RESUMEN
Glypholeciaqinghaiensis An C. Yin, Q. Y. Zhong & Li S. Wang is described as new to science. It is characterized by its squamulose thallus, compound apothecia, ellipsoid ascospores, and the presence of rhizines on the lower surface of the thallus. A phylogenetic tree of Glypholecia species was constructed based on nrITS and mtSSU sequences. Two species G.qinghaiensis and G.scabra are confirmed in China.
RESUMEN
During the Second Tibetan Plateau Scientific Expedition and Research Program, we discovered that white terricolous lichenized fungal species of Buellia De Not. were widely distributed across the Tibetan Plateau. After examining their morphology, chemistry and phylogeny, we describe Buelliaalpina Xin Y. Wang & Li S. Wang, sp. nov. as new to science. It is present in alpine meadows, and is characterized by its effigurate thallus, distinct linear marginal lobes, cover of thick white pruina and four-spored asci. This is also the first report of Buelliaelegans Poelt and Buelliaepigaea (Pers.) Tuck from China. The Buelliaepigaea-group has previously been characterized by white and often effigurate thalli that occur mainly on soil. However, our results show that species in this group actually belong to two distinct clades. This conclusion is based on analyses of the nuITS region and the combined regions dataset (nuITS-nuLSU-mtSSU-ß-tubulin). We discuss differences in morphology, anatomy, chemistry and ecology among the putative Buelliaepigaea-group. Detailed descriptions and figures for the three species from China and a key for species of Buelliaepigaea-group are provided.
RESUMEN
Chloroplasts are semiautonomous organelles found in photosynthetic plants. The major functions of chloroplasts include photosynthesis and carbon fixation, which are mainly regulated by its circular genomes. In the highly conserved chloroplast genome, the chloroplast transfer RNA genes (cp tRNA) play important roles in protein translation within chloroplasts. However, the evolution of cp tRNAs remains unclear. Thus, in the present study, we investigated the evolutionary characteristics of chloroplast tRNAs in five Adoxaceae species using 185 tRNA gene sequences. In total, 37 tRNAs encoding 28 anticodons are found in the chloroplast genome in Adoxaceae species. Some consensus sequences are found within the Ψ-stem and anticodon loop of the tRNAs. Some putative novel structures were also identified, including a new stem located in the variable region of tRNATyr in a similar manner to the anticodon stem. Furthermore, phylogenetic and evolutionary analyses indicated that synonymous tRNAs may have evolved from multiple ancestors and frequent tRNA duplications during the evolutionary process may have been primarily caused by positive selection and adaptive evolution. The transition and transversion rates are uneven among different tRNA isotypes. For all tRNAs, the transition rate is greater with a transition/transversion bias of 3.13. Phylogenetic analysis of cp tRNA suggested that the type I introns in different taxa (including eukaryote organisms and cyanobacteria) share the conserved sequences "U-U-x2-C" and "U-x-G-x2-T," thereby indicating the diverse cyanobacterial origins of organelles. This detailed study of cp tRNAs in Adoxaceae may facilitate further investigations of the evolution, phylogeny, structure, and related functions of chloroplast tRNAs.
