Kn. Lambert et al., Identification of genes whose transcripts accumulate rapidly in tomato after root-knot nematode infection, PHYSL MOL P, 55(6), 1999, pp. 341-348
Root-knot nematodes (Meloidogyne spp) penetrate tomato (Lycoprrsicon escule
ntum) and other hosts near root tips and migrate intercellularly to the dev
eloping vascular tissue where they induce formation of feeding cells or, in
the case of resistant tomato, trigger a localized necrosis. To investigate
early events in the host response to nematode infection, a seedling inocul
ation procedure was designed that produced hundreds of root tips synchronou
sly infected with Meloidogyne javanica. RNA extracted from these tips was u
sed to produce a cDNA library. Differential screening of a subset of this c
DNA library identified eight cDNA clones representing genes that are reprod
ucibly increased in level after nematode infection. Sequence analysis revea
led that two clones correspond to previously isolated genes encoding ascorb
ate free radical reductase and an extensin. A third appears to encode a per
oxidase. A fourth encodes a product similar to a tumor-induced tobacco gene
and belongs to the Kunitz trypsin inhibitor family of proteins. Another en
codes a protein highly similar to a tobacco LEA5-like protein. Transcripts
of all eight genes are present at higher levels after nematode infection in
both susceptible and resistant tomato cultivars. (C) 1999 Academic Press.