOI: 10.3109/15569543.2010.515370] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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67
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Peer M, Stegmann M, Mueller MJ, Waller F. Pseudomonas syringaeinfection triggers de novo synthesis of phytosphingosine from sphinganine inArabidopsis thaliana. FEBS Lett 2010; 584:4053-6. [DOI: 10.1016/j.febslet.2010.08.027] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Revised: 08/17/2010] [Accepted: 08/17/2010] [Indexed: 10/19/2022]
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68
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Ashrafi H, Kinkade M, Foolad MR. A new genetic linkage map of tomato based on a Solanum lycopersicum x S. pimpinellifolium RIL population displaying locations of candidate pathogen response genes. Genome 2010; 52:935-56. [PMID: 19935918 DOI: 10.1139/g09-065] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The narrow genetic base of the cultivated tomato, Solanum lycopersicum L., necessitates introgression of new variation from related species. Wild tomato species represent a rich source of useful genes and traits. Exploitation of genetic variation within wild species can be facilitated by the use of molecular markers and genetic maps. Recently we identified an accession (LA2093) within the red-fruited wild tomato species Solanum pimpinellifolium L. with exceptionally desirable characteristics, including disease resistance, abiotic stress tolerance, and high fruit lycopene content. To facilitate genetic characterization of such traits and their exploitation in tomato crop improvement, we developed a new recombinant inbred line (RIL) population from a cross between LA2093 and an advanced tomato breeding line (NCEBR-1). Furthermore, we constructed a medium-density molecular linkage map of this population using 294 polymorphic markers, including standard RFLPs, EST sequences (used as RFLP probes), CAPS, and SSRs. The map spanned 1091 cM of the tomato genome with an average marker spacing of 3.7 cM. A majority of the EST sequences, which were mainly chosen based on the putative role of their unigenes in disease resistance, defense-related response, or fruit quality, were mapped onto the tomato chromosomes for the first time. Co-localizations of relevant EST sequences with known disease resistance genes in tomato were also examined. This map will facilitate identification, genetic exploitation, and positional cloning of important genes or quantitative trait loci in LA2093. It also will allow the elucidation of the molecular mechanism(s) underlying important traits segregating in the RIL population. The map may further facilitate characterization and exploitation of genetic variation in other S. pimpinellifolium accessions as well as in modern cultivars of tomato.
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Affiliation(s)
- Hamid Ashrafi
- Department of Horticulture, The Pennsylvania State University, University Park, PA 16802, USA
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69
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Abstract
Sphingolipids are a ubiquitous class of lipids present in a variety of organisms including eukaryotes and bacteria. In the last two decades, research has focused on characterizing the individual species of this complex family of lipids, which has led to a new field of research called 'sphingolipidomics'. There are at least 500 (and perhaps thousands of) different molecular species of sphingolipids in cells, and in Arabidopsis alone it has been reported that there are at least 168 different sphingolipids. Plant sphingolipids can be divided into four classes: glycosyl inositol phosphoceramides (GIPCs), glycosylceramides, ceramides, and free long-chain bases (LCBs). Numerous enzymes involved in plant sphingolipid metabolism have now been cloned and characterized, and, in general, there is broad conservation in the way in which sphingolipids are metabolized in animals, yeast and plants. Here, we review the diversity of sphingolipids reported in the literature, some of the recent advances in our understanding of sphingolipid metabolism in plants, and the physiological roles that sphingolipids and sphingolipid metabolites play in plant physiology.
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Affiliation(s)
- Mickael O Pata
- Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR 441-2594 (INRA-CNRS), Chemin de Borde Rouge BP 52627, 31326 Castanet-Tolosan, France
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70
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Zäuner S, Ternes P, Warnecke D. Biosynthesis of Sphingolipids in Plants (and Some of Their Functions). ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 688:249-63. [DOI: 10.1007/978-1-4419-6741-1_18] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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71
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Sanseverino W, Roma G, De Simone M, Faino L, Melito S, Stupka E, Frusciante L, Ercolano MR. PRGdb: a bioinformatics platform for plant resistance gene analysis. Nucleic Acids Res 2009; 38:D814-21. [PMID: 19906694 PMCID: PMC2808903 DOI: 10.1093/nar/gkp978] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
PRGdb is a web accessible open-source (http://www.prgdb.org) database that represents the first bioinformatic resource providing a comprehensive overview of resistance genes (R-genes) in plants. PRGdb holds more than 16,000 known and putative R-genes belonging to 192 plant species challenged by 115 different pathogens and linked with useful biological information. The complete database includes a set of 73 manually curated reference R-genes, 6308 putative R-genes collected from NCBI and 10463 computationally predicted putative R-genes. Thanks to a user-friendly interface, data can be examined using different query tools. A home-made prediction pipeline called Disease Resistance Analysis and Gene Orthology (DRAGO), based on reference R-gene sequence data, was developed to search for plant resistance genes in public datasets such as Unigene and Genbank. New putative R-gene classes containing unknown domain combinations were discovered and characterized. The development of the PRG platform represents an important starting point to conduct various experimental tasks. The inferred cross-link between genomic and phenotypic information allows access to a large body of information to find answers to several biological questions. The database structure also permits easy integration with other data types and opens up prospects for future implementations.
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Affiliation(s)
- Walter Sanseverino
- Department of Soil, Plant, Environmental and Animal Production Sciences, University of Naples 'Federico II', Via Università 100, 80055 Portici, Italy
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72
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de Zélicourt A, Montiel G, Pouvreau JB, Thoiron S, Delgrange S, Simier P, Delavault P. Susceptibility of Phelipanche and Orobanche species to AAL-toxin. PLANTA 2009; 230:1047-1055. [PMID: 19705146 DOI: 10.1007/s00425-009-1008-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2009] [Accepted: 08/05/2009] [Indexed: 05/28/2023]
Abstract
Fusarium and Alternaria spp. are phytopathogenic fungi which are known to be virulent on broomrapes and to produce sphinganine-analog mycotoxins (SAMs). AAL-toxin is a SAM produced by Alternaria alternata which causes the inhibition of sphinganine N-acyltransferase, a key enzyme in sphingolipid biosynthesis, leading to accumulation of sphingoid bases. These long chain bases (LCBs) are determinant in the occurrence of programmed cell death (PCD) in susceptible plants. We showed that broomrapes are sensitive to AAL-toxin, which is not common plant behavior, and that AAL-toxin triggers cell death at the apex of the radicle as well as LCB accumulation and DNA laddering. We also demonstrated that three Lag1 homologs, encoding components of sphinganine N-acyltransferase in yeast, are present in the Orobanche cumana genome and two of them are mutated leading to an enhanced susceptibility to AAL-toxin. We therefore propose a model for the molecular mechanism governing broomrape susceptibility to the fungus Alternaria alternata.
