甘蔗类泛素蛋白UBL5应答SCMV侵染及其与SCMV-6K2的互作

Abstract

<p id="C3">Ubiquitylation plays key roles in the regulation of protein function, growth and development, and response to stress. Ubiquitin-like proteins (UBLs) are the main components of the ubiquitin-proteasome system (UPS). In our previous study, the UBL5 homologue was isolated from sugarcane (<italic>Saccharum </italic>spp. hybrid) by yeast two-hybrid (Y2H) with the 6K2 of <italic>Sugarcane mosaic virus</italic> (SCMV) as bait, and then designated as ScUBL5 with 73 aa in length. In the present study, the interaction of ScUBL5 with the SCMV-6K2 was further confirmed by bimolecular fluorescence complementation assays (BiFC). Bioinformatics analysis showed that ScUBL5 is a stable hydrophilic non-secretory protein without signal peptide or transmembrane domain. Phylogenetic tree analysis showed that <italic>ScUBL5</italic> is species specific. Subcellular localization analysis showed that ScUBL5 is localized in cytoplasm and nucleus. <italic>ScUBL5</italic> gene shows obvious tissue specificity in sugarcane by real-time quantitative PCR analysis. The expression levels of ScUBL5 gene in the established morphogenesis tissues such as the 1st leaf, the 7th leaf, the 8th internode and the root were significantly higher than those in the immature tissues such as leaf roll and the 3rd internode. The expression of<italic> ScUBL5</italic> gene is significantly affected by SCMV infection. <italic>ScUBL5</italic> was significantly upregulated in the early stage of SCMV infection, then downregulated but significantly higher than the control at the late stage of SCMV infection.