Hannes Kollist

Hannes Kollist
University of Tartu · Institute of Technology

About

108
Publications
21,640
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
6,459
Citations

Publications

Publications (108)
Article
Full-text available
Plant cells can be distinguished from animal cells by their cell walls and high-turgor pressure. Although changes in turgor and the stiffness of cell walls seem coordinated, we know little about the mechanism responsible for coordination. Evidence has accumulated that plants, like yeast, have a dedicated cell wall integrity maintenance mechanism. I...
Article
Full-text available
Plant stress signalling involves bursts of reactive oxygen species (ROS), which can be mimicked by the application of acute pulses of ozone (O3). Such O3‐pulses inhibit photosynthesis and trigger stomatal closure in a few minutes, but the signalling that underlies these responses remains largely unknown. We measured changes in Arabidopsis thaliana...
Article
Biological processes are highly dynamic, and during plant growth, development, and environmental interactions, they occur and influence each other on diverse spatiotemporal scales. Understanding plant physiology on an organismic scale requires analyzing biological processes from various perspectives, down to the cellular and molecular levels. Ideal...
Preprint
Full-text available
Plant cells can be distinguished from animal cells by their cell walls and high turgor pressure. Although changes in turgor and stiffness of cell walls seem coordinated, we know little about the mechanism responsible for coordination. Evidence has accumulated that plants, like yeast, have a dedicated cell wall integrity maintenance mechanism. This...
Article
Full-text available
Jasmonic acid (JA) and salicylic acid (SA) regulate stomatal closure, preventing pathogen invasion into plants. However, to which extent abscisic acid (ABA), SA, and JA interact and what the roles of SA and JA are in stomatal responses to environmental cues remains unclear. Here, by using intact plant gas-exchange measurements in JA and SA single a...
Preprint
Stomatal pores, formed of paired guard cells, mediate CO 2 uptake for photosynthesis and water loss via transpiration in plants. Globally rising atmospheric CO 2 concentration triggers stomatal closure, contributing to increased leaf temperature and reduced nutrient uptake due to lower transpiration rate. Hence, it is important to understand the si...
Article
Initiation of stomatal closure by various stimuli requires activation of guard cell plasma membrane anion channels, which are defined as rapid (R)- and slow (S)-type. The single-gene loss-of-function mutants of these proteins are well characterized. However, the impact of suppressing both the S- and R-type channels has not been studied. Here, by ge...
Article
Full-text available
Tropospheric ozone (O3) is a major air pollutant that decreases yield of important crops worldwide. Despite long-lasting research of its negative effects on plants, there are many gaps in our knowledge on how plants respond to O3. In this study, we used natural variation in the model plant Arabidopsis (Arabidopsis thaliana) to characterize molecula...
Article
Low concentrations of CO2 cause stomatal opening, whereas [CO2] elevation leads to stomatal closure. Classical studies have suggested a role for Ca²⁺ and protein phosphorylation in CO2-induced stomatal closing. Calcium-dependent protein kinases (CPKs) and calcineurin-B-like proteins (CBLs) can sense and translate cytosolic elevation of the second m...
Preprint
Full-text available
Guard cells regulate plant gas exchange by controlling the aperture of stomatal pores. Stomatal closure involves a multi-input signaling network that governs the activity of ion channels, which in turn regulate guard cell turgor pressure and volume. We describe a forward genetic screen to identify novel components involved in stomatal movements. Th...
Article
Full-text available
Sucrose-non-fermenting-1-related protein kinase-2s (SnRK2s) are critical for plant abiotic stress responses, including abscisic acid (ABA) signaling. Here, we develop a genetically encoded reporter for SnRK2 kinase activity. This sensor, named SNACS, shows an increase in the ratio of yellow to cyan fluorescence emission by OST1/SnRK2.6-mediated pho...
Article
Full-text available
Sucrose-non-fermenting-1-related protein kinase-2s (SnRK2s) are critical for plant abiotic stress responses, including abscisic acid (ABA) signaling. Here, we develop a genetically encoded reporter for SnRK2 kinase activity. This sensor, named SNACS, shows an increase in the ratio of yellow to cyan fluorescence emission by OST1/SnRK2.6-mediated pho...