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Affiliation(s)
- Axel de Zélicourt
- Laboratoire de Biologie et Pathologie Végétales, EA 1157, IFR 149 QUASAV, Université de Nantes, 44322 Nantes cedex 3, France
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73
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Gupta V, Mathur S, Solanke AU, Sharma MK, Kumar R, Vyas S, Khurana P, Khurana JP, Tyagi AK, Sharma AK. Genome analysis and genetic enhancement of tomato. Crit Rev Biotechnol 2009; 29:152-81. [PMID: 19319709 DOI: 10.1080/07388550802688870] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The Solanaceae is an important family of vegetable crops, ornamentals and medicinal plants. Tomato has served as a model member of this family largely because of its enriched cytogenetic, genetic, as well as physical, maps. Mapping has helped in cloning several genes of importance such as Pto, responsible for resistance against bacterial speck disease, Mi-1.2 for resistance against nematodes, and fw2.2 QTL for fruit weight. A high-throughput genome-sequencing program has been initiated by an international consortium of 10 countries. Since heterochromatin has been found to be concentrated near centromeres, the consortium is focusing on sequencing only the gene-rich euchromatic region. Genomes of the members of Solanaceae show a significant degree of synteny, suggesting that the tomato genome sequence would help in the cloning of genes for important traits from other Solanaceae members as well. ESTs from a large number of cDNA libraries have been sequenced, and microarray chips, in conjunction with wide array of ripening mutants, have contributed immensely to the understanding of the fruit-ripening phenomenon. Work on the analysis of the tomato proteome has also been initiated. Transgenic tomato plants with improved abiotic stress tolerance, disease resistance and insect resistance, have been developed. Attempts have also been made to develop tomato as a bioreactor for various pharmaceutical proteins. However, control of fruit quality and ripening remains an active and challenging area of research. Such efforts should pave the way to improve not only tomato, but also other solanaceous crops.
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Affiliation(s)
- Vikrant Gupta
- Interdisciplinary Centre for Plant Genomics, Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, India
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74
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Horizontal chromosome transfer, a mechanism for the evolution and differentiation of a plant-pathogenic fungus. EUKARYOTIC CELL 2009; 8:1732-8. [PMID: 19749175 DOI: 10.1128/ec.00135-09] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The tomato pathotype of Alternaria alternata produces host-specific AAL toxin and causes Alternaria stem canker on tomato. A polyketide synthetase (PKS) gene, ALT1, which is involved in AAL toxin biosynthesis, resides on a 1.0-Mb conditionally dispensable chromosome (CDC) found only in the pathogenic and AAL toxin-producing strains. Genomic sequences of ALT1 and another PKS gene, both of which reside on the CDC in the tomato pathotype strains, were compared to those of tomato pathotype strains collected worldwide. This revealed that the sequences of both CDC genes were identical among five A. alternata tomato pathotype strains having different geographical origins. On the other hand, the sequences of other genes located on chromosomes other than the CDC are not identical in each strain, indicating that the origin of the CDC might be different from that of other chromosomes in the tomato pathotype. Telomere fingerprinting and restriction fragment length polymorphism analyses of the A. alternata strains also indicated that the CDCs in the tomato pathotype strains were identical, although the genetic backgrounds of the strains differed. A hybrid strain between two different pathotypes was shown to harbor the CDCs derived from both parental strains with an expanded range of pathogenicity, indicating that CDCs can be transmitted from one strain to another and stably maintained in the new genome. We propose a hypothesis whereby the ability to produce AAL toxin and to infect a plant could potentially be distributed among A. alternata strains by horizontal transfer of an entire pathogenicity chromosome. This could provide a possible mechanism by which new pathogens arise in nature.
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75
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Alexander NJ, Proctor RH, McCormick SP. Genes, gene clusters, and biosynthesis of trichothecenes and fumonisins inFusarium. TOXIN REV 2009. [DOI: 10.1080/15569540903092142] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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76
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Li Y, Shen Y, Zhu X, Du L. Introduction of the AAL-toxin polyketide synthase gene ALT1 into FUM1-disrupted Fusarium verticillioides produces metabolites with the fumonisin methylation pattern. JOURNAL OF NATURAL PRODUCTS 2009; 72:1328-1330. [PMID: 19449880 DOI: 10.1021/np900193j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Fumonisins and AAL toxins are polyketide-derived mycotoxins produced by several important fungal pathogens of crop plants. The toxins contain a linear, dimethylated polyketide chain, but differ in chain length and methylation positions. Here, we have isolated the major metabolites from a fumonisin null mutant, Fusarium verticillioides strain 5777, that has been transformed with the AAL-toxin polyketide synthase gene (ALT1). The results showed that the metabolites maintained the chain length and methylation pattern of fumonisins. This suggests that the timing and regioselectivity of the methyltransferase of the ALT1 PKS could be reprogrammed in this Fusarium transformant.
