Characterization of the alkaline/neutral invertase gene in Dendrobium officinale and its relationship with polysaccharide accumulation

Abstract

ABSTRACT. Dendrobium officinale is one of the most wellknown traditional Chinese medicines, and polysaccharide is its main active ingredient. Many studies have investigated the synthesis and accumulation mechanisms of polysaccharide, but until recently, little was known about the molecular mechanism of how polysaccharide is synthesized because no related genes have been cloned. In this study, we cloned an alkaline/neutral invertase gene from D. officinale (DoNI) by the rapid amplification of cDNA ends (RACE) method. DoNI was 2231 bp long and contained an open reading frame that predicted a 62.8-kDa polypeptide with 554-amino acid residues. An alkaline/neutral invertase conserved domain was predicted from this deduced amino acid sequence, and DoNI had a similar deduced amino acid sequence to Setaria italica and Oryza brachyantha. We also found that DoNI expression in different tissues was closely related to DoNI activity, and more importantly, polysaccharide level. Our results indicate that DoNI is associated with polysaccharide accumulation in D. officinale.

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

“…The other PeNIs in the same branch of DcNIs have similar positions. The great similarity between DcNI and PeNI indicates a high degree of relatedness between the two species, which is consistent with previous reports [23]. The α1 group mainly includes AT1G56560, AT3G05820, AT3G06500, DcNI1, DcNI3 and DcNI6.…”

“…The polysaccharides have significant biological activity and can effectively prevent gastric ulcers, strengthen immunity, lower blood sugar and lipid levels [21,22]. The DoNI1 gene in D. catenatum is highly expressed in the stem, which is consistent with the high polysaccharide content in D. catenatum stems [23], so alkaline/NI is likely to play an important role in D. catenatum polysaccharide synthesis [24]. However, most of the alkaline/NI genes of D. catenatum have not been identified.…”

“…Alkaline/NI were previously reported to play an important role in sugar metabolism during plant development [24]. However, no more information is available on the D. dendrobium alkaline/NI gene family, and only two genes have been cloned and studied [23]. According to previous studies on other species, there are species differences in the members of the alkaline/ NI gene family, such as A. thaliana with nine members [10], Capsicum annuum with seven members [11] and Populus with 12 members [12].…”

Transcriptomic Landscape of Medicinal Dendrobium Reveals Genes Associated With the Biosynthesis of Bioactive Components

“…An NI gene, DoNI, was cloned in D. officinale by the rapid amplification of cDNA ends (RASE) method. The expression of DoNI was associated with its activities in different tissues and, more importantly, the polysaccharide accumulation (Gao et al, 2016). Uridine diphosphate glucose (UDPG) is an important direct or indirect glycosyl donor for synthesis of polysaccharides.…”