甘蔗类四跨膜蛋白ScTSPAN18与6K2互作应答SCMV侵染研究OA

Tetraspanins(TETs)are a conserved class of transmembrane proteins that are widely distributed across cellular orga-nisms and play important roles.TETs function in part by assembling tetraspanin-enriched microdomains(TEMs).In our previous study,we screened and identified a TET-like protein,ScTSPAN18,from a sugarcane cDNA yeast library using the 6K2 protein of sugarcane mosaic virus(SCMV)as bait,and we also characterized the TET gene family in the sugarcane(Saccharum spp.hybrid)cultivar Xintaitang 22(XTT22).Here,the interaction between SCMV-6K2 and ScTSPAN18 was further validated using bimol-ecular fluorescence complementation(BiFC)and luciferase complementation assay(LCA).Bioinformatic analyses showed that ScTSPAN18 is 251 amino acids long and comprises four transmembrane domains.Structural modeling indicated that ScTSPAN18 differs from classical TETs,and yeast two-hybrid(Y2H)assays showed that ScTSPAN18 neither self-interacts nor interacts with classical TETs.Phylogenetic analysis suggested that TET like proteins are divergent between monocotyledonous and dicotyledo-nous species,as well as between C3 and C4 plants.Subcellular localization assays indicated that ScTSPAN18 is localized to the endoplasmic reticulum.RT-qPCR analysis showed that ScTSPAN18 exhibits tissue-specific expression,with relatively high transcript levels in leaves and roots;expression in the+1 leaf was significantly higher than that in the 3rd and 8th internodes.Following SCMV challenge,ScTSPAN18 expression increased significantly at early infection stages and remained high until day 14,after which it decreased to the basal level.