Article
Full-text available
Sucrose-non-fermenting-1-related protein kinase-2s (SnRK2s) are critical for plant abiotic stress responses, including abscisic acid (ABA) signaling. Here, we develop a genetically encoded reporter for SnRK2 kinase activity. This sensor, named SNACS, shows an increase in the ratio of yellow to cyan fluorescence emission by OST1/SnRK2.6-mediated pho...
Article
Full-text available
Upon recognition of microbes, pattern-recognition receptors (PRRs) activate pattern-triggered immunity (PTI). FLAGELLIN SENSING2 (FLS2) and BRASSINOSTEROID INSENSITIVE1-ASSOCIATED KINASE1 (BAK1) form a typical PRR complex that senses bacteria. Here we report that the kinase activity of the malectin-like receptor-like kinase STRESS INDUCED FACTOR 2...
Article
Full-text available
Background and aims: The stomatal conductance (gs) of most plant species decreases in response to elevated atmospheric CO2 concentration. This response could have a significant impact on plant water use in a future climate. However, the regulation of the CO2-induced stomatal closure response is not fully understood. Moreover, the potential genetic...
Article
Full-text available
Strigolactones are a group of phytohormones that control developmental processes including shoot branching and various plant–environment interactions in plants. We previously showed that the strigolactone perception mutant more axillary branches 2 (max2) has increased susceptibility to plant pathogenic bacteria. Here we show that both strigolactone...
Article
Full-text available
Land plants are considered monophyletic, descending from a single successful colonization of land by an aquatic algal ancestor. The ability to survive dehydration to the point of desiccation is a key adaptive trait enabling terrestrialization. In extant land plants, desiccation tolerance depends on the action of the hormone abscisic acid (ABA) that...
Article
Full-text available
Stomata are microscopic pores found on the surfaces of leaves that act to control CO2 uptake and water loss. By integrating information derived from endogenous signals with cues from the surrounding environment, the guard cells, which surround the pore, ‘set’ the stomatal aperture to suit the prevailing conditions. Much research has concentrated on...
Article
Full-text available
During drought, abscisic acid (ABA) induces closure of stomata via a signaling pathway that involves the Ca2+‐independent protein kinase OST1, as well as Ca2+‐dependent protein kinases (CPKs). However, the interconnection between OST1 and Ca2+ signaling in ABA‐induced stomatal closure has not been fully resolved. ABA‐induced Ca2+ signals were monit...
Preprint
Full-text available
The phytohormone strigolactone controls branching in Arabidopsis thaliana, but in recent years it has been shown to also affect many other plant functions. We previously showed that the strigolactone perception mutant max2 has increased susceptibility to plant pathogenic bacteria as a result of increased stomatal conductance as well as alterations...
Article
Plants must continually balance the influx of CO2 for photosynthesis against the loss of water vapor through stomatal pores in their leaves. This balance can be achieved by controlling the aperture of the stomatal pores in response to several environmental stimuli. Elevation in atmospheric [CO2] induces stomatal closure and further impacts leaf tem...
Article
Full-text available
Plants grow and reproduce within a highly dynamic environment that can see abrupt changes in conditions, such as light intensity, temperature, humidity, or interactions with biotic agents. Recent studies revealed that plants can respond within seconds to some of these conditions, engaging many different metabolic and molecular networks, as well as...
Article
Full-text available
Guard cells control the aperture of stomatal pores to balance photosynthetic carbon dioxide uptake with evaporative water loss. Stomatal closure is triggered by several stimuli that initiate complex signaling networks to govern the activity of ion channels. Activation of SLOW ANION CHANNEL1 (SLAC1) is central to the process of stomatal closure and...
Article
Guard cells control the aperture of stomatal pores to balance photosynthetic carbon dioxide uptake with evaporative water loss. Stomatal closure is triggered by several stimuli that initiate complex signaling networks to govern the activity of ion channels. Activation of SLOW ANION CHANNEL1 (SLAC1) is central to the process of stomatal closure and...
