1
|
Liu L, Ashraf MA, Morrow T, Facette M. Stomatal closure in maize is mediated by subsidiary cells and the PAN2 receptor. THE NEW PHYTOLOGIST 2024; 241:1130-1143. [PMID: 37936339 DOI: 10.1111/nph.19379] [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: 05/02/2023] [Accepted: 10/19/2023] [Indexed: 11/09/2023]
Abstract
Stomata are epidermal pores that facilitate plant gas exchange. Grasses have fast stomatal movements, likely due to their dumbbell-shaped guard cells and lateral subsidiary cells. Subsidiary cells reciprocally exchange water and ions with guard cells. However, the relative contribution of subsidiary cells during stomatal closure is unresolved. We compared stomatal gas exchange and stomatal aperture dynamics in wild-type and pan1, pan2, and pan1;pan2 Zea mays (L.) (maize) mutants, which have varying percentages of aberrantly formed subsidiary cells. Stomata with 1 or 2 defective subsidiary cells cannot close properly, indicating that subsidiary cells are essential for stomatal function. Even though the percentage of aberrant stomata is similar in pan1 and pan2, pan2 showed a more severe defect in stomatal closure. In pan1, only stomata with abnormal subsidiary cells fail to close normally. In pan2, all stomata have stomatal closure defects, indicating that PAN2 has an additional role in stomatal closure. Maize Pan2 is orthologous to Arabidopsis GUARD CELL HYDROGEN PEROXIDE-RESISANT1 (GHR1), which is also required for stomatal closure. PAN2 acts downstream of Ca2+ in maize to promote stomatal closure. This is in contrast to GHR1, which acts upstream of Ca2+ , and suggests the pathways could be differently wired.
Collapse
Affiliation(s)
- Le Liu
- Department of Biology, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - M Arif Ashraf
- Department of Biology, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Taylor Morrow
- Department of Biology, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| | - Michelle Facette
- Department of Biology, University of Massachusetts Amherst, Amherst, MA, 01003, USA
| |
Collapse
|
2
|
Dong H, Xu C, Zhang C, Zhang L, Yao Y, Zhang S. Occurrence, structure, and function of short cells in maize leaf epidermis. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2024; 206:108200. [PMID: 38029620 DOI: 10.1016/j.plaphy.2023.108200] [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: 07/08/2023] [Revised: 10/19/2023] [Accepted: 11/13/2023] [Indexed: 12/01/2023]
Abstract
Short cells are specialised epidermal cells of grasses and they include cork and silica cells. The time of occurrence, distribution, and number of short cells differ among plants or tissues of the same plant. The present study aimed to assess the occurrence, structure, and function of short cells in the epidermis of maize (Zea mays L.) leaves from cultivar "Zhengdan 958″ under field and potted experimental conditions. Results showed that short cells occurred synchronously in multiple maize leaves. Few short cells occurred at the base of the fifth leaf; most were found at the middle and base of the sixth leaf, and throughout the seventh leaf. The accumulation of K+ and H2O2 in cork cells changed periodically with stomatal opening and closure, which was consistent with the accumulation of K+ and H2O2 in subsidiary cells; whereas no accumulation was observed in silica cells. Moreover, photosynthetic parameters and stomatal aperture were significantly higher in leaves containing short cells than in those without them in the same parts of different leaves or in different leaves at the same leaf position. Accumulation of K+ and H2O2 in cork cells increased with increasing water stress. In conclusion, short cells not only improved leaf mechanical support and photosynthetic performance, and maize drought resistance, but they also participated in stomatal regulation.
Collapse
Affiliation(s)
- He Dong
- College of Traditional Chinese Medicine, Weifang Medical University, Weifang, Shandong, 261053, China; College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Chongmei Xu
- College of Traditional Chinese Medicine, Weifang Medical University, Weifang, Shandong, 261053, China
| | - Chengtao Zhang
- College of Traditional Chinese Medicine, Weifang Medical University, Weifang, Shandong, 261053, China
| | - Li Zhang
- College of Traditional Chinese Medicine, Weifang Medical University, Weifang, Shandong, 261053, China.
