Salicylic acid antagonizes abscisic acid inhibition of shoot growth and cell cycle progression in rice.

We analysed effects of abscisic acid (ABA, a negative regulatory hormone), alone and in combination with positive or neutral hormones, including salicylic acid (SA), on rice growth and expression of cell cycle-related genes. ABA significantly inhibited shoot growth and induced expression of OsKRP4, OsKRP5, and OsKRP6. A yeast two-hybrid assay showed that OsKRP4, OsKRP5, and OsKRP6 interacted with OsCDKA;1 and/or OsCDKA;2.

Tobacco calmodulin-like protein provides secondary defense by binding to and directing degradation of virus RNA silencing suppressors.

RNA silencing (RNAi) induced by virus-derived double-stranded RNA (dsRNA), which is in a sense regarded as a pathogen-associated molecular pattern (PAMP) of viruses, is a general plant defense mechanism. To counteract this defense, plant viruses express RNA silencing suppressors (RSSs), many of which bind to dsRNA and attenuate RNAi. We showed that the tobacco calmodulin-like protein, rgs-CaM, counterattacked viral RSSs by binding to their dsRNA-binding domains and sequestering them from inhibiting RNAi.

The C-terminal residues of the 2b protein of Cucumber mosaic virus are important for efficient expression in Escherichia coli and DNA-binding.

The RNA silencing suppressor 2b protein of Cucumber mosaic virus (CMV) is difficult to produce in Escherichia coli. We compared two CMV 2b proteins that differ in their toxicity against E. coli and found that the acidic amino acid residues in the C-terminal significantly affected the toxicity and expression level of the protein in E.

A strategy for screening an inhibitor of viral silencing suppressors, which attenuates symptom development of plant viruses.

To find out whether we can control plant virus diseases by blocking viral RNA silencing suppressors (RSSs), we developed a strategy to screen inhibitors that block the association of RSSs with siRNAs using a surface plasmon resonance assay. The screened chemicals were tested in competition with RSSs for binding to siRNAs using a mobility shift assay. We then confirmed that tested chemicals actually inhibited the RSS activity in vivo using a protoplast assay which was developed for this purpose.

Identification of a gene for UDP-sulfoquinovose synthase of a green alga, Chlamydomonas reinhardtii, and its phylogeny.

Sulfoquinovosyl diacylglycerol is responsible for the structural and functional integrity of the photosystem II complex of a green alga, Chlamydomonas reinhardtii. We cloned a cDNA of C. reinhardtii containing an open reading frame for a protein 36-64% identical in the primary structure to known UDP-sulfoquinovose synthases, which are required for SQDG synthesis, in other organisms.

Differing involvement of sulfoquinovosyl diacylglycerol in photosystem II in two species of unicellular cyanobacteria.

Sulfoquinovosyl diacylglycerol (SQDG) is involved in the maintenance of photosystem II (PSII) activity in Chlamydomonas reinhardtii[Minoda, A., Sato, N., Nozaki, H.