1
|
Kasteel M, Ketelaar T, Govers F. Fatal attraction: How Phytophthora zoospores find their host. Semin Cell Dev Biol 2023; 148-149:13-21. [PMID: 36792439 DOI: 10.1016/j.semcdb.2023.01.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 01/30/2023] [Accepted: 01/31/2023] [Indexed: 02/15/2023]
Abstract
Oomycete plant pathogens, such as Phytophthora and Pythium species produce motile dispersal agents called zoospores that actively target host plants. Zoospores are exceptional in their ability to display taxis to chemical, electrical and physical cues to navigate the phyllosphere and reach stomata, wound sites and roots. Many components of root exudates have been shown attractive or repulsive to zoospores. Although some components possess very strong attractiveness, it seems that especially the mix of components exuded by the primary host is most attractive to zoospores. Zoospores actively approach attractants with swimming behaviour reminiscent of other microswimmers. To achieve a unified description of zoospore behaviour when sensing an attractant, we propose the following terms for the successive stages of the homing response: reorientation, approaching, retention and settling. How zoospores sense and process attractants is poorly understood but likely involves signal perception via cell surface receptors. Since zoospores are important for infection, undermining their activity by luring attractants or blocking receptors seem promising strategies for disease control.
Collapse
Affiliation(s)
- Michiel Kasteel
- Laboratory of Phytopathology, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB Wageningen, the Netherlands; Laboratory of Cell Biology, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB Wageningen, the Netherlands.
| | - Tijs Ketelaar
- Laboratory of Cell Biology, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB Wageningen, the Netherlands.
| | - Francine Govers
- Laboratory of Phytopathology, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB Wageningen, the Netherlands.
| |
Collapse
|
2
|
Amponsah J, Tegg RS, Thangavel T, Wilson CR. Subversion of Phytomyxae Cell Communication With Surrounding Environment to Control Soilborne Diseases; A Case Study of Cytosolic Ca 2+ Signal Disruption in Zoospores of Spongospora subterranea. Front Microbiol 2022; 13:754225. [PMID: 35300485 PMCID: PMC8921600 DOI: 10.3389/fmicb.2022.754225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 02/09/2022] [Indexed: 11/13/2022] Open
Abstract
Ca2+ signaling regulates physiological processes including chemotaxis in eukaryotes and prokaryotes. Its inhibition has formed the basis for control of human disease but remains largely unexplored for plant disease. This study investigated the role of Ca2+ signaling on motility and chemotaxis of Spongospora subterranea zoospores, responsible for root infections leading to potato root and tuber disease. Cytosolic Ca2+ flux inhibition with Ca2+ antagonists were found to alter zoospore swimming patterns and constrain zoospore chemotaxis, root attachment and zoosporangia infection. LaCl3 and GdCl3, both Ca2+ channel blockers, at concentrations ≥ 50 μM showed complete inhibition of zoospore chemotaxis, root attachment and zoosporangia root infection. The Ca2+ chelator EGTA, showed efficient chemotaxis inhibition but had relatively less effect on root attachment. Conversely the calmodulin antagonist trifluoperazine had lesser effect on zoospore chemotaxis but showed strong inhibition of zoospore root attachment. Amiloride hydrochloride had a significant inhibitory effect on chemotaxis, root attachment, and zoosporangia root infection with dose rates ≥ 150 μM. As expected, zoospore attachment was directly associated with root infection and zoosporangia development. These results highlight the fundamental role of Ca2+ signaling in zoospore chemotaxis and disease establishment. Their efficient interruption may provide durable and practical control of Phytomyxea soilborne diseases in the field.