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Affiliation(s)
- Yaoyao Li
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
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77
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Sharon A, Finkelstein A, Shlezinger N, Hatam I. Fungal apoptosis: function, genes and gene function. FEMS Microbiol Rev 2009; 33:833-54. [PMID: 19416362 DOI: 10.1111/j.1574-6976.2009.00180.x] [Citation(s) in RCA: 147] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Cells of all living organisms are programmed to self-destruct under certain conditions. The most well known form of programmed cell death is apoptosis, which is essential for proper development in higher eukaryotes. In fungi, apoptotic-like cell death occurs naturally during aging and reproduction, and can be induced by environmental stresses and exposure to toxic metabolites. The core apoptotic machinery in fungi is similar to that in mammals, but the apoptotic network is less complex and of more ancient origin. Only some of the mammalian apoptosis-regulating proteins have fungal homologs, and the number of protein families is drastically reduced. Expression in fungi of animal proteins that do not have fungal homologs often affects apoptosis, suggesting functional conservation of these components despite the absence of protein-sequence similarity. Functional analysis of Saccharomyces cerevisiae apoptotic genes, and more recently of those in some filamentous species, has revealed partial conservation, along with substantial differences in function and mode of action between fungal and human proteins. It has been suggested that apoptotic proteins might be suitable targets for novel antifungal treatments. However, implementation of this approach requires a better understanding of fungal apoptotic networks and identification of the key proteins regulating apoptotic-like cell death in fungi.
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Affiliation(s)
- Amir Sharon
- Department of Plant Sciences, Tel Aviv University, Tel Aviv, Israel.
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78
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Dhawan R, Luo H, Foerster AM, Abuqamar S, Du HN, Briggs SD, Mittelsten Scheid O, Mengiste T. HISTONE MONOUBIQUITINATION1 interacts with a subunit of the mediator complex and regulates defense against necrotrophic fungal pathogens in Arabidopsis. THE PLANT CELL 2009; 21:1000-19. [PMID: 19286969 PMCID: PMC2671699 DOI: 10.1105/tpc.108.062364] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2008] [Revised: 02/11/2009] [Accepted: 02/26/2009] [Indexed: 05/17/2023]
Abstract
This work examines the role of the Arabidopsis thaliana RING E3 ligase, HISTONE MONOUBIQUITINATION1 (HUB1) in disease resistance. Loss-of-function alleles of HUB1 show increased susceptibility to the necrotrophic fungal pathogens Botrytis cinerea and Alternaria brassicicola, whereas HUB1 overexpression conferred resistance to B. cinerea. By contrast, responses to the bacterial pathogen Pseudomonas syringae are unaltered in hub1 plants. hub1 mutants have thinner cell walls but increased callose around an infection site. HUB1 acts independently of jasmonate, but ethylene (ET) responses and salicylate modulate the resistance of hub1 mutants to necrotrophic fungi. The ET response factor ETHYLENE INSENSITIVE2 is epistatic to HUB1 for A. brassicicola resistance but additive to HUB1 for B. cinerea resistance. HUB1 interacts with MED21, a subunit of the Arabidopsis Mediator, a conserved complex that regulates RNA polymerase II. RNA interference lines with reduced MED21 expression are highly susceptible to A. brassicicola and B. cinerea, whereas T-DNA insertion alleles are embryonic lethal, suggesting an essential role for MED21. However, HUB1-mediated histone H2B modification is independent of histone H3 and DNA methylation. In sum, histone H2B monoubiquitination is an important chromatin modification with regulatory roles in plant defense against necrotrophic fungi most likely through modulation of gene expression.
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Affiliation(s)
- Rahul Dhawan
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907-2054, USA
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79
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Egusa M, Ozawa R, Takabayashi J, Otani H, Kodama M. The jasmonate signaling pathway in tomato regulates susceptibility to a toxin-dependent necrotrophic pathogen. PLANTA 2009; 229:965-976. [PMID: 19148670 DOI: 10.1007/s00425-009-0890-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2008] [Accepted: 01/03/2009] [Indexed: 05/27/2023]
Abstract
The plant hormone, jasmonic acid (JA), is known to have a critical role in both resistance and susceptibility against bacterial and fungal pathogen attack. However, little is known about the involvement of JA in the interactions between plants and toxigenic necrotrophic fungal pathogens. Using the tomato pathotype of Alternaria alternata (Aa) and its AAL-toxin/tomato interaction as a model system, we demonstrate a possible role for JA in susceptibility of plants against pathogens, which utilize host-specific toxins as virulence effectors. Disease development and in planta growth of the tomato pathotype of Aa were decreased in the def1 mutant, defective in biosynthesis of JA, compared with the wild-type (WT) cultivar. Exogenous methyl jasmonate (MeJA) application restored pathogen disease symptoms to the def1 mutant and led to increased disease in the WT. On the other hand, necrotic cell death was similarly induced by AAL-toxin both on def1 and WT, and MeJA application to the tomatoes did not affect the degree of cell death by the toxin. These results indicate that the JA-dependent signaling pathway is not involved in host basal defense responses against the tomato pathotype of Aa, but rather might affect pathogen acceptability via a toxin-independent manner. Data further suggest that JA has a promotional effect on susceptibility of tomato to toxigenic and necrotrophic pathogens, such that pathogens might utilize the JA signaling pathway for successful infection.
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Affiliation(s)
- Mayumi Egusa
- Laboratory of Plant Pathology, Faculty of Agriculture, Tottori University, 4-101 Koyama-Minami, Tottori, 680-8553, Japan
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80
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Dhawan R, Luo H, Foerster AM, Abuqamar S, Du HN, Briggs SD, Mittelsten Scheid O, Mengiste T. HISTONE MONOUBIQUITINATION1 interacts with a subunit of the mediator complex and regulates defense against necrotrophic fungal pathogens in Arabidopsis. THE PLANT CELL 2009. [PMID: 19286969 DOI: 10.2307/40537446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
This work examines the role of the Arabidopsis thaliana RING E3 ligase, HISTONE MONOUBIQUITINATION1 (HUB1) in disease resistance. Loss-of-function alleles of HUB1 show increased susceptibility to the necrotrophic fungal pathogens Botrytis cinerea and Alternaria brassicicola, whereas HUB1 overexpression conferred resistance to B. cinerea. By contrast, responses to the bacterial pathogen Pseudomonas syringae are unaltered in hub1 plants. hub1 mutants have thinner cell walls but increased callose around an infection site. HUB1 acts independently of jasmonate, but ethylene (ET) responses and salicylate modulate the resistance of hub1 mutants to necrotrophic fungi. The ET response factor ETHYLENE INSENSITIVE2 is epistatic to HUB1 for A. brassicicola resistance but additive to HUB1 for B. cinerea resistance. HUB1 interacts with MED21, a subunit of the Arabidopsis Mediator, a conserved complex that regulates RNA polymerase II. RNA interference lines with reduced MED21 expression are highly susceptible to A. brassicicola and B. cinerea, whereas T-DNA insertion alleles are embryonic lethal, suggesting an essential role for MED21. However, HUB1-mediated histone H2B modification is independent of histone H3 and DNA methylation. In sum, histone H2B monoubiquitination is an important chromatin modification with regulatory roles in plant defense against necrotrophic fungi most likely through modulation of gene expression.
