1
|
Basak S, Paul D, Das R, Dastidar SG, Kundu P. A novel acidic pH-dependent metacaspase governs defense-response against pathogens in tomato. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2024; 213:108850. [PMID: 38917737 DOI: 10.1016/j.plaphy.2024.108850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 06/07/2024] [Accepted: 06/15/2024] [Indexed: 06/27/2024]
Abstract
The importance of metacaspases in programmed cell death and tissue differentiation is known, but their significance in disease stress response, particularly in a crop plant, remained enigmatic. We show the tomato metacaspase expression landscape undergoes differential reprogramming during biotrophic and necrotrophic modes of pathogenesis; also, the metacaspase activity dynamics correlate with the disease progression. These stresses have contrasting effects on the expression pattern of SlMC8, a Type II metacaspase, indicating that SlMC8 is crucial for stress response. In accordance, selected biotic stress-related transcription factors repress SlMC8 promoter activity. Interestingly, SlMC8 exhibits maximum proteolysis at an acidic pH range of 5-6. Molecular dynamics simulation identified the low pH-driven protonation event of Glu246 as critical to stabilize the interaction of SlMC8 with its substrate. Mutagenesis of Glu246 to charge-neutral glutamine suppressed SlMC8's proteolytic activity, corroborating the importance of the amino acid in SlMC8 activation. The glutamic acid residue is found in an equivalent position in metacaspases having acidic pH dependence. SlMC8 overexpression leads to heightened ROS levels, cell death, and tolerance to PstDC3000, and SlMC8 repression reversed the phenomena. However, the overexpression of SlMC8 increases tomato susceptibility to necrotrophic Alternaria solani. We propose that SlMC8 activation due to concurrent changes in cellular pH during infection contributes to the basal resistance of the plant by promoting cell death at the site of infection, and the low pH dependence acts as a guard against unwarranted cell death. Our study confirms the essentiality of a low pH-driven Type II metacaspase in tomato biotic stress-response regulation.
Collapse
Affiliation(s)
- Shrabani Basak
- Department of Biological Sciences, Bose Institute, EN-80, Sector V, Bidhannagar, Kolkata, 700091, West Bengal, India
| | - Debarati Paul
- Department of Biological Sciences, Bose Institute, EN-80, Sector V, Bidhannagar, Kolkata, 700091, West Bengal, India
| | - Rohit Das
- Department of Biological Sciences, Bose Institute, EN-80, Sector V, Bidhannagar, Kolkata, 700091, West Bengal, India
| | - Shubhra Ghosh Dastidar
- Department of Biological Sciences, Bose Institute, EN-80, Sector V, Bidhannagar, Kolkata, 700091, West Bengal, India
| | - Pallob Kundu
- Department of Biological Sciences, Bose Institute, EN-80, Sector V, Bidhannagar, Kolkata, 700091, West Bengal, India.
| |
Collapse
|
2
|
Zou Y, Sabljić I, Horbach N, Dauphinee AN, Åsman A, Sancho Temino L, Minina EA, Drag M, Stael S, Poreba M, Ståhlberg J, Bozhkov PV. Thermoprotection by a cell membrane-localized metacaspase in a green alga. THE PLANT CELL 2024; 36:665-687. [PMID: 37971931 PMCID: PMC10896300 DOI: 10.1093/plcell/koad289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 10/10/2023] [Accepted: 11/12/2023] [Indexed: 11/19/2023]
Abstract
Caspases are restricted to animals, while other organisms, including plants, possess metacaspases (MCAs), a more ancient and broader class of structurally related yet biochemically distinct proteases. Our current understanding of plant MCAs is derived from studies in streptophytes, and mostly in Arabidopsis (Arabidopsis thaliana) with 9 MCAs with partially redundant activities. In contrast to streptophytes, most chlorophytes contain only 1 or 2 uncharacterized MCAs, providing an excellent platform for MCA research. Here we investigated CrMCA-II, the single type-II MCA from the model chlorophyte Chlamydomonas (Chlamydomonas reinhardtii). Surprisingly, unlike other studied MCAs and similar to caspases, CrMCA-II dimerizes both in vitro and in vivo. Furthermore, activation of CrMCA-II in vivo correlated with its dimerization. Most of CrMCA-II in the cell was present as a proenzyme (zymogen) attached to the plasma membrane (PM). Deletion of CrMCA-II by genome editing compromised thermotolerance, leading to increased cell death under heat stress. Adding back either wild-type or catalytically dead CrMCA-II restored thermoprotection, suggesting that its proteolytic activity is dispensable for this effect. Finally, we connected the non-proteolytic role of CrMCA-II in thermotolerance to the ability to modulate PM fluidity. Our study reveals an ancient, MCA-dependent thermotolerance mechanism retained by Chlamydomonas and probably lost during the evolution of multicellularity.
Collapse
Affiliation(s)
- Yong Zou
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, SE-756 51 Uppsala, Sweden
| | - Igor Sabljić
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, SE-756 51 Uppsala, Sweden
| | - Natalia Horbach
- Department of Chemical Biology and Bioimaging, Wroclaw University of Science and Technology, 50-370 Wroclaw, Poland
| | - Adrian N Dauphinee
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, SE-756 51 Uppsala, Sweden
| | - Anna Åsman
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, SE-756 51 Uppsala, Sweden
| | - Lucia Sancho Temino
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, SE-756 51 Uppsala, Sweden
| | - Elena A Minina
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, SE-756 51 Uppsala, Sweden
| | - Marcin Drag
- Department of Chemical Biology and Bioimaging, Wroclaw University of Science and Technology, 50-370 Wroclaw, Poland
| | - Simon Stael
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, SE-756 51 Uppsala, Sweden
| | - Marcin Poreba
- Department of Chemical Biology and Bioimaging, Wroclaw University of Science and Technology, 50-370 Wroclaw, Poland
| | - Jerry Ståhlberg
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, SE-756 51 Uppsala, Sweden
| | - Peter V Bozhkov
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, SE-756 51 Uppsala, Sweden
| |
Collapse
|
3
|
Stael S, Sabljić I, Audenaert D, Andersson T, Tsiatsiani L, Kumpf RP, Vidal-Albalat A, Lindgren C, Vercammen D, Jacques S, Nguyen L, Njo M, Fernández-Fernández ÁD, Beunens T, Timmerman E, Gevaert K, Van Montagu M, Ståhlberg J, Bozhkov PV, Linusson A, Beeckman T, Van Breusegem F. Structure-function study of a Ca 2+-independent metacaspase involved in lateral root emergence. Proc Natl Acad Sci U S A 2023; 120:e2303480120. [PMID: 37216519 PMCID: PMC10235996 DOI: 10.1073/pnas.2303480120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 04/24/2023] [Indexed: 05/24/2023] Open
Abstract
Metacaspases are part of an evolutionarily broad family of multifunctional cysteine proteases, involved in disease and normal development. As the structure-function relationship of metacaspases remains poorly understood, we solved the X-ray crystal structure of an Arabidopsis thaliana type II metacaspase (AtMCA-IIf) belonging to a particular subgroup not requiring calcium ions for activation. To study metacaspase activity in plants, we developed an in vitro chemical screen to identify small molecule metacaspase inhibitors and found several hits with a minimal thioxodihydropyrimidine-dione structure, of which some are specific AtMCA-IIf inhibitors. We provide mechanistic insight into the basis of inhibition by the TDP-containing compounds through molecular docking onto the AtMCA-IIf crystal structure. Finally, a TDP-containing compound (TDP6) effectively hampered lateral root emergence in vivo, probably through inhibition of metacaspases specifically expressed in the endodermal cells overlying developing lateral root primordia. In the future, the small compound inhibitors and crystal structure of AtMCA-IIf can be used to study metacaspases in other species, such as important human pathogens, including those causing neglected diseases.
Collapse
Affiliation(s)
- Simon Stael
- Department of Plant Biotechnology and Bioinformatics, Ghent University,9052Ghent, Belgium
- Center for Plant Systems Biology, VIB, 9052Ghent, Belgium
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, 75007Uppsala, Sweden
| | - Igor Sabljić
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, 75007Uppsala, Sweden
| | - Dominique Audenaert
- VIB Screening Core, VIB,9052Ghent, Belgium
- Centre for Bioassay Development and Screening, Ghent University,9000Ghent, Belgium
| | | | - Liana Tsiatsiani
- Department of Plant Biotechnology and Bioinformatics, Ghent University,9052Ghent, Belgium
- Center for Plant Systems Biology, VIB, 9052Ghent, Belgium
| | | | | | | | - Dominique Vercammen
- Department of Plant Biotechnology and Bioinformatics, Ghent University,9052Ghent, Belgium
- Center for Plant Systems Biology, VIB, 9052Ghent, Belgium
| | - Silke Jacques
- Department of Plant Biotechnology and Bioinformatics, Ghent University,9052Ghent, Belgium
- Center for Plant Systems Biology, VIB, 9052Ghent, Belgium
| | - Long Nguyen
- VIB Screening Core, VIB,9052Ghent, Belgium
- Centre for Bioassay Development and Screening, Ghent University,9000Ghent, Belgium
| | - Maria Njo
- Department of Plant Biotechnology and Bioinformatics, Ghent University,9052Ghent, Belgium
- Center for Plant Systems Biology, VIB, 9052Ghent, Belgium
| | - Álvaro D. Fernández-Fernández
- Department of Plant Biotechnology and Bioinformatics, Ghent University,9052Ghent, Belgium
- Center for Plant Systems Biology, VIB, 9052Ghent, Belgium
| | - Tine Beunens
- Department of Plant Biotechnology and Bioinformatics, Ghent University,9052Ghent, Belgium
- Center for Plant Systems Biology, VIB, 9052Ghent, Belgium
| | - Evy Timmerman
- Department of Biomolecular Medicine, Ghent University,9052Ghent, Belgium
- Center for Medical Biotechnology, VIB, 9052Ghent, Belgium
| | - Kris Gevaert
- Department of Biomolecular Medicine, Ghent University,9052Ghent, Belgium
- Center for Medical Biotechnology, VIB, 9052Ghent, Belgium
| | - Marc Van Montagu
- Department of Plant Biotechnology and Bioinformatics, Ghent University,9052Ghent, Belgium
- Center for Plant Systems Biology, VIB, 9052Ghent, Belgium
| | - Jerry Ståhlberg
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, 75007Uppsala, Sweden
| | - Peter V. Bozhkov
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, 75007Uppsala, Sweden
| | - Anna Linusson
- Department of Chemistry, Umeå University,90187Umeå, Sweden
| | - Tom Beeckman
- Department of Plant Biotechnology and Bioinformatics, Ghent University,9052Ghent, Belgium
- Center for Plant Systems Biology, VIB, 9052Ghent, Belgium
| | - Frank Van Breusegem
- Department of Plant Biotechnology and Bioinformatics, Ghent University,9052Ghent, Belgium
- Center for Plant Systems Biology, VIB, 9052Ghent, Belgium
| |
Collapse
|
4
|
Basak S, Kundu P. Plant metacaspases: Decoding their dynamics in development and disease. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2022; 180:50-63. [PMID: 35390704 DOI: 10.1016/j.plaphy.2022.03.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 03/02/2022] [Accepted: 03/20/2022] [Indexed: 06/14/2023]
Abstract
Plant metacaspases were evolved in parallel to well-characterized animal counterpart caspases and retained the similar histidine-cysteine catalytic dyad, leading to functional congruity between these endopeptidases. Although phylogenetic relatedness of the catalytic domain and functional commonality placed these proteases in the caspase family, credible counterarguments predominantly about their distinct substrate specificity raised doubts about the classification. Metacaspases are involved in regulating the PCD during development as well as in senescence. Balancing acts of metacaspase activity also dictate cell fate during defense upon the perception of adverse environmental cues. Accordingly, their activity is tightly regulated, while suppressing spurious activation, by a combination of genetic and post-translational modifications. Structural insights from recent studies provided vital clues on the functionality. This comprehensive review aims to explore the origin of plant metacaspases, and their regulatory and functional diversity in different plants while discussing their analogy to mammalian caspases. Besides, we have presented various modern methodologies for analyzing the proteolytic activity of these indispensable molecules in the healthy or stressed life of a plant. The review would serve as a repository of all the available pieces of evidence indicating metacaspases as the key regulator of PCD across the plant kingdom and highlight the prospect of studying metacaspases for their inclusion in a crop improvement program.
