bims-plasge Biomed News
on Plastid genes
Issue of 2021‒03‒21
two papers selected by
Vera S. Bogdanova
Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences

  1. Theor Appl Genet. 2021 Mar 16.
      KEY MESSAGE: A mitochondria-localized pentatricopeptide repeat protein was identified by positional cloning and transferred into the hau CMS line, where it successfully restored fertility Cytoplasmic male sterility (CMS) is a maternally inherited trait that can be controlled by restorer-of-fertility (Rf) genes present in the nucleus. The hau CMS was identified as a new form of CMS associated with the mitochondrial transcript orf288; however, a lack of a restorer gene has limited its utilization in Brassica crops. Here, the combination of Brassica 60 K array with bulk segregant analysis and map-based cloning was used to delimit the Rfh locus to an 82.2-kb region on chromosome A09. A candidate gene encoding a mitochondria-localized pentatricopeptide repeat (PPR) protein was identified and transferred into the hau CMS line, where it successfully restored the fertility of the hau CMS plants. Furthermore, the expression analysis showed that Rfh was highly expressed in the flower buds, and the sequence analysis results implied that functional divergence between RFH and rfh could be due to 59 amino acid residue differences in the deduced protein sequences. In addition, a co-separated molecular marker was developed based on the divergent sequences between the dominant and recessive alleles. These results will help enable the heterosis of Brassica crops in the future.
  2. G3 (Bethesda). 2021 Mar 15. pii: jkab081. [Epub ahead of print]
      Pea (Pisum sativum) was chosen as the research material by Gregor Mendel to discover the laws of inheritance. Out of seven traits studied by Mendel, genes controlling three traits including pod shape, pod color, and flower position have not been identified to date. With the aim of identifying the genomic region controlling pod color, we determined the genome sequence of a pea line with yellow pods. Genome sequence reads obtained using a Nanopore sequencing technology were assembled into 117,981 contigs (3.3 Gb), with an N50 value of 51.2 kb. A total of 531,242 potential protein-coding genes were predicted, of which 519,349 (2.8 Gb) were located within repetitive sequences. The assembled sequences were ordered using a reference as a guide to build pseudomolecules. Subsequent genetic and association analyses led to the identification of a genomic region that controls pea pod color. DNA sequences at this genomic location and transcriptome profiles of green and yellow pod lines were analyzed, and genes encoding 3' exoribonucleases were selected as potential candidates controlling pod color. The results presented in this study are expected to accelerate pan-genome studies in pea and facilitate the identification of the gene controlling one of the traits studied by Mendel.w.
    Keywords:  Double-digest restriction site-associated DNA sequencing; Genetic mapping; Genome sequence; Mendel’s genes; Nanopore sequencing