| | - Yaqin Yao
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Suiqi Zhang
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, China
| |
Collapse
|
3
|
Nguyen T, Silva‐Alvim FAL, Hills A, Blatt MR. OnGuard3e: A predictive, ecophysiology-ready tool for gas exchange and photosynthesis research. PLANT, CELL & ENVIRONMENT 2023; 46:3644-3658. [PMID: 37498151 PMCID: PMC10946835 DOI: 10.1111/pce.14674] [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: 03/14/2023] [Revised: 06/20/2023] [Accepted: 07/17/2023] [Indexed: 07/28/2023]
Abstract
Gas exchange across the stomatal pores of leaves is a focal point in studies of plant-environmental relations. Stomata regulate atmospheric exchange with the inner air spaces of the leaf. They open to allow CO2 entry for photosynthesis and close to minimize water loss. Models that focus on the phenomenology of stomatal conductance generally omit the mechanics of the guard cells that regulate the pore aperture. The OnGuard platform fills this gap and offers a truly mechanistic approach with which to analyse stomatal gas exchange, whole-plant carbon assimilation and water-use efficiency. Previously, OnGuard required specialist knowledge of membrane transport, signalling and metabolism. Here we introduce OnGuard3e, a software package accessible to ecophysiologists and membrane biologists alike. We provide a brief guide to its use and illustrate how the package can be applied to explore and analyse stomatal conductance, assimilation and water use efficiencies, addressing a range of experimental questions with truly predictive outputs.
Collapse
Affiliation(s)
- Thanh‐Hao Nguyen
- Laboratory of Plant Physiology and BiophysicsUniversity of GlasgowGlasgowUK
| | | | - Adrian Hills
- Laboratory of Plant Physiology and BiophysicsUniversity of GlasgowGlasgowUK
| | - Michael R. Blatt
- Laboratory of Plant Physiology and BiophysicsUniversity of GlasgowGlasgowUK
| |
Collapse
|
4
|
Nguyen TBA, Lefoulon C, Nguyen TH, Blatt MR, Carroll W. Engineering stomata for enhanced carbon capture and water-use efficiency. TRENDS IN PLANT SCIENCE 2023; 28:1290-1309. [PMID: 37423785 DOI: 10.1016/j.tplants.2023.06.002] [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: 02/13/2023] [Revised: 05/29/2023] [Accepted: 06/02/2023] [Indexed: 07/11/2023]
Abstract
Stomatal pores facilitate gaseous exchange between the inner air spaces of the leaf and the atmosphere. As gatekeepers that balance CO2 entry for photosynthesis against transpirational water loss, they are a focal point for efforts to improve crop performance, especially in the efficiency of water use, within the changing global environment. Until recently, engineering strategies had focused on stomatal conductance in the steady state. These strategies are limited by the physical constraints of CO2 and water exchange such that gains in water-use efficiency (WUE) commonly come at a cost in carbon assimilation. Attention to stomatal speed and responsiveness circumvents these constraints and offers alternatives to enhancing WUE that also promise increases in carbon assimilation in the field.
Collapse
Affiliation(s)
- Thu Binh-Anh Nguyen
- Laboratory of Plant Physiology and Biophysics, Bower Building, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Cecile Lefoulon
- Laboratory of Plant Physiology and Biophysics, Bower Building, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Thanh-Hao Nguyen
- Laboratory of Plant Physiology and Biophysics, Bower Building, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Michael R Blatt
- Laboratory of Plant Physiology and Biophysics, Bower Building, University of Glasgow, Glasgow, G12 8QQ, UK.