Collapse
Affiliation(s)
- Shrabani Basak
- Division of Plant Biology, Bose Institute, EN-80, Sector V, Bidhannagar, Kolkata, 700091, West Bengal, India.
| | - Pallob Kundu
- Division of Plant Biology, Bose Institute, EN-80, Sector V, Bidhannagar, Kolkata, 700091, West Bengal, India.
| |
Collapse
|
5
|
Ma S, Shi H, Wang GF. The potential roles of different metacaspases in maize defense response. PLANT SIGNALING & BEHAVIOR 2021; 16:1906574. [PMID: 33843433 PMCID: PMC8143262 DOI: 10.1080/15592324.2021.1906574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/15/2021] [Accepted: 03/17/2021] [Indexed: 06/12/2023]
Abstract
Metacaspases (MCs), a class of cysteine-dependent proteases, act as important regulators in plant defense response. In maize genome, there are 11 ZmMCs which have been categorized into two types (type I and II) based on their structural differences. In this study, we investigated the different transcript patterns of 11 ZmMCs in maize defense response mediated by the nucleotide-binding, leucine-rich-repeat protein Rp1-D21. We further predicted that many cis-elements responsive to salicylic acid (SA), methyl jasmonate (MeJA), abscisic acid (ABA) and auxin were identified in the promoter regions of ZmMCs, and several different transcription factors were predicted to bind to their promoters. We analyzed the localization of ZmMCs with previously identified quantitative trait loci (QTLs) in maize disease resistance, and found that all other ZmMCs, except for ZmMC6-8, are co-located with at least one QTL associated with disease resistance to southern leaf blight, northern leaf blight, gray leaf spot or Fusarium ear rot. Based on previous RNA-seq analysis, different ZmMCs display different transcript levels in response to Cochliobolous heterostrophus and Fusarium verticillioides. All the results imply that the members of ZmMCs might have differential functions to different maize diseases. This study lays the basis for further investigating the roles of ZmMCs in maize disease resistance.
Collapse
Affiliation(s)
- Shijun Ma
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong, PR China
| | - Hong Shi
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong, PR China
| | - Guan-Feng Wang
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong, PR China
| |
Collapse
|
6
|
Chen Y, Inzé D, Vanhaeren H. Post-translational modifications regulate the activity of the growth-restricting protease DA1. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:3352-3366. [PMID: 33587751 DOI: 10.1093/jxb/erab062] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 02/06/2021] [Indexed: 06/12/2023]
Abstract
Plants are a primary food source and can form the basis for renewable energy resources. The final size of their organs is by far the most important trait to consider when seeking increased plant productivity. Being multicellular organisms, plant organ size is mainly determined by the coordination between cell proliferation and cell expansion. The protease DA1 limits the duration of cell proliferation and thereby restricts final organ size. Since its initial identification as a negative regulator of organ growth, various transcriptional regulators of DA1, but also interacting proteins, have been identified. These interactors include cleavage substrates of DA1, and also proteins that modulate the activity of DA1 through post-translational modifications, such as ubiquitination, deubiquitination, and phosphorylation. In addition, many players in the DA1 pathway display conserved phenotypes in other dicot and even monocot species. In this review, we provide a timely overview of the complex, but intriguing, molecular mechanisms that fine-tune the activity of DA1 and therefore final organ size. Moreover, we lay out a roadmap to identify and characterize substrates of proteases and frame the substrate cleavage events in their biological context.
Collapse
Affiliation(s)
- Ying Chen
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Dirk Inzé
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Hannes Vanhaeren
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- Center for Plant Systems Biology, VIB, Ghent, Belgium
| |
Collapse
|
7
|
Luan QL, Zhu YX, Ma S, Sun Y, Liu XY, Liu M, Balint-Kurti PJ, Wang GF. Maize metacaspases modulate the defense response mediated by the NLR protein Rp1-D21 likely by affecting its subcellular localization. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 105:151-166. [PMID: 33107667 DOI: 10.1111/tpj.15047] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 09/03/2020] [Accepted: 09/15/2020] [Indexed: 05/22/2023]
Abstract
Plants usually employ resistance (R) genes to defend against the infection of pathogens, and most R genes encode intracellular nucleotide-binding, leucine-rich repeat (NLR) proteins. The recognition between R proteins and their cognate pathogens often triggers a rapid localized cell death at the pathogen infection sites, termed the hypersensitive response (HR). Metacaspases (MCs) belong to a cysteine protease family, structurally related to metazoan caspases. MCs play crucial roles in plant immunity. However, the underlying molecular mechanism and the link between MCs and NLR-mediated HR are not clear. In this study, we systematically investigated the MC gene family in maize and identified 11 ZmMCs belonging to two types. Further functional analysis showed that the type I ZmMC1 and ZmMC2, but not the type II ZmMC9, suppress the HR-inducing activity of the autoactive NLR protein Rp1-D21 and of its N-terminal coiled-coil (CCD21 ) signaling domain when transiently expressed in Nicotiana benthamiana. ZmMC1 and ZmMC2 physically associate with CCD21 in vivo. We further showed that ZmMC1 and ZmMC2, but not ZmMC9, are predominantly localized in a punctate distribution in both N. benthamiana and maize (Zea mays) protoplasts. Furthermore, the co-expression of ZmMC1 and ZmMC2 with Rp1-D21 and CCD21 causes their re-distribution from being uniformly distributed in the nucleocytoplasm to a punctate distribution co-localizing with ZmMC1 and ZmMC2. We reveal a novel role of plant MCs in modulating the NLR-mediated defense response and derive a model to explain it.
Collapse
Affiliation(s)
- Qing-Ling Luan
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong, 266237, PR China
| | - Yu-Xiu Zhu
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong, 266237, PR China
| | - Shijun Ma
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong, 266237, PR China
| | - Yang Sun
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong, 266237, PR China
| | - Xiao-Ying Liu
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong, 266237, PR China
| | - Mengjie Liu
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong, 266237, PR China
| | - Peter J Balint-Kurti
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, North Carolina, 27695, USA
- U.S. Department of Agriculture-Agricultural Research Service, Plant Science Research Unit, Raleigh, North Carolina, 27695, USA
| | - Guan-Feng Wang
- The Key Laboratory of Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong, 266237, PR China
| |
Collapse
|
8
|
Valandro F, Menguer PK, Cabreira-Cagliari C, Margis-Pinheiro M, Cagliari A. Programmed cell death (PCD) control in plants: New insights from the Arabidopsis thaliana deathosome. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2020; 299:110603. [PMID: 32900441 DOI: 10.1016/j.plantsci.2020.110603] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 05/28/2020] [Accepted: 07/14/2020] [Indexed: 06/11/2023]
Abstract
Programmed cell death (PCD) is a genetically controlled process that leads to cell suicide in both eukaryotic and prokaryotic organisms. In plants PCD occurs during development, defence response and when exposed to adverse conditions. PCD acts controlling the number of cells by eliminating damaged, old, or unnecessary cells to maintain cellular homeostasis. Unlike in animals, the knowledge about PCD in plants is limited. The molecular network that controls plant PCD is poorly understood. Here we present a review of the current mechanisms involved with the genetic control of PCD in plants. We also present an updated version of the AtLSD1 deathosome, which was previously proposed as a network controlling HR-mediated cell death in Arabidopsis thaliana. Finally, we discuss the unclear points and open questions related to the AtLSD1 deathosome.
Collapse
Affiliation(s)
- Fernanda Valandro
- Programa de Pós-Graduação em Genética e Biologia Molecular, Departamento de Genética, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil; Universidade Federal do Rio Grande do Sul (UFRGS), RS, Brazil.
| | - Paloma Koprovski Menguer
- Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil; Universidade Federal do Rio Grande do Sul (UFRGS), RS, Brazil.
| | | | - Márcia Margis-Pinheiro
- Programa de Pós-Graduação em Biologia Celular e Molecular, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil; Universidade Federal do Rio Grande do Sul (UFRGS), RS, Brazil.
| | - Alexandro Cagliari
- Programa de Pós-Graduação em Ambiente e Sustentabilidade, Universidade Estadual do Rio Grande do Sul, RS, Brazil; Universidade Estadual do Rio Grande do Sul (UERGS), RS, Brazil.
| |
Collapse
|
9
|
Vafadar F, Amooaghaie R, Ehsanzadeh P, Ghanadian M, Talebi M, Ghanati F. Melatonin and calcium modulate the production of rosmarinic acid, luteolin, and apigenin in Dracocephalum kotschyi under salinity stress. PHYTOCHEMISTRY 2020; 177:112422. [PMID: 32593901 DOI: 10.1016/j.phytochem.2020.112422] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 05/19/2020] [Accepted: 05/25/2020] [Indexed: 05/27/2023]
Abstract
Melatonin (Mel) and calcium (Ca2+) have a regulatory role in the induction of specialized metabolites production and defensive responses against stresses. Therefore, in this study, the effects of Mel and Ca2+ and the possible relationship between them in the increase of the production of phenolic compounds in Dracocephalum kotschyi Boiss. under both control and salinity stress conditions were investigated. The results showed that 75 mM NaCl reduced shoot dry biomass but elevated H2O2 content, electrolyte leakage (EL) level, total phenolic and flavonoid contents (TPC and TFC), and DPPH scavenging capacity. Salinity stress also upregulated gene expression of phenylalanine ammonia-lyase (PAL) and rosmarinic acid synthase (RAS), as well as the activities of PAL and tyrosine ammonia-lyase (TAL) enzymes. Pre-treatment of the plants with CaCl2 and Mel affected these attributes in a dose-dependent manner. Application of 5 mM Ca2+ and 100 μM Mel improved shoot dry biomass and reduced the level of EL and H2O2 content but enhanced TPC and TFC, DPPH scavenging capacity, PAL and TAL activities, PAL and RAS transcripts, and content of rosmarinic acid (RA), luteolin flavone (LF) and apigenin flavone (AF) under salinity stress. Pre-treatment of D. kotschyi with lanthanum chloride (LaCl3) as a plasma membrane channel blocker, ethylene glycol tetra-acetic acid (EGTA) as a Ca2+ chelator and trifluoperazine (TFP) as a calmodulin (CaM) antagonist, impaired Mel effects on the above attributes under salinity stress. In contrast, pre-treatment with p-chlorophenylalanine (p-CPA), as an inhibitor of Mel biosynthesis, did not impair the impacts of Ca2+ on the production of phenolic compounds in salt-exposed plants. These results suggested that the effect of Mel on the induction of phenolic compounds production requires the influx of extracellular Ca2+ into the cells and is dependent on Ca2+/CaM signaling.
Collapse
Affiliation(s)
- Farinaz Vafadar
- Plant Biology Department, Faculty of Science, Shahrekord University, Shahrekord, Iran.
| | - Rayhaneh Amooaghaie
- Plant Biology Department, Faculty of Science, Shahrekord University, Shahrekord, Iran; Biotechnology Research Institute, Shahrekord University, Shahrekord, Iran.
| | - Parviz Ehsanzadeh
- Department of Agronomy and Plant Breeding, College of Agriculture, Isfahan University of Technology, Isfahan, 84156-83111, Iran.
| | - Mustafa Ghanadian
- Department of Pharmacognosy, Isfahan Pharmaceutical Sciences Research Center, Isfahan University of Medical Sciences, Isfahan, Iran.
| | - Majid Talebi
- Department of Biotechnology, College of Agriculture, Isfahan University of Technology, Isfahan, 84156-83111, Iran.
| | - Faezeh Ghanati
- Department of Plant Biology, Faculty of Biological Science, Tarbiat Modares University (TMU), POB141115-154, Tehran, Iran.
| |
Collapse
|
10
|
Song J, Yang F, Xun M, Xu L, Tian X, Zhang W, Yang H. Genome-Wide Identification and Characterization of Vacuolar Processing Enzyme Gene Family and Diverse Expression Under Stress in Apple ( Malus × Domestic). FRONTIERS IN PLANT SCIENCE 2020; 11:626. [PMID: 32528498 PMCID: PMC7264823 DOI: 10.3389/fpls.2020.00626] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 04/22/2020] [Indexed: 05/06/2023]
Abstract
Vacuolar processing enzymes (VPEs) play an important role in stress resistance and development of plants. Despite their diverse roles, little information is available in apple (Malus × domestic). This study firstly presents the genome-wide identification of VPE family genes in apple, resulting in 20 family members those are unevenly distributed across six out of the 17 chromosomes. Phylogenetic analysis assigned these genes into four groups. Analysis of exon-intron junctions and motifs of each candidate gene revealed high levels of conservation within and between phylogenetic groups. Cis-element including w box, ABRE, LTR, and TC-rich repeats were found in promoters of MdVPEs. NCBI-GEO database shown that the expression of MdVPEs exhibited diverse patterns in different tissues as well as the infection of Pythium ultimum and Apple Stem Grooving Virus. Furthermore, qRT-PCR showed that MdVPE genes were responsive to salt, cadmium, low-temperature, and drought. Overexpression of MDP0000172014, which was strongly induced by salt and drought stress, significantly decreased Arabidopsis tolerance to salt stress. The genome-wide identification and characterization of MdVPEs in apple provided basic information for the potential utilization of MdVPEs in stress resistance.
