Cloning and Functional Analysis of ClVND1, a Member of the OsNAC7 Subfamily of the NAC Family in Chrysanthemum lavandulifolium

<i>Chrysanthemum × morifolium</i> is a commercially important flower worldwide. <i>Chrysanthemum lavandulifolium</i> is the main model plant for the research on <i>Chrysanthemum</i>. Enhancing stress resistance in <i>C. lavandulifolium</i> is highly significant for improving commercial <i>chrysanthemum</i> production. <i>NAC</i> transcription factors are key regulators of plant growth, development, and stress responses. In this study, we cloned <i>ClVND1</i>-a member of the OsNAC7 subfamily within the NAC transcription factor family-from <i>Chrysanthemum lavandulifolium</i>. The gene comprises a 1164 bp coding sequence (CDS) encoding a protein of 387 amino acids. Overexpression of <i>ClVND1</i> promotes secondary cell wall thickening in the stems of transgenic <i>Arabidopsis</i>, stimulates lateral root growth, and consequently enhances tolerance to salt and low-temperature stress in seedlings. Phenotypic analysis showed that transgenic <i>Arabidopsis</i> exhibited reduced inflorescence elongation and plant height compared to wild-type controls, but an earlier flowering time. These findings suggest that <i>ClVND1</i> enhances stress resistance by promoting lateral root development, while also suppressing inflorescence growth and accelerating flowering time.