| | - William Carroll
- Laboratory of Plant Physiology and Biophysics, Bower Building, University of Glasgow, Glasgow, G12 8QQ, UK
| |
Collapse
|
5
|
Chen Z, Li H, Zhang WH, Wang B. The roles of stomatal morphologies in transpiration and nutrient transportation between grasses and forbs in a temperate steppe. ANNALS OF BOTANY 2023; 132:229-239. [PMID: 37470240 PMCID: PMC10583208 DOI: 10.1093/aob/mcad096] [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: 03/28/2023] [Accepted: 07/18/2023] [Indexed: 07/21/2023]
Abstract
BACKGROUND AND AIMS Grasses and forbs are dominant functional groups in temperate grasslands and display substantial differences in many biological traits, especially in root and stomatal morphologies, which are closely related to the use of water and nutrients. However, few studies have investigated the differences in nutrient accumulation and stomatal morphology-mediated transportation of water and nutrients from roots to shoots comparatively between the two functional groups. METHODS Here, we explored the patterns of accumulation of multiple nutrients (N, P, K, Ca, Mg and S) in leaves and roots, transpiration-related processes and interactions between nutrients and transpiration at functional group levels by experiments in a temperate steppe and collection of data from the literature. KEY RESULTS The concentrations of all the examined nutrients were obviously higher in both leaves and roots of forbs than those in grasses, especially for leaf Ca and Mg concentrations. Grasses with dumbbell-shaped stomata displayed significantly lower transpiration and stomatal conductance than forbs with kidney-shaped stomata. In contrast, grasses showed much higher water-use efficiency (WUE) than forbs. The contrasting patterns of nutrient accumulation, transpiration and WUE between grasses and forbs were less sensitive to varied environments. Leaf N, P and S concentrations were not affected by transpiration. In contrast, leaf Mg concentrations were positively correlated with transpiration in forb species. Furthermore, linear regression and principal component analysis showed that leaf Ca and Mg concentrations were positively correlated with transpiration between the two functional groups. CONCLUSIONS Our results revealed contrasting differences in acquisition of multiple nutrients and transpiration between grasses and forbs, and that stomatal morphologies are an important driver for the distinct WUE and translocation of Ca and Mg from roots to leaves between the two functional groups in temperate steppes. These findings will contribute to our understanding of the important roles of functional traits in driving water and nutrient cycling.
Collapse
Affiliation(s)
- Zhuo Chen
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, the Chinese Academy of Sciences, Beijing 100093, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hongbo Li
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Wen-hao Zhang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, the Chinese Academy of Sciences, Beijing 100093, China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Baolan Wang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, the Chinese Academy of Sciences, Beijing 100093, China
| |
Collapse
|
6
|
Long SP, Taylor SH, Burgess SJ, Carmo-Silva E, Lawson T, De Souza AP, Leonelli L, Wang Y. Into the Shadows and Back into Sunlight: Photosynthesis in Fluctuating Light. ANNUAL REVIEW OF PLANT BIOLOGY 2022; 73:617-648. [PMID: 35595290 DOI: 10.1146/annurev-arplant-070221-024745] [Citation(s) in RCA: 48] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Photosynthesis is an important remaining opportunity for further improvement in the genetic yield potential of our major crops. Measurement, analysis, and improvement of leaf CO2 assimilation (A) have focused largely on photosynthetic rates under light-saturated steady-state conditions. However, in modern crop canopies of several leaf layers, light is rarely constant, and the majority of leaves experience marked light fluctuations throughout the day. It takes several minutes for photosynthesis to regain efficiency in both sun-shade and shade-sun transitions, costing a calculated 10-40% of potential crop CO2 assimilation. Transgenic manipulations to accelerate the adjustment in sun-shade transitions have already shown a substantial productivity increase in field trials. Here, we explore means to further accelerate these adjustments and minimize these losses through transgenic manipulation, gene editing, and exploitation of natural variation. Measurement andanalysis of photosynthesis in sun-shade and shade-sun transitions are explained. Factors limiting speeds of adjustment and how they could be modified to effect improved efficiency are reviewed, specifically nonphotochemical quenching (NPQ), Rubisco activation, and stomatal responses.
Collapse
Affiliation(s)
- Stephen P Long
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA;
- Departments of Plant Biology and Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Lancaster Environment Centre, Lancaster University, Lancaster, United Kingdom
| | - Samuel H Taylor
- Lancaster Environment Centre, Lancaster University, Lancaster, United Kingdom
| | - Steven J Burgess
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA;
| | | | - Tracy Lawson
- School of Life Sciences, University of Essex, Colchester, United Kingdom
| | - Amanda P De Souza
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA;
| | - Lauriebeth Leonelli
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA;
- Department of Agricultural and Biological Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Yu Wang
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA;
| |
Collapse
|
7
|
Zhang L, Li D, Yao Y, Zhang S. H 2O 2, Ca 2+, and K + in subsidiary cells of maize leaves are involved in regulatory signaling of stomatal movement. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2020; 152:243-251. [PMID: 32449683 DOI: 10.1016/j.plaphy.2020.04.045] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 04/11/2020] [Accepted: 04/30/2020] [Indexed: 06/11/2023]
Abstract
The stomata of maize (Zea mays) contain a pair of guard cells and a pair of subsidiary cells. To determine whether H2O2, Ca2+, and K+ in subsidiary cells were involved in stomatal movement, we treated four-week-old maize (Zhengdan 958) leaves with H2O2, diphenylene iodonium (DPI), CaCl2, and LaCl3. Changes in content and distribution of H2O2, Ca2+, and K+ during stomatal movement were observed. When exogenous H2O2 was applied, Ca2+ increased and K+ decreased in guard cells, while both ions increased in subsidiary cells, leading to stomatal closure. After DPI treatment, Ca2+ decreased and K+ increased in guard cells, but both Ca2+ and K+ decreased in subsidiary cells, resulting in open stomata. Exogenous CaCl2 increased H2O2 and reduced K+ in guard cells, while significantly increasing them in subsidiary cells and causing stomatal closure. After LaCl3 treatment, H2O2 decreased and K+ increased in guard cells, whereas both decreased in subsidiary cells and stomata became open. Results indicate that H2O2 and Ca2+ correlate positively with each other and with K+ in subsidiary cells during stomatal movement. Both H2O2 and Ca2+ in subsidiary cells promote an inflow of K+, indirectly regulating stomatal closure.