Collapse
Affiliation(s)
- Jianfei Song
- College of Horticulture Science and Engineering, Shandong Agricultural University, Tai’an, China
- State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai’an, China
| | - Fei Yang
- College of Horticulture Science and Engineering, Shandong Agricultural University, Tai’an, China
- State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai’an, China
| | - Mi Xun
- College of Horticulture Science and Engineering, Shandong Agricultural University, Tai’an, China
- State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai’an, China
| | - Longxiao Xu
- College of Horticulture Science and Engineering, Shandong Agricultural University, Tai’an, China
- State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai’an, China
| | - Xiaozhi Tian
- College of Horticulture Science and Engineering, Shandong Agricultural University, Tai’an, China
- State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai’an, China
| | - Weiwei Zhang
- College of Horticulture Science and Engineering, Shandong Agricultural University, Tai’an, China
- State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai’an, China
- *Correspondence: Weiwei Zhang,
| | - Hongqiang Yang
- College of Horticulture Science and Engineering, Shandong Agricultural University, Tai’an, China
- State Key Laboratory of Crop Biology, Shandong Agricultural University, Tai’an, China
- Hongqiang Yang,
| |
Collapse
|
11
|
Shen W, Liu J, Li JF. Type-II Metacaspases Mediate the Processing of Plant Elicitor Peptides in Arabidopsis. MOLECULAR PLANT 2019; 12:1524-1533. [PMID: 31454707 DOI: 10.1016/j.molp.2019.08.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 08/16/2019] [Accepted: 08/18/2019] [Indexed: 05/24/2023]
Abstract
Plants can produce animal cytokine-like immune peptides, among which plant elicitor peptides (Peps) derive from the C termini of their precursors (PROPEPs). Recently, the functions of Peps have been expanded beyond plant immunity. However, a long-standing enigma is how PROPEPs are processed into Peps. Here, we report that the Ca2+-dependent type-II metacaspases (MCs) constitute the proteolytic enzymes to mediate PROPEP processing in Arabidopsis. In protoplasts, co-expression of PROPEP1 with type-II MCs, including MC4 to MC9, can promote the generation of processed Pep1. Destruction of the catalytic cysteine residue in MC4 or the conserved arginine residue preceding the Pep1 sequence blocks PROPEP1 cleavage, whereas the bacterial elicitor flg22 enhances the MC4-mediated PROPEP1 processing. MC4 cleaves PROPEP1 in vitro and also cleaves PROPEP2 to PROPEP8, but, surprisingly, not PROPEP6 in protoplasts. Domain swapping between PROPEP1 and PROPEP6 suggests a hidden role of the sequence context upstream of the Pep sequence for PROPEP processing. flg22-induced PROPEP1 processing and Botrytis cinerea resistance are severely impaired in the mc4/5/6/7 quadruple-mutant plants. Taken together, our study identifies the type-II MCs as new players in Pep signaling, and lays the foundation for understanding the regulation of multifaceted functions of Peps in plant immunity and beyond.
Collapse
Affiliation(s)
- Wenzhong Shen
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources, MOE Key Laboratory of Gene Function and Regulation, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Jiuer Liu
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources, MOE Key Laboratory of Gene Function and Regulation, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China
| | - Jian-Feng Li
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources, MOE Key Laboratory of Gene Function and Regulation, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, China.
| |
Collapse
|
12
|
Fernández-Fernández ÁD, Van der Hoorn RAL, Gevaert K, Van Breusegem F, Stael S. Caught green-handed: methods for in vivo detection and visualization of protease activity. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:2125-2141. [PMID: 30805604 DOI: 10.1093/jxb/erz076] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Revised: 01/25/2019] [Accepted: 01/29/2019] [Indexed: 06/09/2023]
Abstract
Proteases are enzymes that cleave peptide bonds of other proteins. Their omnipresence and diverse activities make them important players in protein homeostasis and turnover of the total cell proteome as well as in signal transduction in plant stress responses and development. To understand protease function, it is of paramount importance to assess when and where a specific protease is active. Here, we review the existing methods to detect in vivo protease activity by means of imaging chemical activity-based probes and genetically encoded sensors. We focus on the diverse fluorescent and luminescent sensors at the researcher's disposal and evaluate the potential of imaging techniques to deliver in vivo spatiotemporal detail of protease activity. We predict that in the coming years, revised techniques will help to elucidate plant protease activity and functions and hence expand the current status of the field.
Collapse
Affiliation(s)
- Álvaro Daniel Fernández-Fernández
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB Center for Plant Systems Biology, Ghent, Belgium
| | | | - Kris Gevaert
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
- VIB Center for Medical Biotechnology, Ghent, Belgium
| | - Frank Van Breusegem
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB Center for Plant Systems Biology, Ghent, Belgium
| | - Simon Stael
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- VIB Center for Plant Systems Biology, Ghent, Belgium
- Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
- VIB Center for Medical Biotechnology, Ghent, Belgium
| |
Collapse
|
13
|
Klemenčič M, Funk C. Evolution and structural diversity of metacaspases. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:2039-2047. [PMID: 30921456 DOI: 10.1093/jxb/erz082] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 01/09/2019] [Indexed: 06/09/2023]
Abstract
Caspases are metazoan proteases, best known for their involvement in programmed cell death in animals. In higher plants genetically controlled mechanisms leading to the selective death of individual cells also involve the regulated interplay of various types of proteases. Some of these enzymes are structurally homologous to caspases and have therefore been termed metacaspases. In addition to the two well-studied metacaspase variants found in higher plants, type I and type II, biochemical data have recently become available for metacaspases of type III and metacaspase-like proteases, which are present only in certain algae. Although increasing in vitro and in vivo data suggest the existence of further sub-types, a lack of structural information hampers the interpretation of their distinct functional properties. However, the identification of key amino acid residues involved in the proteolytic mechanism of metacaspases, as well as the increased availability of plant genomic and transcriptomic data, is increasingly enabling in-depth analysis of all metacaspase types found in plastid-containing organisms. Here, we review the structural distribution and diversification of metacaspases and in doing so try to provide comprehensive guidelines for further analyses of this versatile family of proteases in organisms ranging from simple unicellular species to flowering plants.
Collapse
Affiliation(s)
- Marina Klemenčič
- Department of Chemistry, Umeå University, Umeå, Sweden
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot, Ljubljana, Slovenia
| | | |
Collapse
|
14
|
Liu H, Wei Y, Deng Z, Yang H, Dai L, Li D. Involvement of HbMC1-mediated cell death in tapping panel dryness of rubber tree (Hevea brasiliensis). TREE PHYSIOLOGY 2019; 39:391-403. [PMID: 30496555 DOI: 10.1093/treephys/tpy125] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 10/16/2018] [Accepted: 10/30/2018] [Indexed: 06/09/2023]
Abstract
Tapping panel dryness (TPD) causes a significant reduction in the latex yield of rubber tree (Hevea brasiliensis Muell. Arg.). It is reported that TPD is a typical programmed cell death (PCD) process. Although PCD plays a vital role in TPD occurrence, there is a lack of detailed and systematic study. Metacaspases are key regulators of diverse PCD in plants. Based on our previous result that HbMC1 was associated with TPD, we further elucidate the roles of HbMC1 on rubber tree TPD in this study. HbMC1 was up-regulated by TPD-inducing factors including wounding, ethephon and H2O2. Moreover, the expression level of HbMC1 was increased along with TPD severity in rubber tree, suggesting a positive correlation between HbMC1 expression and TPD severity. To investigate its biological function, HbMC1 was overexpressed in yeast (Saccharomyces cerevisiae) and tobacco (Nicotiana benthamiana). Transgenic yeast and tobacco overexpressing HbMC1 showed growth retardation compared with controls under H2O2-induced oxidative stress. In addition, overexpression of HbMC1 in yeast and tobacco reduced cell survival after high-concentration H2O2 treatment and resulted in enhanced H2O2-induced leaf cell death, respectively. A total of 11 proteins, rbcL, TM9SF2-like, COX3, ATP9, DRP, HbREF/Hevb1, MSSP2-like, SRC2, GATL8, CIPK14-like and STK, were identified and confirmed to interact with HbMC1 by yeast two-hybrid screening and co-transformation in yeast. The 11 proteins mentioned above are associated with many biological processes, including rubber biosynthesis, stress response, autophagy, carbohydrate metabolism, signal transduction, etc. Taken together, our results suggest that HbMC1-mediated PCD plays an important role in rubber tree TPD, and the identified HbMC1-interacting proteins provide valuable information for further understanding the molecular mechanism of HbMC1-mediated TPD in rubber tree.
Collapse
Affiliation(s)
- Hui Liu
- Hainan Provincial Key Laboratory of Tropical Crops Cultivation and Physiology, Key Laboratory of Biology and Genetic Resources of Rubber Tree, Ministry of Agriculture and Rural Affairs, Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences, Danzhou, China
| | - Yongxuan Wei
- Hainan Provincial Key Laboratory of Tropical Crops Cultivation and Physiology, Key Laboratory of Biology and Genetic Resources of Rubber Tree, Ministry of Agriculture and Rural Affairs, Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences, Danzhou, China
- Institute of Tropical Agriculture and Forestry, Hainan University, Haikou, China
| | - Zhi Deng
- Hainan Provincial Key Laboratory of Tropical Crops Cultivation and Physiology, Key Laboratory of Biology and Genetic Resources of Rubber Tree, Ministry of Agriculture and Rural Affairs, Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences, Danzhou, China
| | - Hong Yang
- Hainan Provincial Key Laboratory of Tropical Crops Cultivation and Physiology, Key Laboratory of Biology and Genetic Resources of Rubber Tree, Ministry of Agriculture and Rural Affairs, Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences, Danzhou, China
| | - Longjun Dai
- Hainan Provincial Key Laboratory of Tropical Crops Cultivation and Physiology, Key Laboratory of Biology and Genetic Resources of Rubber Tree, Ministry of Agriculture and Rural Affairs, Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences, Danzhou, China
| | - Dejun Li
- Hainan Provincial Key Laboratory of Tropical Crops Cultivation and Physiology, Key Laboratory of Biology and Genetic Resources of Rubber Tree, Ministry of Agriculture and Rural Affairs, Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences, Danzhou, China
| |
Collapse
|
15
|
Li D, Wu D, Li S, Guo N, Gao J, Sun X, Cai Y. Transcriptomic profiling identifies differentially expressed genes associated with programmed cell death of nucellar cells in Ginkgo biloba L. BMC PLANT BIOLOGY 2019; 19:91. [PMID: 30819114 PMCID: PMC6396491 DOI: 10.1186/s12870-019-1671-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 02/01/2019] [Indexed: 05/11/2023]
Abstract
BACKGROUND Previously, we demonstrated that pollen chamber formation (PCF) in G. biloba ovules was a process of programmed cell death (PCD) within the nucellar cells at the micropylar end. However, the signal triggering the cascades of the programmed events in these nucellar cells remains unexplored. RESULTS A transcriptomic strategy was employed to unravel the mechanism underlying the nucellar PCD via the comparative profiles of RNA-seq between pre-PCF and post-PCF ovules. A total of 5599 differentially expressed genes (DEGs) with significance was identified from G. biloba ovules and classified into three main categories of GO annotation, including 17 biological processes, 15 cellular components and 17 molecular functions. KEGG analysis showed that 72 DEGs were enriched in "Plant hormone signal transduction". Furthermore, 99 DEGs were found to be associated with the PCD process, including the genes involved in ethylene signaling pathway, PCD initiation, and PCD execution. Moreover, calcium-cytochemical localization indicated that calcium could play a role in regulating PCD events within the nucellar cells during pollen chamber formation in G. biloba ovules. CONCLUSIONS A putative working model, consisting of three overlapping processes, is proposed for the nucellar PCD: at the stage of PCD preparation, ethylene signaling pathway is activated for transcriptional regulation of the downstream targets; subsequently, at the stage of PCD initiation, the upregulated expression of several transcription factors, i.e., NAC, bHLH, MADS-box, and MYB, further promotes the corresponding transcript levels of CYTOCHROME C and CALMODULINs, thereby, leads to the PCD initiation via the calcium-dependent signaling cascade; finally, at the stage of PCD execution, some proteases like metacaspases and vacuolar processing enzyme for hydrolysis, together with the process of autophagy, play roles in the clearance of cellular components. Afterwards, a pollen chamber is generated from the removal of specific nucellar cells in the developing ovule.
