Tobacco Arogenate Dehydrogenase NtTYRA1 Affects the Release of Phenol in Mainstream Cigarette Smoke
Tyrosine is one of the precursors of phenol in cigarette smoke,and biosynthesized by tyrosine dehydro-genase/arogenate dehydrogenase(TYRA/ADH)catalyzing arroic acid in plastids.In this study,tyrA1 mutants were screened and identified in EMS mutagenesis population of tobacco(Nicotiana tabacum L.)by TILLING method,and their mutation types were defined.The contents of tyrosine and other amino acids in some mutants,as well as the release of phenol and other phenolic substances in cigarette smoke were determined.The results showed that tertiary structures of the key active site in NtTYRA1 protein were changed due to amino acids variation,which affected the catalytic function of the three tyrA 1 functionally deleterious mutants identified.The contents of tyrosine in NtTM01 and NtTM05 mutants were 67.44％and 85.15％lower than those in the wild type control,respectively.Moreover,the release of phenol in the mainstream smoke of NtTM01 mutant was significantly decreased by 11.89％,and the contents of other phenolic substances were also significantly or extremely significantly decreased.These results showed that the mutation of NtTYRA 1 gene can effectively reduce the content of tyrosine,and subsequently reduce the release of phenol in mainstream cigarette smoke.It can be used as a target gene in genetic engineering to cultivate new varieties of flue-cured tobacco with low phenol release in cigarette smoke.
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万方数据
维普
