bims-plasge Biomed news
on Plastid genes
Issue of 2018‒07‒22
five papers selected by
Vera S. Bogdanova
Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences

  1. Plant Cell. 2018 Jul 15. pii: tpc.00363.2018. [Epub ahead of print]
    Hu J, Israeli A, Ori N, Sun TP.
      Fruit initiation following fertilization in angiosperms is strictly regulated by phytohormones. In tomato (Solanum lycopersicum), auxin and gibberellin (GA) play central roles in promoting fruit initiation. Without fertilization, elevated GA or auxin signaling can induce parthenocarpy (seedless fruit production). The GA-signaling repressor SlDELLA and auxin-signaling components SlIAA9 and SlARF7 repress parthenocarpy, but the underlying mechanism is unknown. Here, we show that SlDELLA and the SlARF7/SlIAA9 complex mediate crosstalk between GA and auxin pathways to regulate fruit initiation. Yeast-two-hybrid and co-immunoprecipitation assays showed that SlARF7 and additional activator SlARFs interact with SlDELLA and SlIAA9 through distinct domains. SlARF7/SlIAA9 and SlDELLA antagonistically modulate the expression of feedback-regulated genes involved in GA and auxin metabolism, whereas SlARF7/SlIAA9 and SlDELLA co-regulate the expression of fruit growth-related genes. Analysis of procera (della), SlARF7 RNAi (with downregulated expression of multiple activator SlARFs), and entire (iaa9) single and double mutants indicated that these genes additively affect parthenocarpy, supporting the notion that the SlARFs/SlIAA9 and SlDELLA interaction plays an important role in regulating fruit initiation. Analysis of the GA-deficient mutant gib1 showed that active GA biosynthesis and signaling are required for auxin-induced fruit initiation. Our study reveals how direct crosstalk between auxin- and GA-signaling components is critical for tomato fruit initiation.
  2. Food Res Int. 2018 Sep;pii: S0963-9969(18)30359-4. [Epub ahead of print]111 20-30
    Song EH, Jeong J, Park CY, Kim HY, Kim EH, Bang E, Hong YS.
      Rice (Oryza sativa L.), the major staple food in many countries, has genetic diversity adapted to different environmental conditions. However, metabolic traits about diverse rice plants are rarely discovered. In the present study, rice leaves and grains were collected at whole growth stages from late (LMC) and early (EMC) maturing cultivars. Metabolic dependences of rice plants on both growth and cultivar were investigated in their leaves and grains through NMR-based metabolomics approach. Rice leaf metabolome were differently regulated between two rice cultivars, thereby affecting variations of rice grain metabolome. Sucrose levels in leaves of EMC were markedly decreased compared to those in LMC, and more accumulations of sucrose, amino acids and free fatty acids were found in grains of EMC. These distinct metabolisms between EMC and LMC rice cultivars were associated with temperature during their growing seasons and might affect the eating quality of rice. The current study highlights that metabolomic approach of rice leaves and grains could lead to better understanding of the relationship between their distinct metabolisms and environmental conditions, and provide novel insights to metabolic qualities of rice grains.
    Keywords:  Cultivars; Grain; Leaf; Metabolomics; NMR; Rice
  3. Flora. 2018 Jul;244-245 29-36
    Bailes EJ, Glover BJ.
      At a microscopic scale, the shape and fine cell relief of the petal epidermal cells of a flower play a key role in its interaction with pollinators. In particular, conical shaped petal epidermal cells have been shown to have an important function in providing grip on the surface of bee-pollinated flowers and can influence bee visitation rates. Previous studies have explored interspecific variation in this trait within genera and families, but naturally-occurring intraspecific variation has not yet been comprehensively studied. Here, we investigate petal epidermal cell morphology in 32 genotypes of the crop Vicia faba, which has a yield highly dependent on pollinators. We hypothesise that conical cells may have been lost in some genotypes as a consequence of selective sweeps or genetic drift during breeding programmes. We find that 13% of our lines have a distribution of conical petal epidermal cells that deviates from that normally seen in V. faba flowers. These abnormal phenotypes were specific to the ad/abaxial side of petals, suggesting that these changes are the result of altered gene expression patterns rather than loss of gene function.
    Keywords:  Broad bean; Cell shape; Faba bean; Field bean; Papillose cell; Petal epidermis
  4. Nucleic Acids Res. 2018 Jul 11.
    Ryan DP, Tremethick DJ.
      One of the most intensively studied chromatin binding factors is HP1α. HP1α is associated with silenced, heterochromatic regions of the genome and binds to H3K9me3. While H3K9me3 is necessary for HP1α recruitment to heterochromatin, it is becoming apparent that it is not sufficient suggesting that additional factors are involved. One candidate proposed as a potential regulator of HP1α recruitment is the linker histone H1.4. Changes to the underlying make-up of chromatin, such as the incorporation of the histone variant H2A.Z, has also been linked with regulating HP1 binding to chromatin. Here, we rigorously dissected the effects of H1.4, H2A.Z and H3K9me3 on the nucleosome binding activity of HP1α in vitro employing arrays, mononucleosomes and nucleosome core particles. Unexpectedly, histone H1.4 impedes the binding of HP1α but strikingly, this inhibition is partially relieved by the incorporation of both H2A.Z and H3K9me3 but only in the context of arrays or nucleosome core particles. Our data suggests that there are two modes of interaction of HP1α with nucleosomes. The first primary mode is through interactions with linker DNA. However, when linker DNA is missing or occluded by linker histones, HP1α directly interacts with the nucleosome core and this interaction is enhanced by H2A.Z with H3K9me3.
  5. Carbohydr Polym. 2018 Oct 01. pii: S0144-8617(18)30652-0. [Epub ahead of print]197 246-252
    Blas-Sevillano RH, Veramendi T, La Torre B, Velezmoro-Sánchez CE, Oliva AI, Mena-Martínez ME, Herrera-Kao WA, Uribe-Calderon J, Cervantes-Uc JM.
      Elemental composition, physical dimensions (length and apparent diameter), and crystallinity of different types of naturally colored cotton (NCCs) fibers from Peru were investigated using a CHNS organic elemental analyzer, optical microscopy and X-Ray Diffraction (XRD). Spectroscopic studies involving Fourier Transform Infrared Spectroscopy and X-Ray photoelectron spectroscopy (XPS) were conducted; and the thermal stability of cotton samples were also investigated. Results from organic elemental analyzer and XPS showed that cotton samples contain mainly carbon, oxygen and hydrogen, but darker color samples also presented nitrogen. It was also found that the white cotton sample exhibited the longest fibers whereas the darker color samples showed the shortest values in length. Interestingly, the crystallinity seems also decrease with color intensity of NCCs. Finally, the thermal stability of white cotton fibers was similar to those obtained for the NCCs.
    Keywords:  Cotton fibers characterization; Naturally colored cottons; Peruvian cottons