Collapse
Affiliation(s)
- Dahui Li
- College of Life Science, Anhui Agricultural University, Hefei, 230036 China
| | - Di Wu
- College of Life Science, Anhui Agricultural University, Hefei, 230036 China
| | - Shizhou Li
- College of Life Science, Anhui Agricultural University, Hefei, 230036 China
| | - Ning Guo
- College of Life Science, Anhui Agricultural University, Hefei, 230036 China
| | - Junshan Gao
- College of Life Science, Anhui Agricultural University, Hefei, 230036 China
| | - Xu Sun
- College of Life Science, Anhui Agricultural University, Hefei, 230036 China
| | - Yongping Cai
- College of Life Science, Anhui Agricultural University, Hefei, 230036 China
| |
Collapse
|
16
|
Cao Y, Meng D, Chen T, Chen Y, Zeng W, Zhang L, Wang Q, Hen W, Abdullah M, Jin Q, Lin Y, Cai Y. Metacaspase gene family in Rosaceae genomes: Comparative genomic analysis and their expression during pear pollen tube and fruit development. PLoS One 2019; 14:e0211635. [PMID: 30794567 PMCID: PMC6386261 DOI: 10.1371/journal.pone.0211635] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 01/17/2019] [Indexed: 12/11/2022] Open
Abstract
Metacaspase (MC), which is discovered gene family with distant caspase homologs in plants, fungi, and protozoa, may be involved in programmed cell death (PCD) processes during plant development and respond abiotic and biotic stresses. To reveal the evolutionary relationship of MC gene family in Rosaceae genomes, we identified 8, 7, 8, 12, 12, and 23 MC genes in the genomes of Fragaria vesca, Prunus mume, Prunus persica, Pyrus communis, Pyrus bretschneideri and Malus domestica, respectively. Phylogenetic analysis suggested that the MC genes could be grouped into three clades: Type I*, Type I and Type II, which was supported by gene structure and conserved motif analysis. Microsynteny analysis revealed that MC genes present in the corresponding syntenic blocks of P. communis, P. bretschneideri and M. domestica, and further suggested that large-scale duplication events play an important role in the expansion of MC gene family members in these three genomes than other Rosaceae plants (F. vesca, P. mume and P. persica). RNA-seq data showed the specific expression patterns of PbMC genes in response to drought stress. The expression analysis of MC genes demonstrated that PbMC01 and PbMC03 were able to be detected in all four pear pollen tubes and seven fruit development stages. The current study highlighted the evolutionary relationship and duplication of the MC gene family in these six Rosaceae genomes and provided appropriate candidate genes for further studies in P. bretschneideri.
Collapse
Affiliation(s)
- Yunpeng Cao
- School of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Dandan Meng
- School of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Tianzhe Chen
- School of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Yu Chen
- School of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Wei Zeng
- School of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Lei Zhang
- School of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Qi Wang
- College of Horticulture, Anhui Agricultural University, Hefei, China
| | - Wei Hen
- College of Horticulture, Anhui Agricultural University, Hefei, China
| | - Muhammad Abdullah
- School of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Qing Jin
- School of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Yi Lin
- School of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Yongping Cai
- School of Life Sciences, Anhui Agricultural University, Hefei, China
| |
Collapse
|
17
|
Fortin J, Lam E. Domain swap between two type-II metacaspases defines key elements for their biochemical properties. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 96:921-936. [PMID: 30176090 DOI: 10.1111/tpj.14079] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2018] [Accepted: 08/08/2018] [Indexed: 06/08/2023]
Abstract
Type-II metacaspases are conserved cysteine proteases found in eukaryotes with oxygenic photosynthesis, including green plants and some algae, such as Chlamydomonas and Volvox. Genetic and biochemical studies showed that some members in this protease family could be involved in oxidative stress-induced cell death in higher plants, but their regulatory mechanisms remain unclear. Biochemically, two distinct classes of type-II metacaspases are exemplified by AtMC4 and AtMC9 from Arabidopsis, with AtMC4 activation dependent on calcium under neutral pH, whereas AtMC9 is active only under mildly acidic pH, regardless of the availability of calcium. Here, we constructed all six possible combinations between the p20, linker, and p10 domains from AtMC4 and AtMC9. Our results show that calcium stimulation of AtMC4 activity is associated with essential amino acids located in its p20 domain. In contrast, the acidic pH optimum trait is lost from AtMC9 if one or two of its domains are replaced by that from AtMC4, suggesting that multiple interactions between domains in AtMC9 may be responsible for this property. Consistent with this, we found conserved 'signature' residues in each of the three domains that distinguish AtMC4- and AtMC9-like classes of metacaspases. Tracing the origin of the AtMC9 class, we found evidence for its appearance between lycophytes and gymnosperms, coincident with the evolution of more complex root archetypes in terrestrial plants. Our work suggests that the distinctive properties of the AtMC9-like protease could be associated with special cellular physiology in the roots of gymnosperms and angiosperms that are distinct from lycophytes.
Collapse
Affiliation(s)
- Jianqiao Fortin
- Department of Plant Biology, Rutgers,The State University of New Jersey, New Brunswick, NJ, 08901, USA
| | - Eric Lam
- Department of Plant Biology, Rutgers,The State University of New Jersey, New Brunswick, NJ, 08901, USA
| |
Collapse
|
18
|
Fraikin GY, Belenikina NS, Rubin AB. Damaging and Defense Processes Induced in Plant Cells by UVB Radiation. BIOL BULL+ 2018. [DOI: 10.1134/s1062359018060031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
19
|
Fraikin GY. Signaling Mechanisms Regulating Diverse Plant Cell Responses to UVB Radiation. BIOCHEMISTRY (MOSCOW) 2018; 83:787-794. [PMID: 30200863 DOI: 10.1134/s0006297918070027] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
UVB radiation (290-320 nm) causes diverse effects in plant cells that vary with the fluence rate of exposure. High fluence rates of UVB radiation cause damage to DNA and formation of reactive oxygen species in mitochondria and chloroplasts, which lead to oxidation of membrane proteins and lipids and inhibition of cellular functions. In response to oxidative stress, mitochondrial transmembrane potential dissipates, resulting in cytochrome c release and activation of metacaspases. This leads to the apoptosis-like cell death. The signaling mechanism based on UVB DNA damage includes checkpoint activation, cell-cycle arrest, and finally programmed cell death with characteristic DNA fragmentation and morphological hallmarks typical of apoptotic cells. Recently, it was shown that among the components of this signaling mechanism the transcriptional factor SOG1 (suppressor of gamma response 1) plays a key role in regulation of programmed cell death in plants. In contrast to its damaging effects, UVB radiation at low fluence rates can act as a regulatory signal that is specifically perceived by plants to promote acclimation and survival in sunlight. The protective action of UVB is based on expression of various genes, including those encoding flavonoid synthesis enzymes that provide a UVB-absorbing sunscreen in epidermal tissues and DNA photorepair enzymes. These processes are mediated by the UVB photoreceptor UVR8, which has been recently characterized at the molecular level. Now progress is made in uncovering the UVR8-mediated signaling pathway mechanism in the context of UVB photon perception and revealing the biochemical components of the early stages of light signal transduction. In this review, attention is focused on the achievements in studying these UVB-induced signaling processes.
Collapse
Affiliation(s)
- G Ya Fraikin
- Lomonosov Moscow State University, Moscow, 119991, Russia.
| |
Collapse
|
20
|
The cloak, dagger, and shield: proteases in plant-pathogen interactions. Biochem J 2018; 475:2491-2509. [PMID: 30115747 DOI: 10.1042/bcj20170781] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 07/10/2018] [Accepted: 07/13/2018] [Indexed: 01/03/2023]
Abstract
Plants sense the presence of pathogens or pests through the recognition of evolutionarily conserved microbe- or herbivore-associated molecular patterns or specific pathogen effectors, as well as plant endogenous danger-associated molecular patterns. This sensory capacity is largely mediated through plasma membrane and cytosol-localized receptors which trigger complex downstream immune signaling cascades. As immune signaling outputs are often associated with a high fitness cost, precise regulation of this signaling is critical. Protease-mediated proteolysis represents an important form of pathway regulation in this context. Proteases have been widely implicated in plant-pathogen interactions, and their biochemical mechanisms and targets continue to be elucidated. During the plant and pathogen arms race, specific proteases are employed from both the plant and the pathogen sides to contribute to either defend or invade. Several pathogen effectors have been identified as proteases or protease inhibitors which act to functionally defend or camouflage the pathogens from plant proteases and immune receptors. In this review, we discuss known protease functions and protease-regulated signaling processes involved in both sides of plant-pathogen interactions.
Collapse
|
21
|
Ma H, Xiang G, Li Z, Wang Y, Dou M, Su L, Yin X, Liu R, Wang Y, Xu Y. Grapevine VpPR10.1 functions in resistance to Plasmopara viticola through triggering a cell death-like defence response by interacting with VpVDAC3. PLANT BIOTECHNOLOGY JOURNAL 2018; 16:1488-1501. [PMID: 29377445 PMCID: PMC6041444 DOI: 10.1111/pbi.12891] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Revised: 01/10/2018] [Accepted: 01/22/2018] [Indexed: 05/04/2023]
Abstract
As one of the most serious diseases in grape, downy mildew caused by Plasmopara viticola is a worldwide grape disease. Much effort has been focused on improving susceptible grapevine resistance, and wild resistant grapevine species are important for germplasm improvement of commercial cultivars. Using yeast two-hybrid screen followed by a series of immunoprecipitation experiments, we identified voltage-dependent anion channel 3 (VDAC3) protein from Vitis piasezkii 'Liuba-8' as an interacting partner of VpPR10.1 cloned from Vitis pseudoreticulata 'Baihe-35-1', which is an important germplasm for its resistance to a range of pathogens. Co-expression of VpPR10.1/VpVDAC3 induced cell death in Nicotiana benthamiana, which accompanied by ROS accumulation. VpPR10.1 transgenic grapevine line showed resistance to P. viticola. We conclude that the VpPR10.1/VpVDAC3 complex is responsible for cell death-mediated defence response to P. viticola in grapevine.
Collapse
Affiliation(s)
- Hui Ma
- State Key Laboratory of Crop Stress Biology for Arid AreasCollege of HorticultureNorthwest A&F UniversityYanglingShaanxiChina
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest ChinaMinistry of AgricultureNorthwest A&F UniversityYanglingShaanxiChina
| | - Gaoqing Xiang
- State Key Laboratory of Crop Stress Biology for Arid AreasCollege of HorticultureNorthwest A&F UniversityYanglingShaanxiChina
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest ChinaMinistry of AgricultureNorthwest A&F UniversityYanglingShaanxiChina
| | - Zhiqian Li
- State Key Laboratory of Crop Stress Biology for Arid AreasCollege of HorticultureNorthwest A&F UniversityYanglingShaanxiChina
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest ChinaMinistry of AgricultureNorthwest A&F UniversityYanglingShaanxiChina
| | - Yuting Wang
- State Key Laboratory of Crop Stress Biology for Arid AreasCollege of HorticultureNorthwest A&F UniversityYanglingShaanxiChina
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest ChinaMinistry of AgricultureNorthwest A&F UniversityYanglingShaanxiChina
| | - Mengru Dou
- State Key Laboratory of Crop Stress Biology for Arid AreasCollege of HorticultureNorthwest A&F UniversityYanglingShaanxiChina
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest ChinaMinistry of AgricultureNorthwest A&F UniversityYanglingShaanxiChina
| | - Li Su
- State Key Laboratory of Crop Stress Biology for Arid AreasCollege of HorticultureNorthwest A&F UniversityYanglingShaanxiChina
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest ChinaMinistry of AgricultureNorthwest A&F UniversityYanglingShaanxiChina
| | - Xiao Yin
- State Key Laboratory of Crop Stress Biology for Arid AreasCollege of HorticultureNorthwest A&F UniversityYanglingShaanxiChina
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest ChinaMinistry of AgricultureNorthwest A&F UniversityYanglingShaanxiChina
| | - Ruiqi Liu
- State Key Laboratory of Crop Stress Biology for Arid AreasCollege of HorticultureNorthwest A&F UniversityYanglingShaanxiChina
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest ChinaMinistry of AgricultureNorthwest A&F UniversityYanglingShaanxiChina
| | - Yuejin Wang
- State Key Laboratory of Crop Stress Biology for Arid AreasCollege of HorticultureNorthwest A&F UniversityYanglingShaanxiChina
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest ChinaMinistry of AgricultureNorthwest A&F UniversityYanglingShaanxiChina
| | - Yan Xu
- State Key Laboratory of Crop Stress Biology for Arid AreasCollege of HorticultureNorthwest A&F UniversityYanglingShaanxiChina
- Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest ChinaMinistry of AgricultureNorthwest A&F UniversityYanglingShaanxiChina
| |
Collapse
|
22
|
Klemenčič M, Funk C. Structural and functional diversity of caspase homologues in non-metazoan organisms. PROTOPLASMA 2018; 255:387-397. [PMID: 28744694 PMCID: PMC5756287 DOI: 10.1007/s00709-017-1145-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 07/05/2017] [Indexed: 05/03/2023]
Abstract
Caspases, the proteases involved in initiation and execution of metazoan programmed cell death, are only present in animals, while their structural homologues can be found in all domains of life, spanning from simple prokaryotes (orthocaspases) to yeast and plants (metacaspases). All members of this wide protease family contain the p20 domain, which harbours the catalytic dyad formed by the two amino acid residues, histidine and cysteine. Despite the high structural similarity of the p20 domain, metacaspases and orthocaspases were found to exhibit different substrate specificities than caspases. While the former cleave their substrates after basic amino acid residues, the latter accommodate substrates with negative charge. This observation is crucial for the re-evaluation of non-metazoan caspase homologues being involved in processes of programmed cell death. In this review, we analyse the structural diversity of enzymes containing the p20 domain, with focus on the orthocaspases, and summarise recent advances in research of orthocaspases and metacaspases of cyanobacteria, algae and higher plants. Although caspase homologues were initially proposed to be involved in execution of cell death, accumulating evidence supports the role of metacaspases and orthocaspases as important contributors to cell homeostasis during normal physiological conditions or cell differentiation and ageing.
Collapse
Affiliation(s)
- Marina Klemenčič
- Department of Chemistry, Umeå University, 901 87, Umeå, Sweden.
