Alteration of host gene silencing during root-knot nematode infection
E. K. WALSH (1), C. G. Taylor (1)
(1) Ohio State University, OARDC, Wooster, OH, U.S.A.
Phytopathology 101:S185

Root-knot nematodes (RKN, Meloidogyne spp.) are an agronomically important pathogen that are capable of establishing intimate feeding sites (giant cells) within the roots of a variety of plant hosts. Elucidating the mechanisms that allow RKN to establish and maintain these giant cells will be crucial in improving our ability to manage the economic damage they cause to crops world-wide. Much of the molecular underpinnings of this interaction however, remain unclear. We utilized functional genomic tools in order to gain more insight into what is necessary for a successful RKN infection. Trends observed in the transcriptome of laser-captured giant cells in Arabidopsis thaliana roots (microarray data obtained from 14 and 21 days post infection) suggest that the RKN infection process may be influencing mechanisms in host gene silencing. A subset of genes altered in their expression during nematode-infestation are found to be up-regulated in Arabidopsis plants over-expressing the suppressor of gene silencing, Hc-Pro. Furthermore, genes normally down-regulated by trans-acting small RNAs are also up-regulated during the nematode infection process. Gene silencing is known to play an important part in plant defense responses to other pathogens, yet little is known with regards to how this pathway is involved during RKN infection. These results may help elucidate the role of gene silencing during the RKN infection process.