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Differential Expression of a β-1,4-Endoglucanase Induced by Diet Change in the Foliar Nematode Aphelenchoides fragariae

August 2012 , Volume 102 , Number  8
Pages  804 - 811

Zhen Fu, Paula Agudelo, and Christina E. Wells

First and second authors: School of Agricultural, Forest, and Environmental Sciences, 114 Long Hall, and third author: School of Agricultural, Forest, and Environmental Sciences, 168 Poole Agricultural Center, Clemson University, Clemson, SC 29634.

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Accepted for publication 27 April 2012.

We identified and characterized a β-1,4-endoglucanase, Afr-ENG-1, in the foliar nematode Aphelenchoides fragariae that is differentially expressed when the nematode feeds on fungi or plants. When individuals from hosta plants were transferred to a fungus culture, expression of the enzyme decreased 1,812-fold after five generations on the fungus diet. Afr-eng-1 was readily detected in the genome of 75% of nematodes from the plant population but only in 38% of the diet-changed population. The gene cannot be detected in nematodes maintained on fungus for over 100 generations. Diet was also associated with changes in nematode body size and in the severity of symptoms caused on hosta leaves. Plant-diet nematodes caused larger lesions and were longer and thinner than fungus-diet nematodes. Nematodes moved from a plant diet to a fungus diet for five generations had the same body size as the nematodes that had fed on the fungus for 100 generations. Full-length sequences of Afr-eng-1 were obtained and found to encode a glycosyl hydrolase family 5 protein. This is the first β-1,4-endoglucanase and plant-parasitism-related gene described in the genus Aphelenchoides.

Additional keyword: cellulases.

© 2012 The American Phytopathological Society