Molecular and morphological characterization of Pyricularia and allied genera

The phylogenetic relationships of Pyricularia species and species from related genera were established from sequences of the internal transcribed spacer ribosomal RNA gene. Phylogenetic analysis disclosed a consistent correlation with spore morphology. Most Pyricularia species studied, and two species of Dactylaria that have obpyriform conidia, fell within the Magnaporthaceae cluster with high bootstrap support. Pyricularia variabilis was more related to Dactylaria, Tumularia or Ochroconis species than to the Magnaporthaceae. Dactylaria and species of Nakataea, Ochroconis, Pyriculariopsis and Tumularia were distinct from the Magnaporthaceae, and the genus Dactylaria is polyphyletic. The combination of morphological and molecular characters, such as spore morphology and ITS ribosomal DNA sequences data, suggested that conidial shape could be a primary character to distinguish Pyricularia from related genera.published_or_final_versio

Genome Physical Mapping of Polyploids: A BIBAC Physical Map of Cultivated Tetraploid Cotton, Gossypium hirsutum L

Polyploids account for approximately 70% of flowering plants, including many field, horticulture and forage crops. Cottons are a world-leading fiber and important oilseed crop, and a model species for study of plant polyploidization, cellulose biosynthesis and cell wall biogenesis. This study has addressed the concerns of physical mapping of polyploids with BACs and/or BIBACs by constructing a physical map of the tetraploid cotton, Gossypium hirsutum L. The physical map consists of 3,450 BIBAC contigs with an N50 contig size of 863 kb, collectively spanning 2,244 Mb. We sorted the map contigs according to their origin of subgenome, showing that we assembled physical maps for the A- and D-subgenomes of the tetraploid cotton, separately. We also identified the BIBACs in the map minimal tilling path, which consists of 15,277 clones. Moreover, we have marked the physical map with nearly 10,000 BIBAC ends (BESs), making one BES in approximately 250 kb. This physical map provides a line of evidence and a strategy for physical mapping of polyploids, and a platform for advanced research of the tetraploid cotton genome, particularly fine mapping and cloning the cotton agronomic genes and QTLs, and sequencing and assembling the cotton genome using the modern next-generation sequencing technology

CenH3 evolution in diploids and polyploids of three angiosperm genera

BACKGROUND: Centromeric DNA sequences alone are neither necessary nor sufficient for centromere specification. The centromere specific histone, CenH3, evolves rapidly in many species, perhaps as a coevolutionary response to rapidly evolving centromeric DNA. To gain insight into CenH3 evolution, we characterized patterns of nucleotide and protein diversity among diploids and allopolyploids within three diverse angiosperm genera, Brassica, Oryza, and Gossypium (cotton), with a focus on evidence for diversifying selection in the various domains of the CenH3 gene. In addition, we compare expression profiles and alternative splicing patterns for CenH3 in representatives of each genus. RESULTS: All three genera retain both duplicated CenH3 copies, while Brassica and Gossypium exhibit pronounced homoeologous expression level bias. Comparisons among genera reveal shared and unique aspects of CenH3 evolution, variable levels of diversifying selection in different CenH3 domains, and that alternative splicing contributes significantly to CenH3 diversity. CONCLUSIONS: Since the N terminus is subject to diversifying selection but the DNA binding domains do not appear to be, rapidly evolving centromere sequences are unlikely to be the primary driver of CenH3 sequence diversification. At present, the functional explanation for the diversity generated by both conventional protein evolution in the N terminal domain, as well as alternative splicing, remains unexplained. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12870-014-0383-3) contains supplementary material, which is available to authorized users

Dendrobium roseiodorum (Orchidaceae): a new species from Vietnam

In the course of revisionary work of Dendrobium section Formosae, we found some misinterpretations of Dendrobium kontumense. Dendrobium schildhaueri is placed as a synonym of D. kontumense and D. roseiodorum, a new species from Vietnam, is described

Ten New Records of Mosses from Doi Inthanon National Park in Thailand

Volume: 61Start Page: 389End Page: 40