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, 1000, Ljubljana, Slovenia.
| | - Christiane Funk
- Department of Chemistry, Umeå University, 901 87, Umeå, Sweden
| |
Collapse
|
23
|
Djabou ASM, Carvalho LJCB, Li QX, Niemenak N, Chen S. Cassava postharvest physiological deterioration: a complex phenomenon involving calcium signaling, reactive oxygen species and programmed cell death. ACTA PHYSIOLOGIAE PLANTARUM 2017; 39:91. [PMID: 28316353 PMCID: PMC5336541 DOI: 10.1007/s11738-017-2382-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2015] [Revised: 01/30/2017] [Accepted: 02/11/2017] [Indexed: 05/19/2023]
Abstract
Postharvest physiological deterioration (PPD) of cassava (Manihot esculenta) storage roots is a complex physiological and biochemical process which involve many regulatory networks linked with specific proteins modulation and signaling transduction pathways. However, it is poorly understood regarding biological regulation, and the interactions among protein groups and signals to determine PPD syndrome in cassava storage roots. This review sheds some light on the possible molecular mechanisms involved in reactive oxygen species (ROS), calcium signaling transduction, and programmed cell death (PCD) in cassava PPD syndrome. A model for predicting crosstalk among calcium signaling, ROS and PCD is suggested to fine-tune PPD syndrome. This would clues to cassava molecular breeding to alleviate the PPD effects on the shelf-life.
Collapse
Affiliation(s)
- Astride S. M. Djabou
- Tropical Crops Genetic Resources Institute, Chinese Academy of Tropical Agricultural Sciences/Key Laboratory of Ministry of Agriculture for Germplasm Resources Conservation and Utilization of Cassava, Hainan, China
- Laboratory of Plant Physiology, Department of Biological Science, Higher Teachers’ Training College, University of Yaounde I, Yaounde, Cameroon
| | | | - Qing X. Li
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, USA
| | - Nicolas Niemenak
- Laboratory of Plant Physiology, Department of Biological Science, Higher Teachers’ Training College, University of Yaounde I, Yaounde, Cameroon
| | - Songbi Chen
- Tropical Crops Genetic Resources Institute, Chinese Academy of Tropical Agricultural Sciences/Key Laboratory of Ministry of Agriculture for Germplasm Resources Conservation and Utilization of Cassava, Hainan, China
| |
Collapse
|
24
|
Peña MS, Cabral GC, Fotoran WL, Perez KR, Stolf BS. Metacaspase-binding peptide inhibits heat shock-induced death in Leishmania (L.) amazonensis. Cell Death Dis 2017; 8:e2645. [PMID: 28252649 PMCID: PMC5386556 DOI: 10.1038/cddis.2017.59] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2016] [Revised: 12/05/2016] [Accepted: 01/18/2017] [Indexed: 01/07/2023]
Abstract
Leishmania (Leishmania) amazonensis is an important agent of cutaneous leishmaniasis in Brazil. This parasite faces cell death in some situations during transmission to the vertebrate host, and this process seems to be dependent on the activity of metacaspase (MCA), an enzyme bearing trypsin-like activity present in protozoans, plants and fungi. In fact, the association between MCA expression and cell death induced by different stimuli has been demonstrated for several Leishmania species. Regulators and natural substrates of MCA are poorly known. To fulfill this gap, we have employed phage display over recombinant L. (L.) amazonensis MCA to identify peptides that could interact with the enzyme and modulate its activity. Four peptides were selected for their capacity to specifically bind to MCA and interfere with its activity. One of these peptides, similar to ecotin-like ISP3 of L. (L.) major, decreases trypsin-like activity of promastigotes under heat shock, and significantly decreases parasite heat shock-induced death. These findings indicate that peptide ligands identified by phage display affect trypsin-like activity and parasite death, and that an endogenous peptidase inhibitor is a possible natural regulator of the enzyme.
Collapse
Affiliation(s)
- Mauricio S Peña
- Department of Parasitology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Guilherme C Cabral
- Department of Parasitology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Wesley L Fotoran
- Department of Parasitology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Katia R Perez
- Department of Biophysics, Federal University of Sao Paulo, Sao Paulo, Brazil
| | - Beatriz S Stolf
- Department of Parasitology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, Brazil
| |
Collapse
|
25
|
Pathirana R, West P, Hedderley D, Eason J. Cell death patterns in Arabidopsis cells subjected to four physiological stressors indicate multiple signalling pathways and cell cycle phase specificity. PROTOPLASMA 2017; 254:635-647. [PMID: 27193098 DOI: 10.1007/s00709-016-0977-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 04/25/2016] [Indexed: 06/05/2023]
Abstract
Corpse morphology, nuclear DNA fragmentation, expression of senescence-associated genes (SAG) and cysteine protease profiles were investigated to understand cell death patterns in a cell cycle-synchronised Arabidopsis thaliana cell suspension culture treated with four physiological stressors in the late G2 phase. Within 4 h of treatment, polyethylene glycol (PEG, 20 %), mannose (100 mM) and hydrogen peroxide (2 mM) caused DNA fragmentation coinciding with cell permeability to Evans Blue (EB) and produced corpse morphology corresponding to apoptosis-like programmed cell death (AL-PCD) with cytoplasmic retraction from the cell wall. Ethylene (8 mL per 250-mL flask) caused permeability of cells to EB without concomitant nuclear DNA fragmentation and cytoplasmic retraction, suggesting necrotic cell death. Mannose inducing glycolysis block and PEG causing dehydration resulted in relatively similar patterns of upregulation of SAG suggesting similar cell death signalling pathways for these two stress factors, whereas hydrogen peroxide caused unique patterns indicating an alternate pathway for cell death induced by oxidative stress. Ethylene did not cause appreciable changes in SAG expression, confirming necrotic cell death. Expression of AtDAD, BoMT1 and AtSAG2 genes, previously shown to be associated with plant senescence, also changed rapidly during AL-PCD in cultured cells. The profiles of nine distinct cysteine protease-active bands ranging in size from ca. 21.5 to 38.5 kDa found in the control cultures were also altered after treatment with the four stressors, with mannose and PEG again producing similar patterns. Results also suggest that cysteine proteases may have a role in necrotic cell death.
Collapse
Affiliation(s)
- Ranjith Pathirana
- The New Zealand Institute for Plant & Food Research Limited, Private Bag 11600, Palmerston North, New Zealand.
| | - Phillip West
- The New Zealand Institute for Plant & Food Research Limited, Private Bag 11600, Palmerston North, New Zealand
- NZ Avocado, Level 5 Harrington House, 32 Harington Street, Tauranga, 3110, New Zealand
| | - Duncan Hedderley
- The New Zealand Institute for Plant & Food Research Limited, Private Bag 11600, Palmerston North, New Zealand
| | - Jocelyn Eason
- The New Zealand Institute for Plant & Food Research Limited, Private Bag 11600, Palmerston North, New Zealand
| |
Collapse
|
26
|
Zhu S, Tang S, Tan Z, Yu Y, Dai Q, Liu T. Comparative transcriptomics provide insight into the morphogenesis and evolution of fistular leaves in Allium. BMC Genomics 2017; 18:60. [PMID: 28068920 PMCID: PMC5223570 DOI: 10.1186/s12864-016-3474-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 12/26/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Fistular leaves frequently appear in Allium species, and previous developmental studies have proposed that the process of fistular leaf formation involves programmed cell death. However, molecular evidence for the role of programmed cell death in the formation of fistular leaf cavities has yet to be reported. RESULTS In this study, we characterized the leaf transcriptomes of nine Allium species, including six fistular- and three solid-leaved species. In addition, we identified orthologous genes and estimated their Ka and Ks values, in order to ascertain their selective pattern. Phylogenetic analysis based on the transcriptomes revealed that A. tuberosum was the most ancestral among the nine species, and analysis of orthologous genes between A. tuberosum and the other eight species indicated that 149 genes were subject to positive selection; whereas >3000 had undergone purifying selection in each species. CONCLUSIONS We found that many genes that are potentially related to programmed cell death either exhibited rapid diversification in fistular-leaved species, or were conserved in solid-leaved species in evolutionary history. These genes potentially involved in programmed cell death might play important roles in the formation of fistular leaf cavities in Allium, and the differing selection patterns in fistular- and solid-leaved species may be responsible for the evolution of fistular leaves.
Collapse
Affiliation(s)
- Siyuan Zhu
- Institute of Bast Fiber Crops and Center of Southern Economic Crops, Chinese Academy of Agricultural Sciences, Changsha, China
| | - Shouwei Tang
- Institute of Bast Fiber Crops and Center of Southern Economic Crops, Chinese Academy of Agricultural Sciences, Changsha, China
| | - Zhijian Tan
- Institute of Bast Fiber Crops and Center of Southern Economic Crops, Chinese Academy of Agricultural Sciences, Changsha, China
| | - Yongting Yu
- Institute of Bast Fiber Crops and Center of Southern Economic Crops, Chinese Academy of Agricultural Sciences, Changsha, China
| | - Qiuzhong Dai
- Institute of Bast Fiber Crops and Center of Southern Economic Crops, Chinese Academy of Agricultural Sciences, Changsha, China
| | - Touming Liu
- Institute of Bast Fiber Crops and Center of Southern Economic Crops, Chinese Academy of Agricultural Sciences, Changsha, China.
| |
Collapse
|
27
|
Wang C, Lü P, Zhong S, Chen H, Zhou B. LcMCII-1 is involved in the ROS-dependent senescence of the rudimentary leaves of Litchi chinensis. PLANT CELL REPORTS 2017; 36:89-102. [PMID: 27682163 DOI: 10.1007/s00299-016-2059-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 09/21/2016] [Indexed: 06/06/2023]
Abstract
KEY MESSAGE LcMCII - 1 is a type II metacaspase. Over-expression of LcMCII- 1 in Arabidopsis promoted ROS-dependent and natural senescence. Virus-induced LcMCII- 1 silencing delayed the ROS-dependent senescence of the rudimentary leaves of Litchi chinensis . Litchi is an evergreen woody fruit tree that is widely cultivated in subtropical and tropical regions. Its floral buds are mixed with axillary or apical panicle primordia, leaf primordia and rudimentary leaves. A low spring temperature is vital for litchi production as it promotes the abscission of the rudimentary leaves, which could otherwise prevent panicle development. Hence, climate change could present additional challenges for litchi production. We previously reported that reactive oxygen species (ROS) can substitute low-temperature treatment to induce the senescence of rudimentary leaves. We have now identified from RNA-Seq data a litchi type II metacaspase gene, LcMCII-1, that is responsive to ROS. Silencing LcMCII-1 by virus-induced gene silencing delayed ROS-dependent senescence. The ectopic over-expression of LcMCII-1 in transgenic Arabidopsis promoted ROS-dependent and natural senescence. Consistently, the transient expression of LcMCII-1 in tobacco leaf by agroinfiltration resulted in leaf yellowing. Our findings demonstrate that LcMCII-1 is positively involved in the regulation of rudimentary leaf senescence in litchi and provide a new target for the future molecular breeding of new cultivars that can set fruit in warmer climates.
