Fifty-eight cDNA clones isolated from a library of transcripts exhibiting up regulation in tomato root giant cells induced by infection with the parasitic nematode Meloidogyne incognita were characterized. A survey of plant tissues identified 31 transcripts present in tissues other than root, including actively dividing and expanding tissues and mature leaf tissues. The identities of approximately 20% of the giant cell transcripts were inferred from DNA sequence data; they include sequences encoding a plasmalemma proton ATPase, a putative Myb-type transcription factor, and the largest subunit of RNA polymerase II.