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Affiliation(s)
- Rahul Dhawan
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907-2054, USA
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82
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Arabidopsis AAL-toxin-resistant mutant atr1 shows enhanced tolerance to programmed cell death induced by reactive oxygen species. Biochem Biophys Res Commun 2008; 375:639-44. [DOI: 10.1016/j.bbrc.2008.08.056] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2008] [Accepted: 08/12/2008] [Indexed: 12/19/2022]
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83
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Petersen NHT, McKinney LV, Pike H, Hofius D, Zakaria A, Brodersen P, Petersen M, Brown RE, Mundy J. Human GLTP and mutant forms of ACD11 suppress cell death in the Arabidopsis acd11 mutant. FEBS J 2008; 275:4378-88. [PMID: 18657186 PMCID: PMC2585820 DOI: 10.1111/j.1742-4658.2008.06584.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The Arabidopsis acd11 mutant exhibits runaway, programmed cell death due to the loss of a putative sphingosine transfer protein (ACD11) with homology to mammalian GLTP. We demonstrate that transgenic expression in Arabidopsis thaliana of human GLTP partially suppressed the phenotype of the acd11 null mutant, resulting in delayed programmed cell death development and plant survival. Surprisingly, a GLTP mutant form impaired in glycolipid transfer activity also complemented the acd11 mutants. To understand the relationship between functional complementarity and transfer activity, we generated site-specific mutants in ACD11 based on homologous GLTP residues required for glycolipid transfer. We show that these ACD11 mutant forms are impaired in their in vitro transfer activity of sphingolipids. However, transgenic expression of these mutant forms fully complemented acd11 mutant cell death, and transgenic plants showed normal induction of hypersensitive cell death upon infection with avirulent strains of Pseudomonas syringae. The significance of these findings with respect to the function(s) of ACD11 in sphingolipid transport and cell death regulation is discussed.
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Affiliation(s)
- Nikolaj H. T. Petersen
- Department of Biology, Copenhagen Biocenter, Ole Maaløesvej 5, 2200 Copenhagen N, Denmark
| | - Lea Vig McKinney
- Department of Biology, Copenhagen Biocenter, Ole Maaløesvej 5, 2200 Copenhagen N, Denmark
| | - Helen Pike
- Laboratory of Membrane Biochemistry, The Hormel Institute, University of Minnesota, 801 16th Ave NE, Austin, MN 55912 USA
| | - Daniel Hofius
- Department of Biology, Copenhagen Biocenter, Ole Maaløesvej 5, 2200 Copenhagen N, Denmark
| | - Asif Zakaria
- Laboratory of Membrane Biochemistry, The Hormel Institute, University of Minnesota, 801 16th Ave NE, Austin, MN 55912 USA
| | - Peter Brodersen
- Department of Biology, Copenhagen Biocenter, Ole Maaløesvej 5, 2200 Copenhagen N, Denmark
- Present address: Institut de Biologie Moléculaire des Plantes CNRS UPR 2357, 12, rue du Général Zimmer, 67084 Strasbourg Cedex, France
| | - Morten Petersen
- Department of Biology, Copenhagen Biocenter, Ole Maaløesvej 5, 2200 Copenhagen N, Denmark
| | - Rhoderick E. Brown
- Laboratory of Membrane Biochemistry, The Hormel Institute, University of Minnesota, 801 16th Ave NE, Austin, MN 55912 USA
| | - John Mundy
- Department of Biology, Copenhagen Biocenter, Ole Maaløesvej 5, 2200 Copenhagen N, Denmark
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84
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Zhu X, Vogeler C, Du L. Functional complementation of fumonisin biosynthesis in FUM1-disrupted fusarium verticillioides by the AAL-toxin polyketide synthase gene ALT1 from Alternaria alternata f. sp. Lycopersici. JOURNAL OF NATURAL PRODUCTS 2008; 71:957-960. [PMID: 18435561 DOI: 10.1021/np8000514] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Fumonisins and AAL-toxins are mycotoxins produced by several widespread fungal pathogens of crops. The carbon backbone of the mycotoxins originates from a highly reduced, acyclic polyketide, a C18 chain for fumonisins and a C16 chain for AAL-toxins. Fungal reduced polyketides are assembled by iterative modular polyketide synthases (PKS), and their biosynthetic mechanism is not very clear. Here, we cloned the PKS gene, ALT1, from the tomato pathogen Alternaria alternata f. sp. Lycopersici and introduced it into Fusarium verticillioides 5777, which does not produce fumonisins due to a disrupted fumonisin PKS gene, FUM1. An ALT1 transformant of strain 5777 produced fumonisin B series as well as fumonisin analogues. The results provide experimental evidence for the function of ALT1, which encodes a PKS for mycotoxin biosynthesis. The results also show that the C16-synthesizing ALT1 is able to support the C18 fumonisin biosynthesis in F. verticillioides, suggesting that the final size of the fungal reduced polyketides is not determined by the PKSs alone. Unlike other PKSs, these PKSs do not have a thioesterase/cyclase domain. The release of polyketide precursors that are covalently attached to the PKSs involves a distinct mechanism, which probably determines the structure of the final products.
