The Euonymus lectin (EUL) family is a unique group of carbohydrate-binding proteins that is omnipresent in plants. Sequences encoding EUL-related lectins have been retrieved from all completely sequenced plant genomes. The rice (Oryza sativa) genome contains 5 functional EUL genes referred to as OsEULS2, OsEULS3, OsEULD1a, OsEULD1b, and OsEULD2. In this study we focused on the tissue specific expression, stress inducibility and subcellular localization of the rice EULs. Even though the EUL domain sequence is highly conserved among the rice EULs (at least 80% sequence similarity) different biotic and abiotic stress treatments yielded unique responses for the different EULs. Transcript levels for OsEULs were differentially affected by drought and salt stress, ABA treatment, pathogen infection or insect infestation. Analysis of promoter activity revealed differential expression and tissue specificity for the 5 OsEUL genes, with most expression observed in the vascular system of roots and shoots, as well as in the root tips and seeds. At cell level, all OsEULs are located in the nucleus whereas OsEULD1b and OsEULD2 also locate to the cytoplasm. This paper contributes to the functional characterization of the EULs and provides insight in the biological importance of this family of proteins for rice.

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Ribosome-inactivating proteins (RIPs) are a class of cytotoxic enzymes that can inhibit protein translation by depurinating rRNA. Most plant RIPs are synthesized with a leader sequence that sequesters the proteins to a cell compartment away from the host ribosomes. However, several rice RIPs lack these signal peptides suggesting they reside in the cytosol in close proximity to the plant ribosomes. This paper aims to elucidate the physiological function of two nucleocytoplasmic RIPs from rice, in particular, the type 1 RIP referred to as OsRIP1 and a presumed type 3 RIP called nuRIP. Transgenic rice lines overexpressing these RIPs were constructed and studied for developmental effects resulting from this overexpression under greenhouse conditions. In addition, the performance of transgenic seedlings in response to drought, salt, abscisic acid and methyl jasmonate treatment was investigated. Results suggest that both RIPs can affect methyl jasmonate mediated stress responses.

Powdery mildew caused by the fungal pathogen Erysiphe necator is a global disease that reduces yield and quality in grapes (Vitis vinifera L.). Most grape cultivars are susceptible to this pathogen and thus the selection of powdery mildew resistant cultivars is a major objective of grape breeding programs. In this study, we evaluated powdery mildew resistance of a diverse set of 28 commonly cultivated local and international V. vinifera cultivars after artificial inoculations with Erysiphe necator. Of these, seven cultivars were found to be resistant while ten and eleven, moderately resistant and susceptible, respectively to powdery mildew. We also analyzed pathogen-responsive expression profiles of two defense genes, VvPR1 and VvGLP3 encoding a Pathogenesis-Related Protein 1 homolog and a Germin-Like protein, respectively, in the same cultivars by qRT-PCR to determine whether defense gene expression is correlated with powdery mildew resistance. There was no significant correlation between powdery mildew ratings and induction patterns of these two defense genes. However, a significant correlation was found between VvPR1 and VvGLP3 expression only in cultivars that show increased powdery mildew resistance. In addition, the grape cultivars we analyzed differed by berry ripening times, was shown to influence disease resistance. However, no significant correlation was found between powdery mildew ratings and the ripening times. Although potential mechanisms of powdery mildew resistance or susceptibility remain unclear, powdery mildew resistant grape cultivars identified here will be useful for growers and breeders interested in using these lines as parents in grape breeding programs.