RESUMO
Fungi are a large and diverse group of microorganisms, and although the estimated number of species ranges between 2 and 11 million, only around 150,000 species have been described thus far. The investigation of plant-associated fungi is beneficial for estimating global fungal diversity, for ecosystem conservation, and for the continued development of industry and agriculture. Mango, one of the world's five most economically important fruit crops, is grown in over 100 countries and has been demonstrated to have a great economical value. During surveys of mango-associated saprobic fungi in Yunnan (China), we discovered three new species (Acremoniisimulans hongheensis, Chaenothecopsis hongheensis and Hilberina hongheensis) and five new records. The phylogenetic analyses of multi-gene sequences (LSU, SSU, ITS, rpb2, tef1-α and tub2) coupled with morphological examinations were used to identify all the taxa.
RESUMO
A new heptaketide named oryzanigral (1) was isolated from the fermentation extract of the endophytic fungus Nigrospora oryzae isolated from the leaves of Coccinia grandis, along with five known compounds, (R)-mellein, (R)-O-methylmellein, (3R,4R)-4-hydroxymellein, (3R,4S)-4-hydroxymellein and abscisic acid. The structure of oryzanigral was elucidated by spectroscopic analyses including 2D-NMR. A plausible biosynthetic pathway involving Diels-Alder reaction was proposed for compound 1 and related polyketides previously reported. In addition, structure revision of the double bond geometry for coicenal A was described.
