Strigolactones (SLs) are a new class of carotenoid-derived phytohormones essential for developmental processes shaping plant architecture and interactions with parasitic weeds and symbiotic arbuscular mycorrhizal fungi. Despite the rapid progress in elucidating the SL biosynthetic pathway, the perception and signaling mechanisms of SL remain poorly understood. Here we show that DWARF53 (D53) acts as a repressor of SL signaling and SLs induce its degradation. We found that the rice d53 mutant, which produces an exaggerated number of tillers compared to wild type plants, is caused by a gain-of-function mutation and is insensitive to exogenous SL treatment. The D53 gene product shares predicted features with the class I Clp ATPase proteins and can form a complex with the α/β hydrolase protein DWARF14 (D14) and the F-box protein DWARF3 (D3), two previously identified signaling components potentially responsible for SL perception. We demonstrate that, in a D14- and D3-dependent manner, SLs induce D53 degradation by the proteasome and abrogate its activity in promoting axillary bud outgrowth. Our combined genetic and biochemical data reveal that D53 acts as a repressor of the SL signaling pathway, whose hormone-induced degradation represents a key molecular link between SL perception and responses.

Carriers of CYP2C19 loss-of-function alleles are at greater risk of stroke and composite vascular events than noncarriers among patients with ischemic stroke or TIA treated with clopidogrel.

AimStroke is the leading cause of disability and death in China. Ischaemic stroke accounts for about 60%–80% of all strokes. It is of considerable significance to carry out multidimensional management of ischaemic cerebrovascular diseases. This evidence-based guideline aims to provide the latest detailed and comprehensive recommendations on the diagnosis, treatment and secondary prevention of ischaemic cerebrovascular diseases.MethodsWe had performed comprehensive searches of MEDLINE (via PubMed) (before 30 June 2019), and integrated the relevant information into charts and distributed to the writing group. Writing group members discussed and determined the recommendations through teleconference. We used the level of evidence grading algorithm of Chinese Stroke Association to grade each recommendation. The draft was reviewed by the Guideline Writing Committee of Chinese Stroke Association Stroke and finalised. This guideline is fully updated every 3 years.ResultsThis evidence-based guideline is based on the treatment, care and prevention of ischaemic cerebrovascular diseases, which emphasises on pathogenesis evaluation, intravenous thrombolysis, endovascular therapy, antiplatelet therapy, prevention and treatment of complications, and risk factor management.ConclusionsThis updated guideline presents a framework for the management of ischaemic cerebrovascular diseases. Timely first-aid measures, professional care in the acute stage, and proactive secondary prevention will be helpful to patients.