Collapse
Affiliation(s)
- Li Zhang
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, Shaanxi, 712100, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Dongyang Li
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, China
| | - Yaqin Yao
- College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, China.
| | - Suiqi Zhang
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, Shaanxi, 712100, China; State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling, Shaanxi, 712100, China.
| |
Collapse
|
8
|
Abstract
The control of gaseous exchange between the leaf and external atmosphere is governed by stomatal conductance (gs); therefore, stomata play a critical role in photosynthesis and transpiration and overall plant productivity. Stomatal conductance is determined by both anatomical features and behavioral characteristics. Here we review some of the osmoregulatory pathways in guard cell metabolism, genes and signals that determine stomatal function and patterning, and the recent work that explores coordination between gs and carbon assimilation (A) and the influence of spatial distribution of functional stomata on underlying mesophyll anatomy. We also evaluate the current literature on mesophyll-driven signals that may coordinate stomatal behavior with mesophyll carbon assimilation and explore stomatal kinetics as a possible target to improve A and water use efficiency. By understanding these processes, we can start to provide insight into manipulation of these regulatory pathways to improve stomatal behavior and identify novel unexploited targets for altering stomatal behavior and improving crop plant productivity.
Collapse
Affiliation(s)
- Tracy Lawson
- School of Life Science, University of Essex, Colchester CO4 3SQ, United Kingdom;
| | - Jack Matthews
- School of Life Science, University of Essex, Colchester CO4 3SQ, United Kingdom;
| |
Collapse
|
9
|
Nunes TDG, Zhang D, Raissig MT. Form, development and function of grass stomata. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 101:780-799. [PMID: 31571301 DOI: 10.1111/tpj.14552] [Citation(s) in RCA: 81] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 09/13/2019] [Accepted: 09/17/2019] [Indexed: 05/20/2023]
Abstract
Stomata are cellular breathing pores on leaves that open and close to absorb photosynthetic carbon dioxide and to restrict water loss through transpiration, respectively. Grasses (Poaceae) form morphologically innovative stomata, which consist of two dumbbell-shaped guard cells flanked by two lateral subsidiary cells (SCs). This 'graminoid' morphology is associated with faster stomatal movements leading to more water-efficient gas exchange in changing environments. Here, we offer a genetic and mechanistic perspective on the unique graminoid form of grass stomata and the developmental innovations during stomatal cell lineage initiation, recruitment of SCs and stomatal morphogenesis. Furthermore, the functional consequences of the four-celled, graminoid stomatal morphology are summarized. We compile the identified players relevant for stomatal opening and closing in grasses, and discuss possible mechanisms leading to cell-type-specific regulation of osmotic potential and turgor. In conclusion, we propose that the investigation of functionally superior grass stomata might reveal routes to improve water-stress resilience of agriculturally relevant plants in a changing climate.