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Affiliation(s)
- Xiangcheng Zhu
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, USA
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85
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Involvement of sphingoid bases in mediating reactive oxygen intermediate production and programmed cell death in Arabidopsis. Cell Res 2008; 17:1030-40. [PMID: 18059378 DOI: 10.1038/cr.2007.100] [Citation(s) in RCA: 155] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Sphingolipids have been suggested to act as second messengers for an array of cellular signaling activities in plant cells, including stress responses and programmed cell death (PCD). However, the mechanisms underpinning these processes are not well understood. Here, we report that an Arabidopsis mutant, fumonisin B1 resistant 11-1 (fbr 11-1), which fails to generate reactive oxygen intermediates (ROIs), is incapable of initiating PCD when the mutant is challenged by fumonisin B(1) (FB(1)), a specific inhibitor of ceramide synthase. Molecular analysis indicated that FBR11 encodes a long-chain base 1 (LCB1) subunit of serine palmitoyltransferase (SPT), which catalyzes the first rate-limiting step of de novo sphingolipid synthesis. Mass spectrometric analysis of the sphingolipid concentrations revealed that whereas the fbr 11-1 mutation did not affect basal levels of sphingoid bases, the mutant showed attenuated formation of sphingoid bases in response to FB(1). By a direct feeding experiment, we show that the free sphingoid bases dihydrosphingosine, phytosphingosine and sphingosine efficiently induce ROI generation followed by cell death. Conversely, ROI generation and cell death induced by dihydrosphingosine were specifically blocked by its phosphorylated form dihydrosphingosine-1-phosphate in a dose-dependent manner, suggesting that the maintenance of homeostasis between a free sphingoid base and its phosphorylated derivative is critical to determining the cell fate. Because alterations of the sphingolipid level occur prior to the ROI production, we propose that the free sphingoid bases are involved in the control of PCD in Arabidopsis, presumably through the regulation of the ROI level upon receiving different developmental or environmental cues.
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86
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Kamphuis LG, Lichtenzveig J, Oliver RP, Ellwood SR. Two alternative recessive quantitative trait loci influence resistance to spring black stem and leaf spot in Medicago truncatula. BMC PLANT BIOLOGY 2008; 8:30. [PMID: 18366746 PMCID: PMC2324085 DOI: 10.1186/1471-2229-8-30] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2007] [Accepted: 03/26/2008] [Indexed: 05/04/2023]
Abstract
BACKGROUND Knowledge of the genetic basis of plant resistance to necrotrophic pathogens is incomplete and has been characterised in relatively few pathosystems. In this study, the cytology and genetics of resistance to spring black stem and leaf spot caused by Phoma medicaginis, an economically important necrotrophic pathogen of Medicago spp., was examined in the model legume M. truncatula. RESULTS Macroscopically, the resistant response of accession SA27063 was characterised by small, hypersensitive-like spots following inoculation while the susceptible interaction with accessions A17 and SA3054 showed necrotic lesions and spreading chlorosis. No unique cytological differences were observed during early infection (<48 h) between the resistant and susceptible genotypes, except pathogen growth was restricted to one or a few host cells in SA27063. In both interactions reactive oxygen intermediates and phenolic compounds were produced, and cell death occurred. Two F2 populations segregating for resistance to spring black stem and leaf spot were established between SA27063 and the two susceptible accessions, A17 and SA3054. The cross between SA27063 and A17 represented a wider cross than between SA27063 and SA3054, as evidenced by higher genetic polymorphism, reduced fertility and aberrant phenotypes of F2 progeny. In the SA27063 x A17 F2 population a highly significant quantitative trait locus (QTL, LOD = 7.37; P < 0.00001) named resistance to the necrotroph Phoma medicaginis one (rnpm1) genetically mapped to the top arm of linkage group 4 (LG4). rnpm1 explained 33.6% of the phenotypic variance in the population's response to infection depicted on a 1-5 scale and was tightly linked to marker AW256637. A second highly significant QTL (LOD = 6.77; P < 0.00001), rnpm2, was located on the lower arm of LG8 in the SA27063 x SA3054 map. rnpm2 explained 29.6% of the phenotypic variance and was fine mapped to a 0.8 cM interval between markers h2_16a6a and h2_21h11d. rnpm1 is tightly linked to a cluster of Toll/Interleukin1 receptor-nucleotide binding site-leucine-rich repeat (TIR-NBS-LRR) genes and disease resistance protein-like genes, while no resistance gene analogues (RGAs) are apparent in the genomic sequence of the reference accession A17 at the rnpm2 locus. CONCLUSION The induction of defence responses and cell death in the susceptible interaction following infection by P. medicaginis suggested this pathogen is not negatively affected by these responses and may promote them. A QTL for resistance was revealed in each of two populations derived from crosses between a resistant accession and two different susceptible accessions. Both loci are recessive in nature, and the simplest explanation for the existence of two separate QTLs is the occurrence of host genotype-specific susceptibility loci that may interact with undetermined P. medicaginis virulence factors.
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Affiliation(s)
- Lars G Kamphuis
- Australian Centre for Necrotrophic Fungal Pathogens, State Agricultural Biotechnology Centre, Murdoch University, Perth 6150, Western Australia, Australia
| | - Judith Lichtenzveig
- Australian Centre for Necrotrophic Fungal Pathogens, State Agricultural Biotechnology Centre, Murdoch University, Perth 6150, Western Australia, Australia
- Commonwealth Scientific and Industrial Research Organisation, Plant Industry, Private Bag No. 5, Wembley 6913, Western Australia, Australia
| | - Richard P Oliver
- Australian Centre for Necrotrophic Fungal Pathogens, State Agricultural Biotechnology Centre, Murdoch University, Perth 6150, Western Australia, Australia
| | - Simon R Ellwood
- Australian Centre for Necrotrophic Fungal Pathogens, State Agricultural Biotechnology Centre, Murdoch University, Perth 6150, Western Australia, Australia
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87
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Programmed cell death suppression in transformed plant tissue by tomato cDNAs identified from an Agrobacterium rhizogenes-based functional screen. Mol Genet Genomics 2008; 279:509-21. [DOI: 10.1007/s00438-008-0329-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2007] [Accepted: 01/31/2008] [Indexed: 01/17/2023]
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88
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Du L, Zhu X, Gerber R, Huffman J, Lou L, Jorgenson J, Yu F, Zaleta-Rivera K, Wang Q. Biosynthesis of sphinganine-analog mycotoxins. J Ind Microbiol Biotechnol 2008; 35:455-64. [PMID: 18214562 DOI: 10.1007/s10295-008-0316-y] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2007] [Accepted: 01/10/2008] [Indexed: 10/22/2022]
Abstract
Sphinganine-analog mycotoxins (SAMT) are polyketide-derived natural products produced by a number of plant pathogenic fungi and are among the most economically important mycotoxins. The toxins are structurally similar to sphinganine, a key intermediate in the biosynthesis of ceramides and sphingolipids, and competitive inhibitors for ceramide synthase. The inhibition of ceramide and sphingolipid biosynthesis is associated with several fatal diseases in domestic animals and esophageal cancer and neural tube defects in humans. SAMT contains a highly reduced, acyclic polyketide carbon backbone, which is assembled by a single module polyketide synthase. The biosynthesis of SAMT involves a unique polyketide chain-releasing mechanism, in which a pyridoxal 5'-phosphate-dependent enzyme catalyzes the termination, offloading and elongation of the polyketide chain. This leads to the introduction of a new carbon-carbon bond and an amino group to the polyketide chain. The mechanism is fundamentally different from the thioesterase/cyclase-catalyzed polyketide chain releasing found in bacterial and other fungal polyketide biosynthesis. Genetic data suggest that the ketosynthase domain of the polyketide synthase and the chain-releasing enzyme are important for controlling the final product structure. In addition, several post-polyketide modifications have to take place before SAMT become mature toxins.
