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1.
Plants (Basel) ; 10(11)2021 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-34834689

RESUMO

Potassium (K) is a crucial element of plant nutrition, involved in many physiological and molecular processes. K+ membrane transporters are playing a pivotal role in K+ transport and tissue distribution as well as in various plant stress responses and developmental processes. Two-pore K+-channels (TPKs) are essential to maintain plant K+ homeostasis and are mainly involved in potassium transport from the vacuoles to the cytosol. Besides vacuolar specialization, some TPK members display different membrane localization including plasma membrane, protein storage vacuole membrane, and probably the organelles. In this manuscript, we elucidate the evolution of the voltage-independent TPK (two-pore K+-channels) family, which could be represented in some species by one pore, K+-inward rectifier (Kir)-like channels. A comprehensive investigation of existing databases and application of modern bioinformatic tools allowed us to make a detailed phylogenetic inventory of TPK/KCO3 (KCO: potassium channel, outward rectifying) channels through many taxa and gain insight into the evolutionary origin of TPK family proteins. Our results reveal the fundamental evolutional difference between the first and second pores, traced throughout multiple taxa variations in the ion selection filter motif, presence of thansposon, and methylation site in the proximity of some KCO members and suggest virus-mediated horizontal transfer of a KCO3-like ancestor by viruses. Additionally, we suggest several interconnected hypotheses to explain the obtained results and provide a theoretical background for future experimental validation.

2.
J Mol Evol ; 89(9-10): 665-677, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34757471

RESUMO

Plant hormone cytokinins are important regulators of plant development, response to environmental stresses and interplay with other plant hormones. Cytokinin dehydrogenases (CKXs) are proteins responsible for the irreversible break-down of cytokinins to the adenine and aldehyde. Even though plant CKXs have been extensively studied, homologous proteins from other taxa remain mainly uncharacterised. Here we present our study on the molecular evolution and divergence of the CKX from bacteria, fungi, amoeba and viridiplantae. Although CKXs are present in eukaryotes and prokaryotes, they are missing in algae and metazoan taxa. The prevalent domain architecture consists of the FAD-binding and cytokinin binding domains, whereas some bacteria appear to have only cytokinin binding domain proteins. The CKXs play important role in the various aspects of plant life including control of plant development, response to biotic and abiotic stress, influence nutrition. Results of our study suggested that CKX originates from the FAD-linked C-terminal oxidase and has a defence-oriented function. The obtained results significantly extend the current understanding of the cytokinin dehydrogenases structure-function from the relationship to homologues from other taxa and provide a starting point baseline for their future functional characterization.


Assuntos
Citocininas , Regulação da Expressão Gênica de Plantas , Animais , Oxirredutases/genética , Oxirredutases/metabolismo , Estresse Fisiológico
3.
Plants (Basel) ; 10(2)2021 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-33498844

RESUMO

Soil salinity is one of the major factors obstructing the growth and development of agricultural crops. Eukaryotes have two main transport systems involved in active Na+ removal: cation/H+ antiporters and Na+-P-type ATPases. Key transport proteins, Na+/K+-P-ATPases, are widely distributed among the different taxa families of pumps which are responsible for keeping cytosolic Na+ concentrations below toxic levels. Na+/K+-P-ATPases are considered to be absent in flowering plants. The data presented here are a complete inventory of P-type Na+/K+-P-ATPases in the major branches of the plant kingdom. We also attempt to elucidate the evolution of these important membrane pumps in plants in comparison with other organisms. We were able to observe the gradual replacement of the Na+-binding site to the Ca2+-binding site, starting with cyanobacteria and moving to modern land plants. Our results show that the α-subunit likely evolved from one common ancestor to bacteria, fungi, plants, and mammals, whereas the ß-subunit did not evolve in green algae. In conclusion, our results strongly suggest the significant differences in the domain architecture and subunit composition of plant Na+/K+-P-ATPases depending on plant taxa and the salinity of the environment. The obtained data clarified and broadened the current views on the evolution of Na+/K+-P-ATPases. The results of this work would be helpful for further research on P-type ATPase functionality and physiological roles.

4.
Front Plant Sci ; 11: 573564, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33123183

RESUMO

The processes of plant nutrition, stress tolerance, plant growth, and development are strongly dependent on transport of mineral nutrients across cellular membranes. Plant membrane transporters are key components of these processes. Among various membrane transport proteins, the monovalent cation proton antiporter (CPA) superfamily mediates a broad range of physiological and developmental processes such as ion and pH homeostasis, development of reproductive organs, chloroplast operation, and plant adaptation to drought and salt stresses. CPA family includes plasma membrane-bound Na+/H+ exchanger (NhaP) and intracellular Na+/H+ exchanger NHE (NHX), K+ efflux antiporter (KEA), and cation/H+ exchanger (CHX) family proteins. In this review, we have completed the phylogenetic inventory of CPA transporters and undertaken a comprehensive evolutionary analysis of their development. Compared with previous studies, we have significantly extended the range of plant species, including green and red algae and Acrogymnospermae into phylogenetic analysis. Our data suggest that the multiplication and complexation of CPA isoforms during evolution is related to land colonisation by higher plants and associated with an increase of different tissue types and development of reproductive organs. The new data extended the number of clades for all groups of CPAs, including those for NhaP/SOS, NHE/NHX, KEA, and CHX. We also critically evaluate the latest findings on the biological role, physiological functions and regulation of CPA transporters in relation to their structure and phylogenetic position. In addition, the role of CPA members in plant tolerance to various abiotic stresses is summarized, and the future priority directions for CPA studies in plants are discussed.