Collapse
Affiliation(s)
- Jonathan Amponsah
- Tasmanian Institute of Agriculture, University of Tasmania, Hobart, TAS, Australia
- Biotechnology and Nuclear Agricultural Research Institute Centre, Ghana Atomic Energy Commission, Accra, Ghana
| | - Robert S. Tegg
- Tasmanian Institute of Agriculture, University of Tasmania, Hobart, TAS, Australia
| | | | - Calum R. Wilson
- Tasmanian Institute of Agriculture, University of Tasmania, Hobart, TAS, Australia
| |
Collapse
|
3
|
Amponsah J, Tegg RS, Thangavel T, Wilson CR. Moments of weaknesses - exploiting vulnerabilities between germination and encystment in the Phytomyxea. Biol Rev Camb Philos Soc 2021; 96:1603-1615. [PMID: 33821562 DOI: 10.1111/brv.12717] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 03/23/2021] [Accepted: 03/24/2021] [Indexed: 11/30/2022]
Abstract
Attempts at management of diseases caused by protozoan plant parasitic Phytomyxea have often been ineffective. The dormant life stage is characterised by long-lived highly robust resting spores that are largely impervious to chemical treatment and environmental stress. This review explores some life stage weaknesses and highlights possible control measures associated with resting spore germination and zoospore taxis. With phytomyxid pathogens of agricultural importance, zoospore release from resting spores is stimulated by plant root exudates. On germination, the zoospores are attracted to host roots by chemoattractant components of root exudates. Both the relatively metabolically inactive resting spore and motile zoospore need to sense the chemical environment to determine the suitability of these germination stimulants or attractants respectively, before they can initiate an appropriate response. Blocking such sensing could inhibit resting spore germination or zoospore taxis. Conversely, the short life span and the vulnerability of zoospores to the environment require them to infect their host within a few hours after release. Identifying a mechanism or conditions that could synchronise resting spore germination in the absence of host plants could lead to diminished pathogen populations in the field.
Collapse
Affiliation(s)
- Jonathan Amponsah
- Tasmanian Institute of Agriculture, New Town Research Laboratories, University of Tasmania, 13 St Johns Avenue, New Town, TAS, 7008, Australia.,Biotechnology and Nuclear Agricultural Research Institute Centre, Ghana Atomic Energy Commission, P.O. Box LG 80, Legon, Accra, Ghana
| | - Robert S Tegg
- Tasmanian Institute of Agriculture, New Town Research Laboratories, University of Tasmania, 13 St Johns Avenue, New Town, TAS, 7008, Australia
| | - Tamilarasan Thangavel
- Tasmanian Institute of Agriculture, New Town Research Laboratories, University of Tasmania, 13 St Johns Avenue, New Town, TAS, 7008, Australia
| | - Calum R Wilson
- Tasmanian Institute of Agriculture, New Town Research Laboratories, University of Tasmania, 13 St Johns Avenue, New Town, TAS, 7008, Australia
| |
Collapse
|
4
|
Zheng L, Prestwich BD, Harrison PT, Mackrill JJ. Polycystic Kidney Disease Ryanodine Receptor Domain (PKDRR) Proteins in Oomycetes. Pathogens 2020; 9:pathogens9070577. [PMID: 32708691 PMCID: PMC7399828 DOI: 10.3390/pathogens9070577] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 07/13/2020] [Accepted: 07/14/2020] [Indexed: 11/16/2022] Open
Abstract
In eukaryotes, two sources of Ca2+ are accessed to allow rapid changes in the cytosolic levels of this second messenger: the extracellular medium and intracellular Ca2+ stores, such as the endoplasmic reticulum. One class of channel that permits Ca2+ entry is the transient receptor potential (TRP) superfamily, including the polycystic kidney disease (PKD) proteins, or polycystins. Channels that release Ca2+ from intracellular stores include the inositol 1,4,5-trisphosphate/ryanodine receptor (ITPR/RyR) superfamily. Here, we characterise a family of proteins that are only encoded by oomycete genomes, that we have named PKDRR, since they share domains with both PKD and RyR channels. We provide evidence that these proteins belong to the TRP superfamily and are distinct from the ITPR/RyR superfamily in terms of their evolutionary relationships, protein domain architectures and predicted ion channel structures. We also demonstrate that a hypothetical PKDRR protein from Phytophthora infestans is produced by this organism, is located in the cell-surface membrane and forms multimeric protein complexes. Efforts to functionally characterise this protein in a heterologous expression system were unsuccessful but support a cell-surface localisation. These PKDRR proteins represent potential targets for the development of new "fungicides", since they are of a distinctive structure that is only found in oomycetes and not in any other cellular organisms.
