Identification of the NTL Gene Family in Beta vulgaris L. and Functional Role of BvNTL2 in Drought Resistance

NAC transcription factors form a plant-specific family essential for growth, development, and stress responses. NTLs, a subfamily of the NAC transcription factor family, belong to the membrane-bound transcription factors (MTFs). These proteins contain transmembrane domains that enable rapid nuclear translocation in response to environmental stimuli, thereby regulating target gene expression. As a major sugar crop, sugar beet is primarily cultivated in arid and semi-arid regions, where drought stress significantly impairs yield and quality, underscoring the urgent need to improve its drought tolerance. This study identified the NTL gene family in sugar beet and analyzed its gene structure, evolutionary relationships, cis-regulatory elements, drought-induced expression patterns, and <i>BvNTL2</i>'s role in drought resistance. The <i>BvNTLs</i> family comprises five members located on five distinct chromosomes. Their promoters harbor cis-regulatory elements related to ABA and drought stress, and their expression is drought-responsive. Under drought stress, <i>BvNTL2</i> translocates to the nucleus, where its transmembrane domain is cleaved, resulting in its direct nuclear localization. Functional validation in <i>Arabidopsis</i> demonstrated that <i>BvNTL2</i> overexpression enhances drought tolerance by increasing antioxidant enzyme activities and promoting the expression of ABA-related genes. This study highlights <i>BvNTL2</i> as a promising candidate gene for the genetic improvement of drought-resistant sugar beet.