RESULTS:
1 - 8 of 8 for ""State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Science, Beijing 100101, PR China""
Insights into the genomic evolution and the alkali tolerance mechanisms of Agaricus sinodeliciosus by comparative genomic and transcriptomic analyses
Agaricus sinodeliciosus is a rare wild edible mushroom from northwest China and grows naturally in mild saline-alkali soil which is also unusual in mushrooms. A. sinodeliciosus represents a potential model organism for explaining saline-alkali tolerance mechanisms and revealing related physiological processes in mushrooms. Here we provide a high-quality genome of A. sinodeliciosus. Comparative genomic analyses reveal A. sinodeliciosus has numerous changes to its genome organization after a solitary evolutionary history under saline-alkali environments such as gene family contraction retrotransposon expansion and rapid evolution of adaptative genes. Our saline and alkali tolerance tests show that mycelium growth and fruit body formation of this species are effected by mild alkalinity. Transcriptomic analyses reveal that genes involved in carbon and nitrogen utilization cell stability and fruit body formation of A. sinodeliciosus could be activated under mildly alkaline conditions. In particular the ‘starch and sucrose metabolism’ ‘biosynthesis of amino acids’ and ‘phenylpropanoid biosynthesis’ pathways are important for mildly alkaline tolerance of A. sinodeliciosus. Like plants and arbuscular mycorrhizal fungi in the rot fungus A. sinodeliciosus the biosynthesis of intracellular small molecules could be enhanced to counter osmotic and oxidative stresses caused by mild alkalinity and the biosynthesis of monolignol could be suppressed to increase cell wall infiltrates under mildly alkaline conditions. This research provides an understanding of the genomic evolution and mechanisms of A. sinodeliciosus in tolerance to saline-alkali environments. The A. sinodeliciosus genome constitutes a valuable resource for evolutionary and ecological studies of Agaricus.
Comparative molecular evolution of chitinases in ascomycota with emphasis on mycoparasitism lifestyle
Chitinases are involved in multiple aspects of fungal life cycle such as cell wall remodelling chitin degradation and mycoparasitism lifestyle. To improve our knowledge of the chitinase molecular evolution of Ascomycota the gene family of 72 representatives of this phylum was identified and subjected to phylogenetic evolution trajectory and selective pressure analyses. Phylogenetic analysis showed that the chitinase gene family size and enzyme types varied significantly along with species evolution especially for groups B and C. In addition two new subgroups C3 and C4 are recognized in group C chitinases. Random birth and death testing indicated that gene expansion and contraction occurred in most of the taxa particularly for species in the order Hypocreales (class Sordariomycetes). From an enzyme function point of view we speculate that group A chitinases are mainly involved in species growth and development while the expansion of genes in group B chitinases is related to fungal mycoparasitic and entomopathogenic abilities and to a certain extent the expansion of genes in group C chitinases seems to be correlated with the host range broadening of some plant-pathogenic fungi in Sordariomycetes. Further selection pressure testing revealed that chitinases and the related amino acid sites were under positive selection in the evolutionary history especially at the nodes sharing common ancestors and the terminal branches of Hypocreales. These results give a reasonable explanation for the size and function differences of chitinase genes among ascomycetes and provide a scientific basis for understanding the evolutionary trajectories of chitinases particularly that towards a mycoparasitic lifestyle.
Pichia kurtzmaniana f.a. sp. nov., with the transfer of eight Candida species to Pichia
Three yeast strains belonging to the ascomycetous yeast genus Pichia were isolated from two soil samples from Yunnan and Guizhou provinces and a marine water sample from Liaoning province PR China. Phylogenetic analyses based on the sequences of the D1/D2 domains of the large subunit(LSU) rRNA gene and the internal transcribed spacer (ITS) region indicate that these three strains together with 12 additional strains isolated from various substrates collected in different regions or countries of the world represent a novel species of the genus Pichia for which the name Pichia kurtzmaniana sp. nov. (holotype: strain CGMCC 2.7213) is proposed. The novel species differs from its close relatives Candida californica by eight (1.5 %) and 26 (11.1 %) mismatches in the D1/D2 domains and the ITS region respectively; and from Pichia chibodasensis by 11 (2.1 %) and 20 (8.7 %) mismatches in the D1/D2 domains and the ITS region respectively. In addition eight Candida species which belong to the Pichia clade are transferred to the genus Pichia resulting in the proposal of the following new combinations: Pichia cabralensis comb. nov. Pichia californica comb. nov. Pichia ethanolica comb. nov. Pichia inconspicua comb. nov. Pichia phayaonensis comb. nov. Pichia pseudolambica comb. nov. Pichia rugopelliculosa comb. nov. and Pichia thaimueangensis comb. nov.
