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 BvNTL2’s role in drought resistance. The BvNTLs 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, BvNTL2 translocates to the nucleus, where its transmembrane domain is cleaved, resulting in its direct nuclear localization. Functional validation in Arabidopsis demonstrated that BvNTL2 overexpression enhances drought tolerance by increasing antioxidant enzyme activities and promoting the expression of ABA-related genes. This study highlights BvNTL2 as a promising candidate gene for the genetic improvement of drought-resistant sugar beet.

Sugar beet is one of the important sugar crops in China, and drought has become the main constraint on the high-quality development of the sugar beet industry due to the regional factors such as lower precipitation, uneven seasonal distribution and limited water resources and so on. Heat shock protein 70 (HSP70) plays an important role in plant growth, development and abiotic stress response. However, there is still very limited information about the identification of HSP70s and drought resistance in sugar beet. In this study, bioinformatics was used to explore the HSP70s in sugar beet, and their gene structure, phylogenetic relationship, chromosome mapping, cis element distribution and expression under drought stress were analyzed. The results showed that a total of 28 BvHSP70 genes were identified, with sequence length ranges from 1551 bp to 3240 bp, which were distributed on 9 chromosomes of sugar beet. The number of amino acids encoding proteins are 516 ~ 1079, and the theoretical isoelectric point is between 4.98 and 9.33, most of which are acidic hydrophobic proteins, which are mainly located in the endoplasmic reticulum and cytoplasm. Collinearity analysis showed higher homology with rice and maize, and analysis of gene structure and protein conserved motif showed that it had different degrees of differentiation during the evolution of sugar beet. Analysis of cis-elements in the promoters revealed their association with growth and development, hormone response, and abiotic stress. RNA-seq and proteomics analysis showed that 20 genes of BvHSP70s responded to drought stress, and qRT-PCR validation confirmed that 10 of these genes were upregulated, and they were specifically expressed in roots, petioles and leaves of sugar beet, and more genes were expressed in roots. The results of this study lay a foundation for the subsequent in-depth analysis of the gene function of the BvHSP70 family in sugar beet, and also provided a theoretical basis for further exploring the response mechanism of beet under drought stress.

Sugar beet is an important sugar crop, and its roots are mainly used for processing raw materials to produce products such as sugar, molasses, and saccharin, as well as being used as fodder for livestock. BvCPD, a key enzyme gene for brassinosteroid (BR) synthesis, regulates the development of parenchyma cells and vascular bundles by promoting BR synthesis, which promotes the expansion of the sugar beet taproot and influences the growth, development, and yield of sugar beets. This study investigated the impact of BvCPD on the physiological metabolism of sugar beet utilizing BvCPD overexpression, silent, and wild-type (WT) lines. BvCPD increased the chlorophyll content and maximum photochemical efficiency and improved the photosynthetic characteristics of sugar beet leaves. Simultaneously, BvCPD increased the rate of sugar beet taproot respiration and ATP content by enhancing the activities of phosphoglycerate kinase, alcohol dehydrogenase, sucrose synthase, and sucrose synthase catabolism. Moreover, BvCPD induced changes in the sugar fraction content, which increased the sugar yield of a single plant. In addition, BvCPD promoted water absorption, nitrogen accumulation, and lignin/cellulose synthesis activities, facilitated by increased activities of phenylalanine ammonia-lyase, cinnamyl alcohol dehydrogenase, cellulose synthase, and protein serine/threonine phosphatases, providing the requisite energy and materials for sugar beet growth. These findings not only provide a new perspective for understanding the physiological mechanisms regulating the growth of sugar beets but also provide a theoretical basis for the future improvement of sugar beet varieties through molecular breeding techniques.

