bims-plasge Biomed News
on Plastid genes
Issue of 2018‒11‒11
two papers selected by
Vera S. Bogdanova
Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences

  1. Plant Physiol Biochem. 2018 Oct 26. pii: S0981-9428(18)30463-7. [Epub ahead of print]133 57-70
      The key mechanisms of salinity tolerance (ST) in durum wheat were investigated, with five genotypes used to determine changes in morpho-physiological traits and mineral and metabolite contents after exposure to 50, 100 and 200 mM NaCl. Plant growth impairment was evident at the highest salt level. Under this condition, a wide range of shoot Na+ contents and ST were observed within genotypes. However, no significant correlation was seen between ST and Na+ exclusion from the shoots, which indicates that tissue tolerance also has a role. Consistent with this, there was significant correlation between ST and the Na+:K+ ratio in the shoots. Indeed, the maintenance of the shoot Na+ and K+ homeostasis was found to be essential to achieve osmotic adjustment, which relied substantially on inorganic osmolytes, and to avoid toxicity symptoms, such as chlorophyll loss, which appeared only at the highest salinity level. Consistently, the metabolite changes occurred mainly in the shoots, with a dual response to salinity: (i) a conserved response that was common to all the genotypes and resulted in the accumulation of proline and in the depletion of organic acids, including some intermediates of the Krebs cycle; and (ii) a genotype-specific response that involved the accumulation of GABA, threonine, leucine, glutamic acid, glycine, mannose and fructose and appeared related to the different tolerance of genotypes to salinity. The lower magnitude of response to salinity detected in the roots confirmed the major role of the shoots in the determination of ST of durum wheat.
    Keywords:  Durum wheat; Metabolic response; Potassium retention; Salinity tolerance; Sodium exclusion
  2. Biol Res. 2018 Nov 03. 51(1): 43
      BACKGROUND: CircRNAs are widespread in plants and play important roles in response to abiotic stresses. Low nitrogen (LN) promotes the growth of plant root system, allowing it to explore more nitrogen. However, whether circRNAs involved in the response to LN stress and the regulation of LN-promoted root growth in wheat remains unclear.METHODS: Two wheat varieties (LH9 and XN979) with contrasting root phenotypes to LN stress were used as materials to identify circRNAs under control and LN conditions by using high-throughput sequencing technology.
    RESULTS: Six differentially expressed circRNAs (DECs) involved in the common response to LN stress and 23 DECs involved in the regulation of LN-promoted root growth were successfully identified. GO analysis of the DEC-host genes involved in the regulation of LN-promoted root growth showed that GO terms related to biological regulation, responses to stimuli and signalling were significantly enriched. Moreover, seven DECs were predicted to have miRNA binding sites and may serve as miRNA sponges to capture miRNAs from their target genes.
    CONCLUSIONS: LN stress altered the expression profiles of circRNAs in wheat. This is the first report of LN stress responsive circRNAs in plants. Our results provided new clues for investigating the functions of circRNAs in response to LN stress and in the regulation of LN-promoted wheat root growth.
    Keywords:  CircRNAs; Low nitrogen; Root; Triticum aestivum L.