Cloning and expression of class I chitinase gene from four mangrove species under heavy metal stress

AimsCu, Pb and Cd are common heavy metals in mangroves. Objective to clone chitinase I gene in mangrove plants and explore the role of chitinase I gene in plants under heavy metal stress. MethodsHomologous cloning and RACE cloning were used to clone chitinase type I gene in mangrove plants, and bioinformatics analysis software was used to analyze and predict gene structure and functional domain. The mRNA expression pattern of chitinase gene in mangrove plants under heavy metal stress was analyzed by real-time quantitative PCR analysis. ResultsAll Four cDNA with a full length of 1092 bp, and an ORF (open reading frame) 831 bp, coding with 276 amino acids, while are differences in the sequences among the four species. Four genes owned signal peptide and were located at vacuole inside the cell. Protein sequence domain analysis indicates that all have the same typical structural characteristics of GH19 chitinase family. The sequence of CHI had high similarity to the protein sequences of Camellia fraternal chitinases. Real-time PCR was used to analyze the expression of CHI under different concentration heavy metal with time of four mangrove species. The gene expression of CHI I was highly induced in the B.gymnorrhiza leaves than other mangrove species. With the increase of heavy metal stress time, the expression level of B.gymnorrhiza increased continuously.ConclusionChitinase was induced under heavy metal in mangrove plants, and chitinase plays an active part in heavy metal tolerance in mangrove plants which was located at vacuole inside the cell.