The sugar beet (Beta vulgaris L.) industry in China occupies a pivotal position in the national sugar supply, yet drought in its major cultivation areas has become a key limiting factor for its high-quality development. Glycosyltransferases (GTs) play a pivotal role in plant responses to abiotic stress, particularly in the regulation of drought resistance. However, the systematic identification of the BvUGT90 gene family in sugar beet and the functional characterization of its members under drought stress remain largely unexplored. In this study, drought stress was simulated in the sugar beet cultivar ‘HI0466’ using the weighing method to regulate soil moisture. Samples were collected at different stress durations and after rewatering for subsequent experimental analyses. In this study, 121 members of the BvUGT90 family were identified in sugar beet, and a comprehensive analysis was conducted on their gene structures, phylogenetic relationships, promoter cis-acting elements and expression patterns under drought stress. The results showed that these 121 members were unevenly distributed across 9 chromosomes. The proteins they encode had an average amino acid length of 474, with molecular weights ranging from 10.78 to 99.10 kDa and theoretical isoelectric points (pI) from 4.68 to 8.69 (with an average of 5.76). Notably, 110 of these members (accounting for 90.91%) were identified as hydrophilic proteins. Synteny analysis indicated a high degree of homology between the BvUGT90 family members in sugar beet and their orthologous genes in Arabidopsis thaliana. Analysis of promoter cis-acting elements revealed the presence of six major categories of core elements in the promoter regions of BvUGT90 genes, including hormone-responsive elements, stress-responsive elements and pathway regulatory elements. Transcriptomic data showed that 45 BvUGT90 family members exhibited significant responsiveness to drought stress. Proteomic analysis demonstrated that 10 of these members were significantly upregulated at the protein level under drought stress, and these results were further validated by quantitative real-time polymerase chain reaction (qRT-PCR). Integrated transcriptomic and proteomic analyses identified Bv_005070_jjst.t1 and Bv6_140060_stjc.t1 as the family members with the most prominent responses to drought stress. Furthermore, transgenic transformation of sugar beet was performed, which confirmed that Bv_005070_jjst.t1 plays an important role in drought stress resistance. The findings of this study provide direct candidate genes from this family for drought-tolerant sugar beet breeding.

Tandem-pore potassium (TPK/KCO) channels play important roles in plant salt tolerance and K⁺ homeostasis. However, the TPK/KCO gene family has not been systematically characterized in sugar beet (Beta vulgaris L.), the world’s second-largest sugar crop, and its functions in salt-stress responses remain largely unknown. In this study, six TPK/KCO family members were identified from the sugar beet genome and systematically analyzed by bioinformatics and expression analyses. The BvTPK genes were unevenly distributed across three chromosomes, designated BvTPK1–BvTPK6, and contained characteristic Ion_trans_2 and PRK10537 domains. Phylogenetic analysis classified TPK/KCO proteins into three major groups, with BvTPK1, BvTPK2, BvTPK3, and BvTPK6 in Group II, BvTPK5 in Group I, and BvTPK4 in Group III. The promoter regions of BvTPKs contained numerous cis-regulatory elements associated with light, hormone, and stress responses. Transcriptomic and RT–qPCR analyses revealed that several BvTPK genes responded to salt stress, with BvTPK2 showing strong salt-induced expression in leaves. Subcellular localization confirmed that BvTPK2 was localized to the tonoplast. Moreover, heterologous overexpression of BvTPK2 enhanced seed germination and survival, improved plant growth and fresh and dry weights, and maintained better photosynthetic performance in Arabidopsis under salt stress, indicating that BvTPK2 positively contributes to salt tolerance. The overexpressing lines also exhibited reduced Na⁺ accumulation, enhanced K⁺ retention, and lower Na⁺/K⁺ ratios, indicating improved ionic homeostasis under salt stress. Collectively, these findings provide a characterization of the TPK/KCO gene family in sugar beet and identify BvTPK2 as a key candidate gene associated with salt tolerance.

Non-specific lipid transfer proteins (nsLTPs) participate in lipid-related processes and plant responses to abiotic stress, yet their roles in drought tolerance in sugar beet remain largely unclear. In this study, a genome-wide analysis identified 15 nsLTP genes in sugar beet, distributed across six chromosomes, and promoter analysis revealed multiple cis-acting elements associated with abiotic stress responses. Among these genes, BvnsLTP10 exhibits sustained up-regulation in leaves and peak induction in roots and stems under PEG-induced drought. Subcellular localization analysis showed that BvnsLTP10 is a secreted protein localized to the cell wall/apoplast, suggesting a role in extracellular lipid transport. Functional characterization in transgenic Arabidopsis demonstrated that BvnsLTP10 overexpression enhanced drought tolerance, as evidenced by increased fresh weight (1.85-fold), relative water content (1.41-fold), chlorophyll content (+ 36%), and Fv/Fm (+ 19.6%), along with elevated antioxidant enzyme activities (POD + 65.1%, SOD + 37.5%, CAT + 54.3%) and reduced electrolyte leakage (- 17.63%). SEM observations indicated potential changes in leaf and stem surface structures, and coordinated upregulation of wax biosynthesis and transport genes (KCS1, CER1, CER3, WSD1, FAR3, ABCG11; ~ 20-40-fold) under drought stress, suggesting a possible involvement of wax-related pathways. These findings indicate that BvnsLTP10 enhances drought tolerance by improving plant water status, strengthening antioxidant defense systems, and promoting extracellular structural modifications. Notably, the functional validation was conducted in Arabidopsis thaliana rather than sugar beet, which may limit direct functional extrapolation to the crop species. Nevertheless, BvnsLTP10 represents a promising candidate gene for future studies aimed at enhancing drought resilience in sugar beet.