Cloning and expression analysis of PwTCP-1 in Picea wilsonii.

Molecular chaperonins belong to a conserved protein family and play crucial roles in protein folding and assembling. The molecular chaperonin TCP-1 has been shown to be involved in the regulation of plant development. However, little is known of its molecular mechanism in the development of woody plants and their response to abiotic stresses. The PwTCP-1 (T-complex polypeptide 1) gene, encoding molecular chaperonin, was isolated from the cDNA library of Picea wilsonii. The full-length cDNA of PwTCP-1 was obtained by jointing an EST fragment and the end sequence of PwTCP-1 with RACE-PCR. Several bioinformatic tools, such as clustalx, Mega5.0, DNAMAN and Expasy, were used to analyze its physical and chemical properties, as well as secondary and tertiary structures of PwTCP-1. Bioinformatic analysis showed that PwTCP-1 cDNA had a full length of 2 024 bp and a major open reading frame of 1 605 bp, encoding a protein of 534 amino acids, with a molecular mass of 59.2 kDa and a theoretical isoelectric point of 6.12. PwTCP-1 is rich in α-Helix and highly conservative. The expression patterns of PwTCP-1 in various tissues, phytohormone responses and seed germination were investigated by RT-qPCR. The results of tissue-specific expression revealed that it was expressed in every tissue of P. wilsonii, with the expression level in pollen the highest among all tissues and the lowest in the stem. During seed germination, the expression level of PwTCP-1 increased, peaked at the fourth day and then decreased slowly. It should be noted that PwTCP-1 can respond to several phytohormone treatments. The expression level of PwTCP-1 was significantly inhibited by both brassinolide and gibberellin treatments, but up-regulated by a methyl jasmonate treatment. These results suggest that PwTCP-1 is involved in the process of seed germination and a response to several phytohormones.