Abstract:

In the present study, life cycle and transmission of Guignardia mangiferae were determined by conventional isolation of endophytic fungi from asymptomatic leaves, withered leaves, cuttage seedlings, seeds and seedlings of various tea plants. The results showed that the highest isolation rate of G. mangiferae was found from species of Camellia sinensis, followed by C. oleifera and then C. japonica. There was also significant difference in G. mangiferaecolonization among various tea cultivars. In tea plants, the newlyflushed leaves were endophytefree. As the leaf was developing, colonization of G. mangiferaegradually increased, and the highest isolation rate of G. mangiferae reached to 73.5% in the mature. Isolation rate of G. mangiferae was also affected by other factors such as date of sprouting, harvest stages, temperature and precipitation. The low isolation rates of G. mangiferae were observed in spring, from February through June, whereas higher isolation rates were observed in May, July August and December. There was a temporal variation of endophytic G. mangiferaein leaves of tea plants in Fujian Province. G. mangiferae was not isolated from seeds and the newly germinated seedlings. With the seedlings developed, G. mangiferae colonized on the seedlings gradually. G. mangiferaecould grow out from the spores collected from the air in tea orchards. G. mangiferaecould transmit from mother stocks to cuttage seedlings, which showed a special pattern of vertical transmission. Based on these data, we suggest that G. mangiferae has two modes of transmission in tea plant orchards, horizontal transmission by ascospores and vertical transmission by mother stocks.

Key words: Camellia sinensis, Guignardia mangiferae, distribution, transmission mode, life cycle