ts and bapt genes between taxol-producing fungi and Taxus The amplified DNA fragments of ts (from strain HBA29) and bapt (from strains HAA11 and TA67) were sequenced and analyzed using Blastn in the NCBI database. The ts segment from strain HBA29 shares 40.6% identity with cDNA of ts from T. media [GenBank accession no. AY461450]. The bapt segments
from strains HAA11 and TA67 have lower identity (40.0% and 44.1%, respectively) with cDNA of bapt from T. media [GenBank accession no. AY563630], indicating that it might be a fragment of the new putative fungal bapt gene. Despite our findings are contrary to all previous works of ts and bapt from endophytic fungi buy Doramapimod which show high homology (> 96% sequence identity) with theirs plant counterparts [10, 16, 25–27], the success of our screening for microbial ts, dbat and bapt using the designed PCR primer based on the check details conserved regions of key genes of taxol biosynthetic pathway in yew provides crucial evidence for the molecular blueprint of taxol biosynthesis being an inherent genetic trait of endophytic fungi. Moreover, the detection of taxol production affords definitive proof for the presence of taxol pathway in endophytic fungi. Consequently, low similarity of ts and bapt between plant and
microbial origin seems to give a new insight to the controversial hypothesis of horizontal gene transfer (HGT). The evolutionary trajectory of taxol gene cluster between microbial and plant origin might be coexisting. Although HGT in fungi are largely reported [28], the ultimate plausibility of microbial taxol gene cluster by HGT hypothesis should be revisited and further 4��8C investigated because approximately 20 genes involved in the taxol biosynthesis make HGT rather unlikely. Additionally, taxol-producing endophytic fungi have been isolated from plants which themselves are not capable of producing taxol [29–34], suggesting that taxol biosynthesis in fungi may not be acquired from HGT. In
nature, gibberellin biosynthetic pathways in fungi and higher plants have evolved independently and not by HGT [35, 36]. We thus assumed that taxol biosynthetic cluster might be repeatedly invented during evolution. Moreover, it raises an intriguing question: whether the genes responsible for fungal taxol biosynthesis are indeed grouped in a contiguous cluster? Conclusions Eighty-one endophytic fungi isolated from T. media were grouped into 8 genera based on the morphological and molecular identification. Guignardia and Colletotrichum were the dominant genera, whereas the remaining genera were infrequent groups. Three representative species of the distinct genera can produce taxol. This is the first Temsirolimus report of taxol prodcer from Guignardia. The highest taxol yield was 720 ng/l by Guignardia mangiferae HAA-11.