Genome-wide analysis of the P450 gene family in tea plant (Camellia sinensis) reveals functional diversity in abiotic stress

Abstract

Background: Cytochrome P450 (Cytochrome P450s) genes are involved in the catalysis of various reactions, including growth, development, and secondary metabolite biosynthetic pathways. However, little is known about the characteristics and functions of the P450 gene family in Camellia sinensis (C. sinensis).

Results: To reveal the mechanisms of tea plant P450s coping with abiotic stresses, analyses of the tea plant P450 gene family were conducted using bioinformatics-based methods. In total, 273 putative P450 genes were identified from the genome database of C. sinensis. The results showed that P450s were well-balanced across the chromosomes I to XV of entire genome, with amino acid lengths of 268-612 aa, molecular weights of 30.95-68.5 kDa, and isoelectric points of 4.93-10.17. Phylogenetic analysis divided CsP450s into 34 subfamilies, of which CYP71 was the most abundant. The predicted subcellular localization results showed that P450 was distributed in a variety of organelles, with chloroplasts, plasma membrane,,and cytoplasm localized more frequently. The promoter region of CsP450s contained various cis-acting elements related to phytohormones and stress responses. In addition, ten conserved motifs (Motif1-Motif10) were identified in the CsP450 family proteins, with 27 genes lacking introns and only one exon. The results of genome large segment duplication showed that there were 37 pairs of genes with tandem duplication. Interaction network analysis showed that CsP450 could interact with multiple types of target genes, and there are protein interactions within the family. Tissue expression analysis showed that P450 was highly expressed in roots and stems. Moreover, qPCR analysis of the relative expression level of the gene under drought and cold stress correlated with the sequencing results.

Conclusions: This study lays the foundation for resolving the classification and functional study of P450 family genes and provides a reference for the molecular breeding of C. sinensis.

Keywords: Camellia sinensis; Gene expression; P450 gene family; Promoter; Synteny analysis.

Fig. 1

Phylogenetic relationships of C.sinensis and A. thaliana P450 transporter proteins. The blue triangle represents AtP450 gene and the red asterisk represents CsP450

Fig. 2

Phylogenetic relationship, gene structure, and distribution of conserved motifs of CsP450 proteins in C.sinensis. Diferent motifs are represented by diferent colored numbered boxes

Fig. 3

Chromosomal locations of P450 transporter proteins in C.sinensis. Chromosome numbers are represented at the top of each chromosome

Fig. 4

Synteny analysis of P450 genes in C.sinensis. The red line is a large segment replication between gene family members

Fig. 5

Synteny analysis of P450 genes between the genomes of C.sinensis and A. thaliana. Cs represents C. sinensis genome and AT represents A. thaliana genome. The gray lines are all collinear relationships among different genomes, and the colored lines are collinear relationships among P450 gene family genes

Fig. 6

Protein interactions network diagram of P450 genes in C.sinensis. The red dots are CsP450 genes; the green dots are other genes added based on the String database. The size of the dots represents the size of the degree, and the thickness of the line represents the level of confidence

Fig. 7

Heatmap of CsP450 genes expression clustering in eight different tissues in C.sinensis. The heat blocks represent high and low expression, with red color representing high gene expression and blue color representing low gene expression

Fig. 8

Heatmap of CsP450 genes expression clustering under drought stress in C. sinensis. The heat blocks represent high and low expression, with red color representing high gene expression and blue color representing low gene expression

Fig. 9

Heatmap of CsP450 genes expression clustering under cold stress in C. sinensis. The heat blocks represent high and low expression, with red color representing high gene expression and blue color representing low gene expression

Fig. 10

The relative expression levels of selected CsP450 genes under drought and cold treatments, as determined by qPCR. A The expression profiles of genes under drought treatments at different time points. B The expression profiles of genes under cold treatments at different time points. Error bars show standard deviations among three independent biological replications. * represents p < 0.05