Collapse
Affiliation(s)
- Limian Zheng
- Department of Physiology, School of Medicine, University College Cork, T12 XF62 Cork, Ireland; (L.Z.); (P.T.H.)
| | - Barbara Doyle Prestwich
- School of Biological, Earth and Environmental Sciences, University College Cork, T23 TK30 Cork, Ireland;
| | - Patrick T. Harrison
- Department of Physiology, School of Medicine, University College Cork, T12 XF62 Cork, Ireland; (L.Z.); (P.T.H.)
| | - John J. Mackrill
- Department of Physiology, School of Medicine, University College Cork, T12 XF62 Cork, Ireland; (L.Z.); (P.T.H.)
- Correspondence:
| |
Collapse
|
5
|
Zhang C, Cui T, Zhang F, Xue Z, Miao J, Wang W, Liu X. Identification of differentially activated pathways in Phytophthora sojae at the mycelial, cyst, and oospore stages by TMT-based quantitative proteomics analysis. J Proteomics 2020; 221:103776. [PMID: 32268220 DOI: 10.1016/j.jprot.2020.103776] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 03/25/2020] [Accepted: 04/02/2020] [Indexed: 01/24/2023]
Abstract
Phytophthora sojae is a widely distributed, destructive oomycete plant pathogen that has been developed as a model for oomycete biology. Given the important but limited reports on the comparison of the sexual and asexual stages in Phytophthora, we performed a large-scale quantitative proteomics study on two key asexual life stages of P. sojae-the mycelium and cyst-as well as on the oospore, which is a key sexual stage. Over 29,631 peptides from 4688 proteins were analyzed. Briefly, 445 proteins, 624 proteins, and 579 proteins were defined as differentially quantified proteins in cyst vs mycelium, oospore vs cyst, and oospore vs mycelium comparisons, respectively (|log2 fold change| > 1 and P < 0.05). Compared to the mycelium and oospore, fatty acid and nitrogen metabolism were specifically induced in cysts. In oospores, the up-regulated proteins focused on RNA transport and protein processing in endoplasmic reticulum, indicating translation, folding, and the secretion of core cellular or stage-specific proteins active in oospores, which might be used for oospore germination. The data presented expand our knowledge of pathways specifically linked to asexual and sexual stages of this pathogen. BIOLOGICAL SIGNIFICANCE: The sexual spores (oospores) in oomycetes have thick cell walls and can survive in the soil for years, thus providing a primary source and allowing the reinfection of their host plant in subsequent growing seasons. However, the proteomic study on oospores remains very limited as they are generally considered to be dormant. In the present study, we successfully isolated oospores, and performed a large-scale comparative quantitative proteomics study on this key sexual stage and two representative asexual stages of P. sojae. The results provide an improved understanding of P. sojae biology and suggest potential metabolic targets for disease control at the three different developmental stages in oomycetes.
Collapse
Affiliation(s)
- Can Zhang
- Department of Plant Pathology, China Agricultural University, Beijing 100193, China
| | - Tongshan Cui
- Department of Plant Pathology, China Agricultural University, Beijing 100193, China
| | - Fan Zhang
- Department of Plant Pathology, China Agricultural University, Beijing 100193, China
| | - Zhaolin Xue
- Department of Plant Pathology, China Agricultural University, Beijing 100193, China
| | - Jianqiang Miao
- State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling 712100, China
| | - Weizhen Wang
- Department of Plant Pathology, China Agricultural University, Beijing 100193, China
| | - Xili Liu
- State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling 712100, China.
