1
|
Breen S, Hussain R, Breeze E, Brown H, Alzwiy I, Abdelsayed S, Gaikwad T, Grant M. Chloroplasts play a central role in facilitating MAMP-triggered immunity, pathogen suppression of immunity and crosstalk with abiotic stress. Plant Cell Environ 2022; 45:3001-3017. [PMID: 35892221 PMCID: PMC9544062 DOI: 10.1111/pce.14408] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 07/21/2022] [Accepted: 07/24/2022] [Indexed: 05/22/2023]
Abstract
Microbe-associated molecular pattern (MAMP)-triggered immunity (MTI) research has traditionally centred around signal transduction pathways originating from activated membrane-localized pattern recognition receptors (PRRs), culminating in nuclear transcription and posttranslational modifications. More recently, chloroplasts have emerged as key immune signalling hubs, playing a central role in integrating environmental signals. Notably, MAMP recognition induces chloroplastic reactive oxygen species (cROS) that is suppressed by pathogen effectors, which also modify the balance of chloroplast-synthesized precursors of the defence hormones, jasmonic acid, salicylic acid (SA) and abscisic acid. This study focuses on how well-characterized PRRs and coreceptors modulate chloroplast physiology, examining whether diverse signalling pathways converge to similarly modulate chloroplast function. Pretreatment of receptor mutant plants with MAMP and D(Damage)AMP peptides usually protect against effector modulation of chlorophyll fluorescence and prevent Pseudomonas syringae effector-mediated quenching of cROS and suppression of maximum dark-adapted quantum efficiency (the ratio of variable/maximum fluorescence [Fv /Fm ]). The MTI coreceptor double mutant, bak1-5/bkk1-1, exhibits a remarkable decrease in Fv /Fm compared to control plants during infection, underlining the importance of MTI-mediated signalling in chloroplast immunity. Further probing the role of the chloroplast in immunity, we unexpectedly found that even moderate changes in light intensity can uncouple plant immune signalling.
Collapse
Affiliation(s)
- Susan Breen
- School of Life SciencesUniversity of WarwickCoventryUK
| | - Rana Hussain
- School of Life SciencesUniversity of WarwickCoventryUK
| | - Emily Breeze
- School of Life SciencesUniversity of WarwickCoventryUK
| | - Hannah Brown
- School of Biosciences, College of Life and Environmental SciencesUniversity of ExeterExeterUK
- Present address:
Department of Health and Social CareVictoria Street, London SW1H 0EU, UK
| | - Ibrahim Alzwiy
- School of Biosciences, College of Life and Environmental SciencesUniversity of ExeterExeterUK
- Present address:
Authority of Natural Science Research and TechnologyP.O. Box 30666, Tripoli, Libya
| | - Sara Abdelsayed
- School of Life SciencesUniversity of WarwickCoventryUK
- Botany Department, Faculty of scienceBenha UniversityBenhaEgypt
| | - Trupti Gaikwad
- School of Life SciencesUniversity of WarwickCoventryUK
- Present address:
Marine Biology AssociationPlymouth PL1 2PB, UK
| | - Murray Grant
- School of Life SciencesUniversity of WarwickCoventryUK
| |
Collapse
|
2
|
Kleiner FH, Helliwell KE, Chrachri A, Hopes A, Parry-Wilson H, Gaikwad T, Mieszkowska N, Mock T, Wheeler GL, Brownlee C. Cold-induced [Ca2+]cyt elevations function to support osmoregulation in marine diatoms. Plant Physiol 2022; 190:1384-1399. [PMID: 35894667 PMCID: PMC9516774 DOI: 10.1093/plphys/kiac324] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 06/15/2022] [Indexed: 06/15/2023]
Abstract
Diatoms are a group of microalgae that are important primary producers in a range of open ocean, freshwater, and intertidal environments. The latter can experience substantial long- and short-term variability in temperature, from seasonal variations to rapid temperature shifts caused by tidal immersion and emersion. As temperature is a major determinant in the distribution of diatom species, their temperature sensory and response mechanisms likely have important roles in their ecological success. We examined the mechanisms diatoms use to sense rapid changes in temperature, such as those experienced in the intertidal zone. We found that the diatoms Phaeodactylum tricornutum and Thalassiosira pseudonana exhibit a transient cytosolic Ca2+ ([Ca2+]cyt) elevation in response to rapid cooling, similar to those observed in plant and animal cells. However, [Ca2+]cyt elevations were not observed in response to rapid warming. The kinetics and magnitude of cold-induced [Ca2+]cyt elevations corresponded with the rate of temperature decrease. We did not find a role for the [Ca2+]cyt elevations in enhancing cold tolerance but showed that cold shock induces a Ca2+-dependent K+ efflux and reduces mortality of P. tricornutum during a simultaneous hypo-osmotic shock. As intertidal diatom species may routinely encounter simultaneous cold and hypo-osmotic shocks during tidal cycles, we propose that cold-induced Ca2+ signaling interacts with osmotic signaling pathways to aid in the regulation of cell volume. Our findings provide insight into the nature of temperature perception in diatoms and highlight that cross-talk between signaling pathways may play an important role in their cellular responses to multiple simultaneous stressors.
