RAF22, ABI1 and OST1 form a dynamic interactive network that optimizes plant growth and responses to drought stress in Arabidopsis.

Plants adapt to their ever-changing environment via positive and negative signals induced by environmental stimuli. Drought stress, for instance, induces accumulation of the plant hormone abscisic acid (ABA), triggering ABA signal transduction. However, the molecular mechanisms for switching between plant growth promotion and stress response remain poorly understood. Here we report that RAF (rapidly accelerated fibrosarcoma)-LIKE MITOGEN-ACTIVATED PROTEIN KINASE KINASE KINASE 22 (RAF22) in Arabidopsis thaliana physically interacts with ABA INSENSITIVE 1 (ABI1) and phosphorylates ABI1 at Ser416 residue to enhance its phosphatase activity. Interestingly, ABI1 can also enhance the activity of RAF22 through dephosphorylation, reciprocally inhibiting ABA signaling and promoting the maintenance of plant growth under normal conditions. Under drought stress, however, the ABA-activated OPEN STOMATA1 (OST1) phosphorylates the Ser81 residue of RAF22 and inhibits its kinase activity, restraining its enhancement of ABI1 activity. Taken together, our study reveals that RAF22, ABI1, and OST1 form a dynamic regulatory network that plays crucial roles in optimizing plant growth and environmental adaptation under drought stress.

[Study on Filtrating Separated Constituents of Epimedii Folium Based on Its Anti-osteoporosis].

Objective: To investigate the pharmacological effects of Epimedii Folium and its different separate compositions on the rats with RA-induced osteoporosis and to screen the most active constituent. Methods: With the establishment of animal model of osteoporotic rats induced by RA, the efftects of different constituents extracted from Epimedii Folium on the contents of Ca2+, P3+, ALP, StrACP, BCG and E2 in serum were measured, and their influence on the calcium and phosphate of bone, bilateral femur mass/body mass, unilateral femur ash mass/dry mass was evaluated. The femur morphology was observed through histomorphology. Results: The 30% ethanol section can significantly increase the contents of Ca2+, P3+ in model rats, promote the level of E2 in serum, and decrease the contents of ALP, StrACP, BCG and P3+ in serum, significantly raising the unilateral femur ash mass/dry mass and bilateral femur mass/body mass. The total constituents can significantly increase Ca2+, unilateral femur ash mass/dry mass, and unilateralbilateral femur mass/body mass, and decrease ALP and P3+ in serum. In comparing with other groups, except for the positive control group, the observation of histomorphology exhibited that the 30% ethanol section improved the pathomorphism of bone most obviously and significantly increased the density and space of trabecular, with discontinuous spongy bone existing in local gusongzhiincus buttress. The sequence of the effect on anti-osteoporosis was 30% ethanol section > total constituents > water section > 95% ethanol section > polysaccharide. Conclusion: The 30% ethanol section manifested the most significant effect on anti-osteoporosis. The total constituents also had a certain degree of effect on anti-osteoporosis which was weaker than 30% ethanol section. The water and 95% ethanol sections showed a certain extent of preventive effect on anti-osteoporosis, and the effects of polysaccharide group were inapparent.Objective:To investigate the pharmacological effects of Epimedii Folium and its different extacted constituents on the rats with RA-induced osteoporosis.To screening the most active constituent. Methods: With building animal model of osteoporotic rat induced by RA, different constituents extracted from Epimedii Folium affected the content of Ca2+,P3+,ALP,Str ACP,BCG and E2in serum were measured, and on the calcium and phosphate of bone,mass-ratio of in bilateral femur, ash to dry ratio in unilateral were evaluated. The thigh-bone morphological was observed through histomorphology. Results: The 30%alcohol section can significantly increase the content of Ca2+,P3+in model rats, promote the level of E2in serum, and decrease the content of Str ACP,BCG and P3+in serum, significantly raise the mass-ratio of in bilateral femur, and ash to dry in unilateral. The entire ingredient section can significantly increase Ca2+,mass-ratio of in bilateral femur, and ash to dry in unilateral, decrease ALP and P3+in serum. In comparing with other groups, except for the positive control group, the observation of histomorphology exhibit that the 30%alcohol section improved the pathomorphism of bone most obviously and significantly increased the density and space of trabecular, with discontinuous spongy bone existing in local gusongzhiincus buttress. The sequence for anti-osteoporosis was 30%alcohol section>entire ingredien>water section>95%alcohol section>polysaccharide. Conclusion: The 30%alcohol section manifests the most significant effect on anti-osteoporosis. The entire ingredient section also has a certain degree of effect on anti-osteoporosis but weaker than 30%alchol section. The water and 95%alcohol sections show a certain extent of preventive effect on anti-osteoporosis, and the effects of polysaccharide group are inapparent.