Infection process and the interaction of rice roots with rhizobia.

Most rhizobial strains inhibit rice root growth in the presence of calcium or potassium nitrates, but not ammonium nitrate. Certain rhizobial strains, however, such as strain R4, do not inhibit rice growth and can enter rice roots and multiply in the intercellular spaces. By using the green fluorescent protein (GFP) as a visual marker, it was found that Rhizobium became intimately associated with rice seedling roots within 24-48 h.

Low temperature treatment at the young microspore stage induces protein changes in rice anthers.

Male reproductive development in rice is very sensitive to various forms of environmental stresses including low temperature. A few days of cold treatment (<20 degrees C) at the young microspore stage induce severe pollen sterility and thus large grain yield reductions. To investigate this phenomenon, anther proteins at the early stages of microspore development, with or without cold treatment at 12 degrees C, were extracted, separated by two-dimensional gel electrophoresis, and compared.

Effect of early cold stress on the maturation of rice anthers.

Male reproductive development in rice (Oryza sativa Linnaeus is very sensitive to various forms of environmental stresses including low temperature. Here, we present our findings on the proteomic analysis of the later developmental consequences of low temperature treatment on rice anthers. Anther proteins at the trinucleate stage, with or without cold treatment for four days at 12 degrees C at the young microspore stage, were extracted, separated by two-dimensional gel electrophoresis (2-DE) and compared.

Proteomic analysis reveals developmentally expressed rice homologues of grass group II pollen allergens.

Three isoallergens of Ory s 2, homologues of grass group II pollen allergens, were identified from rice and characterised by proteome and immunochemical analyses. The N-terminal amino acid sequence profiles of three proteins on a 2-dimensional electrophoresis (2-DE) gel of rice pollen proteins matched 100% to the protein sequences encoded by three rice expressed sequence tags (ESTs). The deduced protein sequences from these ESTs share sequence identities of 41-43% with the protein sequences of the group II pollen allergens of different grasses, and sequence identity of 39% with the C-terminal portion of rice group I pollen allergens.

Proteome analysis of male gametophyte development in rice anthers.

We used proteomic analysis to investigate the changing patterns of protein synthesis during pollen development in anthers from rice plants grown under strictly controlled growth conditions. Cytological analysis and external growth measurements such as anther length, auricle distances and days before flowering were used to determine pollen developmental stages. This allowed the collection of synchronous anther materials representing six discrete pollen developmental stages.

Evaluation of proteome reference maps for cross-species identification of proteins by peptide mass fingerprinting.

We tested whether proteome reference maps established for one species can be used for cross-species protein identification by comparing two-dimensional protein gel patterns and protein identification data of two closely related bacterial strains and four plant species. First, proteome profiles of two strains of the fully sequenced bacterium Sinorhizobium meliloti were compared as an example of close relatedness, high reproducibility and sequence availability. Secondly, the proteome profiles of three legumes (Medicago truncatula, Melilotus alba and Trifolium subterraneum), and the nonlegume rice (Oryza sativa) were analysed to test cross-species similarities.