Vishniacozyma pseudocarnescens sp. nov., a new anamorphic tremellomycetous yeast species
Three strains belonging to the basidiomycetous yeast genus Vishniacozyma were isolated from marine water samples collected from intertidal zones in Liaoning province northeast China. Phylogenetic analyses based on the sequences of the small subunit (SSU) ribosomal DNA (rDNA) the D1/D2 domain of the large subunit (LSU) ribosomal DNA (rDNA) the internal transcribed spacer region (ITS) the two subunits of DNA polymerase II (RPB1 and RPB2) the translation elongation factor 1-α (TEF1) and the mitochondrial gene cytochrome b (CYTB) showed that these strains together with 20 strains from various geographic and ecological origins from other regions of the world represent a novel species in the genus Vishniacozyma. We propose the name Vishniacozyma pseudocarnescens sp. nov. (holotype CGMCC 2.6457) for the new species which differs phenotypically from its close relatives V. carnescens V. tephrensis and V. victoriae by its ability to grow at 30 °C and on 50 % (w/v) glucose-yeast extract agar.
Cystofilobasidium josepaulonis sp. nov., a novel basidiomycetous yeast species
A yeast strain belonging to the basidiomycetous yeast genus Cystofilobasidium was isolated from a marine sediment sample collected in an intertidal zone in Shandong province PR China. The results of phylogenetic analyses based on sequences of the D1/D2 domain of the 26S ribosomal RNA gene and the internal transcribed spacer (ITS) region indicate that this strain together with three other strains isolated from basal ice collected in Norway the gut of an insect and an alga collected in Russia represent a novel species of the genus for which the name Cystofilobasidium josepaulonis sp. nov. (holotype strain CGMCC 2.6672T) is proposed. The novel species differs from the known species of the genus Cystofilobasidium by 1.7 %–4.1 and 11.3 %–17.1 % mismatches in the D1/D2 domain and the ITS region respectively. This species forms teliospores on potato dextrose agar (PDA) and 10 % V8 juice agar but teliospore germination with basidia was not observed.
Saturnispora sinensis sp. nov., a new ascomycetous yeast species from soil and rotten wood
A yeast strain (CGMCC 2.6937T) belonging to the ascomycetous yeast genus Saturnispora was recently isolated from soil collected in Xinghuacun Shanxi Province PR China. The strain produces one or two ellipsoid or spherical ascospores in asci formed by the conjugation between a cell and its bud. Phylogenetic analyses of the internal transcribed spacer (ITS) region and the D1/D2 domain of the large subunit rRNA gene suggest that this strain is conspecific with strains NYNU 14639 isolated from rotten wood collected in Funiu Mountain Henan province and ES13S05 from soil collected in Nantou County Taiwan. The CGMCC 2.6937T group is most closely related to Saturnispora dispora and Saturnispora zaruensis. However strain CGMCC 2.6937T differs from S. dispora by 17 (3.2 % 13 substitutions and four gaps) and 77 (18.8 % 52 substitutions and 25 gaps) mismatches and from S. zaruensis by 15 (2.9 % 12 substitutions and three gaps) and 64 (15.6 % 44 substitutions and 20 gaps) mismatches in the D1/D2 domain and ITS region respectively. The results suggest that the CGMCC 2.6937T group represents an undescribed species in the genus Saturnispora for which the name Saturnispora sinensis sp. nov. is proposed. The holotype strain is CGMCC 2.6937T.
Starmerella fangiana f.a. sp. nov., a new ascomycetous yeast species from Daqu-making environment and other sources
In the survey of yeast diversity in high-temperature Daqu which is a fermentation starter for Chinese sauce-flavoured Baijiu six yeast strains representing one novel species of the genus Starmerella were isolated from samples of Daqu and surrounding environments collected in Zunyi city Guizhou Province China. Phylogenetic analyses of the internal transcribed spacer (ITS) region and the D1/D2 domains of the large subunit rRNA gene indicate that these six strains are conspecific with three other strains isolated from flowers and duckweed collected in Samoa India and Thailand. The representative strain QFC-8 of the new species differs from the closet species Starmerella caucasica resolved by the D1/D2 sequence analysis by 13 (3.1 % 12 substitutions and 1 gap) and 40 (10.3 % 9 substitutions and 31 gaps) mismatches in the D1/D2 domain and ITS region respectively. The results suggest that the novel group represents an undescribed species in the genus Starmerella for which the name Starmerella fangiana sp. nov. is proposed. The holotype strain is CGMCC 2.7773.
Teunia rosae sp. nov. and Teunia rudbeckiae sp. nov. (Cryptococcaceae, Tremellales), two novel basidiomycetous yeast species isolated from flowers
Three yeast strains isolated from three flower samples were identified as representing two novel species of Teunia based on molecular phylogenetic analysis and phenotypic comparisons. Strains 12A8 and 21S4 with pink cream colonies and subglobose to globose cells had identical sequences in the ITS and LSU D1/D2 regions which differed from strain X54 with cream colonies and ovoid to ellipsoidal cells by 6 nt substitutions (1 %) and 9 nt mismatches (1.5 %) in the D1/D2 domains and ITS region respectively. They could also be distinguished from each other in assimilation of glucitol and salicin growth at 28 °C and cell fibrillar appendages under scanning electron microscopy. The three strains differed from known species of Teunia by more than 8 nt (1.3 %) and 30 nt (5 %) in the D1/D2 domains and ITS region respectively. Therefore the names Teunia rudbeckiae sp. nov. (Holotype CGMCC 2.5840 Mycobank MB 835892) and Teunia rosae sp. nov. (Holotype CGMCC 2.5830 MycoBank MB 835891) are proposed to accommodate strain X54 and strains 12A8 and 21S4 respectively.