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Affiliation(s)
- L Du
- Department of Chemistry, University of Nebraska, Lincoln, NE 68588, USA.
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89
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Glenn AE, Zitomer NC, Zimeri AM, Williams LD, Riley RT, Proctor RH. Transformation-mediated complementation of a FUM gene cluster deletion in Fusarium verticillioides restores both fumonisin production and pathogenicity on maize seedlings. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2008; 21:87-97. [PMID: 18052886 DOI: 10.1094/mpmi-21-1-0087] [Citation(s) in RCA: 124] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The filamentous ascomycete Fusarium verticillioides is a pathogen of maize and produces the fumonisin mycotoxins. However, a distinct population of F. verticillioides is pathogenic on banana and does not produce fumonisins. Fumonisin-producing strains from maize cause leaf lesions, developmental abnormalities, stunting, and sometimes death of maize seedlings, whereas fumonisin-nonproducing banana strains do not. A Southern analysis of banana strains did not detect genes in the fumonisin biosynthetic gene (FUM) cluster but did detect genes flanking the cluster. Nucleotide sequence analysis of the genomic region carrying the flanking genes revealed that the FUM cluster was absent in banana strains except for portions of FUM21 and FUM19, which are the terminal genes at each end of the cluster. Polymerase chain reaction analysis confirmed the absence of the cluster in all banana strains examined. Cotransformation of a banana strain with two overlapping cosmids, which together contain the entire FUM cluster, yielded fumonisin-producing transformants that were pathogenic on maize seedlings. Conversely, maize strains that possess the FUM cluster but do not produce fumonisins because of mutations in FUM1, a polyketide synthase gene, were not pathogenic on maize seedlings. Together, the data indicate that fumonisin production may have been lost by deletion of the FUM cluster in the banana population of F. verticillioides but that fumonisin production could be restored by molecular genetic complementation. The results also indicate that fumonisin production by F. verticillioides is required for development of foliar disease symptoms on maize seedlings.
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Affiliation(s)
- Anthony E Glenn
- United States Department of Agriculture-Agricultural Research Service, Russell Research Center, Toxicology & Mycotoxin Research Unit, Athens, GA 30605, USA.
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90
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Gadjev I, Stone JM, Gechev TS. Programmed cell death in plants: new insights into redox regulation and the role of hydrogen peroxide. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2008; 270:87-144. [PMID: 19081535 DOI: 10.1016/s1937-6448(08)01403-2] [Citation(s) in RCA: 206] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Programmed cell death (PCD), the highly regulated dismantling of cells, is essential for plant growth and survival. PCD plays key roles in embryo development, formation and maturation of many cell types and tissues, and plant reaction/adaptation to environmental conditions. Reactive oxygen species (ROS) are not only toxic by products of aerobic metabolism with strictly controlled cellular levels, but they also function as signaling agents regulating many biological processes and producing pleiotropic effects. Over the last decade, ROS have become recognized as important modulators of plant PCD. Molecular genetic approaches using plant mutants and transcriptome studies related to ROS-mediated PCD have revealed a wide array of plant-specific cell death regulators and have contributed to unraveling the elaborate redox signaling network. This review summarizes the biological processes, in which plant PCD participates and discusses the signaling functions of ROS with emphasis on hydrogen peroxide.
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Affiliation(s)
- Ilya Gadjev
- Department of Plant Physiology and Plant Molecular Biology, University of Plovdiv, Plovdiv 4000, Bulgaria
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91
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Jiménez-Gómez JM, Alonso-Blanco C, Borja A, Anastasio G, Angosto T, Lozano R, Martínez-Zapater JM. Quantitative genetic analysis of flowering time in tomato. Genome 2007; 50:303-15. [PMID: 17502904 DOI: 10.1139/g07-009] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Artificial selection of cultivated tomato (Solanum lycopersicum L.) has resulted in the generation of early-flowering, day-length-insensitive cultivars, despite its close relationship to other Solanum species that need more time and specific photoperiods to flower. To investigate the genetic mechanisms controlling flowering time in tomato and related species, we performed a quantitative trait locus (QTL) analysis for flowering time in an F2 mapping population derived from S. lycopersicum and its late-flowering wild relative S. chmielewskii. Flowering time was scored as the number of days from sowing to the opening of the first flower (days to flowering), and as the number of leaves under the first inflorescence (leaf number). QTL analyses detected 2 QTLs affecting days to flowering, which explained 55.3% of the total phenotypic variance, and 6 QTLs for leaf number, accounting for 66.7% of the corresponding phenotypic variance. Four of the leaf number QTLs had not previously been detected for this trait in tomato. Colocation of some QTLs with flowering-time genes included in the genetic map suggests PHYB2, FALSIFLORA, and a tomato FLC-like sequence as candidate genes that might have been targets of selection during the domestication of tomato.
