Glucosyltransferases catalyze the transfer of glucose molecules from an active donor to acceptor molecules and are involved in many plant processes. SIP68, a tobacco glucosyltransferase protein, is a SABP2-interacting protein. It was identified in a yeast two-hybrid screen using SABP2 as bait and tobacco proteins as prey. SABP2, converts methyl salicylate to salicylic acid (SA) as a part of the signal transduction pathways in SA-mediated defense signaling. Subcellular localization is a crucial aspect of protein functional analysis to assess its biological function. The recombinant SIP68 tagged with eGFP was expressed transiently in Nicotiana benthamiana and observed under confocal microscopy. Fluorescent signals were observed in the epidermal cells. Subcellular fractionation of the tobacco leaves transiently expressing SIP68-+eGFP confirmed that SIP68 is localized in the cytosol. To study the role of SIP68 in plant stress signaling, transgenic lines with altered SIP68 expression were generated using RNAi and CRISPR Cas9 and analyzed.

Analysis of SIP68: A UDP Glucosyltransferase for Its Role in Plant Growth and Immunity UDP-glucosyltransferases (GTs) are a group of enzymes that play a crucial role in plant metabolism by transferring glucosyl groups from UDP-glucose to various acceptor molecules. SIP68 is a UDP-glucosyltransferase enzyme that has been identified to interact with SABP2 in a yeast two-hybrid screen. Previous research conducted in our lab has demonstrated that SIP68 is involved in salicylic acid (SA)-mediated defense signaling in tobacco plants. In the current study, we aimed to investigate the potential role of SIP68 in plant development and immune response. Our analysis of SIP68 revealed that this UDP-glucosyltransferase has a gene family, and its gene and protein sequence, molecular attributes, gene structure, and localization in the chromosome, exon-intron distribution, cis-regulatory elements in the promoter region, homology modeling of protein, domain architecture, motif analysis, phylogenetic tree, and protein-protein interaction were analyzed to better understand its potential function in plant metabolism. Our in-silico analysis predicted that SIP68 may play a role in the cytokinin-mediated metabolic pathway, which could affect plant growth and cell proliferation. Specifically, our analysis suggested that SIP68 might transfer glucosyl groups to various acceptor molecules involved in the cytokinin-mediated metabolic pathway. This suggests that SIP68 may play a role in regulating plant growth and development by affecting the cytokinin pathway. To investigate the potential role of SIP68 in plant development, we generated SIP68-deficient transgenic tobacco plants by silencing the SIP68 protein. The observed phenotype of these plants was compared to that of wild-type plants. We found that root, shoot, leaf width, and overall biomass development were all affected in SIP68-deficient plants. This suggests that SIP68 plays a crucial role in regulating various aspects of plant growth and development. This agrees with our previous finding that SIP68 is involved in SA-mediated defense signaling in tobacco plants. Our analysis of protein-protein interactions revealed that SIP68 interacts with various classes of flavanols in-vitro. This interaction provides a starting point for investigating potential targets of SIP68 in tobacco plants. However, the specific in-planta substrate(s) of SIP68 has not yet been identified. Therefore, further investigation is needed to determine the intracellular targets of SIP68 and its specific role in plant metabolism. In conclusion, our study provides insights into the potential role of SIP68 in plant development and immune response. Our findings suggest that SIP68 plays a crucial role in regulating various aspects of plant growth and development. Furthermore, our in-silico analysis predicts that SIP68 may play a role in the cytokinin-mediated metabolic pathway, which could affect plant growth and cell proliferation. Future investigation is needed to determine the intracellular targets of SIP68 and its specific role in plant metabolism. Overall, this study highlights the importance of UDP-glucosyltransferase enzymes (SIP68) in plant development and immune response.