Collapse
Affiliation(s)
- Congcong Wang
- Guangdong Litchi Engineering Research Center, College of Horticulture, South China Agricultural University, Guangzhou, 510642, China
| | - Peitao Lü
- State Key Laboratory of Agrobiotechnology, School of Life Sciences, Chinese University of Hong Kong, Hong Kong, China
| | - Silin Zhong
- State Key Laboratory of Agrobiotechnology, School of Life Sciences, Chinese University of Hong Kong, Hong Kong, China
| | - Houbin Chen
- Guangdong Litchi Engineering Research Center, College of Horticulture, South China Agricultural University, Guangzhou, 510642, China
| | - Biyan Zhou
- Guangdong Litchi Engineering Research Center, College of Horticulture, South China Agricultural University, Guangzhou, 510642, China.
| |
Collapse
|
28
|
Identification and analysis of the metacaspase gene family in tomato. Biochem Biophys Res Commun 2016; 479:523-529. [DOI: 10.1016/j.bbrc.2016.09.103] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 09/20/2016] [Indexed: 11/23/2022]
|
29
|
Kissen R, Øverby A, Winge P, Bones AM. Allyl-isothiocyanate treatment induces a complex transcriptional reprogramming including heat stress, oxidative stress and plant defence responses in Arabidopsis thaliana. BMC Genomics 2016; 17:740. [PMID: 27639974 PMCID: PMC5027104 DOI: 10.1186/s12864-016-3039-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 08/24/2016] [Indexed: 01/30/2023] Open
Abstract
Background Isothiocyanates (ITCs) are degradation products of the plant secondary metabolites glucosinolates (GSLs) and are known to affect human health as well as plant herbivores and pathogens. To investigate the processes engaged in plants upon exposure to isothiocyanate we performed a genome scale transcriptional profiling of Arabidopsis thaliana at different time points in response to an exogenous treatment with allyl-isothiocyanate. Results The treatment triggered a substantial response with the expression of 431 genes affected (P < 0.05 and log2 ≥ 1 or ≤ -1) already after 30 min and that of 3915 genes affected after 9 h of exposure, most of the affected genes being upregulated. These are involved in a considerable number of different biological processes, some of which are described in detail: glucosinolate metabolism, sulphate uptake and assimilation, heat stress response, oxidative stress response, elicitor perception, plant defence and cell death mechanisms. Conclusion Exposure of Arabidopsis thaliana to vapours of allyl-isothiocyanate triggered a rapid and substantial transcriptional response affecting numerous biological processes. These include multiple stress stimuli such as heat stress response and oxidative stress response, cell death and sulphur secondary defence metabolism. Hence, effects of isothiocyanates on plants previously reported in the literature were found to be regulated at the gene expression level. This opens some avenues for further investigations to decipher the molecular mechanisms underlying the effects of isothiocyanates on plants. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-3039-x) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Ralph Kissen
- Department of Biology, Norwegian University of Science and Technology (NTNU), NO-7491, Trondheim, Norway
| | - Anders Øverby
- Department of Biology, Norwegian University of Science and Technology (NTNU), NO-7491, Trondheim, Norway.,Present address: Center for Clinical Pharmacy and Clinical Sciences, School of Pharmaceutical Sciences, Kitasato University, Minato-ku, Tokyo, Japan
| | - Per Winge
- Department of Biology, Norwegian University of Science and Technology (NTNU), NO-7491, Trondheim, Norway
| | - Atle M Bones
- Department of Biology, Norwegian University of Science and Technology (NTNU), NO-7491, Trondheim, Norway.
| |
Collapse
|
30
|
Liu H, Deng Z, Chen J, Wang S, Hao L, Li D. Genome-wide identification and expression analysis of the metacaspase gene family in Hevea brasiliensis. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2016; 105:90-101. [PMID: 27085600 DOI: 10.1016/j.plaphy.2016.04.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 04/05/2016] [Accepted: 04/05/2016] [Indexed: 05/13/2023]
Abstract
Metacaspases, a family of cysteine proteases, have been suggested to play important roles in programmed cell death (PCD) during plant development and stress responses. To date, no systematic characterization of this gene family has been reported in rubber tree (Hevea brasiliensis). In the present study, nine metacaspase genes, designated as HbMC1 to HbMC9, were identified from whole-genome sequence of rubber tree. Multiple sequence alignment and phylogenetic analyses suggested that these genes were divided into two types: type I (HbMC1-HBMC7) and type II (HbMC8 and HbMC9). Gene structure analysis demonstrated that type I and type II HbMCs separately contained four and two introns, indicating the conserved exon-intron organization of HbMCs. Quantitative real-time PCR analysis revealed that HbMCs showed distinct expression patterns in different tissues, suggesting the functional diversity of HbMCs in various tissues during development. Most of the HbMCs were regulated by drought, cold, and salt stress, implying their possible functions in regulating abiotic stress-induced cell death. Of the nine HbMCs, HbMC1, HbMC2, HbMC5, and HbMC8 displayed a significantly higher relative transcript accumulation in barks of tapping panel dryness (TPD) trees compared with healthy trees. In addition, the four genes were up-regulated by ethephon (ET) and methyl jasmonate (MeJA), indicating their potential involvement in TPD resulting from ET- or JA-induced PCD. In summary, this work provides valuable information for further functional characterization of HbMC genes in rubber tree.
Collapse
Affiliation(s)
- Hui Liu
- Key Laboratory of Biology and Genetic Resources of Rubber Tree, Ministry of Agriculture, Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences, Danzhou 571737, China.
| | - Zhi Deng
- Key Laboratory of Biology and Genetic Resources of Rubber Tree, Ministry of Agriculture, Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences, Danzhou 571737, China.
| | - Jiangshu Chen
- College of Agriculture, Hainan University, Haikou 570228, China.
| | - Sen Wang
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101, China.
| | - Lili Hao
- CAS Key Laboratory of Genome Sciences and Information, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101, China.
| | - Dejun Li
- Key Laboratory of Biology and Genetic Resources of Rubber Tree, Ministry of Agriculture, Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences, Danzhou 571737, China.
| |
Collapse
|
31
|
Liu JX, Howell SH. Managing the protein folding demands in the endoplasmic reticulum of plants. THE NEW PHYTOLOGIST 2016; 211:418-28. [PMID: 26990454 DOI: 10.1111/nph.13915] [Citation(s) in RCA: 128] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 01/25/2016] [Indexed: 05/18/2023]
Abstract
Endoplasmic reticulum (ER) stress occurs in plants during certain developmental stages or under adverse environmental conditions, as a result of the accumulation of unfolded or misfolded proteins in the ER. To minimize the accumulation of misfolded proteins in the ER, a protein quality control (PQC) system monitors protein folding and eliminates misfolded proteins through either ER-associated protein degradation (ERAD) or autophagy. ER stress elicits the unfolded protein response (UPR), which enhances the operation in plant cells of the ER protein folding machinery and the PQC system. The UPR also reduces protein folding demands in the ER by degrading mRNAs encoding secretory proteins. In plants subjected to severe or chronic stress, UPR promotes programmed cell death (PCD). Progress in the field in recent years has provided insights into the regulatory networks and signaling mechanisms of the ER stress responses in plants. In addition, novel physiological functions of the ER stress responses in plants for coordinating plant growth and development with changing environment have been recently revealed.
Collapse
Affiliation(s)
- Jian-Xiang Liu
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, 200433, China
| | - Stephen H Howell
- Department of Genetics, Development and Cell Biology, Plant Sciences Institute, Iowa State University, Ames, IA, 50011, USA
| |
Collapse
|
32
|
Daneva A, Gao Z, Van Durme M, Nowack MK. Functions and Regulation of Programmed Cell Death in Plant Development. Annu Rev Cell Dev Biol 2016; 32:441-468. [PMID: 27298090 DOI: 10.1146/annurev-cellbio-111315-124915] [Citation(s) in RCA: 137] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Programmed cell death (PCD) is a collective term for diverse processes causing an actively induced, tightly controlled cellular suicide. PCD has a multitude of functions in the development and health of multicellular organisms. In comparison to intensively studied forms of animal PCD such as apoptosis, our knowledge of the regulation of PCD in plants remains limited. Despite the importance of PCD in plant development and as a response to biotic and abiotic stresses, the complex molecular networks controlling different forms of plant PCD are only just beginning to emerge. With this review, we provide an update on the considerable progress that has been made over the last decade in our understanding of PCD as an inherent part of plant development. We highlight both functions of developmental PCD and central aspects of its molecular regulation.
Collapse
Affiliation(s)
- Anna Daneva
- Department of Plant Systems Biology, VIB, B-9052 Ghent, Belgium; .,Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium
| | - Zhen Gao
- Department of Plant Systems Biology, VIB, B-9052 Ghent, Belgium; .,Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium
| | - Matthias Van Durme
- Department of Plant Systems Biology, VIB, B-9052 Ghent, Belgium; .,Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium
| | - Moritz K Nowack
- Department of Plant Systems Biology, VIB, B-9052 Ghent, Belgium; .,Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium
| |
Collapse
|
33
|
Wang W, Li R, Zhu Q, Tang X, Zhao Q. Transcriptomic and physiological analysis of common duckweed Lemna minor responses to NH4(+) toxicity. BMC PLANT BIOLOGY 2016; 16:92. [PMID: 27091123 PMCID: PMC4835947 DOI: 10.1186/s12870-016-0774-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 04/11/2016] [Indexed: 05/29/2023]
Abstract
BACKGROUND Plants can suffer ammonium (NH4 (+)) toxicity, particularly when NH4 (+) is supplied as the sole nitrogen source. However, our knowledge about the underlying mechanisms of NH4 (+) toxicity is still largely unknown. Lemna minor, a model duckweed species, can grow well in high NH4 (+) environment but to some extent can also suffer toxic effects. The transcriptomic and physiological analysis of L. minor responding to high NH4 (+) may provide us some interesting and useful information not only in toxic processes, but also in tolerance mechanisms. RESULTS The L. minor cultured in the Hoagland solution were used as the control (NC), and in two NH4 (+) concentrations (NH4 (+) was the sole nitrogen source), 84 mg/L (A84) and 840 mg/L (A840) were used as stress treatments. The NH4 (+) toxicity could inhibit the growth of L. minor. Reactive oxygen species (ROS) and cell death were studied using stained fronds under toxic levels of NH4 (+). The malondialdehyde content and the activities of superoxide dismutase and peroxidase increased from NC to A840, rather than catalase and ascorbate peroxidase. A total of 6.62G nucleotides were generated from the three distinct libraries. A total of 14,207 differentially expressed genes (DEGs) among 70,728 unigenes were obtained. All the DEGs could be clustered into 7 profiles. Most DEGs were down-regulated under NH4 (+) toxicity. The genes required for lignin biosynthesis in phenylpropanoid biosynthesis pathway were up-regulated. ROS oxidative-related genes and programmed cell death (PCD)-related genes were also analyzed and indicated oxidative damage and PCD occurring under NH4 (+) toxicity. CONCLUSIONS The first large transcriptome study in L. minor responses to NH4 (+) toxicity was reported in this work. NH4 (+) toxicity could induce ROS accumulation that causes oxidative damage and thus induce cell death in L. minor. The antioxidant enzyme system was activated under NH4 (+) toxicity for ROS scavenging. The phenylpropanoid pathway was stimulated under NH4 (+) toxicity. The increased lignin biosynthesis might play an important role in NH4 (+) toxicity resistance.
Collapse
Affiliation(s)
- Wenguo Wang
- />Biogas Institute of Ministry of Agriculture, Section 4-13, Renmin Road South, Chengdu, 610041 Sichuan PR China
- />Key Laboratory of Development and Application of Rural Renewable Energy, Ministry of Agriculture, Section 4-13, Renmin Road South, Chengdu, 610041 Sichuan PR China
| | - Rui Li
- />Faculty of Biotechnology Industry, Chengdu University, 1 Shiling Street, Chengluo Road, 610106 Chengdu, Sichuan PR China
| | - Qili Zhu
- />Biogas Institute of Ministry of Agriculture, Section 4-13, Renmin Road South, Chengdu, 610041 Sichuan PR China
- />Key Laboratory of Development and Application of Rural Renewable Energy, Ministry of Agriculture, Section 4-13, Renmin Road South, Chengdu, 610041 Sichuan PR China
| | - Xiaoyu Tang
- />Biogas Institute of Ministry of Agriculture, Section 4-13, Renmin Road South, Chengdu, 610041 Sichuan PR China
- />Key Laboratory of Development and Application of Rural Renewable Energy, Ministry of Agriculture, Section 4-13, Renmin Road South, Chengdu, 610041 Sichuan PR China
| | - Qi Zhao
- />Faculty of Biotechnology Industry, Chengdu University, 1 Shiling Street, Chengluo Road, 610106 Chengdu, Sichuan PR China
| |
Collapse
|
34
|
Van Aken O, Van Breusegem F. Licensed to Kill: Mitochondria, Chloroplasts, and Cell Death. TRENDS IN PLANT SCIENCE 2015; 20:754-766. [PMID: 26442680 DOI: 10.1016/j.tplants.2015.08.002] [Citation(s) in RCA: 103] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2015] [Revised: 08/03/2015] [Accepted: 08/10/2015] [Indexed: 05/18/2023]
Abstract
Programmed cell death (PCD) is crucial in plant organogenesis and survival. In this review the involvement of mitochondria and chloroplasts in PCD execution is critically assessed. Recent findings support a central role for mitochondria in PCD, with newly identified components of the mitochondrial electron transport chain (mETC), FOF1 ATP synthase, cardiolipins, and ATPase AtOM66. While chloroplasts received less attention, their contribution to PCD is well supported, suggesting that they possibly contribute by producing reactive oxygen species (ROS) in the presence of light or even contribute through cytochrome f release. Finally we discuss two working models where mitochondria and chloroplasts could cooperatively execute PCD: mitochondria initiate the commitment steps and recruit chloroplasts for swift execution or, alternatively, mitochondria and chloroplasts could operate in parallel.
Collapse
Affiliation(s)
- Olivier Van Aken
- ARC Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley, Australia.
| | - Frank Van Breusegem
- Department of Plant Systems Biology, VIB, Ghent University, B-9052 Gent, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Gent, Belgium
| |
Collapse
|
35
|
Fagundes D, Bohn B, Cabreira C, Leipelt F, Dias N, Bodanese-Zanettini MH, Cagliari A. Caspases in plants: metacaspase gene family in plant stress responses. Funct Integr Genomics 2015; 15:639-49. [PMID: 26277721 DOI: 10.1007/s10142-015-0459-7] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Revised: 07/22/2015] [Accepted: 07/24/2015] [Indexed: 12/26/2022]
Abstract
Programmed cell death (PCD) is an ordered cell suicide that removes unwanted or damaged cells, playing a role in defense to environmental stresses and pathogen invasion. PCD is component of the life cycle of plants, occurring throughout development from embryogenesis to the death. Metacaspases are cysteine proteases present in plants, fungi, and protists. In certain plant-pathogen interactions, the PCD seems to be mediated by metacaspases. We adopted a comparative genomic approach to identify genes coding for the metacaspases in Viridiplantae. We observed that the metacaspase was divided into types I and II, based on their protein structure. The type I has a metacaspase domain at the C-terminus region, presenting or not a zinc finger motif in the N-terminus region and a prodomain rich in proline. Metacaspase type II does not feature the prodomain and the zinc finger, but has a linker between caspase-like catalytic domains of 20 kDa (p20) and 10 kDa (p10). A high conservation was observed in the zinc finger domain (type I proteins) and in p20 and p10 subunits (types I and II proteins). The phylogeny showed that the metacaspases are divided into three principal groups: type I with and without zinc finger domain and type II metacaspases. The algae and moss are presented as outgroup, suggesting that these three classes of metacaspases originated in the early stages of Viridiplantae, being the absence of the zinc finger domain the ancient condition. The study of metacaspase can clarify their assignment and involvement in plant PCD mechanisms.