Collapse
Affiliation(s)
- Friedrich H Kleiner
- The Marine Biological Association of the United Kingdom, The Laboratory, Plymouth PL1 2PB, UK
- School of Ocean and Earth Science, University of Southampton, Southampton SO14 3ZH, UK
| | - Katherine E Helliwell
- The Marine Biological Association of the United Kingdom, The Laboratory, Plymouth PL1 2PB, UK
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QD, UK
| | - Abdul Chrachri
- The Marine Biological Association of the United Kingdom, The Laboratory, Plymouth PL1 2PB, UK
| | - Amanda Hopes
- School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, UK
| | - Hannah Parry-Wilson
- The Marine Biological Association of the United Kingdom, The Laboratory, Plymouth PL1 2PB, UK
- School of Ocean and Earth Science, University of Southampton, Southampton SO14 3ZH, UK
| | - Trupti Gaikwad
- The Marine Biological Association of the United Kingdom, The Laboratory, Plymouth PL1 2PB, UK
| | - Nova Mieszkowska
- The Marine Biological Association of the United Kingdom, The Laboratory, Plymouth PL1 2PB, UK
- School of Environmental Sciences, University of Liverpool, Liverpool, L69 3GP, UK
| | - Thomas Mock
- School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, UK
| | | | | |
Collapse
|
3
|
Helliwell KE, Kleiner FH, Hardstaff H, Chrachri A, Gaikwad T, Salmon D, Smirnoff N, Wheeler GL, Brownlee C. Spatiotemporal patterns of intracellular Ca 2+ signalling govern hypo-osmotic stress resilience in marine diatoms. New Phytol 2021; 230:155-170. [PMID: 33486789 DOI: 10.1111/nph.17162] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Accepted: 12/11/2020] [Indexed: 05/15/2023]
Abstract
Diatoms are globally important phytoplankton that dominate coastal and polar-ice assemblages. These environments exhibit substantial changes in salinity over dynamic spatiotemporal regimes. Rapid sensory systems are vital to mitigate the harmful consequences of osmotic stress. Population-based analyses have suggested that Ca2+ signalling is involved in diatom osmotic sensing. However, mechanistic insight of the role of osmotic Ca2+ signalling is limited. Here, we show that Phaeodactylum Ca2+ elevations are essential for surviving hypo-osmotic shock. Moreover, employing novel single-cell imaging techniques we have characterised real-time Ca2+ signalling responses in single diatom cells to environmental osmotic perturbations. We observe that intracellular spatiotemporal patterns of osmotic-induced Ca2+ elevations encode vital information regarding the nature of the osmotic stimulus. Localised Ca2+ signals evoked by mild or gradual hypo-osmotic shocks are propagated globally from the apical cell tips, enabling fine-tuned cell volume regulation across the whole cell. Finally, we demonstrate that diatoms adopt Ca2+ -independent and dependent mechanisms for osmoregulation. We find that efflux of organic osmolytes occurs in a Ca2+ -independent manner, but this response is insufficient to mitigate cell damage during hypo-osmotic shock. By comparison, Ca2+ -dependent signalling is necessary to prevent cell bursting via precise coordination of K+ transport, and therefore is likely to underpin survival in dynamic osmotic environments.
