Lateral organ boundaries domain (LBD) proteins belong to a particular class of transcription factors of lateral organ boundary (LOB) specific domains that play essential roles in plant growth and development. However, a potato phylogenetic analysis of the LBD family has not been fully studied by scholars and researchers. In this research, bioinformatics methods and the growth of potatoes were used to identify 43 StLBD proteins. We separated them into seven subfamilies: Ia, Ib, Ic, Id, Ie, IIa and IIb. The number of amino acids encoded by the potato LBD family ranged from 94 to 327. The theoretical isoelectric point distribution ranged from 4.16 to 9.12 Kda, and they were distributed among 10 chromosomes. The results of qRT-PCR showed that the expression levels of StLBD2-6 and StLBD3-5 were up-regulated under drought stress in the stem. The expression levels of StLBD1-5 and StLBD2-6 were down-regulated in leaves. We hypothesized that StLBD1-5 was down-regulated under drought stress, and that StLBD2-6 and StLBD3-5 up-regulation might help to maintain the normal metabolism of potato and enhance the potatoes' resistance to drought.
Keywords: drought stress; gene expression; lateral organ boundaries domain; potato.