A two-staged model of Na+ exclusion in rice explained by 3d modeling of HKT transporters and alternative splicing

Olivier Cotsaftis*, Darren Plett, Neil Shirley, Mark Tester, Maria Hrmova

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

124 Scopus citations

Abstract

The HKT family of Na+ and Na+/K+ transporters is implicated in plant salinity tolerance. Amongst these transporters, the cereal HKT1;4 and HKT1;5 are responsible for Na+ exclusion from photosynthetic tissues, a key mechanism for plant salinity tolerance. It has been suggested that Na+ is retrieved from the xylem transpiration stream either in the root or the leaf sheath, protecting the leaf blades from excessive Na+ accumulation. However, direct evidence for this scenario is scarce. Comparative modeling and evaluation of rice (Oryza sativa) HKT-transporters based on the recent crystal structure of the bacterial TrkH K+ transporter allowed to reconcile transcriptomic and physiological data. For OsHKT1;5, both transcript abundance and protein structural features within the selectivity filter could control shoot Na+ accumulation in a range of rice varieties. For OsHKT1;4, alternative splicing of transcript and the anatomical complexity of the sheath needed to be taken into account. Thus, Na+ accumulation in a specific leaf blade seems to be regulated by abundance of a correctly spliced OsHKT1;4 transcript in a corresponding sheath. Overall, allelic variation of leaf blade Na+ accumulation can be explained by a complex interplay of gene transcription, alternative splicing and protein structure.

Original languageEnglish (US)
Article numbere39865
JournalPloS one
Volume7
Issue number7
DOIs
StatePublished - Jul 11 2012

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Agricultural and Biological Sciences(all)
  • General

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