Collapse
Affiliation(s)
- Tiago D G Nunes
- Centre for Organismal Studies Heidelberg, Heidelberg University, 69120, Heidelberg, Germany
| | - Dan Zhang
- Centre for Organismal Studies Heidelberg, Heidelberg University, 69120, Heidelberg, Germany
| | - Michael T Raissig
- Centre for Organismal Studies Heidelberg, Heidelberg University, 69120, Heidelberg, Germany
| |
Collapse
|
10
|
Gray A, Liu L, Facette M. Flanking Support: How Subsidiary Cells Contribute to Stomatal Form and Function. FRONTIERS IN PLANT SCIENCE 2020; 11:881. [PMID: 32714346 PMCID: PMC7343895 DOI: 10.3389/fpls.2020.00881] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Accepted: 05/29/2020] [Indexed: 05/18/2023]
Abstract
Few evolutionary adaptations in plants were so critical as the stomatal complex. This structure allows transpiration and efficient gas exchange with the atmosphere. Plants have evolved numerous distinct stomatal architectures to facilitate gas exchange, while balancing water loss and protection from pathogens that can egress via the stomatal pore. Some plants have simple stomata composed of two kidney-shaped guard cells; however, the stomatal apparatus of many plants includes subsidiary cells. Guard cells and subsidiary cells may originate from a single cell lineage, or subsidiary cells may be recruited from cells adjacent to the guard mother cell. The number and morphology of subsidiary cells varies dramatically, and subsidiary cell function is also varied. Subsidiary cells may support guard cell function by offering a mechanical advantage that facilitates guard cell movements, and/or by acting as a reservoir for water and ions. In other cases, subsidiary cells introduce or enhance certain morphologies (such as sunken stomata) that affect gas exchange. Here we review the diversity of stomatal morphology with an emphasis on multi-cellular stomata that include subsidiary cells. We will discuss how subsidiary cells arise and the divisions that produce them; and provide examples of anatomical, mechanical and biochemical consequences of subsidiary cells on stomatal function.
Collapse
|
11
|
Gao YQ, Wu WH, Wang Y. Electrophysiological Identification and Activity Analyses of Plasma Membrane K+ Channels in Maize Guard Cells. PLANT & CELL PHYSIOLOGY 2019; 60:765-777. [PMID: 30590755 DOI: 10.1093/pcp/pcy242] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2017] [Accepted: 12/19/2018] [Indexed: 05/11/2023]
Abstract
Stomatal movement, which plays an essential role in plant transpiration and photosynthesis, is controlled by ion channels that mediate K+ and anion fluxes across the plasma membrane (PM) of guard cells. These channels in dicots are accurately regulated by various physiological factors, such as pH, abscisic acid (ABA) and Ca2+; however, the data in monocots are limited. Here the whole-cell patch-clamping technique was applied to analyze the properties and regulations of PM K+ channels in maize guard cells. The results indicated that the hyperpolarization-activated inward-rectifying channels were highly K+-selective. These inward K+ (Kin) channels were sensitive to extracellular K+. Their slope factor (S) decreased when the apoplastic K+ concentration decline, causing a positive shift of the half-activation potential (V1/2). Their activities were promoted by apoplastic acidification but inhibited by apoplastic and cytosolic alkalization. Nevertheless, the outward K+ (Kout) channel activities were uniquely promoted by cytosolic alkalization. Both apoplastic and cytosolic ABA inhibited Kin channels independent of cytosolic Ca2+ ([Ca2+]cyt). And two Ca2+-dependent mechanisms with different Ca2+ affinities may mediate resting- and high-[Ca2+]cyt-induced inhibition on Kin channels, respectively. However, resting [Ca2+]cyt impaired the inhibition of Kin channels induced by apoplastic ABA, not cytosolic ABA. Furthermore, the result that high [Ca2+]cyt attenuated ABA-induced inhibition highlighted the importance of [Ca2+]cyt for Kin channel regulation. There may exist a Ca2+-dependent regulation of the Ca2+-independent ABA signaling pathways for Kin channel inhibition. These results provided an electrophysiological view of the multiple level regulations of PM K+ channel activities and kinetics in maize guard cells.
