This invention belongs to the field of
agricultural biotechnology and discloses a low-temperature synergistic
biological agent, its preparation method, and its application. The core innovation lies in using a unique engineered
Bacillus subtilis strain as the core functional carrier, and performing a ternary targeted compounding with polydeoxyribonucleotides (PDRN) and biostimulants to achieve a triple synergistic low-
temperature resistance effect. The engineered
Bacillus subtilis strain was deposited at the China General
Microbiological Culture Collection Center (CGMCC) on March 11, 2026, with accession number CGMCC No. 37899. The
chassis strain of
Bacillus subtilis was deposited at the same center on March 3, 2026, with accession number CGMCC No. 37834. The modification strategy involves knocking out the α-
subunit gene of
acetoin dehydrogenase and the phosphoacetyltransferase
gene from the
genome of Bacillus subtilis CGMCC No. 37834, and expressing the acetyllactate synthase
gene and the α-acetyllactate decarboxylase gene.