Among the Rosaceae species, the gametophytic self-incompatibility (GSI) is controlled by a single multi-allelic S locus, which is composed of the pistil-S and pollen-S genes. The pistil-S gene encodes a polymorphic ribonuclease (S-RNase), which is essential for identifying self-pollen. However, the S-RNase system has not been fully characterized. In this study, the self-S-RNase inhibited the Ca...

Cultured pear (Pyrus communis 1. cv Passe Crassane) cells were subjected to temperatures of 39,42, and 45°C. Heat-shock protein (hsp) synthesis was greater at 39'C than at temperatures above 40'C and continued for up to 8 h. Both cellular uptake of radiolabeled methionine and total protein synthesis were progressively lower as the temperature was increased. Polysome levels decreased immediately...

Ribosome-inactivating proteins (RIPs) are widespread among higher plants of different taxonomic orders. In this study, we report on the RIP sequences found in the genome/transcriptome of several important Rosaceae species, including many economically important edible fruits such as apple, pear, peach, apricot, and strawberry. All RIP domains from Rosaceae share high sequence similarity with con...

Pear (Pyrus pyrifolia L.) has an S-RNase-based gametophytic self-incompatibility (SI) mechanism, and S-RNase has also been implicated in the rejection of self-pollen and genetically identical pollen. However, RNA degradation might be only the beginning of the SI response, not the end. Recent in vitro studies suggest that S-RNase triggers mitochondrial alteration and DNA degradation in the incom...

Please also refer to the excellent obituaries written by Miriam Poirier in Carcinogenesis and by Allan Conney in Cancer Research.

A loss and recovery of polysomes coincident with the temperature-dependent interruption and resumption of pear fruit (Pyrus communis, L.) senescence establishes a close correlation between the presence of protein-synthesizing machinery and the progression of senescence and ripening.

Black spot disease, which is caused by the Japanese pear pathotype of the filamentous fungus Alternaria alternata (Fries) Keissler, is one of the most harmful diseases in Japanese pear cultivation. We mapped a gene for susceptibility to black spot disease in the Japanese pear (Pyrus pyrifolia Nakai) cultivar 'Kinchaku' (Aki gene) at the top of linkage group 11, similar to the positions of the s...

Cultured pear (Pyrus communis L. cv Passe Crassane) cells were subjected to temperatures of 39, 42, and 45[deg]C. Heat-shock protein (hsp) synthesis was greater at 30[deg]C than at temperatures above 40[deg]C and continued for up to 8 h. Both cellular uptake of radiolabeled methionine and total protein synthesis were progressively lower as the temperature was increased. Polysome levels decrease...

Gametophytic self-incompatibility in Japanese pear (Pyrus pyrifolia Nakai) is controlled by the single, multi-allelic S-locus. Information about the S-genotypes is important for breeding and the selection of pollen donors for fruit production. Rapid and reliable S-genotype identification system is necessary for efficient breeding of new cultivars in Japanese pear. We designed S allele-specific ...