Functional characterisation of an intron retaining K+ transporter of barley reveals intron-mediated alternate splicing

K. Shahzad, M. Rauf, M. Ahmed, Z. A. Malik, I. Habib, Z. Ahmed, K. Mahmood, R. Ali, K. Masmoudi, F. Lemtiri-Chlieh, C. Gehring, G. A. Berkowitz, N. A. Saeed

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)

Abstract

Intron retention in transcripts and the presence of 5 and 3 splice sites within these introns mediate alternate splicing, which is widely observed in animals and plants. Here, functional characterisation of the K+ transporter, HvHKT2;1, with stably retained introns from barley (Hordeum vulgare) in yeast (Saccharomyces cerevisiae), and transcript profiling in yeast and transgenic tobacco (Nicotiana tabacum) is presented. Expression of intron-retaining HvHKT2;1 cDNA (HvHKT2;1-i) in trk1, trk2 yeast strain defective in K+ uptake restored growth in medium containing hygromycin in the presence of different concentrations of K+ and mediated hypersensitivity to Na+. HvHKT2;1-i produces multiple transcripts via alternate splicing of two regular introns and three exons in different compositions. HKT isoforms with retained introns and exon skipping variants were detected in relative expression analysis of (i) HvHKT2;1-i in barley under native conditions, (ii) in transgenic tobacco plants constitutively expressing HvHKT2;1-i, and (iii) in trk1, trk2 yeast expressing HvHKT2;1-i under control of an inducible promoter. Mixed proportions of three HKT transcripts: HvHKT2;1-e (first exon region), HvHKT2;1-i1 (first intron) and HvHKT2;1-i2 (second intron) were observed. The variation in transcript accumulation in response to changing K+ and Na+ concentrations was observed in both heterologous and plant systems. These findings suggest a link between intron-retaining transcripts and different splice variants to ion homeostasis, and their possible role in salt stress.

Original languageEnglish
Pages (from-to)840-851
Number of pages12
JournalPlant Biology
Volume17
Issue number4
DOIs
Publication statusPublished - Jul 1 2015

Keywords

  • Alternate splicing
  • Functional complementation
  • HvHKT2
  • Intron retention
  • Transcriptional gene regulation
  • Transporters and channels

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Plant Science

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