Fuente: WIPO "tobacco agriculture" The invention discloses a NtHMA4 gene mutant and application thereof. One nucleotide in the NtHMA4 gene mutates, the unmutated NtHMA4 sequence comprises an SEQ ID NO:1 nucleotide sequence, wherein the 152nd C mutates into T, so the 51st amino acid in the gene encoding protein sequence mutates from threonine (Thr) into isoleucine (Ile). Compared with tobacco leaves containing the SEQ ID NO:1 sequence, in tobacco leaves containing the mutated sequence, the content of cadmium is reduced by about 50%, the contents of copper, zinc and nickel are reduced by about 40%, the contents of iron and manganese are reduced by about 30%, and the contents of lead and chromium are reduced by about 20%.