Project description:Wild rice, Oryza grandiglumis shows hyper-resistance response to pathogen infection. In order to identify genes necessary for defense response in plants, we have carried out a subtractive hybridization coupled with a cDNA macroarray. An acidic PATHOGENESIS-RELATED1 (PR1) gene of the wild rice is highly identical to the acidic PR1 genes of different plant species. The OgPR1a cDNA has an apparent single open reading frame with a predicted molecular mass 40,621 Da and an isoelectic point of 5.14. Both in silico analysis and a transient expression assay in onion epidermal cells revealed that the OgPR1a protein could be localized in intercellular space in plants. The OgPR1a mRNA was strongly transcribed by the exogenous treatment with ethylene and jasmonic acid as well as protein phosphatase inhibitors. Additionally, ectopic expression of the OgPR1a conferred disease resistance on Arabidopsis to the bacterial and fungal infections.
| S-EPMC4174849 | biostudies-literature
Project description:chloroplast genome sequencing of Kengyilia hirsuta
Project description:The level and pattern of nucleotide variation in duplicate gene provide important information on the evolutionary history of polyploids and divergent process between homoeologous loci within lineages. Kengyilia is a group of allohexaploid species with the StYP genomic constitutions in the wheat tribe. To investigate the evolutionary dynamics of the Pgk1 gene in Kengyilia and its diploid relatives, three copies of Pgk1 homoeologues were isolated from all sampled hexaploid Kengyilia species and analyzed with the Pgk1 sequences from 47 diploid taxa representing 18 basic genomes in Triticeae. Sequence diversity patterns and genealogical analysis suggested that (1) Kengyilia species from the Central Asia and the Qinghai-Tibetan plateau have independent origins with geographically differentiated P genome donors and diverged levels of nucleotide diversity at Pgk1 locus; (2) a relatively long-time sweep event has allowed the Pgk1 gene within Agropyron to adapt to cold climate triggered by the recent uplifts of the Qinghai-Tibetan Plateau; (3) sweep event and population expansion might result in the difference in the d(N)/d(S) value of the Pgk1 gene in allopatric Agropyron populations, and this difference may be genetically transmitted to Kengyilia lineages via independent polyploidization events; (4) an 83 bp MITE element insertion has shaped the Pgk1 loci in the P genome lineage with different geographical regions; (5) the St and P genomes in Kengyilia were donated by Pseudoroegneria and Agropyron, respectively, and the Y genome is closely related to the Xp genome of Peridictyon sanctum. The interplay of evolutionary forces involving diverged natural selection, population expansion, and transposable events in geographically differentiated P genome donors could attribute to geographical differentiation of Kengyilia species via independent origins.
Project description:Kengyilia is a group of allohexaploid species that arose from two hybridization events followed by genome doubling of three ancestral diploid species with different genomes St, Y, and P in the Triticeae. Estimating the phylogenetic relationship in resolution of the maternal lineages has been difficult, owing to the extremely low rate of sequence divergence. Here, phylogenetic reconstructions based on the plastome sequences were used to explore the role of maternal progenitors in the establishment of Kengyilia polyploid species. The plastome sequences of 11 Kengyilia species were analyzed together with 12 tetraploid species (PP, StP, and StY) and 33 diploid taxa representing 20 basic genomes in the Triticeae. Phylogenomic analysis and genetic divergence patterns suggested that (1) Kengyilia is closely related to Roegneria, Pseudoroegneria, Agropyron, Lophopyrum, Thinopyrum, and Dasypyrum; (2) both the StY genome Roegneria tetraploids and the PP genome Agropyron tetraploids served as the maternal donors during the speciation of Kengyilia species; (3) the different Kengyilia species derived their StY genome from different Roegneria species. Multiple origins of species via independent polyploidization events have occurred in the genus Kengyilia, resulting in a maternal haplotype polymorphism. This helps explain the rich diversity and wide adaptation of polyploid species in the genus Kengyilia.