TECHNOLOGY FOCUS - BIOTECHNOLOGY - Preferred Gene: The Bacillius subtilis FZB42nprE gene targeted mutagenesis carrier pUNprEK comprises: (a) the plasmid pBT2-arcA as donor carrier of antibiotic lox-km, using pstI restriction enzyme to enzyme digest, and recycling the lox-km segment, connected to the common cloning carrier pUC18 to successfully construct intermediate cloning vector pUK; (b) the genome of Bacillius subtilis FZB42 as a template, using the primers nrpE-L1-blunt (EheI) and nrpE-L2 (sphI) to augment nprE gene and sequence on its left side which are totally 1492bp, the program of augment as 95 degrees C, 4 minutes; 94 degrees C, 45 seconds; 62 degrees C, 30 seconds; 72 degrees C, 2 minutes; 30 circulations; 72 degrees C, 10 minutes; connecting the augmented segment to the intermediate cloning carrier pUK in (a) to successfully construct the cloning intermediate carrier pUKN-L; nrpE-L1-blunt (EheI): tcactgttgtctgaatcccttg (SEQ ID NO. not defined); nrpE-L2 (sphI): fully defined 33 bp (SEQ ID NO. not defined); and (c) the genome of Bacillius subtilis FZB42 as a template, using the primers nrpE2274R1 (Sa1I) and nrpE3662R2(KpnI) to augment nprE gene and sequence on its right side which are totally 1388bp, the program of augment as 95 degrees C, 4 minutes; 94 degrees C, 45 seconds; 62 degrees C, 30 seconds; 72 degrees C, 2 minutes; 30 circulations; 72 degrees C, 10 minutes; connecting the augmented segment to the intermediate cloning carrier pUKN-L in (b) after double enzyme digesting the augmented segment by Sa1I and KpnI to successfully construct the Bacillius subtilis FZB42nprE gene targeted mutagenesis carrier pUNprEK; nrpE2274R1 (Sa1I): aatcgtcgacctcgcctatgatgtaac (SEQ ID NO. not defined); nrpE3662R2(KpnI): aaggtaccatgtacaatggaacatggc (SEQ ID NO. not defined). Preferred Bacteria: The gene engineering bacteria has no antibiotic marker. Preferred Method: Constricting method of the Bacillius subtilis gene engineering bacteria of the expression Harpin protein comprises: using conversion method of chemical competence, firstly using the recombinant vector pGAprEHS of expression Harpin protein to transfer the Bacillius subtilis FZB42nprE to attain the intermediate engineering bacteria FZB42/AHS; then transferring the Bacillius subtilis FZB42nprE gene targeted mutagenesis carrier pUNprEK in the intermediate engineering bacteria FZB42/AHS, mutating nprEgene, successfully constructing the Bacillius subtilis gene engineering bacteria FZB42/ANHSK of the expression Harpin protein. It comprises: using conversion method of chemical competence, firstly using the recombinant vector pGAprEHS of expression Harpin protein to transfer the Bacillius subtilis FZB42nprE to attain the intermediate engineering bacteria FZB42/AHS; then transferring the Bacillius subtilis FZB42nprE gene targeted mutagenesis carrier pUNprEK in the intermediate engineering bacteria FZB42/AHS, mutating nprEgene, successfully constructing the Bacillius subtilis gene engineering bacteria FZB42/ANHSK of the expression Harpin protein; finally using the plasmid pBRI-Cre of the expression recombinant enzyme protein Cre to transfer the engineering bacteria FZB42/ANHSK, wiping out the antibiotic marker gene thereof at a low temperature, and successfully constructing Bacillius subtilis gene engineering bacteria FZB42/ANH without antibiotic marker of expression Harpin protein. Preparing biological product of Bacillius subtilis gene engineering bacteria of expression Harpin protein comprises: (a) preparing the fermentation medium in fermentation tank: comprising 10-20g glucose or 10-20g sucrose or 25-35g corn steep liquor, 0.5-1g saccharomyces, 0.5g sodium glutamate, 0.5g magnesium sulfate (MgSO4), 0.5g potassium chloride (KCl), 1g potassium biphosphate (KH2PO4), 0.15g ferrous sulfate (Fe2SO4).6H2O, 5.0mg manganese sulfate (MnSO4).H2O, and 0.16mg copper sulfate (CuSO4).5H2O in culture per milliliter, mixing pH range to 6.8-7.0, adding water to 1L; (b) adding Bacillius subtilis gene engineering bacteria of expression Harpin protein as seed bacteria according to 1%-3% of the fermentation medium volume, temperature at 30-37 degrees C, rotation 300-800 revolutions per minute, dissolved oxygen 30-36 hours, directly using the fermentation liquid as the biological product after the end of fermentation; or centrifugal collecting the spore, vacuuming the spore, adding cornstarch with 99% mass ratio, that is the biological product of Bacillius subtilis gene engineering bacteria of expression Harpin protein. ACTIVITY - Plant Growth Regulant; Plant Protectant.    ADMINISTRATION - Dosage is 1-5x106 to 1-5x108 cfu/ml. Administration can be through seeding bed or spaying (claimed).