Abstract
Root-knot nematodes (Meloidogyne spp.) invade a wide range of host plants and alter cell growth and development by inducing the formation of giant cells at the nematode feeding site. To investigate the specific gene expression in giant cells resulting from nematode infection, a rapid method was developed to extract cytoplasmic contents directly from individual giant cells in tomato cv. Grosse Lisse roots infected by M. javanica. Using a modified pressure probe system, up to 1 nl of cytoplasmic contents was extracted from individual giant cells at 25 days post-infection. The origin of the extracted cytoplasm was confirmed by the presence of nuclei in extracts after fluorescent staining. mRNA was isolated from the extracted cytoplasm, and RT-PCR was carried out to analyse gene expression of two house-keeping genes for actin and glyceraldehyde-3-phosphate dehydrogenase, and two genes (Lemmi9 and IC9) up-regulated after nematode infection. This direct extraction method provides a new approach to collect starting material for studies on the molecular events that occur in plant-nematode interactions.