(800-26) Identifying candidate genes for nicotine content in tobacco (Nicotiana tabacum) using a MAGIC population through the GWAS and expression profile analysis
research associate zhengzhou tobacco research institute zheng zhou, Henan, China (People's Republic)
Body of Abstract: Plants have enormous metabolic plasticity and can synthesis a wide range of natural products. Nicotine, the main alkaloid in tobacco, is synthesized mainly in the tobacco roots and accumulated in tobacco leaves for defense against pests through transport. The type of tobacco, the position of tobacco leaf on the plant or the degree of maturity may all affect the alkaloids in the tobacco leaf. For example, nicotine content varies greatly between tobacco varieties, with white flue-cured tobacco typically having lower levels and burley tobacco generally having higher levels. Therefore, to uncover the genetic variation that regulates the nicotine content in tobacco, a genome-wide association analysis was performed to identify SNP loci associated with nicotine content and to predict candidate genes using MAGIC population of eight different type of tobacco germplasm as parents. Using 65,143 SNPs developed by 430K SNP microarray technology and detecting the leaf nicotine content of tobacco plants cultivated in two places (Zhucheng and Chenzhou), we carried out the genome-wide association analysis (GWAS) in a population of 600 inbred lines of MAGIC with large genetic variation and nicotine content of tobacco leaf differences. Then a total of 43 significant single-nucleotide polymorphism (SNP) loci associated with leaf starch content were identified using the MLM model, and QTL regulating nicotine content were identified on chromosomes 2 and 12. Finally, combined with the co-expression analysis of candidate gene in QTL region by expression profiling data of tobacco using the tobacco expression profiling microarrays, we obtained 5 candidate genes for regulating the nicotine content of tobacco leaves. The integration of GWAS and expression profile analysis provide an effective strategy to explore the SNPs and candidate genes, which has a potential to develop molecular markers for breeding low nicotine tobacco varieties along with theoretical basis of molecular mechanisms for nicotinic metabolites of plants.