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Monodispersed vanadium dioxide (VO 2 ) hollow microspheres aggregated by elliptical nanorods were synthesized via a onestep template-free method. The inside-out Ostwald ripening mechanism is responsible for the formation of the hollow microspheres.Hollow micro-and nano-structures which are hierarchically porous have attracted considerable attention recently because of their fantastic features, such as large interior spaces, low densities, high specific surface areas and high mass transfer rates with wide potential applications in the field, such as in energy conversion and storage devices, water treatment, drug-delivery carriers, gas sensing, and catalysis. [1][2][3][4][5][6][7][8][9] Much effort has been exerted on developing synthetic strategies for fabricating inorganic hollow micro-and nano-structures. Various removable or sacrificial templates, such as mono-dispersed silica or polymer latex spheres, emulsion droplets/micelles 10 and even gas bubbles, 11 have been used in preparing hollow structures. Generally, these methods usually encounter numerous obstacles, such as size limitation by the templates, damaged structures during template removal, high cost and tedious synthetic procedures, and thus are not suitable for large-scale applications.A number of template-free methods have been developed very recently in fabricating hollow micro-and nano-structures by using different mechanisms, such as the nanoscale Kirkendall effect, 12,13 corrosion-based inside-out evacuation, 14,15 oriented attachment and Ostwald ripening. 16,17 Amongst them, Ostwald ripening, a process by which larger particles grow at the expense of smaller ones has been proven to be a facile approach to generate hollow structures. 18 Different materials, such as SnO 2 , 16 TiO 2 , 17 CaF 2 , 19 ZnS 20 and Co 3 O 4 , 20 have been synthesized based on the Ostwald ripening mechanism. However, there are no reports on the synthesis of VO 2 hollow spheres based on the Ostwald ripening mechanism through a hydrothermal route in the literature.As a well-known transition-metal oxide, vanadium dioxide has been extensively studied. Various nanostructures, such as hollow spheres, nanowires, nanobelts, nanorings and nanorods, have been CrystEngComm

Chloroplasts fuel plant development and growth by converting solar into chemical energy. They mature from proplastids through the concerted action of genes in both the organellar and the nuclear genome. Defects in such genes impair chloroplast development and may lead to pigment-deficient seedlings or seedlings with variegated leaves. Such mutants are instrumental as tools for dissecting genetic factors underlying the mechanisms involved in chloroplast biogenesis. Characterization of the green-white variegated albostrians mutant of barley has greatly broadened the field of chloroplast biology including the discovery of retrograde signaling. Here, we report the identification of the ALBOSTRIANS gene HvAST by positional cloning as well as its functional validation based on independently induced mutants by TILLING and RNA-guided Cas9 endonuclease mediated gene editing. The phenotypes of the independent HvAST mutants imply residual activity of HvAST in the original albostrians allele conferring an imperfect penetrance of the variegated phenotype even at homozygous state of the mutation. HvAST is a homolog of the Arabidopsis thaliana CCT Motif transcription factor gene AtCIA2, which was reported to be involved in the expression of nuclear genes essential for chloroplast biogenesis. Interestingly, in barley we localized HvAST to the chloroplast indicating novel without any clear evidence of nuclear localization.One-sentence summaryLeaf variegation in the barley mutant albostrians is caused by mutation of a single CCT-domain containing gene with residual activity, which is directed to the chloroplast.