Collapse
Affiliation(s)
- Yong-Qiang Gao
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, China
- Center for Crop Functional Genomics and Molecular Breeding, China Agricultural University, Beijing, China
| | - Wei-Hua Wu
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, China
- Center for Crop Functional Genomics and Molecular Breeding, China Agricultural University, Beijing, China
| | - Yi Wang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, China
- Center for Crop Functional Genomics and Molecular Breeding, China Agricultural University, Beijing, China
| |
Collapse
|
12
|
Yao Y, Liu X, Li Z, Ma X, Rennenberg H, Wang X, Li H. Drought-induced H2O 2 accumulation in subsidiary cells is involved in regulatory signaling of stomatal closure in maize leaves. PLANTA 2013; 238:217-27. [PMID: 23625015 DOI: 10.1007/s00425-013-1886-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2012] [Accepted: 04/15/2013] [Indexed: 05/23/2023]
Abstract
Increasing H2O2 levels in guard cells in response to environmental stimuli are recently considered a general messenger involved in the signaling cascade for the induction of stomatal closure. But little is known as to whether subsidiary cells participate in the H2O2-mediated stomatal closure of grass plants. In the present study, 2-week-old seedlings of maize (Zea mays) were exposed to different degrees of soil water deficit for 3 weeks. The effects of soil water contents on leaf ABA and H2O2 levels and stomatal aperture were investigated using physiological, biochemical, and histochemical approaches. The results showed that even under well-watered conditions, significant amounts of H2O2 were observed in guard cells, whereas H2O2 concentrations in the subsidiary cells were negligible. Decreasing soil water contents led to a significant increase in leaf ABA levels associated with significantly enhanced O2 (-) and H2O2 contents, consistent with reduced degrees of stomatal conductance and aperture. The significant increase in H2O2 appeared in both guard cells and subsidiary cells of the stomatal complex, and H2O2 levels increased with decreasing soil water contents. Drought-induced increase in the activity of antioxidative enzymes could not counteract the significant increase in H2O2 levels in guard cells and subsidiary cells. These results indicate that subsidiary cells participate in H2O2-mediated stomatal closure, and drought-induced H2O2 accumulation in subsidiary cells is involved in the signaling cascade regulating stomatal aperture of grass plants such as maize.
Collapse
Affiliation(s)
- Yaqin Yao
- College of Life Science, Northwest A&F University, Yangling, Shaanxi, China
| | | | | | | | | | | | | |
Collapse
|
13
|
Haji A. Bu MAA, Ahmad R, Iqbal J, Maqbool MM, Ali A, Ishaque M, Hussain S. Nutritional and Physiological Significance of Potassium Application in Maize Hybrid Crop Production. ACTA ACUST UNITED AC 2012. [DOI: 10.3923/pjn.2012.187.202] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
14
|
Mumm P, Wolf T, Fromm J, Roelfsema MRG, Marten I. Cell type-specific regulation of ion channels within the maize stomatal complex. PLANT & CELL PHYSIOLOGY 2011; 52:1365-75. [PMID: 21690176 DOI: 10.1093/pcp/pcr082] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The stomatal complex of Zea mays is composed of two pore-forming guard cells and two adjacent subsidiary cells. For stomatal movement, potassium ions and anions are thought to shuttle between these two cell types. As potential cation transport pathways, K(+)-selective channels have already been identified and characterized in subsidiary cells and guard cells. However, so far the nature and regulation of anion channels in these cell types have remained unclear. In order to bridge this gap, we performed patch-clamp experiments with subsidiary cell and guard cell protoplasts. Voltage-independent anion channels were identified in both cell types which, surprisingly, exhibited different, cell-type specific dependencies on cytosolic Ca(2+) and pH. After impaling subsidiary cells of intact maize plants with microelectrodes and loading with BCECF [(2',7'-bis-(2-carboxyethyl)-5(and6)carboxyflurescein] as a fluorescent pH indicator, the regulation of ion channels by the cytosolic pH and the membrane voltage was further examined. Stomatal closure was found to be accompanied by an initial hyperpolarization and cytosolic acidification of subsidiary cells, while opposite responses were observed during stomatal opening. Our findings suggest that specific changes in membrane potential and cytosolic pH are likely to play a role in determining the direction and capacity of ion transport in subsidiary cells.
Collapse
Affiliation(s)
- Patrick Mumm
- University of Würzburg, Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute, Julius-von-Sachs-Platz 2, D-97082 Würzburg, Germany
| | | | | | | | | |
Collapse
|
15
|
Visnovitz T, Világi I, Varró P, Kristóf Z. Mechanoreceptor Cells on the Tertiary Pulvini of Mimosa pudica L. PLANT SIGNALING & BEHAVIOR 2007; 2:462-6. [PMID: 19517007 PMCID: PMC2634336 DOI: 10.4161/psb.2.6.4743] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2007] [Accepted: 07/13/2007] [Indexed: 05/12/2023]
Abstract
Special red cells were found on the adaxial surface of tertiary pulvini of Mimosa pudica and experiments performed to determine the origin and function of these cells. Using anatomical (light, scanning electron and transmission electron microscopy) and electrophysiological techniques, we have demonstrated that these red cells are real mechanoreceptor cells. They can generate receptor potential following mechanical stimuli and they are in connection with excitable motor cells (through plasmodesmata). We also provide evidence that these red cells are derived from stomatal subsidiary cells and not guard cells. As histochemical studies show red cells contain tannin, which is important in development of action potentials and movements of plants. These cells could be one of unidentified mechanoreceptors of mimosa.
