The presence of indigenous endophytic bacteria in aseptically grown seedlings of Eucalyptus urophylla germinated from surface sterilized seeds was investigated using dilution plating, microscopy, and PCR detection. No culturable endophytic bacteria could be detected in suspensions of ground plant tissue incubated on solid or in liquid cultivation media. However, a large number of endophytic bacterial cells, mostly rod-shaped and measured 2-3 μmÂ0.5-0.8 μm, were observed in in vitro cultured seedlings of E. urophylla using both light and electron microscopy. Using the universal bacterial 16S rDNA primers, a predicted 190-bp fragment was amplified from total DNA isolated from the seedlings of E. urophylla. We concluded that the endophytic bacteria originated from the seed were present in seedlings of E. urophylla. However, the bacterial cells observed appeared to be nonculturable.

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A previously unknown association between Plasmopara viticola, the causal pathogen of grape downy mildew, and the mycoparasite strain F2 was described in this paper. F2 could be consistently isolated from the mildew of diseased spots on grape leaves of Kyoho (Vitis labrusca × V. vinifera cv. Kyoho) infected with P. viticola, but neither from the surfaces of healthy grape leaves nor within lesions of other diseases. It could be observed that strain F2 was capable of coiling around sporangiophores and sporangia of P. viticola under microscope, causing hyphae deformation, decreasing the pathogen growth, and reducing the number of sporangia. This fungal strain was identified as Simplicillium lanosoniveum on the basis of morphological characterizations and 28S rDNA sequencing. To our knowledge, this is the first report of S. lanosoniveum with hyperparasitic characteristics on P. viticola, and the hyperparasite has potential application in the control of grape downy mildew.