Pyk10, a seedling and root specific gene and promoter from Arabidopsis thaliana.

Pyk10 is a root and hypocotyl specific myrosinase from Arabidopsis thaliana. Northern analysis revealed the root specific expression of pyk10. In order to study the pyk10 promoter and the genomic structure of the gene, a genomic clone was isolated and sequenced. The clone contained the complete pyk10 gene and a promoter region of 3569 bp. The gene spans 2963 bp and consists of 12 exons and 11 introns, a structure that reflects the common gene organization of myrosinases. Within the promoter sequence, different development specific, organ specific, elicitor and plant hormone responsive regulatory elements could be identified, which also occur in other promoters. To determine the pattern of expression, four different 5'-promoter deletion fragments were linked to a ss-glucuronidase (gus) reporter gene and transformed into A. thaliana. The results demonstrated that the pyk10 promoter mediates a developmental gene activity with a strong emphasis in the root. Cis-acting sequences regulating root specific expression were identified to reside in the two promoter fragments B and C.