Collapse
Affiliation(s)
- Tamás Visnovitz
- Department of Plant Physiology and Molecular Plant Biology; Institute of Biology; Faculty of Sciences; Eötvös Loránd University; Budapest, Hungary
| | - Ildikó Világi
- Department of Physiology and Neurobiology; Institute of Biology; Faculty of Sciences; Eötvös Loránd University; Budapest, Hungary
| | - Petra Varró
- Department of Physiology and Neurobiology; Institute of Biology; Faculty of Sciences; Eötvös Loránd University; Budapest, Hungary
| | - Zoltán Kristóf
- Department of Plant Anatomy; Institute of Biology; Faculty of Sciences; Eötvös Loránd University; Budapest, Hungary
| |
Collapse
|
16
|
Wolf T, Heidelmann T, Marten I. ABA regulation of K(+)-permeable channels in maize subsidiary cells. PLANT & CELL PHYSIOLOGY 2006; 47:1372-80. [PMID: 16973684 DOI: 10.1093/pcp/pcl007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
An antiparallel-directed potassium transport between subsidiary cells and guard cells which form the graminean stomatal complex has been proposed to drive stomatal movements in maize. To gain insights into the coordinated shuttling of K(+) ions between these cell types during stomatal closure, the effect of ABA on the time-dependent K(+) uptake and K(+) release channels as well as on the instantaneously activating non-selective cation channels (MgC) was examined in subsidiary cells. Patch-clamp studies revealed that ABA did not affect the MgC channels but differentially regulated the time-dependent K(+) channels. ABA caused a pronounced rise in time-dependent outward-rectifying K(+) currents (K(out)) at alkaline pH and decreased inward-rectifying K(+) currents (K(in)) in a Ca(2+)-dependent manner. Our results show that the ABA-induced changes in time-dependent K(in) and K(out) currents from subsidiary cells are very similar to those previously described for guard cells. Thus, the direction of K(+) transport in subsidiary cells and guard cells during ABA-induced closure does not seem to be grounded solely on the cell type-specific ABA regulation of K(+) channels.
Collapse
Affiliation(s)
- Thomas Wolf
- University of Wuerzburg, Molecular Plant Physiology and Biophysics, Julius-von-Sachs Institute for Bioscience, Julius-von-Sachs-Platz 2, D-97082 Wuerzburg, Germany
| | | | | |
Collapse
|
17
|
Büchsenschütz K, Marten I, Becker D, Philippar K, Ache P, Hedrich R. Differential expression of K+ channels between guard cells and subsidiary cells within the maize stomatal complex. PLANTA 2005; 222:968-76. [PMID: 16021501 DOI: 10.1007/s00425-005-0038-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2005] [Accepted: 05/31/2005] [Indexed: 05/03/2023]
Abstract
Grass stomata are characterized by dumbbell-shaped guard cells forming a complex with a pair of specialized epidermal cells, the subsidiary cells. Stomatal movement is accomplished by a reversible exchange of potassium and chloride between these two cell types. To gain insight into the molecular machinery involved in K+ transport within the stomatal complex of Zea mays, we determined the spatial and temporal expression pattern of potassium channels in the maize leaf. KZM2 and ZORK were isolated and identified as new members of the plant Shaker K+ channel family. Northern blot analysis identified fully developed leaves as the predominant site of KZM2 expression. Following enzymatic digestion and separation of leaf tissue into epidermal, mesophyll, and vascular fractions, KZM2 and ZORK transcripts were localized in the epidermis. Using a collection of individually isolated guard cell or subsidiary cell protoplasts, ZORK transcripts were found in both cell types while KZM2 was exclusively expressed in the guard cell population. The previously identified K+ channel genes ZMK1 and KZM1 were expressed in subsidiary cells and guard cells, respectively, whereas ZMK2 transcripts were not detected. These data indicate that the interaction between subsidiary cells and guard cells is based on overlapping as well as differential expression of K+ channels in the two cell types of the maize stomatal complex.