Collapse
Affiliation(s)
- David Fagundes
- Universidade Estadual do Rio Grande do Sul (UERGS), CEP 96816-50, Santa Cruz do Sul, RS, Brazil.
| | - Bianca Bohn
- Universidade Estadual do Rio Grande do Sul (UERGS), CEP 96816-50, Santa Cruz do Sul, RS, Brazil.
| | - Caroline Cabreira
- Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil.
| | - Fábio Leipelt
- Universidade Estadual do Rio Grande do Sul (UERGS), CEP 96816-50, Santa Cruz do Sul, RS, Brazil.
| | - Nathalia Dias
- Universidade Estadual do Rio Grande do Sul (UERGS), CEP 96816-50, Santa Cruz do Sul, RS, Brazil.
| | | | - Alexandro Cagliari
- Universidade Estadual do Rio Grande do Sul (UERGS), CEP 96816-50, Santa Cruz do Sul, RS, Brazil.
| |
Collapse
|
36
|
Stress-Responsive Expression, Subcellular Localization and Protein-Protein Interactions of the Rice Metacaspase Family. Int J Mol Sci 2015; 16:16216-41. [PMID: 26193260 PMCID: PMC4519946 DOI: 10.3390/ijms160716216] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2015] [Revised: 06/17/2015] [Accepted: 07/03/2015] [Indexed: 02/01/2023] Open
Abstract
Metacaspases, a class of cysteine-dependent proteases like caspases in animals, are important regulators of programmed cell death (PCD) during development and stress responses in plants. The present study was focused on comprehensive analyses of expression patterns of the rice metacaspase (OsMC) genes in response to abiotic and biotic stresses and stress-related hormones. Results indicate that members of the OsMC family displayed differential expression patterns in response to abiotic (e.g., drought, salt, cold, and heat) and biotic (e.g., infection by Magnaporthe oryzae, Xanthomonas oryzae pv. oryzae and Rhizoctonia solani) stresses and stress-related hormones such as abscisic acid, salicylic acid, jasmonic acid, and 1-amino cyclopropane-1-carboxylic acid (a precursor of ethylene), although the responsiveness to these stresses or hormones varies to some extent. Subcellular localization analyses revealed that OsMC1 was solely localized and OsMC2 was mainly localized in the nucleus. Whereas OsMC3, OsMC4, and OsMC7 were evenly distributed in the cells, OsMC5, OsMC6, and OsMC8 were localized in cytoplasm. OsMC1 interacted with OsLSD1 and OsLSD3 while OsMC3 only interacted with OsLSD1 and that the zinc finger domain in OsMC1 is responsible for the interaction activity. The systematic expression and biochemical analyses of the OsMC family provide valuable information for further functional studies on the biological roles of OsMCs in PCD that is related to abiotic and biotic stress responses.
Collapse
|
37
|
Klemenčič M, Novinec M, Dolinar M. Orthocaspases are proteolytically active prokaryotic caspase homologues: the case of
M
icrocystis aeruginosa. Mol Microbiol 2015; 98:142-50. [DOI: 10.1111/mmi.13110] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/25/2015] [Indexed: 01/29/2023]
Affiliation(s)
- Marina Klemenčič
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology University of Ljubljana Večna pot 113 SI‐1000 Ljubljana Slovenia
| | - Marko Novinec
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology University of Ljubljana Večna pot 113 SI‐1000 Ljubljana Slovenia
| | - Marko Dolinar
- Department of Chemistry and Biochemistry, Faculty of Chemistry and Chemical Technology University of Ljubljana Večna pot 113 SI‐1000 Ljubljana Slovenia
| |
Collapse
|
38
|
Wang L, Zhang H. Genomewide survey and characterization of metacaspase gene family in rice (Oryza sativa). J Genet 2015; 93:93-102. [PMID: 24840826 DOI: 10.1007/s12041-014-0343-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Metacaspases (MCs), which are cysteine-dependent proteases found in plants, fungi, and protozoa, may be involved in programmed cell death processes, being distant relatives of metazoan caspases. In this study, we analysed the structures, phylogenetic relationship, genome localizations, expression patterns and domestic selections of eight MC genes identified in rice (OsMC). Alignment analysis of the corresponding protein sequences suggested OsMC proteins can be classified into two subtypes. The expression profiles of eight OsMC genes were analysed in 27 tissues covering the whole life cycle of rice. There are four OsMC genes uniquely expressed in mature tissues, indicating that these genes might play certain roles in senescence. Under abiotic and biotic stresses, four OsMC genes were expressed with treatments of one or more of Magnaporthe oryzae (M. oryzae) infected, pest damaged, cold stress and drought stress, indicating they might be involved in plant defense. In addition, gene trees and genetic diversity (π) were performed to measure whether candidate genes were selected during rice domestication. The results suggested that all the type I genes could not be domestication genes. However, two of five type II OsMC genes showed strong evidence for selective sweep, suggesting that these genes might be involved in cultivated rice domestication. These results provide a foundation for future functional genomic studies of this family in rice.
Collapse
Affiliation(s)
- Likai Wang
- National Key Laboratory of Crop Genetic Improvement, National Centre of Plant Gene Research (Wuhan), Huazhong Agricultural University, 430070 Wuhan, People's Republic of China.
| | | |
Collapse
|
39
|
Yoshiyama KO. SOG1: a master regulator of the DNA damage response in plants. Genes Genet Syst 2015; 90:209-16. [DOI: 10.1266/ggs.15-00011] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
|
40
|
Wrzaczek M, Vainonen JP, Stael S, Tsiatsiani L, Help-Rinta-Rahko H, Gauthier A, Kaufholdt D, Bollhöner B, Lamminmäki A, Staes A, Gevaert K, Tuominen H, Van Breusegem F, Helariutta Y, Kangasjärvi J. GRIM REAPER peptide binds to receptor kinase PRK5 to trigger cell death in Arabidopsis. EMBO J 2014; 34:55-66. [PMID: 25398910 DOI: 10.15252/embj.201488582] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Recognition of extracellular peptides by plasma membrane-localized receptor proteins is commonly used in signal transduction. In plants, very little is known about how extracellular peptides are processed and activated in order to allow recognition by receptors. Here, we show that induction of cell death in planta by a secreted plant protein GRIM REAPER (GRI) is dependent on the activity of the type II metacaspase METACASPASE-9. GRI is cleaved by METACASPASE-9 in vitro resulting in the release of an 11 amino acid peptide. This peptide bound in vivo to the extracellular domain of the plasma membrane-localized, atypical leucine-rich repeat receptor-like kinase POLLEN-SPECIFIC RECEPTOR-LIKE KINASE 5 (PRK5) and was sufficient to induce oxidative stress/ROS-dependent cell death. This shows a signaling pathway in plants from processing and activation of an extracellular protein to recognition by its receptor.
Collapse
Affiliation(s)
- Michael Wrzaczek
- Plant Biology, Department of Biosciences University of Helsinki, Helsinki, Finland
| | - Julia P Vainonen
- Plant Biology, Department of Biosciences University of Helsinki, Helsinki, Finland
| | - Simon Stael
- Department of Plant Systems Biology, VIB, Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium Department of Medical Protein Research, VIB, Ghent, Belgium Department of Biochemistry, Ghent University, Ghent, Belgium
| | - Liana Tsiatsiani
- Department of Plant Systems Biology, VIB, Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium Department of Medical Protein Research, VIB, Ghent, Belgium Department of Biochemistry, Ghent University, Ghent, Belgium
| | - Hanna Help-Rinta-Rahko
- Plant Biology, Department of Biosciences University of Helsinki, Helsinki, Finland Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Adrien Gauthier
- Plant Biology, Department of Biosciences University of Helsinki, Helsinki, Finland
| | - David Kaufholdt
- Plant Biology, Department of Biosciences University of Helsinki, Helsinki, Finland
| | - Benjamin Bollhöner
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden
| | - Airi Lamminmäki
- Plant Biology, Department of Biosciences University of Helsinki, Helsinki, Finland
| | - An Staes
- Department of Medical Protein Research, VIB, Ghent, Belgium Department of Biochemistry, Ghent University, Ghent, Belgium
| | - Kris Gevaert
- Department of Medical Protein Research, VIB, Ghent, Belgium Department of Biochemistry, Ghent University, Ghent, Belgium
| | - Hannele Tuominen
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden
| | - Frank Van Breusegem
- Department of Plant Systems Biology, VIB, Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
| | - Ykä Helariutta
- Plant Biology, Department of Biosciences University of Helsinki, Helsinki, Finland Institute of Biotechnology, University of Helsinki, Helsinki, Finland The Sainsbury Laboratory, University of Cambridge, Cambridge, UK
| | - Jaakko Kangasjärvi
- Plant Biology, Department of Biosciences University of Helsinki, Helsinki, Finland Distinguished Scientist Fellowship Program, College of Science, King Saud University, Riyadh, Saudi Arabia
| |
Collapse
|
41
|
Wi SJ, Kim SJ, Kim WT, Park KY. Constitutive S-adenosylmethionine decarboxylase gene expression increases drought tolerance through inhibition of reactive oxygen species accumulation in Arabidopsis. PLANTA 2014; 239:979-88. [PMID: 24477528 DOI: 10.1007/s00425-014-2027-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 01/06/2014] [Indexed: 05/21/2023]
Abstract
Using subtractive hybridization analysis, the S-adenosylmethionine decarboxylase (SAMDC) gene from Capsicum annuum was isolated and renamed CaSAMDC. We generated independent transgenic Arabidopsis (Arabidopsis thaliana) lines constitutively expressing a 35S::CaSAMDC construct. Drought tolerance was significantly enhanced in Arabidopsis T4 transgenic homozygous lines as compared to wild-type (WT) plants. The levels of main polyamines (PAs) were more significantly increased in CaSAMDC-overexpressing transgenic plants after 6 h of drought stress as compared to stressed WT plants. Basal transcription of polyamine oxidase (PAO) showed at a much higher level in unstressed-transgenic plants as compared to unstressed WT plants. However, the difference in PAO transcription level between WT and transgenic plants was reduced after drought stress. Cellular accumulation of reactive oxygen species (ROS) was significantly reduced following drought stress in transgenic Arabidopsis plants as compared to WT plants. These results were in agreement with additional observations that stress-induced ROS generation, as determined by qRT-PCR analysis of NADPH oxidase (RbohD and RbohF), was significantly suppressed while transcription of ROS-detoxifying enzymes was notably elevated in transgenic lines in response to drought stress. Further, ROS-induced transcription of the metacaspase II gene was remarkably inhibited in transgenic plants. Collectively, these results suggest that drought stress tolerance due to reduction of ROS production and enhancement of ROS detoxification can be attributed to elevation of PAs.
Collapse
Affiliation(s)
- Soo Jin Wi
- Department of Biology, Sunchon National University, Sunchon, Chonnam, 540-742, Korea,
| | | | | | | |
Collapse
|
42
|
Matthews BF, Beard H, Brewer E, Kabir S, MacDonald MH, Youssef RM. Arabidopsis genes, AtNPR1, AtTGA2 and AtPR-5, confer partial resistance to soybean cyst nematode (Heterodera glycines) when overexpressed in transgenic soybean roots. BMC PLANT BIOLOGY 2014; 14:96. [PMID: 24739302 PMCID: PMC4021311 DOI: 10.1186/1471-2229-14-96] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 03/28/2014] [Indexed: 05/20/2023]
Abstract
BACKGROUND Extensive studies using the model system Arabidopsis thaliana to elucidate plant defense signaling and pathway networks indicate that salicylic acid (SA) is the key hormone triggering the plant defense response against biotrophic and hemi-biotrophic pathogens, while jasmonic acid (JA) and derivatives are critical to the defense response against necrotrophic pathogens. Several reports demonstrate that SA limits nematode reproduction. RESULTS Here we translate knowledge gained from studies using Arabidopsis to soybean. The ability of thirty-one Arabidopsis genes encoding important components of SA and JA synthesis and signaling in conferring resistance to soybean cyst nematode (SCN: Heterodera glycines) are investigated. We demonstrate that overexpression of three of thirty-one Arabidoposis genes in transgenic soybean roots of composite plants decreased the number of cysts formed by SCN to less than 50% of those found on control roots, namely AtNPR1(33%), AtTGA2 (38%), and AtPR-5 (38%). Three additional Arabidopsis genes decreased the number of SCN cysts by 40% or more: AtACBP3 (53% of the control value), AtACD2 (55%), and AtCM-3 (57%). Other genes having less or no effect included AtEDS5 (77%), AtNDR1 (82%), AtEDS1 (107%), and AtPR-1 (80%), as compared to control. Overexpression of AtDND1 greatly increased susceptibility as indicated by a large increase in the number of SCN cysts (175% of control). CONCLUSIONS Knowledge of the pathogen defense system gained from studies of the model system, Arabidopsis, can be directly translated to soybean through direct overexpression of Arabidopsis genes. When the genes, AtNPR1, AtGA2, and AtPR-5, encoding specific components involved in SA regulation, synthesis, and signaling, are overexpressed in soybean roots, resistance to SCN is enhanced. This demonstrates functional compatibility of some Arabidopsis genes with soybean and identifies genes that may be used to engineer resistance to nematodes.
