Genome-wide identification and expression pattern of alkaline/neutral invertase gene family in Dendrobium catenatum

Alkaline/neutral invertase (NI) proteins irreversibly break down sucrose into glucose and fructose and play a vital role in carbohydrate and plant growth and development. Currently, a comprehensive understanding of NI genes in Dendrobium catenatum is lacking. After genome-wide identification and prediction, nine DcNI genes were identified and named DcNI1-DcNI9. Through comprehensive analysis of gene structure, amino acid sequence, conserved motif and phylogenetic tree, it was found that the DcNI gene family has a typical conserved region and its amino acid sequence is similar to other plant NI genes. However, DcNI3 lost amino acid sequences at both the N-terminus and C-terminus, while DcNI8 lost amino acids at the C-terminus. Phylogenetic analysis revealed that the DcNI family could be divided into alpha and beta groups. It reveals conservation and divergence of DcNIs. Predictive analysis of cis-acting elements in the promoter region reveals the potential response of DcNI protein to hormones and environmental stress and suggests it to be widely involved in growth and development. DcNIs were differentially expressed in different tissues such as roots, stems and leaves. In particular, DcNI4 was highly expressed in the stem. They also had a differential expression response under drought, cold, P1 fungus infection and jasmonic acid (JA) treatment. To the best of our knowledge, this is the first genome-wide analysis of the DcNI gene family in D. catenatum. This study will provide important and primary information for the functional study of the DcNI gene family and the polysaccharide synthesis pathway in D. catenatum.