Collapse
Affiliation(s)
- Kai Büchsenschütz
- Molecular Plant Physiology and Biophysics, Julius-von-Sachs Institute for Bioscience, University of Wuerzburg, Julius-von-Sachs-Platz 2, 97082, Wuerzburg, Germany
| | | | | | | | | | | |
Collapse
|
18
|
Wolf T, Guinot DR, Hedrich R, Dietrich P, Marten I. Nucleotides and Mg2+ ions differentially regulate K+ channels and non-selective cation channels present in cells forming the stomatal complex. PLANT & CELL PHYSIOLOGY 2005; 46:1682-9. [PMID: 16081526 DOI: 10.1093/pcp/pci184] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Voltage-dependent inward-rectifying (K(in)) and outward-rectifying (K(out)) K(+) channels are capable of mediating K(+) fluxes across the plasma membrane. Previous studies on guard cells or heterologously expressed K(+) channels provided evidence for the requirement of ATP to maintain K(+) channel activity. Here, the nucleotide and Mg(2+) dependencies of time-dependent K(in) and K(out) channels from maize subsidiary cells were examined, showing that MgATP as well as MgADP function as channel activators. In addition to K(out) channels, these studies revealed the presence of another outward-rectifying channel type (MgC) in the plasma membrane that however gates in a nucleotide-independent manner. MgC represents a new channel type distinguished from K(out) channels by fast activation kinetics, inhibition by elevated intracellular Mg(2+) concentration, permeability for K(+) as well as for Na(+) and insensitivity towards TEA(+). Similar observations made for guard cells from Zea mays and Vicia faba suggest a conserved regulation of channel-mediated K(+) and Na(+) transport in both cell types and species.
Collapse
Affiliation(s)
- Thomas Wolf
- Molecular Plant Physiology and Biophysics, Julius-von-Sachs Institute for Bioscience, University of Wuerzburg, Germany
| | | | | | | | | |
Collapse
|
19
|
Philippar K, Büchsenschutz K, Abshagen M, Fuchs I, Geiger D, Lacombe B, Hedrich R. The K+ channel KZM1 mediates potassium uptake into the phloem and guard cells of the C4 grass Zea mays. J Biol Chem 2003; 278:16973-81. [PMID: 12611901 DOI: 10.1074/jbc.m212720200] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In search of K(+) channel genes expressed in the leaf of the C(4) plant Zea mays, we isolated the cDNA of KZM1 (for K(+) channel Zea mays 1). KZM1 showed highest similarity to the Arabidopsis K(+) channels KAT1 and KAT2, which are localized in guard cells and phloem. When expressed in Xenopus oocytes, KZM1 exhibited the characteristic features of an inward-rectifying, potassium-selective channel. In contrast to KAT1- and KAT2-type K(+) channels, however, KZM1 currents were insensitive to external pH changes. Northern blot analyses identified the leaf, nodes, and silks as sites of KZM1 expression. Following the separation of maize leaves into epidermal, mesophyll, and vascular fractions, quantitative real-time reverse transcriptase-PCR allowed us to localize KZM1 transcripts predominantly in vascular strands and the epidermis. Cell tissue separation and KZM1 localization were followed with marker genes such as the bundle sheath-specific ribulose-1,5-bisphosphate carboxylase, the phloem K(+) channel ZMK2, and the putative sucrose transporter ZmSUT1. When expressed in Xenopus oocytes, ZmSUT1 mediated proton-coupled sucrose symport. Coexpression of ZmSUT1 with the phloem K(+) channels KZM1 and ZMK2 revealed that ZMK2 is able to stabilize the membrane potential during phloem loading/unloading processes and KZM1 to mediate K(+) uptake. During leaf development, sink-source transitions, and diurnal changes, KZM1 is constitutively expressed, pointing to a housekeeping function of this channel in K(+) homeostasis of the maize leaf. Therefore, the voltage-dependent K(+)-uptake channel KZM1 seems to mediate K(+) retrieval and K(+) loading into the phloem as well as K(+)-dependent stomatal opening.
Collapse
Affiliation(s)
- Katrin Philippar
- Julius-von-Sachs-Institut, Lehrstuhl Molekulare Pflanzenphysiologie und Biophysik, Universität Würzburg, Julius-von-Sachs-Platz 2, D-97082 Würzburg, Germany
| | | | | | | | | | | | | |
Collapse
|