Construction of RNAi expression vector of heavy metal ATPases gene HMA2 and genetic transformation in Iris lactea

Heavy metal ATPases HMA2 mediated Cd long-distance transport plays important roles in the distribution and detoxification of Cd2+ in plants. However, the molecular mechanism underlying Cd2+ long-distance transport in Iris lactea remains unknown. Total RNA was extracted from the roots of I. lactea to obtain a fragment of IlHMA2 by RT-PCR. Then RNAi expression vector pARTG1G2 with inverted repeats of HMA2 driven by the promoter CaMV35S was constructed based on the intermediate vector pHANNIBAL and the plant expression vector pART27 by restriction enzyme digestion and ligation. Moreover, the recombinant plasmid was transformed into agrobacterium GV3101 by freezing and thawing method, and then was transformed into I. lactea to obtain IlHMA2-RNAi lines. This would be a good basis for clarifying the IlHMA2 mediated Cd2+ long distance transport in the adaptation of I. lactea to Cd2+ contaminated environments.