Collapse
Affiliation(s)
- Katherine E Helliwell
- The Laboratory, Marine Biological Association, Citadel Hill, Plymouth, PL1 2PB, UK
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QD, UK
| | - Friedrich H Kleiner
- The Laboratory, Marine Biological Association, Citadel Hill, Plymouth, PL1 2PB, UK
- School of Ocean and Earth Science, University of Southampton, Southampton, SO14 3ZH, UK
| | - Hayley Hardstaff
- The Laboratory, Marine Biological Association, Citadel Hill, Plymouth, PL1 2PB, UK
| | - Abdul Chrachri
- The Laboratory, Marine Biological Association, Citadel Hill, Plymouth, PL1 2PB, UK
| | - Trupti Gaikwad
- The Laboratory, Marine Biological Association, Citadel Hill, Plymouth, PL1 2PB, UK
| | - Deborah Salmon
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QD, UK
| | - Nicholas Smirnoff
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QD, UK
| | - Glen L Wheeler
- The Laboratory, Marine Biological Association, Citadel Hill, Plymouth, PL1 2PB, UK
| | - Colin Brownlee
- The Laboratory, Marine Biological Association, Citadel Hill, Plymouth, PL1 2PB, UK
- School of Ocean and Earth Science, University of Southampton, Southampton, SO14 3ZH, UK
| |
Collapse
|
4
|
Helliwell KE, Harrison EL, Christie-Oleza JA, Rees AP, Kleiner FH, Gaikwad T, Downe J, Aguilo-Ferretjans MM, Al-Moosawi L, Brownlee C, Wheeler GL. A Novel Ca 2+ Signaling Pathway Coordinates Environmental Phosphorus Sensing and Nitrogen Metabolism in Marine Diatoms. Curr Biol 2020; 31:978-989.e4. [PMID: 33373640 DOI: 10.1016/j.cub.2020.11.073] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 10/26/2020] [Accepted: 11/30/2020] [Indexed: 10/22/2022]
Abstract
Diatoms are a diverse and globally important phytoplankton group, responsible for an estimated 20% of carbon fixation on Earth. They frequently form spatially extensive phytoplankton blooms, responding rapidly to increased availability of nutrients, including phosphorus (P) and nitrogen (N). Although it is well established that diatoms are common first responders to nutrient influxes in aquatic ecosystems, little is known of the sensory mechanisms that they employ for nutrient perception. Here, we show that P-limited diatoms use a Ca2+-dependent signaling pathway, not previously described in eukaryotes, to sense and respond to the critical macronutrient P. We demonstrate that P-Ca2+ signaling is conserved between a representative pennate (Phaeodactylum tricornutum) and centric (Thalassiosira pseudonana) diatom. Moreover, this pathway is ecologically relevant, being sensitive to sub-micromolar concentrations of inorganic phosphate and a range of environmentally abundant P forms. Notably, we show that diatom recovery from P limitation requires rapid and substantial increases in N assimilation and demonstrate that this process is dependent on P-Ca2+ signaling. P-Ca2+ signaling thus governs the capacity of diatoms to rapidly sense and respond to P resupply, mediating fundamental cross-talk between the vital nutrients P and N and maximizing diatom resource competition in regions of pulsed nutrient supply.
Collapse
Affiliation(s)
- Katherine E Helliwell
- Marine Biological Association, The Laboratory, Citadel Hill, Plymouth PL1 2PB, UK; Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter EX4 4QD, UK.
