In-vitro expression method for pear PMEI (pectin mthylesterase inhibitor) protein, and application of pear PMEI

The invention discloses an in-vitro expression and purification method for a pear PMEI (pectin mthylesterase inhibitor) protein, and application of the pear PMEI. A primer cloning pear PMEI gene is designed; an escherichia coli recombinant expression plasmid PMEI-pCold-TF is constructed; the constructed recombinant expression plasmid PMEI-pCold-TF is converted into escherichia coli Rosetta (DE3) to construct a pear PMEI protein recombinant expression strain; the recombinant strain is subjected to protein induced expression, and a nickel column affinity chromatography method is used for purifying a recombinant pear PMEI protein; and then, the pollen tube of the pear and the root part of arabidopsis thaliana are processed by the obtained recombinant pear PMEI protein. Through the method disclosed by the invention, the first-time in-vitro expression and purification of the pear PMEI protein is realized, expression efficiency is high, a purified protein stably exists, and the purity of thepurified protein completely can meet the requirements of a related experiment. Through processing for the pollen tube of the pear and the root part of the arabidopsis thaliana by the recombinant pearPMEI protein, the pollen tube of the pear and the root part of the arabidopsis thaliana are accelerated to grow.