Cloning, sequence characterization, expression profiling of hormones response of phenylalanine ammonia-lyase gene in Bletilla striata / 中草药

ABSTRACT

Objective: Phenylalanine ammonia-lyase gene (PAL) is one of the key enzymes associated with stress resistance in secondary metabolism pathway of plants. Exploring its sequence information and expression profiling information in stress response could comprehensively peep at the protein structure, functions and signal network of plant stress resistance. Methods: The full cDNA length of PAL from Bletilla striata was cloned by RT-PCR and RACE approaches. Physicochemical properties and conserved domain of BsPAL protein were determined by a series of bioinformatics tools as Protparam, SOPMA, SWISS-MODEL, etc. Multiple alignment and phylogenetic tree were achieved by DNAMAN and MEGA Software, respectively. The qPCR was employed to examine the expression profiles of BsPAL under exogenous hormone stress. Results: The full cDNA of BsPAL was 2 708 bp, encoding a 797 amino-acid protein with a molecular weight of 86 216.94 and an isoelectric point (pI) of 6.24. The BsPAL protein included the typical structural domain and active site of PALs in other plants, and without transmembrane region, which was more homologous with PALs of Dendrobium officinale and Phalaenopsis aphrodita. The qPCR Results: revealed the expression level of BsPAL in roots was much higher than that in leaves and stems. Under MeJA treatment, the expression trend of BsPAL was first gradually ascending and then descending, while SA treatment had the reverse effect. Conclusion: The BsPAL’s sequence characterizing, expression profiling and responding patterns against SA and MEJA provided a research basis for elucidating the metabolic pathways of phenylpropanoid and hormone signaling research in B. striata.