Abstract: ObjectiveThe present experiment was conducted to clone NAC transcription factor Rd26 gene (MeRd26) from Manihot esculenta Crantz and detect its expression level under drought stress,in order to provide a foundation for fur-ther research on regulation mechanism of MeRd26 gene in response to drought. MethodMeRd26 gene was cloned from M. esculenta leaf by RT-PCR,and its sequence was aligned with sequences of other species,then their phylogenetic tree was constructed. Subsequently,its structural variation between wild variety W14 and cultivated variety Ku50 was revealed, and its expression level under PEG-6000 drought stress was detected by quantitive real-time PCR ( qPCR ) . ResultMeRd26 gene was cloned successfully from M. esculenta leaf,with length of 1288 bp,containing open reading frame (1041 bp),encoding 346 amino acids,containing NAC conserved domain. Phylogenetic tree showed that,MeRd26 protein had close genetic relationship with Rd26 protein of Populus trichocarpa( Potri . 011G123300 . 1 ) and Salix purpurea( SapurV1A . 0127s0020.1). Gene structure variation analysis revealed that MeRd26 gene had 33 SNPs and 7 InDels,and most of these variations were located in the non-coding region and second half of last exon. Expression analysis showed that,MeRd26 gene in leaf of cultivated variety Ku50 was expressed 130 times as that in wild variety W14,while difference was small in root. Under drought stress,expression of MeRd26 gene was rapidly increased in folded leaf,bottom leaf and root with increase of drought stress time,especially in root with the highest expression level. On the contrary,expression of MeRd26 gene was in-hibited and reduced obviously in the first fully expanded leaf. ConclusionMeRd26 gene is involved in drought-resis-tant reaction at transcriptional level,so it can be served as a candidate gene to further study its role in drought-resistant mechanism of M. esculenta.