| |
Collapse
|
6
|
Affiliation(s)
- Chang Xu
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH, 43403-0212
| | - Paul F. Morris
- Department of Biological Sciences, Bowling Green State University, Bowling Green, OH, 43403-0212
| |
Collapse
|
7
|
What has happened to the “aquatic phycomycetes” (sensu Sparrow)? Part II: Shared properties of zoosporic true fungi and fungus-like microorganisms. FUNGAL BIOL REV 2018. [DOI: 10.1016/j.fbr.2017.09.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
8
|
Zitnick-Anderson KK, Norland JE, Del Río Mendoza LE, Fortuna AM, Nelson BD. Probability Models Based on Soil Properties for Predicting Presence-Absence of Pythium in Soybean Roots. MICROBIAL ECOLOGY 2017; 74:550-560. [PMID: 28386770 DOI: 10.1007/s00248-017-0958-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 02/24/2017] [Indexed: 06/07/2023]
Abstract
Associations between soil properties and Pythium groups on soybean roots were investigated in 83 commercial soybean fields in North Dakota. A data set containing 2877 isolates of Pythium which included 26 known spp. and 1 unknown spp. and 13 soil properties from each field were analyzed. A Pearson correlation analysis was performed with all soil properties to observe any significant correlation between properties. Hierarchical clustering, indicator spp., and multi-response permutation procedures were used to identify groups of Pythium. Logistic regression analysis using stepwise selection was employed to calculate probability models for presence of groups based on soil properties. Three major Pythium groups were identified and three soil properties were associated with these groups. Group 1, characterized by P. ultimum, was associated with zinc levels; as zinc increased, the probability of group 1 being present increased (α = 0.05). Pythium group 2, characterized by Pythium kashmirense and an unknown Pythium sp., was associated with cation exchange capacity (CEC) (α < 0.05); as CEC increased, these spp. increased. Group 3, characterized by Pythium heterothallicum and Pythium irregulare, were associated with CEC and calcium carbonate exchange (CCE); as CCE increased and CEC decreased, these spp. increased (α = 0.05). The regression models may have value in predicting pathogenic Pythium spp. in soybean fields in North Dakota and adjacent states.
Collapse
Affiliation(s)
| | - Jack E Norland
- Natural Resources Management, North Dakota State University, Fargo, ND, USA
| | | | - Ann-Marie Fortuna
- Department of Soil Science, North Dakota State University, Fargo, ND, USA
| | - Berlin D Nelson
- Department of Plant Pathology, North Dakota State University, Fargo, ND, USA.
| |
Collapse
|
9
|
Zheng L, Mackrill JJ. Calcium Signaling in Oomycetes: An Evolutionary Perspective. Front Physiol 2016; 7:123. [PMID: 27092083 PMCID: PMC4820453 DOI: 10.3389/fphys.2016.00123] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 03/21/2016] [Indexed: 01/06/2023] Open
Abstract
Oomycetes are a family of eukaryotic microbes that superficially resemble fungi, but which are phylogenetically distinct from them. These organisms cause major global economic losses to agriculture and fisheries, with representative pathogens being Phytophthora infestans, the cause of late potato blight and Saprolegnia diclina, the instigator of “cotton molds” in fish. As in all eukaryotes, cytoplasmic Ca2+ is a key second messenger in oomycetes, regulating life-cycle transitions, controlling motility and chemotaxis and, in excess, leading to cell-death. Despite this, little is known about the molecular mechanisms regulating cytoplasmic Ca2+ concentrations in these organisms. Consequently, this review analyzed the presence of candidate calcium channels encoded within the nine oomycete genomes that are currently available. This revealed key differences between oomycetes and other eukaryotes, in particular the expansion and loss of different channel families, and the presence of a phylum-specific group of proteins, termed the polycystic kidney disease tandem ryanodine receptor domain (PKDRR) channels.
