Abstract:

【Objective】Procyanidins are a kind of important secondary metabolites widely existing in plants. They have higher antioxidant activity increasing plant stress resistance, and endow plants with the health care function of scavenging free radicals at the same time. The study of procyanidins biosynthesis pathway in the pecan kernel is of great significance for improving the germplasm and quality of pecan. 【Method】The sequences of CiDFR, CiLAR and CiANR gene, which are extracted from mixed samples of ‘Pawnee’ 115 and 135 d pecan kernel. These key genes related to the phenolic metabolic pathway, were obtained by RT-PCR amplification, cloning and sequencing.【Result】 CiDFR gene is 1 148 bp long and contains 1 020 bp open reading frame (ORF), encoding 339 amino acids. The CiLAR gene is 1 390 bp long and contains 1 050 bp of ORF, encoding 349 amino acids. CiANR gene is 1 104 bp long, contains 1 014 bp ORF, and encodes 337 amino acids. Fluorescence quantitative PCR showed that CiDFR and CiANR were expressed at high levels in the middle of seed kernel development (95-105 d) and then decreased rapidly to a lower level, while CiLAR was expressed at a higher level at 95 d and then decreased rapidly, and then increased to the highest level at 155 d again. 【Conclusion】CiDFR and CiANR gene expression had a strong correlation with phenolic metabolites, while CiLAR gene had a weak correlation.

Key words: pecan(Carya illinoinensis), metabolism of phenols, gene cloning, bioinformatics analysis, fluorescence quantitative PCR