The invention discloses a new member NtIRL2 of a Nicotiana tabacum isoflavone reductase-like (NtIRL) gene family. The sequence of an open reading frame of the NtIRL2 is shown as 79
nucleotide to 1011
nucleotide in SEQ ID NO.10. The invention performs systemic bioinformatic analysis on the members NtIRL1 and NtIRL2 of the NtIRL gene family, sets forth the expression features of the NtIRL1 and NtIRL2 genes in each tissue and organ of Nicotiana tabacum, constructs a plus sense expression vector and an antisense expression vector, and verifies that the NtIRL1 and NtIRL2 genes are coded with activated nicotine synthesis correlated enzymes through genetic transformation. The NtIRL1 and NtIRL2 genes play vital roles in the biosynthesis and metabolic pathway of tobacco nicotine, participate in the fungal disease defense of tobacco plants, can be used for regulating the nicotine content of Nicotiana tabacum and improving the disease resistance, and is beneficial to the gene engineering breeding of high-quality tobacco having low nicotine content and high fungal disease resistance.