Collapse
Affiliation(s)
- Limian Zheng
- Department of Physiology, BioSciences Institute, University College Cork Cork, Ireland
| | - John J Mackrill
- Department of Physiology, BioSciences Institute, University College Cork Cork, Ireland
| |
Collapse
|
10
|
Hua C, Wang Y, Zheng X, Dou D, Zhang Z, Govers F, Wang Y. A Phytophthora sojae G-protein alpha subunit is involved in chemotaxis to soybean isoflavones. EUKARYOTIC CELL 2008; 7:2133-40. [PMID: 18931042 PMCID: PMC2593195 DOI: 10.1128/ec.00286-08] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2008] [Accepted: 10/08/2008] [Indexed: 11/20/2022]
Abstract
For the soybean pathogen Phytophthora sojae, chemotaxis of zoospores to isoflavones is believed to be critical for recognition of the host and for initiating infection. However, the molecular mechanisms underlying this chemotaxis are largely unknown. To investigate the role of G-protein and calcium signaling in chemotaxis, we analyzed the expression of several genes known to be involved in these pathways and selected one that was specifically expressed in sporangia and zoospores but not in mycelium. This gene, named PsGPA1, is a single-copy gene in P. sojae and encodes a G-protein alpha subunit that shares 96% identity in amino acid sequence with that of Phytophthora infestans. To elucidate the function, expression of PsGPA1 was silenced by introducing antisense constructs into P. sojae. PsGPA1 silencing did not disturb hyphal growth or sporulation but severely affected zoospore behavior, including chemotaxis to the soybean isoflavone daidzein. Zoospore encystment and cyst germination were also altered, resulting in the inability of the PsGPA1-silenced mutants to infect soybean. In addition, the expressions of a calmodulin gene, PsCAM1, and two calcium- and calmodulin-dependent protein kinase genes, PsCMK3 and PsCMK4, were increased in the mutant zoospores, suggesting that PsGPA1 negatively regulates the calcium signaling pathways that are likely involved in zoospore chemotaxis.
Collapse
Affiliation(s)
- Chenlei Hua
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
| | | | | | | | | | | | | |
Collapse
|
11
|
Fjallman T, Hall JC. Antibody engineering--a valuable asset in preventing closed environment epidemics. ACTA ASTRONAUTICA 2005; 57:81-8. [PMID: 16010755 DOI: 10.1016/j.actaastro.2005.03.034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Investigations of Mir, Space Shuttle, Skylab and Apollo missions report extensive colonisation of the spacecraft by bacteria and fungi, which can lead to degradative effects on spacecraft equipment and devastating effects on space-grown crops. More than 80% of terrestrial greenhouse epidemics are due to the fungal genera Phytophthora, Pythium and Fusarium, which have been found in life support system test-beds. The advent of recombinant antibody technologies, including ribosome display and phage display, has made it possible to develop antibodies against virtually any toxin or organism and allows for maturation of antibodies by in vitro molecular evolution. These antibodies may play an important role in an integrated pest management regime for life support systems. Efficacy of existing fungal countermeasures could be increased by chemical linkage to antibodies, which target the site of action of the biocide or trap the pathogen in a biofilter. Novel recombinant antibody-biocide fusions can be expressed in situ by plants or symbiotic microbes to create direct disease resistance.
Collapse
Affiliation(s)
- Ted Fjallman
- Department of Environmental Biology, University of Guelph, Guelph, Canada.
| | | |
Collapse
|
12
|
Appiah AA, van West P, Osborne MC, Gow NAR. Potassium homeostasis influences the locomotion and encystment of zoospores of plant pathogenic oomycetes. Fungal Genet Biol 2005; 42:213-23. [PMID: 15707842 DOI: 10.1016/j.fgb.2004.11.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2004] [Revised: 11/12/2004] [Accepted: 11/13/2004] [Indexed: 11/30/2022]
Abstract
Zoospores of plant pathogenic oomycetes exhibit distinct swimming speeds and patterns under natural conditions. Zoospore swimming is influenced by ion homeostasis and changes in the ionic composition of media. Therefore, we used video microscopy to investigate swimming patterns of five oomycete species in response to changes in potassium homeostasis. In general, zoospore speed tended to be negatively correlated with zoospore size. Three Phytophthora species (Phytophthora palmivora, Phytophthora megakarya, and Phytophthora infestans) swam in straight patterns with speeds ranging from 50 to 250 microm/s whereas two Pythium species (Pythium aphanidermatum and Pythium dissotocum) swam at similar speeds ranging from 180 to 225 microm/s with a pronounced helical trajectory and varying amplitudes. High external concentrations of potassium salts reduced the swimming speed of Ph. palmivora and induced encystment. This was not observed for Py. aphanidermatum. Application of the potassium ionophores gramicidin, nigericin and valinomycin resulted in reduced swimming speeds and changes in the swimming patterns of the Phytophthora species. Therefore, potassium ions play a key role in regulating zoospore behavior.