| | - Ellen L Harrison
- Marine Biological Association, The Laboratory, Citadel Hill, Plymouth PL1 2PB, UK
| | | | - Andrew P Rees
- Plymouth Marine Laboratory, Plymouth, Devon PL1 3DH, UK
| | - Friedrich H Kleiner
- Marine Biological Association, The Laboratory, Citadel Hill, Plymouth PL1 2PB, UK
| | - Trupti Gaikwad
- Marine Biological Association, The Laboratory, Citadel Hill, Plymouth PL1 2PB, UK
| | - Joshua Downe
- Marine Biological Association, The Laboratory, Citadel Hill, Plymouth PL1 2PB, UK
| | | | | | - Colin Brownlee
- Marine Biological Association, The Laboratory, Citadel Hill, Plymouth PL1 2PB, UK; School of Ocean and Earth Science, University of Southampton, Southampton SO14 3ZH, UK
| | - Glen L Wheeler
- Marine Biological Association, The Laboratory, Citadel Hill, Plymouth PL1 2PB, UK
| |
Collapse
|
5
|
Sarode SC, Sarode GS, Gaikwad T, Patekar D, Gadbail A, Gondivkar S, Panta P, Patil S. Usage Analysis of WhatsApp for Dentistry-related Purposes among General Dental Practitioners. J Contemp Dent Pract 2018; 19:1267-1272. [PMID: 30498184 DOI: 10.5005/jp-journals-10024-2415] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/13/2023]
Abstract
INTRODUCTION To assess the knowledge and extent of WhatsApp usage for dentistry related purposes among general dental practitioners (GDPs). MATERIALS AND METHODS A cross-sectional study was conducted among 105 randomly selected GDPs from Pune, Maharashtra, India. Data was collected in a personalized manner by means of validated questionnaire. Results and observations: A total of 105 dentists participated in the survey: 96.19% of dentists had WhatsApp installed in their phones; 67.32% of dentists sought second opinion on WhatsApp; 60.29% of dentists received prompt replies, while 38.23% received late replies; 98.52% of dentists sent clinical photographs and radiographs for second opinion. 88.11% of dentists were a part of various 'dentistry related groups' and 72.27% of dentists told that patients ask their queries on WhatsApp. 36.76% of GDPs obtained verbal consent from the patients for sending clinical materials for second opinion. Majority of population of GDPs 63.23% (43) did not obtain any form of consent from the patients. CONCLUSION Majority of GDPs uses WhatsApp for 'dentistry related purposes' and it has become an integral part of their day-to-day practice. GDPs should obtain written consent before sending clinical materials for second opinion. CLINICAL SIGNIFICANCE Till date, the extent of WhatsApp usage by general dental practitioners was not reported in the literature. It appears that, WhatsApp application has become an integral part of general dental practice in India. By virtue of this, obtaining second opinion, taking appointments and solving queries of patients are no longer a time consuming events. In future, instant messaging services might play major role in providing efficient services in health care industry.
Collapse
Affiliation(s)
- Sachin C Sarode
- Department of Oral Pathology and Microbiology, Dr. D. Y. Patil Dental College and Hospital, Dr. D.Y. Patil Vidyapeeth, Pune, Maharashtra, India, Tel.: +919823871462, e-mail:
| | - Gargi S Sarode
- Department of Oral Pathology and Microbiology, Dr. D. Y. Patil Dental College and Hospital, Dr. D.Y. Patil Vidyapeeth, Pune, Maharashtra, India
| | - Trupti Gaikwad
- Department of Oral Pathology and Microbiology, Dr. D. Y. Patil Dental College and Hospital, Dr. D.Y. Patil Vidyapeeth, Pune, Maharashtra, India
| | - Deepali Patekar
- Department of Oral Pathology and Microbiology, Dr. D. Y. Patil Dental College and Hospital, Dr. D.Y. Patil Vidyapeeth, Pune, Maharashtra, India
| | - Amol Gadbail
- Department of Dentistry, Indira Gandhi Government Medical College and Hospital, Nagpur, Maharashtra, India
| | - Shailesh Gondivkar
- Department of Oral Medicine and Radiology, Government Dental College and Hospital, Nagpur, Maharashtra, India
| | - Prashanth Panta
- Department of Oral Medicine and Radiology, MNR Dental College and Hospital, Sangareddy, Telangana, India
| | - Shankargouda Patil
- Department of Maxillofacial Surgery and Diagnostic Sciences, Division of Oral Pathology, College of Dentistry, Jazan University, Jazan, Kingdom of Saudi Arabia
| |
Collapse
|
6
|
Gaikwad T, Ghosh K, Shetty S. Dosing algorithms for vitamin K antagonists across VKORC1 and CYP2C9 genotypes: comment. J Thromb Haemost 2017; 15:1708. [PMID: 28608988 DOI: 10.1111/jth.13757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Indexed: 11/26/2022]
Affiliation(s)
- T Gaikwad
- Department of Thrombosis and Haemostasis, National Institute of Immunohaematology (ICMR), Mumbai, India
| | - K Ghosh
- Surat Raktadan Kendra and Research Centre, Regional Blood Transfusion Centre, Surat, India
| | - S Shetty
- Department of Thrombosis and Haemostasis, National Institute of Immunohaematology (ICMR), Mumbai, India
| |
Collapse
|