Corrigendum to "Structural and functional characterization of Tomato SUMO1 gene" [Saudi J. Biol. Sci. 27(1) (2020) 352-357].

[This corrects the article DOI: 10.1016/j.sjbs.2019.10.004.].

Molecular Characterization and Functional Localization of a Novel SUMOylation Gene in Oryza sativa.

Small ubiquitin-related modifier (SUMO) regulates the cellular function of diverse proteins through post-translational modifications. The current study defined a new homolog of SUMO genes in the rice genome and named it OsSUMO7. Putative protein analysis of OsSUMO7 detected SUMOylation features, including di-glycine (GG) and consensus motifs (ΨKXE/D) for the SUMOylation site. Phylogenetic analysis demonstrated the high homology of OsSUMO7 with identified rice SUMO genes, which indicates that the OsSUMO7 gene is an evolutionarily conserved SUMO member. RT-PCR analysis revealed that OsSUMO7 was constitutively expressed in all plant organs. Bioinformatic analysis defined the physicochemical properties and structural model prediction of OsSUMO7 proteins. A red fluorescent protein (DsRed), fused with the OsSUMO7 protein, was expressed and localized mainly in the nucleus and formed nuclear subdomain structures. The fusion proteins of SUMO-conjugating enzymes with the OsSUMO7 protein were co-expressed and co-localized in the nucleus and formed nuclear subdomains. This indicated that the OsSUMO7 precursor is processed, activated, and transported to the nucleus through the SUMOylation system of the plant cell.

Biochemical and molecular characterization of non-host resistance keys in food crops.

Generally, under normal conditions plants are resistant to many of the incompatible pathogens (viral, fungal and bacterial), and this is named "non-host resistance phenomenon". To understand this phenomenon, different types of food crops (faba bean, squash, barley and wheat) were inoculated with compatible and incompatible pathogens. Strong resistance symptoms were observed in the non-host/incompatible pathogen combinations as compared with host/compatible pathogen combinations, which showed severe infection (susceptibility). Reactive oxygen species (ROS) mostly hydrogen peroxide and superoxide were significantly increased early 24 and 48 h after inoculation (hai) in the non-host plants comparing to the host. Antioxidant enzymes activity (catalase, polyphenol oxidase and peroxidase) were not increased at the same early time 24, 48 hai in the non-host resistant and host resistant plants, however, it increased later at 72 and 168 hai. Electrolyte leakage decreased significantly in non-host resistant and host resistant/pathogen combinations. Catalase and peroxidase genes were significantly expressed in non-host resistant and in host resistant plants as compared to the host susceptible one, which did not show expression using RT-PCR technique. Furthermore, Yr5, Yr18 and Yr26 resistant genes were identified positively using PCR in all treatments either host susceptible or non-host resistant plants in which prove that no clear role of these resistant genes in resistance. Early accumulation of ROS could have a dual roles, first role is preventing the growth or killing the pathogens early in the non-host, second, stimulating the gene appearance of related genes in addition the activition of antioxidant enzymes later on which thereby, neutralize the harmful effect of ROS and consequently suppressing disease symptoms. The new finding from this study supporting the plant breeders with new source of resistance to develop new resistant cultivars and/or stop the breakdown of resistance in resistant cultivars.

Structural and functional characterization of Tomato SUMO1 gene.

Small ubiquitin-related modifier (SUMO) genes regulate various functions of target proteins through post-translational modification. The SUMO proteins have a similar 3-dimensional structure as that of ubiquitin proteins and occur through a cascade of enzymatic reactions. In the present study we have cloned a new SUMO gene from Tomato (Solanum lycopersicum L.), cv Saudi-1, named SlS-SUMO1 gene by PCR using specific primers. This gene has SUMO member's features such as C-terminal diglycine (GG) motif as processing site by ULP (ubiquitin-like SUMO protease) and has SUMO consensus ΨKXE/D sequence. Phylogenetic analysis showed that SlS-SUMO1 gene is highly conserved and homologous to Potatoes Ca-SUMO1 and Ca-SUMO2 genes based on sequence similarity. Expression protein of SlS-SUMO1 gene found to be localized in the nucleus, cytoplasm, and nuclear envelop or nuclear pore complex. SUMO conjugating enzyme SCE1a with SlS-SUMO1 protein co-expressed and co-localized in nucleus and formed nuclear subdomains. This study reported that the SlS-SUMO1 gene is a member of SUMO family and its SUMO protein processing using GG motif and activate and transport to nucleus through Sumoylation system in the plant cell.