Interaction of Herbicides and Quinone with the Q(B)-Protein of the Diuron-Resistant Chlamydomonas reinhardtii Mutant Dr2.

We have used the diuron-resistant Dr2 mutant of Chlamydomonas reinhardtii which is altered in the 32 kilodalton Q(B)-protein at amino acid 219 (valine to isoleucine), to investigate the interactions of herbicides and plastoquinone with the 32 kilodalton Q(B)-protein. The data contained in this report demonstrate that the effects of this mutation are different from those of the more completely characterized mutant which confers extreme resistance to triazines in higher plants. The mutation in C.

Phosphorylation of Thylakoid Proteins of Oryza sativa: In Vitro Characterization and Effects of Chilling Temperatures.

The phosphorylation of thylakoid proteins of rice (Oryza sativa L.) was studied in vitro using [gamma-(32)P]ATP. Several thylakoid proteins are labeled, including the light-harvesting complex of photosystem II.

Mapping of the triazine binding site to a highly conserved region of the QB-protein.

A number of herbicide classes, including the s-triazines and ureas (atrazine, diuron) inhibit photosynthetic electron transport via a direct interaction with the QB-protein. This protein, also known as the 32-kDa protein or herbicide binding protein, is believed to bind the plastoquinone QB, which functions as the second stable electron acceptor at the reducing side of Photosystem II. The site of covalent attachment of the photoaffinity herbicide analog azido-[14C]atrazine to the QB-protein of spinach chloroplast thylakoid membranes has been determined.

Chilling Sensitivity in Oryza sativa: The Role of Protein Phosphorylation in Protection against Photoinhibition.

The effects of exposure to low temperature on photosynthesis and protein phosphorylation in chilling-sensitive and cold-tolerant plant species were compared. Chilling temperatures resulted in light-dependent loss of photosynthetic electron transport in chilling-sensitive rice (Oryza sativa L.) but not in cold-tolerant barley (Hordeum vulgare L.

Relationship between Rapid, Firm Adhesion and Long-Term Colonization of Roots by Bacteria.

For rhizobacteria to exert physiological effects on plant growth, the bacteria must first effectively colonize the root surface. To examine the relationship between long-term colonization of root systems and adherence to roots in the short term, a binding assay was developed. Adherence was determined by incubating roots of intact radish seedlings with bacteria, washing and homogenizing the roots, and dilution plating the resulting homogenate.