Collapse
Affiliation(s)
- Alex A Appiah
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, Scotland, UK
| | | | | | | |
Collapse
|
13
|
Tani S, Yatzkan E, Judelson HS. Multiple pathways regulate the induction of genes during zoosporogenesis in Phytophthora infestans. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2004; 17:330-337. [PMID: 15000400 DOI: 10.1094/mpmi.2004.17.3.330] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Zoospores are a critical component of the disease cycles of most oomycete pathogens. To better understand this stage, genes induced during zoosporogenesis were identified from Phytophthora infestans, the potato late blight pathogen. Using cDNA arrays representing 2,600 genes expressed during zoosporogenesis, 69 genes showing >fourfold increases in mRNA levels were identified, of which 22 exhibited >100-fold induction. Included were putative protein kinases, transcription factors, ion channels, and other regulators. The expression of 15 genes was characterized in detail using zoosporogenesis time courses, other developmental stages, different temperature regimes, and tissue treated with signaling inhibitors. The latter were of interest because zoosporogenesis is known to be cold induced and inhibited by calcium channel blockers such as verapamil; moreover, in this study, inhibitors of phospholipase C (U-73122) and inositol trisphosphate receptor-gated calcium channels (2-aminoethoxydiphenyl borate) also were shown to block zoosporogenesis. The results indicated that the cytoplasmic and transcriptional changes occurring during zoosporogenesis are regulated by several pathways. For example, verapamil inhibited zoosporogenesis but not the up-regulation of most genes; the induction of some genes required while others were independent of calcium or phospholipid signaling; and, although most genes were induced in sporangia at 10 degrees C but not 24 degrees C, one was induced at both temperatures.
Collapse
Affiliation(s)
- Shuji Tani
- Department of Plant Pathology, University of California, Riverside 92521, USA
| | | | | |
Collapse
|
14
|
Judelson HS, Roberts S. Novel protein kinase induced during sporangial cleavage in the oomycete Phytophthora infestans. EUKARYOTIC CELL 2002; 1:687-95. [PMID: 12455688 PMCID: PMC126747 DOI: 10.1128/ec.1.5.687-695.2002] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2002] [Accepted: 07/09/2002] [Indexed: 11/20/2022]
Abstract
A study of the effect of inhibitors on zoospore development in Phytophthora infestans demonstrated the involvement of protein kinases and calcium and led to the discovery of a gene induced during zoosporogenesis that encoded a protein resembling Ca2+- and calmodulin-regulated serine/threonine protein kinases. The calcium channel blocker verapamil and the calmodulin antagonist trifluoroperazine inhibited zoosporogenesis and encystment. The protein kinase inhibitors K-252a and KN-93 inhibited zoospore release, encystment, and cyst germination, and K-252a reduced zoospore viability. In contrast, the inhibitors had minor or no effects on sporangia directly germinating in media. Spurred by these findings, a survey of putative protein kinase genes was performed to identify any that were up-regulated during zoosporogenesis. A kinase-encoding gene was identified for which mRNA accumulation was first detected soon after chilling sporangia in water, conditions that induce sporangial cytoplasm to cleave and release zoospores. The transcript persisted in motile zoospores and in germinated cysts but was not detected in other tissues, including hyphae, hyphae placed in water, or directly germinating sporangia. The structure of the predicted protein was novel, as its C-terminal region, which binds calmodulin in related proteins, was unusually short. Concentrations of actinomycin D previously used in experiments that suggested that de novo transcription was not needed for zoosporogenesis or encystment only partially inhibited transcription of the kinase gene, probably due to poor uptake into sporangia.
