Abstract

Tobacco prefers nitrate as a nitrogen (N) source. However, little is known about the molecular components responsible for nitrate uptake and the physiological responses of cigar tobacco to N deficiency. In this study, a total of 117 nitrate transporter 1 (NRT1) and peptide transporter (PTR) family (NPF) genes were comprehensively identified and systematically characterized in the whole tobacco genome. TheNtNPFmembers showed significant genetic diversity within and across subfamilies but showed conservation between subfamilies. TheNtNPFgenes are dispersed unevenly across the chromosomes. The phylogenetic analysis revealed that eight subfamilies ofNtNPFgenes are tightly grouped with their orthologues inArabidopsis. The promoter regions of theNtNPFgenes had extensivecis-regulatory elements. Twelve coreNtNPFgenes, which were strongly induced by N limitation, were identified based on the RNA-seq data. Furthermore, N deprivation severely impaired plant growth of two cigar tobaccos, and CX26 may be more sensitive to N deficiency than CX14. Moreover, 12 hub genes respond differently to N deficiency between the two cultivars, indicating the vital roles in regulating N uptake and transport in cigar tobacco. The findings here contribute towards a better knowledge of theNtNPFgenes and lay the foundation for further functional analysis of cigar tobacco.Keywords:cigar tobacco;NRT1/PTR family;expression profile;physiological response;nitrate transport;nitrogen deficiency