Root-specific expression of the LeRse-1 gene in tomato is induced by exposure of the shoot to light.

The tomato gene LeRse-1 was isolated from a root hair-specific cDNA library. The amino acid sequence of the LeRse-1 product displayed a high degree of identity to that of AgMtd, a mannitol dehydrogenase-encoding gene from celery. Expression of LeRse-1 was found to be restricted to the root organs of tomato, with no detectable transcripts in stems and leaves. Transcripts of LeRse-1 were detected in root hairs, as well as other root tissues of mature plants and seedlings. Root-specific LeRse-1 expression increased upon exposure of the shoot to light. Since roots were kept in darkness, shoot-to-root communication is required for light-induced LeRse-1 RNA accumulation.