Phytase gene multisite mutant strain of Deshi spore torula yeast and application of phytase gene multisite mutant strain

The invention discloses a phytase gene multisite mutant strain of Deshi spore torula yeast and application of the phytase gene multisite mutant strain and relates to the technical field of biology. According to the phytase gene multisite mutant strain disclosed by the invention, the yeast is subjected to ultraviolet mutation to mutate a phytase gene to obtain a high-activity phytase gene mutant strain of which three amino acid sites are mutated; the high-activity phytase gene mutant strain has quite high phytic acid hydrolysis activity in an overall acidic environment and satisfies the requirement of well hydrolyzing phytic acid at a pH condition of a stomach environment. The strain can be used for producing phytase which is used as a feed or a food and can also be used for producing a microbial phosphatic fertilizer and (or) a biological organic phosphatic fertilizer; the preservation number of the strain is CGMCC No.8738. The mutated phytase gene sequence can be cloned on a pronucleus and (or) eukaryon biological gene expression vector, and a genetic engineering strain and (or) transgenic plants can be built by a genetic engineering technology, so that the phytase gene can be efficiently expressed to produce phytase.