A newly identified flower-specific splice variant of AUXIN RESPONSE FACTOR8 regulates stamen elongation and endothecium lignification in arabidopsis

In addition to the full-length transcript ARF8.1, a splice variant (ARF8.2) of the auxin response factor gene ARF8 has been reported. Here, we identified an intron-retaining variant of ARF8.2, ARF8.4, whose translated product is imported into the nucleus and has tissue-specific localization in Arabidopsis thaliana. By inducibly expressing each variant in arf8-7 flowers, we show that ARF8.4 fully complements the short-stamen phenotype of the mutant and restores the expression of AUX/IAA19, encoding a key regulator of stamen elongation. By contrast, the expression of ARF8.2 and ARF8.1 had minor or no effects on arf8-7 stamen elongation and AUX/IAA19 expression. Coexpression of ARF8.2 and ARF8.4 in both the wild type and arf8-7 caused premature anther dehiscence: We show that ARF8.2 is responsible for increased expression of the jasmonic acid biosynthetic gene DAD1 and that ARF8.4 is responsible for premature endothecium lignification due to precocious expression of transcription factor gene MYB26. Finally, we show that ARF8.4 binds to specific auxin-related sequences in both the AUX/IAA19 and MYB26 promoters and activates their transcription more efficiently than ARF8.2. Our data suggest that ARF8.4 is a tissue-specific functional splice variant that controls filament elongation and endothecium lignification by directly regulating key genes involved in these processes

A low-cost Cherenkov detector to be tested in CERN's T9 beam line

The TCO-Asa is a 2015 established team of high-school students of the Liceo Scientifico T. Calzecchi Onesti, in Fermo (Italy), who built a detector instrumented by consumer components including a CMOS camera and a silicon photomultiplier readout by the open-source ArduSiPM kit, to study the Cherenkov effect in water.This proceeding presents the main activities of the students that included the definition of the geometry of the detector, the realisation of the structure prepared by Scanny3D, the optimisation of the coupling between the water and the sensors, the experiences with 18F (prepared by Acom SRL) and 226Rd radioactive sources, and the results of the tests performed at the Beam Test Facility in INFN-Frascati in 2016.The team proposed to expose the detector to a test beam at CERN in 2016 and in 2017 within the Beamline for School initiative. The project was assessed among the best in 2016, and won the competition in 2017. A test beam, with an improved detector, has been done September 2017 at CERN, with the PS beam facility