Collapse
Affiliation(s)
- Howard S Judelson
- Department of Plant Pathology, University of California, Riverside, California 92521, USA.
| | | |
Collapse
|
15
|
Tyler BM. Molecular basis of recognition between phytophthora pathogens and their hosts. ANNUAL REVIEW OF PHYTOPATHOLOGY 2002; 40:137-167. [PMID: 12147757 DOI: 10.1146/annurev.phyto.40.120601.125310] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Recognition is the earliest step in any direct plant-microbe interaction. Recognition between Phytophthora pathogens, which are oomycetes, phylogenetically distinct from fungi, has been studied at two levels. Recognition of the host by the pathogen has focused on recognition of chemical, electrical, and physical features of plant roots by zoospores. Both host-specific factors such as isoflavones, and host-nonspecific factors such as amino acids, calcium, and electrical fields, influence zoospore taxis, encystment, cyst germination, and hyphal chemotropism in guiding the pathogen to potential infection sites. Recognition of the pathogen by the host defense machinery has been analyzed using biochemical and genetic approaches. Biochemical approaches have identified chemical elicitors of host defense responses, and in some cases, their cognate receptors from the host. Some elicitors, such as glucans and fatty acids, have broad host ranges, whereas others such as elicitins have narrow host ranges. Most elicitors identified appear to contribute primarily to basic or nonhost resistance. Genetic analysis has identified host resistance (R) genes and pathogen avirulence (Avr) genes that interact in a gene-for-gene manner. One Phytophthora Avr gene, Avr1b from P. sojae, has been cloned and characterized. It encodes a secreted elicitor that triggers a system-wide defense response in soybean plants carrying the cognate R gene, Rps1b.
Collapse
Affiliation(s)
- Brett M Tyler
- Virginia Bioinformatics Institute, Virginia Polytechnic Institute and State University, Blacksburg 24061, USA.
| |
Collapse
|
16
|
Singh UP, Prithiviraj B, Sarma BK. Effect of calcium and calmodulin modulators on the development of Erysiphe pisi on pea leaves. Microbiol Res 2001; 156:65-9. [PMID: 11372655 DOI: 10.1078/0944-5013-00071] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The effect of calcium and calmodulin modulators, viz., ethylene glycol bis (beta-amino ethyl ether)-N,N,N',N'-tetraacetic acid (EGTA), a calcium chelator; verapamil, a plasma membrane Ca2+ channel blocker; ruthenium red, an organelle Ca2+ channel blocker; and chlorpromazine, a calmodulin antagonist; on the development of Erysiphe pisi was studied by floating the inoculated leaves on the respective solutions of chemicals. All the modulators affected the development of E. pisi by inhibiting the colony diameter, number of secondary branches, number of hyphal cells per colony and number of haustoria. The calmodulin antagonist was more effective in reducing E. pisi development. The results suggest the possible involvement of calcium and calmodulin in the development of E. pisi on pea leaves.
Collapse
Affiliation(s)
- U P Singh
- Department of Mycology and Plant Pathology, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, India.
| | | | | |
Collapse
|
17
|
Messenger BJ, Menge JA, Pond E. Effects of Gypsum on Zoospores and Sporangia of Phytophthora cinnamomi in Field Soil. PLANT DISEASE 2000; 84:617-621. [PMID: 30841099 DOI: 10.1094/pdis.2000.84.6.617] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Sporangial production of Phytophthora cinnamomi buried in gypsum-amended avocado soil for 2 days was reduced by as much as 74% in greenhouse trials. P. cinnamomi sporangial volume was reduced an average of 64% in gypsum-amended soil. Soil extracts from gypsum-amended soil reduced in vitro sporangial production and volume. Irrigation with gypsum solutions of buried mycelium in unamended soil also reduced sporangial production and volume. Zoospore production and colony-forming units of P. cinnamomi were reduced in soil amended with calcium sulfate, calcium nitrate, or calcium carbonate. Zoospore encystment or passive movement through soil was not significantly affected by gypsum soil amendments.
