Phosphorus(P)is an essential macronutrient for plant growth and development.Vacuoles play a crucial role in inorganic phosphate(Pi)storage and remobilization in plants.However,the physiological function of vacuolar phosphate efflux transporters in plant Pi remobilization remains obscure.Here,we identified three Zm VPE genes(ZmVPE1,ZmVPE2a,ZmVPE2b)by combining them with transcriptome and quantitative real-time polymerase chain reaction(PCR)analyses,showing a relatively higher expression in older leaves than in younger leaves in maize.Moreover,the expression of the ZmVPEs was triggered by Pi deficiency and abscisic acid.ZmVPEs were localized to the vacuolar membrane and responsible for vacuolar Pi efflux.Compared with the wild-type,Pi remobilization from older to younger leaves was enhanced in Zm VPE-overexpression lines.zmvpe2a mutants displayed an increase in the total P and Pi concentrations in older leaves,but a decrease in younger leaves.In rice,Pi remobilization was impaired in the osvpe1osvpe2 double mutant and enhanced in OsVPE-overexpression plants,suggesting conserved functions of VPEs in modulating Pi homeostasis and remobilization in crop plants.Taken together,our findings revealed a novel mechanism underlying Pi remobilization from older to younger leaves mediated by plant vacuolar Pi efflux transporters,facilitating the development of Pi-efficient crop plants.
Ordered mesoporous materials have received great attention due to their well-defined pore structures and potential applications in catalysis,adsorption,separation,drug delivery,etc.Although various compositions of mesoporous solids have been successfully prepared,the preparation of crystalline non-metallic oxyacid salts with ordered mesoporosity remains a major challenge.Herein,we report the synthesis of a mesoporous solid acid crystalline boron phosphate(BPO_(4))catalyst with a bicontinuous shifted double diamond(SDD)hyperbolic surface structure.The BPO_(4) scaffold was obtained by synergistic selfassembly in a mixed solvent of water and tetrahydrofuran using the diblock copolymer poly(ethylene oxide)-block-polystyrene as template and phosphoric acid and orthoboric acid as inorganic sources.The structure consists of two sets of diamond networks adjacent to each other with a mesostructural scale tetragonal symmetry(space group I4_(1)/amd)with unit cell parameters of a=80 nm and c=113 nm,which affords the scaffold a specific surface area of 44 m^(2)/g.As a solid acid catalytic material,the SDD BPO_(4) scaffold exhibited excellent catalytic activity at room temperature with a conversion of furfural to 2-(dimethoxymethyl)furan over 70%and can be reused after recovery without serious loss of activity.In the propane oxidative dehydrogenation reaction,SDD BPO_(4) demonstrated high olefin productivity and selectivity while maintaining high reaction rate.This study provides ideas for the preparation of ordered mesoporous crystalline catalytic materials and demonstrates their potential for practical applications.
Chao WangWen-Duo LuJiao WangShunai CheAn-Hui LuLu Han