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Affiliation(s)
- José M Jiménez-Gómez
- Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
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92
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Nagy ED, Lee TC, Ramakrishna W, Xu Z, Klein PE, SanMiguel P, Cheng CP, Li J, Devos KM, Schertz K, Dunkle L, Bennetzen JL. Fine mapping of the Pc locus of Sorghum bicolor, a gene controlling the reaction to a fungal pathogen and its host-selective toxin. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2007; 114:961-70. [PMID: 17356869 DOI: 10.1007/s00122-006-0481-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2006] [Accepted: 11/30/2006] [Indexed: 05/14/2023]
Abstract
Milo disease in sorghum is caused by isolates of the soil-borne fungus Periconia circinata that produce PC-toxin. Susceptibility to milo disease is conditioned by a single, semi-dominant gene, termed Pc. The susceptible allele (Pc) converts to a resistant form (pc) spontaneously at a gametic frequency of 10(-3) to 10(-4). A high-density genetic map was constructed around the Pc locus using DNA markers, allowing the Pc gene to be delimited to a 0.9 cM region on the short arm of sorghum chromosome 9. Physically, the Pc-region was covered by a single BAC clone. Sequence analysis of this BAC revealed twelve gene candidates. Several of the predicted genes in the region are homologous to disease resistance loci, including one NBS-LRR resistance gene analogue that is present in multiple tandem copies. Analysis of pc isolines derived from Pc/Pc sorghum suggests that one or more members of this NBS-LRR gene family are the Pc genes that condition susceptibility.
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MESH Headings
- Alleles
- Amino Acid Sequence
- Ascomycota/pathogenicity
- Chromosomes, Artificial, Bacterial
- Chromosomes, Plant
- Cloning, Molecular
- Crosses, Genetic
- DNA, Plant
- Gene Dosage
- Gene Duplication
- Genes, Dominant
- Genes, Plant
- Genetic Markers
- Genotype
- Molecular Sequence Data
- Physical Chromosome Mapping
- Polymorphism, Single-Stranded Conformational
- Recombination, Genetic
- Sequence Homology, Amino Acid
- Sorghum/genetics
- Toxins, Biological/genetics
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Affiliation(s)
- Ervin D Nagy
- Department of Genetics, University of Georgia, Athens, GA, 30602, USA
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93
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Wang B, Shi G, Fu Y, Xu X. Cloning and characterization of a LASS1-GDF1 transcript in rat cerebral cortex: conservation of a bicistronic structure. DNA SEQUENCE : THE JOURNAL OF DNA SEQUENCING AND MAPPING 2007; 18:92-103. [PMID: 17364820 DOI: 10.1080/10425170601060947] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
LASS1 is the mammalian homologue of yeast longevity-assurance gene 1 (LAG1) which is differentially expressed during the yeast replicative life span and was shown to play a role in determining yeast longevity. Growth/differentiation factor 1 (GDF1) is a transforming growth factor-beta family member that was originally isolated from an mouse embryo cDNA library. GDF1 is expressed specifically in the nervous system and functions in left-right patterning of the mouse embryo. To explore the potential role of LASS1 in rat neuron aging, northern blot analysis for LASS1 mRNA was performed and detected a 2.7 kb transcript in adult rat cerebral cortex. Cloning and sequence analysis revealed that this transcript contains two nonoverlapping open reading frames (ORFs), LASS1 and GDF1, which are quite different to the predicted sequences in GenBank (accession number XM_224734 and XM_224733). The alignment with the rat genome database revealed this transcript matches the sequence of rat chromosome 16 genomic contig (GenBank accession number NW_047470) between nucleotide positions 1935060th and 1919439th, which contains eight exons and seven introns. Multiple sequence analysis revealed high conservation of the two ORFs. The phylogenetic analysis showed very close evolutionary relationship among rat, mouse and human. It raises the possibility that this mRNA may give rise to two different proteins and the conserved bicistronic structure might be of unknown significance.
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Affiliation(s)
- Baoheng Wang
- Laboratory of Cell Senescence, Shantou University Medical College, Shantou, Guangdong Province, 515041, People's Republic of China
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94
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van Ooijen G, van den Burg HA, Cornelissen BJC, Takken FLW. Structure and function of resistance proteins in solanaceous plants. ANNUAL REVIEW OF PHYTOPATHOLOGY 2007; 45:43-72. [PMID: 17367271 DOI: 10.1146/annurev.phyto.45.062806.094430] [Citation(s) in RCA: 129] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Gene-for-gene resistance in plants is based on the presence of a resistance (R) gene in the host and a matching Avirulence (Avr) gene in the pathogen. Many R genes have been cloned over the past two decades, mostly from the Solanaceae. The gene products, called R proteins, display modular domain structures. R protein function has recently been shown to require dynamic interactions between the various domains. In addition to these intramolecular interactions, R proteins interact with other proteins to form signaling complexes that are able to activate an innate immune response that arrests proliferation of the invading pathogen, thereby conferring disease resistance. In this review, we summarize current understanding of R protein structure and function, as well as the molecular mechanisms underlying the activation of defense signaling processes. As well as being a rich source for R genes, Solanaceae are a leading model system in which to study inter- and intramolecular interactions of R proteins.
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Affiliation(s)
- Gerben van Ooijen
- Plant Pathology, Swammerdam Institute for Life Sciences, University of Amsterdam, 1090 GB Amsterdam, The Netherlands.
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95
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Markham JE, Jaworski JG. Rapid measurement of sphingolipids from Arabidopsis thaliana by reversed-phase high-performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2007; 21:1304-14. [PMID: 17340572 DOI: 10.1002/rcm.2962] [Citation(s) in RCA: 187] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Changes in sphingolipids have been associated with profound effects in cell fate and development in both plants and animals. Sphingolipids as a group consist of a large number of different compound classes of which numerous individual species may vary in response to environmental stimuli to affect cellular responses. The ability to measure all sphingolipids simultaneously is, therefore, essential to an understanding of the biochemical regulation of sphingolipid metabolism and signaling molecules derived from it. In the model plant Arabidopsis thaliana, the major sphingolipid classes are glycosylinositolphosphoceramides, glucosylceramides, hydroxyceramides and ceramides. Other minor but potentially important sphingolipids are free long-chain bases and their phosphorylated derivates. By using a single solvent system with reversed-phase high-performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry detection we have been able to separate and measure 168 sphingolipids from a crude sample. This greatly speeds up and simplifies the analysis of plant sphingolipids and should pave the way for a better understanding of their role in plant performance.
