Structure-Function Relationships of NHX Antiporters of Arabidopsis thaliana.

Póster presentado en el 18th International Workshop on Plant Membrane Biology, July 7-12, 2019, Glasgow, UKThe K+,Na+/H+ exchangers NHX of Arabidopsis thaliana mediate the accumulation of K+ into the vacuole of cells, thereby increasing the osmotic potential, water uptake and the turgor pressure necessary for cell expansion and growth, as well as for regulation of vacuolar pH. They are part of the Cation Proton Antiporter superfamily (CPA), a highly conserved group of transmembrane proteins that exchange cations for protons in opposite directions to locally modulate pH, as well as electrical and cation balances. Using a phylogenetic approach, we aimed to get a better insight of the NHX1 protein structure, function and regulation. As a result of our studies we could generate new topological and ternary models of NHX1. By conservation analyses we could identify essential structural domains and amino acid residues putatively involved in ion transport, cation coordination, and pH sensing of the protein. Pointmutation alleles of these relevant residues were generated, and their impact on the biochemical activity and pH dependence of NHX1 by functionality tests in yeast was studied. Of special interest are the results obtained from allele mutants generated by emulating the motifs of electrogenic CPA proteins in order to transform the electroneutral nature of NHX1 into electrogenic. Overall, our results demonstrate that AtNHX1 conserves the structural features characteristic of microbial and mammalian members of the CPA superfamily

Erratum: Corrigendum: The genome of Chenopodium quinoa

The Acknowledgements section of this Article should have included the following sentence: “Metabolite imaging was conducted at Metabolomics Australia (School of BioSciences, The University of Melbourne, Australia), a NCRIS initiative under Bioplatforms Australia Pty Ltd.”. The original Article has been corrected online

The genome of Chenopodium quinoa

Chenopodium quinoa (quinoa) is a highly nutritious grain identified as an important crop to improve world food security. Unfortunately, few resources are available to facilitate its genetic improvement. Here we report the assembly of a high-quality, chromosome-scale reference genome sequence for quinoa, which was produced using single-molecule real-time sequencing in combination with optical, chromosome-contact and genetic maps. We also report the sequencing of two diploids from the ancestral gene pools of quinoa, which enables the identification of sub-genomes in quinoa, and reduced-coverage genome sequences for 22 other samples of the allotetraploid goosefoot complex. The genome sequence facilitated the identification of the transcription factor likely to control the production of anti-nutritional triterpenoid saponins found in quinoa seeds, including a mutation that appears to cause alternative splicing and a premature stop codon in sweet quinoa strains. These genomic resources are an important first step towards the genetic improvement of quinoa