Homology modeling identifies crucial amino-acid residues that confer higher Na+ transport capacity of OcHKT1;5 from Oryza coarctata Roxb
| Autor: | Ramanathan Sowdhamini, Kavitha Kumaresan, Sergey Shabala, Claire Corratgé-Faillie, Gayatri Venkataraman, Suji Somasundaram, Shalini Pulipati, Lana Shabala, Anne-Aliénor Véry, Kumkum Kumari, Tetsuya Ishikawa, Rithvik S. Vinekar, Ajay Parida |
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| Přispěvatelé: | Plant Molecular Biology Laboratory, Biochimie et Physiologie Moléculaire des Plantes (BPMP), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), National Centre for Biological Sciences (NCBS), NCBS, Tasmanian Institute of Agriculture, University of Tasmania [Hobart, Australia] (UTAS), Krishi Vigyan Kendra, National Centre for Biological Sciences [TIFR] (NCBS), Tata Institute for Fundamental Research (TIFR), Institute of Life Sciences (ILS), School of Agricultural Sciences |
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
0106 biological sciences
Physiology Sodium Xenopus homology modeling [SDV]Life Sciences [q-bio] Halophyte chemistry.chemical_element Plant Science yeast 01 natural sciences 03 medical and health sciences Xylem Animals [SDV.BV]Life Sciences [q-bio]/Vegetal Biology HKT1 Amino Acids Cation Transport Proteins 030304 developmental biology Plant Proteins Xenopus oocytes chemistry.chemical_classification 0303 health sciences biology Organisms Genetically Modified Sequence Homology Amino Acid Na+transporter Cell Membrane food and beverages Transporter Oryza Salt-Tolerant Plants Cell Biology General Medicine Oryza coarctata biology.organism_classification simulation Amino acid Salinity chemistry Biochemistry Shoot Oocytes 010606 plant biology & botany |
| Zdroj: | Plant and Cell Physiology Plant and Cell Physiology, Oxford University Press (OUP), 2020, 61 (7), pp.1321-1334. ⟨10.1093/pcp/pcaa061⟩ |
| ISSN: | 0032-0781 1471-9053 |
| DOI: | 10.1093/pcp/pcaa061⟩ |
| Popis: | HKT1;5 loci/alleles are important determinants of crop salinity tolerance. HKT1;5s encode plasmalemma-localized Na+ transporters, which move xylem Na+ into xylem parenchyma cells, reducing shoot Na+ accumulation. Allelic variation in rice OsHKT1;5 sequence in specific landraces (Nona Bokra OsHKT1;5-NB/Nipponbare OsHKT1;5-Ni) correlates with variation in salt tolerance. Oryza coarctata, a halophytic wild rice, grows in fluctuating salinity at the seawater–estuarine interface in Indian and Bangladeshi coastal regions. The distinct transport characteristics of the shoots and roots expressing the O. coarctata OcHKT1;5 transporter are reported vis-à-vis OsHKT1;5-Ni. Yeast sodium extrusion-deficient cells expressing OcHKT1;5 are sensitive to increasing Na+ (10–100 mM). Electrophysiological measurements in Xenopus oocytes expressing O. coarctata or rice HKT1;5 transporters indicate that OcHKT1;5, like OsHKT1;5-Ni, is a Na+-selective transporter, but displays 16-fold lower affinity for Na+ and 3.5-fold higher maximal conductance than OsHKT1;5-Ni. For Na+ concentrations >10 mM, OcHKT1;5 conductance is higher than that of OsHKT1;5-Ni, indicating the potential of OcHKT1;5 for increasing domesticated rice salt tolerance. Homology modeling/simulation suggests that four key amino-acid changes in OcHKT1;5 (in loops on the extracellular side; E239K, G207R, G214R, L363V) account for its lower affinity and higher Na+ conductance vis-à-vis OsHKT1;5-Ni. Of these, E239K in OcHKT1;5 confers lower affinity for Na+ transport, as evidenced by Na+ transport assays of reciprocal site-directed mutants for both transporters (OcHKT1;5-K239E, OsHKT1;5-Ni-E270K) in Xenopus oocytes. Both transporters have likely analogous roles in xylem sap desalinization, and differences in xylem sap Na+ concentrations in both species are attributed to differences in Na+ transport affinity/conductance between the transporters. |
| Databáze: | OpenAIRE |
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