Endophytic Stage Research Articles

Effect of some leaf essential oil phenotypes in coastal redwood on the growth of several fungi with endophytic stages

Experiments assessed the effect of four foliar essential oil phenotypes from a coastal redwood ( Sequoia sempervirens) population on isolates of six fungus species with leaf endophytic stages. The hypothesis tested was that leaf essential oil phenotypes would have differential effects in vitro on these endophytic species. Another objective was to determine whether differences in response to redwood essential oils existed among pathogens isolated from redwood and a mutalistic endophtye never isolated from redwood. These species were: Botrytis cinerea, an opportunist generalist pathogen able to attack redwood; Pestalotiopsis funerea, Phomopsis occulta and Seiridium juniperi, actual or potential conifer pathogens isolated as leaf endophytes in redwood; Cryptosporiopsis abietna, a common conifer endophyte with uncertain ecological status isolated from redwood; and Meria parkeri, a mutalistic endophyte known only from Douglas fir. The four essential oil phenotypes were uniformly inhibitory for some species and differentially so for others. Susceptibility to the four phenotypes varied widely within and among fungus species. The conifer-specific pathogens were the least susceptible and the Douglas fir endophyte the most; the other two displayed intermediate susceptibility. The diversity of responses by these fungus species suggests that these redwood terpenoids may have a differential intra- and interspecific importance in preventing pathogenic activity in the species found within redwood foilage.

Studies in the Physioloǵy of Obliǵate Parasitism. V

Some physiological differences (including the study of carotin pigmentation) between the ectophytic and endophytic stages of Puccinia triticina Erikss. have been investigated, and it is suggested that the principal difference is one of cell-wall permeability, the ectophytic stage having a lower permeability than the endophytic stage.