Article
Stomatal pore apertures are narrowing globally due to the continuing rise in atmospheric [CO2]. CO2 elevation and the plant hormone abscisic acid (ABA) both induce rapid stomatal closure. However, the underlying signal transduction mechanisms for CO2/ABA interaction remain unclear. Two models have been considered: (i) CO2 elevation enhances ABA con...
Article
Respiration in leaves and the continued elevation in the atmospheric CO2 concentration cause CO2‐mediated reduction in stomatal pore apertures. Several mutants have been isolated for which stomatal responses to both abscisic acid (ABA) and CO2 are simultaneously defective. However, there are only few mutations that impair the stomatal response to e...
Article
Full-text available
Stomata, small pores on the surfaces of leaves formed by a pair of guard cells, adapt rapidly to changes in the environment by adjusting the aperture width. As a long‐term response, the number of stomata is regulated during stomatal development. The hormone abscisic acid (ABA) regulates both processes. In ABA mediated guard cell signaling the prote...
Preprint
Stomata, small pores on the surfaces of leaves formed by a pair of guard cells, adapt rapidly to changes in the environment by adjusting the aperture width. As a long term response, the number of stomata is regulated during stomatal development. The hormone abscisic acid (ABA) regulates both processes. In ABA mediated guard cell signaling the prote...
Article
Optimization between photosynthetic carbon assimilation and stomatal water loss is the key in order to breed crops for future climate. We analyzed stomatal conductance (gs), CO 2 assimilation rate (Anet), fungal diseases, grain yield and yield components of seven European malting barley genotypes treated with fungicides alone or together with biost...
Article
The atmospheric pollutant ozone (O3) is a strong oxidant that causes extracellular reactive oxygen species (ROS) formation, has significant ecological relevance, and is used here as a non-invasive ROS inducer to study plant signalling. Previous genetic screens identified several mutants exhibiting enhanced O3-sensitivity, but few with enhanced tole...
Article
Full-text available
Guard cells shrink and close stomatal pores when air humidity decreases (i.e. when the difference between the vapor pressures of leaf and atmosphere [VPD] increases). The role of abscisic acid (ABA) in VPD-induced stomatal closure has been studied using ABA-related mutants that respond to VPD in some studies and not in others. The importance of ABA...
Article
Significance: Stomata can sense the intercellular CO2 concentration (Ci) and water availability and adjust their aperture in order to maintain optimal conditions to photosynthesis under changing environmental conditions. Stomatal movements are regulated by complex network of signaling cascades where reactive oxygen species (ROS) play a key role as...
Article
Full-text available
Guard cells shrink and close stomatal pores when air humidity decreases, i.e. when the difference between the vapor pressures of leaf and atmosphere (VPD) increases. The role of abscisic acid (ABA) in VPD-induced stomatal closure has been studied using ABA-related mutants that respond to VPD in some studies and not in others. The importance of ABA...
Article
Full-text available
Increasing drought and diminishing freshwater supplies have stimulated interest in developing chemicals that can be used to control transpiration. Receptors for the plant hormone abscisic acid (ABA) have emerged as key targets for this application, because ABA controls the apertures of stomata, which in turn regulate transpiration. Here we describe...
Article
Full-text available
Changing atmospheric CO2 levels, climate and air humidity affect plant gas exchange that is controlled by stomata, small pores on plant leaves and stems formed by guard cells. Evolution has shaped the morphology and regulatory mechanisms governing stomatal movements to correspond to the needs of various land plant groups over the past 400 million y...
Article
Proper stomatal responses are essential for plant function in an altered environment. The core signaling pathway for abscisic acid (ABA)-induced stomatal closure involves perception of the hormone that leads to the activation of guard cell anion channels by the protein kinase OPEN STOMATA1 (OST1). Several other regulators are suggested to modulate...
