Functioning of the thaumatin-like (TL) protein is known to be pathogenesis- or stress-related. Here we identified TL protein cDNA, from an apple- skin library, that was nearly identical to that of the MdTL1 gene. Transcripts of this so-named gene, MdTL1a, were highly expressed in the fruit, but rarely in other tissue types. Expression was found in both the skin and the flesh of the fruit We also examined the environmental or hormonal control of MdTL1a expression. Exposing the fruit to light caused this gene to be induced in the skin tissues. Accumulation of MdTL1a mRNA reached a peak between Days 1 and 5 after exposure. In the leaves, MdTL1a was induced by salicylic acid (SA), but was not significantly affected by any other stresses. Analysis of the MdTL1a genomic done, λTL1, revealed that transcription of MdTL1a begins 53 bp upstream of the start codon. Sequence analysis of the ca. 1.0-kb MdTL1a promoter region has enabled us to predict that it has a stress-related cis-element, such as the ABA responsive element (ABRE), as well as a light-responsive GT-1 and I-box.