Time-course transcriptomic analysis of Nicotiana tabacum roots under drought stress. Two varieties (ZC208, drought-tolerant; ZY100, drought-sensitive) were subjected to two water treatments (Control: 7375% field capacity; Drought: 3840% field capacity). Root samples were collected at five time points (0, 14, 21, 28, and 35 days after treatment initiation) with three biological replicates per group. Total RNA was extracted, mRNA was enriched using poly-T oligo-attached magnetic beads, and libraries were sequenced on an Illumina HiSeq 4000 platform (150 bp paired-end reads).