Collapse
Affiliation(s)
- B J Messenger
- Department of Plant Pathology, University of California, Riverside 92521
| | - J A Menge
- Department of Plant Pathology, University of California, Riverside 92521
| | - E Pond
- Department of Plant Pathology, University of California, Riverside 92521
| |
Collapse
|
18
|
Connolly MS, Williams N, Heckman CA, Morris PF. Soybean isoflavones trigger a calcium influx in Phytophthora sojae. Fungal Genet Biol 1999; 28:6-11. [PMID: 10512667 DOI: 10.1006/fgbi.1999.1148] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Both the motile zoospores and the hyphal germ tubes of Phytophthora sojae respond chemotropically to the soybean isoflavones daidzein and genistein. The role of Ca(2+) in the cellular response to these host signals was investigated by using X-ray microanalysis of cells to monitor net changes in cellular levels of Ca(2+) and by quantifying the effects of exogenous Ca(2+) and daidzein on the developmental fate of encysted zoospores. Confirmation that isoflavones trigger a net influx of Ca(2+) into the cell was demonstrated by X-ray microanalysis of individual encysted zoospores. Zoospores exposed to 10 mM Ca(2+) and 1 microM daidzein at the time of encystment formed cysts that contained more Ca(2+) than zoospores exposed to Ca(2+) alone. The magnitude of internal Ca(2+) stores appears to be a determining factor affecting the developmental fate of P. sojae cysts.
Collapse
Affiliation(s)
- M S Connolly
- Department of Biological Sciences, Bowling Green State University, Bowling Green, Ohio, 43403, USA
| | | | | | | |
Collapse
|
19
|
von Broembsen SL, Deacon JW. Calcium Interference with Zoospore Biology and Infectivity of Phytophthora parasitica in Nutrient Irrigation Solutions. PHYTOPATHOLOGY 1997; 87:522-528. [PMID: 18945107 DOI: 10.1094/phyto.1997.87.5.522] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
ABSTRACT Calcium, applied as either CaCl2 or Ca(NO3)2 to water or calcium-free soluble fertilizer solution (Peters 20-10-20 Peat Lite Special), affected several important stages of Phytophthora parasitica zoospore behavior relevant to infection and disease spread. Release of zoospores from sporangia was suppressed by Ca(2+) concentrations in the range of 10 to 50 meq. These concentrations also curtailed zoospore motility; 20 meq of Ca(2+) in fertilizer solution caused all zoospores to encyst within 4 h, whereas 94% of zoospores remained motile in unamended solution. In addition, Ca(2+) in the range of 10 to 30 meq stimulated zoospore cysts to germinate in the absence of an organic nutrient trigger, while suppressing the release of a single zoospore (diplanetism) from cysts that did not germinate. In growth chamber experiments, the amendment of the fertilizer solution with 10 or 20 mM Ca(NO3)2 greatly suppressed infection of flood-irrigated, containerized vinca seedlings in a peat-based mix by motile or encysted zoospores of P. parasitica. These results demonstrate that Ca(2+) amendments interfere with P. parasitica zoospore biology at multiple stages, with compounding effects on epidemiology, and suggest that manipulation of Ca(2+) levels in irrigation water or fertilizer solutions could contribute to management of Phytophthora in recirculating irrigation systems.
Collapse
|
20
|
Deacon J, Donaldson S. Molecular recognition in the homing responses of zoosporic fungi, with special reference to Pythium and Phytophthora. ACTA ACUST UNITED AC 1993. [DOI: 10.1016/s0953-7562(09)81278-1] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|