Molecular cloning and expression analysis of a vacuolar invertase gene, DoVIN2, from Dendrobium officinale Kimura et Migo

Abstract

Abstract Background Dendrobium officinale Kimura et Migo, a traditional Chinese orchid herb famous for its great horticultural and medicinal value, grows in an adverse habitat and suffers from abiotic or biotic stresses. Sugar metabolism is a vital metabolic process in plants that involves acid invertase. Moreover, the participation of acid invertases in plant responses to environmental stress has also been unveiled. However, the function and structure of the vacuolar invertase gene in Dendrobium officinale remain unclear. Methods and Results In this study, the vacuolar invertase gene (DoVIN2) was cloned from the “DanXia” cultivar of D. officinale using homologous cloning. The cDNA sequence of DoVIN2 was 1368 bp and included a 455-amino-acid protein with a sugar hydrolase domain. The DoVIN2 protein did not possess a signal peptide or transmembrane region, was a hydrophilic stable protein, and contained 46 phosphorylation sites, with high conservation in evolution. The transient green fluorescent protein gene (GFP) expression results in rice mesophyll protoplasts demonstrated that DoVIN2 was localized in the cell nucleus. The expression level of the DoVIN2 gene differed significantly among different tissues, with the highest expression in flowers followed by stems, roots, and leaves. Several abiotic stress–responsive elements were present in the promoter region of the DoVIN2 gene. Cold stress and abscisic acid (ABA) treatment upregulated DoVIN2 gene expression, while the expression of DoVIN2 was negatively correlated with polyethylene glycol (PEG) treatment duration. Additionally, the DoVIN2 protein interacted with several enzymes closely associated with sugar metabolism, indicating that DoVIN2 might play a role in abiotic stress responses by regulating the expression of these enzyme genes, thereby enhancing the tolerance of D. officinale to adverse conditions. Conclusions The DoVIN2 gene are involved in various biological processes, including growth and development, stress response, and sugar metabolism. The DoVIN2 might participate in the cold stress response through ABA signaling pathways, while also assuming a negative regulatory function in the response to drought stress. The result provided a basis for further exploring the function of the DoVIN2 gene and a foundation for studying the response of D. officinale to abiotic stresses.