Cloning and SNP Analysis of 4CL Gene in Larix kaempferi Hybrids and Their Parent Lines

Based on transcriptome sequencing information, the 4CL gene containing 1 537 bp coding sequences was identified from 11 types of Larix kaempferi cross combinations. Sequence analysis indicated that the coding sequence contained a complete 1 368 bp-ORF fragment, and encoded 455 amino acids. Analysis of qRT-PCR showed that the expression of 4CL in Larix82×Larix13, Larix40×Larix10 and Larix82×Larix61 offsprings were higher than that in their corresponding parent lines, except Larix16×Larix61. The results suggests that the differential expression of 4CL genes in different L. kaempferi cross combinations may be involved in the lignin biosynthesis. In addition, 66 SNPs were identified in 4CL gene, among which 45 SNPs belong to transition type, accounting for 68.18% of the total variance; 20 SNPs belong to transversion type, accounting for 30.30% of the total variance and transition: transversion = 9:4. In the transition type, A/G and C/T transition accounted for 28.79% and 39.39%, respectively; in the types of transversion, A/C, A/T, G/C, and G/T account for 4.55%, 9.09%, 9.09% and 7.58%, respectively. Moreover, the phylogenetic analysis of 4 CL gene in all materials was conducted by NJ method. All results indicated that the 4CL gene showed abundant genetic diversity.