Enhancing effect of Na₂SeO₃ on the growth and physiological parameters of Vitis vinifera × labrusca 'Shuijing' under nitrogen deficiency and underlying transcriptomic mechanisms

The differences in physiological characteristics and transcriptional response of grape growth under Na₂SeO₃ treatment with nitrogen deficiency are explored, and selenium- and nitrogen-responsive genes are screened. Grape cuttings were divided into seven groups: Control, 0.1Se + 15N, 0.2Se + 15N, 0.4Se + 15N, 0.1Se, 0.2Se, and 0.4Se. Morphological and physiological characteristics in different groups were determined, and transcriptome sequencing was analysed. Net increases in plant height, stem diameter, root volume, biomass, and contents of flavonoids, soluble sugar, and nitrogen in the leaves were higher in the 0.2Se + 15N groups than in the Se groups. 0.2Se + 15N versus Control, 0.2Se versus Control, and 0.2Se versus 0.2Se + 15N had 1196, 2238, and 1980 differentially expressed unigenes (DEGs), respectively. Analysis of these DEGs revealed that, under nitrogen supply conditions, Na₂SeO₃ treatment regulated the upregulation of some gene activities of stilbene synthase, phenylalanine ammonia lyase, 4-coumarate-COA ligase, and α-trehalose phosphate synthase; under nitrogen deficiency conditions, genes encoding auxin and gibberellin were upregulated after Na₂SeO₃ treatment; the expression of these genes plays an important role in regulating the growth of grape plants. The study elucidated the mechanism by which Na₂SeO₃ promotes plant growth under both nitrogen supply and nitrogen deficiency conditions.