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96
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Abstract
Phytotoxic compounds produced by plant pathogens are often crucial determinants of plant disease. Knowledge of them provides insights into disease syndromes and may be exploited by conventional breeding and biotechnology to obtain resistant crops.
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Affiliation(s)
- Richard N Strange
- Department of Biology, University College London, Gower Street, London, WC1E 6BT, UK
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97
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Spassieva S, Seo JG, Jiang JC, Bielawski J, Alvarez-Vasquez F, Jazwinski SM, Hannun YA, Obeid LM. Necessary role for the Lag1p motif in (dihydro)ceramide synthase activity. J Biol Chem 2006; 281:33931-8. [PMID: 16951403 DOI: 10.1074/jbc.m608092200] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Lag1 (longevity assurance gene 1) homologues, a family of transmembrane proteins found in all eukaryotes, have been shown to be necessary for (dihydro)ceramide synthesis. All Lag1 homologues contain a highly conserved stretch of 52 amino acids known as the Lag1p motif. However, the functional significance of the conserved Lag1p motif for (dihydro)ceramide synthesis is currently unknown. In this work, we have investigated the function of the motif by introducing eight point mutations in the Lag1p motif of the mouse LASS1 (longevity assurance homologue 1 of yeast Lag1). The (dihydro)ceramide synthase activity of the mutants was tested using microsomes in HeLa cells and in vitro. Six of the mutations resulted in loss of activity in cells and in vitro. In addition, our results showed that C18:0 fatty acid CoA (but not cis-C18:1 fatty acid CoAs) are substrates for LASS1 and that LASS1 in HeLa cells is sensitive to fumonisin B1, an in vitro inhibitor of (dihydro)ceramide synthase. Moreover, we mutated the Lag1p motif of another Lag homologue, human LASS5. The amino acid substitutions in the human LASS5 were the same as in mouse LASS1, and had the same effect on the in vitro activity of LASS5, suggesting the Lag1p motif appears to be essential for the enzyme activity of all Lag1 homologues.
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Affiliation(s)
- Stefka Spassieva
- Department of Medicine, Medical University of South Carolina, Charleston, South Carolina 29425, USA
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98
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Yu Y, Lu H, Pan H, Ma JH, Ding ZJ, Li YY. Expression of LASS2 controlled by LAG1 or ADH1 promoters cannot functionally complement Lag1p. Microbiol Res 2006; 161:203-11. [PMID: 16765836 DOI: 10.1016/j.micres.2005.08.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/04/2005] [Indexed: 11/29/2022]
Abstract
LAG1 contributes to the substrate specificity and catalytic activity of ceramide synthases in Saccharomyces cerevisiae. Double deletion of LAG1 and its yeast homologue LAC1 results in the slow growth defect of the cell under certain genetic backgrounds. LASS2, containing the conserved TLC domain and the specific HOX domain, is a human homologue of Lag1p. In this study, shuffling tests and tetrad analyses were carried out to examine the complementation between Lag1p and LASS2 or its fragment containing the TLC domain but lacking the HOX domain (LASS2DeltaHOX). Controlled by either the natural weak LAG1 promoter or the strong yeast ADH1 promoter, LASS2 and LASS2DeltaHOX could not rescue the slow growth defect of double mutant. The results indicated that LASS2 or LASS2DeltaHOX could not functionally complement Lag1p.
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Affiliation(s)
- Yao Yu
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai 200433, PR China
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99
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Pewzner-Jung Y, Ben-Dor S, Futerman AH. When do Lasses (longevity assurance genes) become CerS (ceramide synthases)?: Insights into the regulation of ceramide synthesis. J Biol Chem 2006; 281:25001-5. [PMID: 16793762 DOI: 10.1074/jbc.r600010200] [Citation(s) in RCA: 357] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Yael Pewzner-Jung
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
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100
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Riley RT, Voss KA. Differential sensitivity of rat kidney and liver to fumonisin toxicity: organ-specific differences in toxin accumulation and sphingoid base metabolism. Toxicol Sci 2006; 92:335-45. [PMID: 16613836 DOI: 10.1093/toxsci/kfj198] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Fumonisins (FBs) are mycotoxins in maize and are inhibitors of ceramide synthase (CS), the most likely proximate cause of FB toxicity. In liver and kidney, the primary target organs in FB-fed rats, inhibition of CS results in a marked increase in the ceramide precursor sphinganine (Sa). This study was conducted to investigate the differential time- and dose-dependent changes in Sa, sphingosine (So), sphinganine 1-phosphate (Sa-1-P), and sphingosine 1-phosphate (So-1-P) in kidney, liver, serum, and heart of male Sprague-Dawley rats (3-4 weeks old) fed diets containing 1.1, 13.5, and 88.6 mug/g of total FB for 10 days. The tissues were microscopically examined for the presence and severity of lesions consistent with FB exposure. There was a time- and dose-dependent increase in Sa in both liver and kidney, which was closely correlated with the tissue concentration of fumonisin B(1) (FB(1)) and histopathologic findings. However, the Sa alone greatly underestimated the degree of disruption of sphingolipid metabolism since accumulated Sa and So were quickly metabolized to Sa-1-P and So-1-P as evidenced by large increases in these metabolites in kidney but not in liver. The concentration of FB(1) in liver and kidney that first elicited an increase in Sa was similar in both tissues, however, over time, the kidney accumulated significantly more FB(1) (10x) and total Sa (Sa plus Sa-1-P) compared to liver. Thus, the relative sensitivity of male Sprague-Dawley rat kidney and liver is most likely a consequence of differences in the mechanisms responsible for both FB(1) uptake/clearance and Sa metabolism.
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Affiliation(s)
- Ronald T Riley
- Toxicology and Mycotoxin Research Unit, US Department of Agriculture/ARS, Athens, GA 30604-5677, USA.
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