5.
Front Plant Sci ; 10: 80, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30828339

RESUMO

Salinity is a major threat to modern agriculture causing inhibition and impairment of crop growth and development. Here, we not only review recent advances in salinity stress research in plants but also revisit some basic perennial questions that still remain unanswered. In this review, we analyze the physiological, biochemical, and molecular aspects of Na+ and Cl- uptake, sequestration, and transport associated with salinity. We discuss the role and importance of symplastic versus apoplastic pathways for ion uptake and critically evaluate the role of different types of membrane transporters in Na+ and Cl- uptake and intercellular and intracellular ion distribution. Our incomplete knowledge regarding possible mechanisms of salinity sensing by plants is evaluated. Furthermore, a critical evaluation of the mechanisms of ion toxicity leads us to believe that, in contrast to currently held ideas, toxicity only plays a minor role in the cytosol and may be more prevalent in the vacuole. Lastly, the multiple roles of K+ in plant salinity stress are discussed.

6.
New Phytol ; 194(3): 716-723, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22380876

RESUMO

• Arsenic contamination has a negative impact on crop cultivation and on human health. As yet, no proteins have been identified in plants that mediate the extrusion of arsenic. Here, we heterologously expressed the yeast (Saccharomyces cerevisiae) arsenite efflux transporter ACR3 into Arabidopsis to evaluate how this affects plant tolerance and tissue arsenic contents. • ACR3 was cloned from yeast and transformed into wild-type and nip7;1 Arabidopsis. Arsenic tolerance was determined at the cellular level using vitality stains in protoplasts, in intact seedlings grown on agar plates and in mature plants grown hydroponically. Arsenic efflux was measured from protoplasts and from intact plants, and arsenic levels were measured in roots and shoots of plants exposed to arsenate. • At the cellular level, all transgenic lines showed increased tolerance to arsenite and arsenate and a greater capacity for arsenate efflux. With intact plants, three of four stably transformed lines showed improved growth, whereas only transgenic lines in the wild-type background showed increased efflux of arsenite into the external medium. The presence of ACR3 hardly affected tissue arsenic levels, but increased arsenic translocation to the shoot. • Heterologous expression of yeast ACR3 endows plants with greater arsenic resistance, but does not lower significantly arsenic tissue levels.


Assuntos
Arabidopsis/genética , Arsênio/metabolismo , Proteínas de Membrana Transportadoras/genética , Proteínas de Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/genética , Estresse Fisiológico/genética , Arabidopsis/metabolismo , Arabidopsis/fisiologia , Arseniatos/metabolismo , Arsênio/análise , Arsenitos/metabolismo , Transporte Biológico , Membrana Celular/metabolismo , Hidroponia , Proteínas de Membrana Transportadoras/metabolismo , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Raízes de Plantas/fisiologia , Brotos de Planta/genética , Brotos de Planta/metabolismo , Brotos de Planta/fisiologia , Plantas Geneticamente Modificadas , Protoplastos , Proteínas Recombinantes de Fusão , Proteínas de Saccharomyces cerevisiae/metabolismo , Plântula/genética , Plântula/metabolismo , Plântula/fisiologia , Transformação Genética , Transgenes
7.
Cell Mol Life Sci ; 66(14): 2329-39, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19350206

RESUMO

Arsenic is a metalloid which is toxic to living organisms. Natural occurrence of arsenic and human activities have led to widespread contamination in many areas of the world, exposing a large section of the human population to potential arsenic poisoning. Arsenic intake can occur through consumption of contaminated crops and it is therefore important to understand the mechanisms of transport, metabolism and tolerance that plants display in response to arsenic. Plants are mainly exposed to the inorganic forms of arsenic, arsenate and arsenite. Recently, significant progress has been made in the identification and characterisation of proteins responsible for movement of arsenite into and within plants. Aquaporins of the NIP (nodulin26-like intrinsic protein) subfamily were shown to transport arsenite in planta and in heterologous systems. In this review, we will evaluate the implications of these new findings and assess how this may help in developing safer and more tolerant crops.


Assuntos
Arsenitos/metabolismo , Plantas/metabolismo , Aquaporinas/genética , Aquaporinas/metabolismo , Arseniatos/metabolismo , Arsênio/metabolismo , Transporte de Íons/genética , Modelos Biológicos , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas/genética
8.
FEBS Lett ; 582(11): 1625-8, 2008 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-18435919

RESUMO

We studied the effect of loss of function in the NIP subfamily II in Arabidopsis thaliana to assess their potential role(s) in arsenite (AsIII) uptake. Loss of function in AtNIP7;1 led to increased plant tolerance to AsIII and reduced total As in planta. AtNIP7;1 expression in various yeast backgrounds increased AsIII sensitivity. In the acr3Delta yeast genotype, AtNIP7;1 caused a moderate increase in AsV tolerance. Short-term As uptake in fsp1Delta expressing AtNIP7;1 was significantly larger than that in the empty vector control. The data suggest that AtNIP7;1 can mediate AsIII transport and contributes to AsIII uptake in plants.


Assuntos
Aquaporinas/fisiologia , Proteínas de Arabidopsis/fisiologia , Arabidopsis/metabolismo , Arsenitos/metabolismo , Aquaporinas/genética , Aquaporinas/metabolismo , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Arsenitos/toxicidade , Mutação
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