Collapse
Affiliation(s)
- Benjamin F Matthews
- United States Department of Agriculture, Agricultural Research Service, Soybean Genomics and Improvement Laboratory, Beltsville, MD 20705, USA
| | - Hunter Beard
- United States Department of Agriculture, Agricultural Research Service, Soybean Genomics and Improvement Laboratory, Beltsville, MD 20705, USA
| | - Eric Brewer
- United States Department of Agriculture, Agricultural Research Service, Soybean Genomics and Improvement Laboratory, Beltsville, MD 20705, USA
| | - Sara Kabir
- United States Department of Agriculture, Agricultural Research Service, Soybean Genomics and Improvement Laboratory, Beltsville, MD 20705, USA
| | - Margaret H MacDonald
- United States Department of Agriculture, Agricultural Research Service, Soybean Genomics and Improvement Laboratory, Beltsville, MD 20705, USA
| | - Reham M Youssef
- United States Department of Agriculture, Agricultural Research Service, Soybean Genomics and Improvement Laboratory, Beltsville, MD 20705, USA
- Fayoum University, Fayoum, Egypt
| |
Collapse
|
43
|
Hierl G, Höwing T, Isono E, Lottspeich F, Gietl C. Ex vivo processing for maturation of Arabidopsis KDEL-tailed cysteine endopeptidase 2 (AtCEP2) pro-enzyme and its storage in endoplasmic reticulum derived organelles. PLANT MOLECULAR BIOLOGY 2014; 84:605-20. [PMID: 24287716 PMCID: PMC3950626 DOI: 10.1007/s11103-013-0157-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Accepted: 11/19/2013] [Indexed: 05/24/2023]
Abstract
Ricinosomes are specialized ER-derived organelles that store the inactive pro-forms of KDEL-tailed cysteine endopeptidases (KDEL-CysEP) associated with programmed cell death (PCD). The Arabidopsis genome encodes three KDEL-CysEP (AtCEP1, AtCEP2, and AtCEP3) that are differentially expressed in vegetative and generative tissues undergoing PCD. These Arabidopsis proteases have not been characterized at a biochemical level, nor have they been localized intracellularly. In this study, we characterized AtCEP2. A 3xHA-mCherry-AtCEP2 gene fusion including pro-peptide and KDEL targeting sequences expressed under control of the endogenous promoter enabled us to isolate AtCEP2 "ex vivo". The purified protein was shown to be activated in a pH-dependent manner. After activation, however, protease activity was pH-independent. Analysis of substrate specificity showed that AtCEP2 accepts proline near the cleavage site, which is a rare feature specific for KDEL-CysEPs. mCherry-AtCEP2 was detected in the epidermal layers of leaves, hypocotyls and roots; in the root, it was predominantly found in the elongation zone and root cap. Co-localization with an ER membrane marker showed that mCherry-AtCEP2 was stored in two different types of ER-derived organelles: 10 μm long spindle shaped organelles as well as round vesicles with a diameter of approximately 1 μm. The long organelles appear to be ER bodies, which are found specifically in Brassicacae. The round vesicles strongly resemble the ricinosomes first described in castor bean. This study provides a first evidence for the existence of ricinosomes in Arabidopsis, and may open up new avenues of research in the field of PCD and developmental tissue remodeling.
Collapse
Affiliation(s)
- Georg Hierl
- Center of Life and Food Sciences Weihenstephan, Lehrstuhl fuer Botanik, Technische Universitaet Muenchen, Emil-Ramann-Str. 4, 85350 Freising, Germany
| | - Timo Höwing
- Center of Life and Food Sciences Weihenstephan, Lehrstuhl fuer Botanik, Technische Universitaet Muenchen, Emil-Ramann-Str. 4, 85350 Freising, Germany
| | - Erika Isono
- Center of Life and Food Sciences Weihenstephan, Department of Plant Systems Biology, Technische Universitaet Muenchen, Emil-Ramann-Str. 4, 85350 Freising, Germany
| | - Friedrich Lottspeich
- Max Planck Institute of Biochemistry, Protein Analysis, 82152 Martinsried, Germany
| | - Christine Gietl
- Center of Life and Food Sciences Weihenstephan, Lehrstuhl fuer Botanik, Technische Universitaet Muenchen, Emil-Ramann-Str. 4, 85350 Freising, Germany
| |
Collapse
|
44
|
The membrane-associated transcription factor NAC089 controls ER-stress-induced programmed cell death in plants. PLoS Genet 2014; 10:e1004243. [PMID: 24675811 PMCID: PMC3967986 DOI: 10.1371/journal.pgen.1004243] [Citation(s) in RCA: 156] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Accepted: 02/02/2014] [Indexed: 12/20/2022] Open
Abstract
The unfolded protein response (UPR) is activated to sustain cell survival by reducing misfolded protein accumulation in the endoplasmic reticulum (ER). The UPR also promotes programmed cell death (PCD) when the ER stress is severe; however, the underlying molecular mechanisms are less understood, especially in plants. Previously, two membrane-associated transcriptions factors (MTFs), bZIP28 and bZIP60, were identified as the key regulators for cell survival in the plant ER stress response. Here, we report the identification of another MTF, NAC089, as an important PCD regulator in Arabidopsis (Arabidopsis thaliana) plants. NAC089 relocates from the ER membrane to the nucleus under ER stress conditions. Inducible expression of a truncated form of NAC089, in which the transmembrane domain is deleted, induces PCD with increased caspase 3/7-like activity and DNA fragmentation. Knock-down NAC089 in Arabidopsis confers ER stress tolerance and impairs ER-stress-induced caspase-like activity. Transcriptional regulation analysis and ChIP-qPCR reveal that NAC089 plays important role in regulating downstream genes involved in PCD, such as NAC094, MC5 and BAG6. Furthermore, NAC089 is up-regulated by ER stress, which is directly controlled by bZIP28 and bZIP60. These results show that nuclear relocation of NAC089 promotes ER-stress-induced PCD, and both pro-survival and pro-death signals are elicited by bZIP28 and bZIP60 during plant ER stress response. Protein folding is fundamentally important for development and responses to environmental stresses in eukaryotes. When excess misfolded proteins are accumulated in the endoplasmic reticulum (ER), the unfolded protein response (UPR) is triggered to promote cell survival through optimizing protein folding, and also promote programmed cell death (PCD) when the stress is severe. However, the link from ER-stress-sensing to PCD is largely unknown. Here, we report the identification of one membrane-associated transcription factor NAC089 as an important regulator of ER stress-induced PCD in plants. We have established a previously unrecognized molecular connection between ER stress sensors and PCD regulators. We have shown that organelle-to-organelle translocation of a transcription factor is important for its function in transcriptional regulation. Our results have provided novel insights into the molecular mechanisms of PCD in plants, especially under ER stress conditions.
Collapse
|
45
|
DNA damage response in plants: conserved and variable response compared to animals. BIOLOGY 2013; 2:1338-56. [PMID: 24833228 PMCID: PMC4009792 DOI: 10.3390/biology2041338] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Revised: 11/08/2013] [Accepted: 11/12/2013] [Indexed: 12/15/2022]
Abstract
The genome of an organism is under constant attack from endogenous and exogenous DNA damaging factors, such as reactive radicals, radiation, and genotoxins. Therefore, DNA damage response systems to sense DNA damage, arrest cell cycle, repair DNA lesions, and/or induce programmed cell death are crucial for maintenance of genomic integrity and survival of the organism. Genome sequences revealed that, although plants possess many of the DNA damage response factors that are present in the animal systems, they are missing some of the important regulators, such as the p53 tumor suppressor. These observations suggest differences in the DNA damage response mechanisms between plants and animals. In this review the DNA damage responses in plants and animals are compared and contrasted. In addition, the function of SUPPRESSOR OF GAMMA RESPONSE 1 (SOG1), a plant-specific transcription factor that governs the robust response to DNA damage, is discussed.
Collapse
|
46
|
Tran D, Rossi M, Biligui B, Kawano T, Mancuso S, Bouteau F. Ozone-induced caspase-like activities are dependent on early ion channel regulations and ROS generation in Arabidopsis thaliana cells. PLANT SIGNALING & BEHAVIOR 2013; 8:25170. [PMID: 23733075 PMCID: PMC3999082 DOI: 10.4161/psb.25170] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Using A. thaliana cultured cells; we recently reported new insights regarding the effect of acute O₃ exposure. This consist in an oxidative dependent controlled cell death process involving cell shrinkage due to an early activation of anion channel (1) and a delayed activation of K(+) outward currents, but also to early events like Ca (2+) influx or singlet oxygen production possibly linked to mitochondrial dysfunction. Here we provide evidence that most of these early events act downstream of caspase-like activities as recently demonstrated for K(+) channel activation.
Collapse
Affiliation(s)
- Daniel Tran
- Univ Paris Diderot, Sorbonne Paris Cité; Institut des Energies de Demain (IED, FRE 3597); Paris, France
- Institut de Biologie des Plantes; Orsay, France
| | - Marika Rossi
- LINV-Department of Plant Soil & Environmental Science; University of Florence; Florence, Italy
| | - Bernadette Biligui
- Univ Paris Diderot, Sorbonne Paris Cité; Institut des Energies de Demain (IED, FRE 3597); Paris, France
- Institut de Biologie des Plantes; Orsay, France
| | - Tomonori Kawano
- LINV-Department of Plant Soil & Environmental Science; University of Florence; Florence, Italy
- Graduate School of Environmental Engineering; University of Kitakyushu 1-1; Kitakyushu, Japan
- University of Florence LINV Kitakyushu Research Center; Kitakyushu, Japan
- Univ Paris Diderot, Sorbonne Paris Cité; Paris Interdisciplinary Energy Research Institute (PIERI); Paris, France
| | - Stefano Mancuso
- LINV-Department of Plant Soil & Environmental Science; University of Florence; Florence, Italy
- University of Florence LINV Kitakyushu Research Center; Kitakyushu, Japan
- Univ Paris Diderot, Sorbonne Paris Cité; Paris Interdisciplinary Energy Research Institute (PIERI); Paris, France
| | - François Bouteau
- Univ Paris Diderot, Sorbonne Paris Cité; Institut des Energies de Demain (IED, FRE 3597); Paris, France
- Institut de Biologie des Plantes; Orsay, France
- LINV-Department of Plant Soil & Environmental Science; University of Florence; Florence, Italy
- University of Florence LINV Kitakyushu Research Center; Kitakyushu, Japan
- Correspondence to: François Bouteau,
| |
Collapse
|
47
|
Trobacher CP, Senatore A, Holley C, Greenwood JS. Induction of a ricinosomal-protease and programmed cell death in tomato endosperm by gibberellic acid. PLANTA 2013; 237:665-79. [PMID: 23086343 DOI: 10.1007/s00425-012-1780-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Accepted: 10/01/2012] [Indexed: 05/08/2023]
Abstract
Several examples of programmed cell death (PCD) in plants utilize ricinosomes, organelles that appear prior to cell death and store inactive KDEL-tailed cysteine proteinases. Upon cell death, the contents of ricinosomes are released into the cell corpse where the proteinases are activated and proceed to degrade any remaining protein for use in adjacent cells or, in the case of nutritive seed tissues, by the growing seedling. Ricinosomes containing pro-SlCysEP have been observed in anther tissues prior to PCD and ricinosome-like structures have been observed in imbibed seeds within endosperm cells of tomato. The present study confirms that the structures in tomato endosperm cells contain pro-SlCysEP making them bona fide ricinosomes. The relative abundance of pro- versus mature SlCysEP is suggested to be a useful indicator of the degree of PCD that has occurred in tomato endosperm, and is supported by biochemical and structural data. This diagnostic tool is used to demonstrate that a sub-region of the micropylar endosperm surrounding the emerged radical is relatively long-lived and may serve to prevent loss of mobilized reserves from the lateral endosperm. We also demonstrate that GA-induced reserve mobilization, SlCysEP accumulation and processing, and PCD in tomato endosperm are antagonized by ABA.
Collapse
|