Article
Full-text available
Author Summary Human activities have increased the concentrations of CO2 and harmful air pollutants such as ozone in the troposphere. These changes can have detrimental consequences for agricultural productivity. Guard cells, which form stomatal pores on leaves, regulate plant gas exchange. To maintain photosynthesis, stomata open to allow CO2 upta...
Data
MPK12 interacts with HT1 and IBR5. Split-ubiquitin yeast two-hybrid assays with MPK12 and different versions of MPK12 with amino acid substitutions; MPK12 G53R with the same point mutation as in Cvi-0, MPK12 K70R kinase inactive version, MPK12 Y122C and MPK12 D196G, E200A constitutively active kinase versions. (A) Yeast growth observed on SD-leu-tr...
Data
RT-PCR analysis of full length MPK12 transcript in Col-0, mpk12-3, and mpk12-4 plants. ACTIN2 was amplified as a control. (TIF)
Data
Stable expression of YFP-labelled MPK12 in intact leaves of Arabidopsis thaliana and transient expression in leaves of Nicotiana benthamiana. Expression of MPK12-YFP (A) and MPK12 G53R-YFP (B) under native MPK12 promoter in A. thaliana Col-0. Transient expression under the CaMV35S promoter was also shown for MPK12-YFP (C) and MPK12 G53R-YFP in N. b...
Data
Identification of Col-S2 and cis mutation. (A) Ion leakage after 6 h of ozone exposure (350 ppb ozone). Experiment was repeated three times (mean ± SD; 1-way ANOVA of ozone treated plants). (B) Scheme of mapping the ozone sensitive trait of Col-S2. (C) CO2-induced changes in stomatal conductance in cas mutants (mean ± SEM; n = 5–6 plants). (D) Mapp...
Data
Stomatal index, length, and density in mpk12. (A) Stomatal index of studied lines (mean ± SEM; 1-way ANOVA, Tukey HSD post hoc test). Experiment was repeated twice (n = 81–84 plants). (B) Stomatal complex length of mpk12 lines (mean ± SEM; 1-way ANOVA). Sample size was 4–6 plants, altogether 84–126 stomatal complexes per line were measured. (C) Sto...
Data
Mutations in MPK12 are causing impaired CO2-responses in both cas-2 and gdsl3-1 mutants. (A) The originally described T-DNA insertions were confirmed in cas-2 and gdsl3-1 (GABI_492D11) plants by genotyping analyses. PCR product for the CAS gene was amplified by primers CASLP and CASRP. PCR product for the cas-2 insert was amplified by primers CASRP...
Data
Time-dependent changes in stomatal conductance. Various stimuli were applied as indicated by the bars or arrows in the legends of each panel. Stomatal opening induced by 100 ppm CO2 (A) and 50 μmol m-2s-1 blue light (B). ABA inhibited light-induced stomatal opening (C). Stomatal closure in response to darkness (D), 800 ppm CO2 (E), decrease in air...
Data
Deletion of MPK12 did not affect ABA-induced stomatal closure. The stomata in the MPK12 deletion mutant mpk12-4 closed after treatment with 10 μM ABA for 30 min, similar as in wild type. Data are average of 3 experiments, 10 stomata per experiment and condition. Small letters denote statistically significant differences according to 2-way ANOVA wit...
Data
MPK11 does not inhibit the activity of HT1. MPK11, an MPK from the same group as MPK12, was not able to inhibit HT1 showing that not all the Arabidopsis MPKs are inhibitors of HT1. This experiment was repeated four times. (TIF)
Data
Primers used in this study. (DOCX)
Data
Raw data for all figures and supplemental figures. (XLSX)
Data
A time course of Col-0, Cvi-0, Col-S and Cvi-T exposed to 350 ppb ozone. (WMV)
Article
Activation of the guard cell S-type anion channel SLAC1 is important for stomatal closure in response to diverse stimuli, including elevated CO2. The majority of known SLAC1 activation mechanisms depend on abscisic acid (ABA) signaling. Several lines of evidence point to a parallel ABA-independent mechanism of CO2-induced stomatal regulation; howev...
