Abstract: In order to study the mechanism of Xinjiang walnut dew, the germplasm Wen 138 of bared-nut walnut was taken as the research object, and the mutant Zhipi walnut was used as the control. The 4CL gene was cloned by RT-PCR and analyzed by bioinformatics method. Fluorescence quantitative PCR was used to study the relative expression of 4CL gene in the process of walnut hardening, and the expression characteristics of 4CL in the development of hard shell walnut and the endocarp of bared-nut walnut were studied. The results showed that the cDNA sequence in WJ-4CL gene contained a 552 bp ORF, encoding 184 amino acids, with the molecular weight of 20.10 ku and isoelectric point of 5.83. The cDNA sequence in ZJ-4CL gene contained a 453 bp ORF, encoding 151 amino acids, and the molecular weight and isoelectric point were 16.52 ku and 9.35, respectively. The phylogenetic tree indicated that Wen 138 and Zhipi were clustered together, and their genetic relationship was relatively close. Real-time fluorescent quantitative PCR analysis indicated that relative expression of WJ-4CL gene in the 100 d after flowering was 117 times that in the 51 d after flowering, while the relative expression of ZJ-4CL gene in the 86 d after flowering was 205 times that in the 51 d after flowering, which preliminarily certified that the expression of 4CL gene was different in different development stages in the two walnut species. The results proved that the 4CL gene participated in the development of walnut endocarp harden processing and affected the synthesis of lignin in the endocarp, resulting in the hypoplasia of walnut endocarp and bared-nut.

Key words: Walnut, Lignin, 4-hydroxycinnamate CoA ligase, Gene cloning, Expression analysis

CLC Number: 

• Q78

• S662.03