Cloning And Functional Analysis Of HKT2in Shanlan Rice In Hainan

Salinity soil is a worldwide problem threatening crop production and leads to yield reduction of a wide variety of crops all over the world.Therefore, the improvement of crop resistance to salt, prevention and improvement of saline soil for more efficient production of crops is a major research topic, and the study of salt tolerance gene through the use of biological technology is the basis of improving crop plants grown in the saline soil.HTK family has played a very important role as one of the cation transporters in plants, and its function is Na+-K+or Na+transporters.Shanlan upland rice is one of the major types of upland rice, which is of important social, ecosystem and economic value. In order to investigate Na+and K+transport mechanism of HKT2in Shanlan upland rice in Hainan, a pair of primers were designed based on the conserved sequences of the HKT2genes registered in GenBank from Oryza sativa. Reverse transcription was performed immediately after the extraction of the total RNA from the root, after the amplification of the partial cDNA by PCR. The PCR product was sub-cloned into pMD18-T vector. The sequencing results indicated that the length of the amplified cDNA fragment was1593bp and encoding530amino acid. Sequence analysis suggested that the nucleotide sequence and the translated amino acid sequence shared over94%and91%of homology to HKT2gene sequences from Oryza sativa, respectively.Over-expression of the HKT2genes and subcellular localization of their product in the Chlamydomonas reinhardtii CC124were also done in this paper. HKT2gene mRNA expression abundance in CC124had greatly improved than in the control group. Through analyzing of subcellular localization, HKT2were located in the cell membrane range.Through cultured in different NaCl concentrations TAP medium, determination the salt-tlerance of the genetically modified algae strains and wild type algae strans. Results indicated that in the TAP medium containing150mmol/LNaCl or225mmol/L KC1, the growth of wide type CC124was significantly inhibited. While in the TAP medium containing100mmol/L NaCl or200mmol/L KC1, the growth of transgenic strains CC124was significantly inhibited. ShuHKT2gene might have reduced Chlamydomonas reinhardtii CC124cells’ salt-tolerant capacity.