Preprint
Full-text available
Plant gas exchange is regulated by guard cells that form stomatal pores. Stomatal adjustments are crucial for plant survival; they regulate uptake of CO 2 for photosynthesis, loss of water and entrance of air pollutants such as ozone. We mapped ozone hypersensitivity, more open stomata and stomatal CO 2 -insensitivity phenotypes of the Arabidopsis...
Article
The cuticle plays a critical role in plant survival during extreme drought conditions. There are, however, surprisingly, many gaps in our understanding of cuticle biosynthesis. An Arabidopsis thaliana T-DNA mutant library was screened for mutants with enhanced transpiration using a simple condensation spot method. Five mutants, named cool breath (c...
Article
Full-text available
Stomata regulate the uptake of CO2 and the loss of water vapor [1] and contribute to the control of water-use efficiency [2] in plants. Although the guard-cell-signaling pathway coupling blue light perception to ion channel activity is relatively well understood [3], we know less about the sources of ATP required to drive K+ uptake [3–6]. Here, we...
Data
Movie S1 Movie of stomatal closure induced by nanoinfusion of 20 nM flg22.
Data
Fig. S1 Sensitivity of platinum‐iridium disc electrode to H2O2 production by mesophyll tissue. Fig. S2 Time‐dependent stomatal movement induced by nanoinfusion of control solution, 10 μM ABA, or 20 nM flg22 in selected accessions and mutants.
Article
Full-text available
Linker (H1) histones play critical roles in chromatin compaction in higher eukaryotes. They are also the most variable of the histones, with numerous non-allelic variants co-occurring in the same cell. Plants contain a distinct subclass of minor H1 variants that are induced by drought and ABA, and have been implicated in mediating adaptive response...
Article
Full-text available
Cysteine-rich receptor-like kinases (CRKs) are transmembrane proteins characterized by the presence of two domains of unknown function 26 (DUF26) in their ectodomain. The CRKs form one of the largest groups of receptor-like protein kinases in plants, but their biological functions have so far remained largely uncharacterized. We conducted a large-s...
Article
Full-text available
Cysteine-rich receptor-like kinases (CRKs) are transmembrane proteins characterized by the presence of two domains of unknown function 26 (DUF26) in their ectodomain. The CRKs form one of the largest groups of receptor-like protein kinases in plants, but their biological functions have so far remained largely uncharacterized. We conducted a large-s...
Article
The discovery of cytosolic ABA receptors is an important breakthrough in stomatal research; signaling via these receptors is involved in determining the basal stomatal conductance and stomatal responsiveness. However, the source of ABA in guard cells is still not fully understood. The level of ABA increases in guard cells by de novo synthesis, recy...
Article
Full-text available
During infection plants recognize microbe-associated molecular patterns (MAMPs), and this leads to stomatal closure. This study analyzes the molecular mechanisms underlying this MAMP response and its interrelation with ABA signaling. Stomata in intact Arabidopsis thaliana plants were stimulated with the bacterial MAMP flg22, or the stress hormone A...
Article
Full-text available
The Arabidopsis thaliana F-box protein MORE AXILLARY GROWTH2 (MAX2) has previously been characterized for its role in plant development. MAX2 appears essential for the perception of the newly characterized phytohormone strigolactone, a negative regulator of polar auxin transport in Arabidopsis. A reverse genetic screen for F-box protein mutants alt...
Article
Background: The Arabidopsis thaliana F-box protein MORE AXILLARY GROWTH2 (MAX2) has previously been characterized for its role in plant development. MAX2 appears essential for the perception of the newly characterized phytohormone strigolactone, a negative regulator of polar auxin transport in Arabidopsis. Results: A reverse genetic screen for F-bo...
Article
Contents 'Summary'I.II.III.IV.V. ReferencesSummaryStomata are an attractive experimental system in plant biology, because the responses of guard cells to environmental signals can be directly linked to changes in the aperture of stomatal pores. In this review, the mechanics of stomatal movement are discussed in relation to ion transport in guard ce...