DDG1 and G Protein α Subunit RGA1 Interaction Regulates Plant Height and Senescence in Rice(Oryza sativa)

Many studies have already shown that dwarfism and moderate delayed leaf senescence positively impact rice yield,but the underlying molecular mechanism of dwarfism and leaf senescence remains largely unknown.Here,using map-based cloning,we identified an allele of DEP2,DDG1,which controls plant height and leaf senescence in rice.The ddg1 mutant displayed dwarfism,short panicles,and delayed leaf senescence.Compared with the wild-type,ddg1 was insensitive to exogenous gibberellins(GA)and brassinolide(BR).DDG1 is expressed in various organs,especially in stems and panicles.Yeast two-hybrid assay,bimolecular fluorescent complementation and luciferase complementation image assay showed that DDG1 interacts with theα-subunit of the heterotrimeric G protein.Disruption of RGA1 resulted in dwarfism,short panicles,and darker-green leaves.Furthermore,we found that ddg1 and the RGA1 mutant was more sensitive to salt treatment,suggesting that DDG1 and RGA1 are involved in regulating salt stress response in rice.Our results show that DDG1/DEP2 regulates plant height and leaf senescence through interacting with RGA1.

Novel biomonitoring method for determining five classes of legacy and alternative flame retardants in human serum samples

Flame retardants(FRs)are ubiquitous in environment and biota and may pose harm to human health.In recent years,concern regarding legacy and alternative FRs has been intensified due to their widespread production and increasing contamination in environmental and human matrices.In this study,we developed and validated a novel analytical method for simultaneous determination of legacy and alternative FRs,including polychlorinated naphthalenes(PCNs),short-and middle-chain chlorinated paraffins(SCCPs and MCCPs),novel brominated flame retardants(NBFRs),and organophosphate esters(OPEs)in human serum.Serum samples were prepared by liquid-liquid extraction using ethyl acetate,and purified with Oasis®HLB cartridge and Florisil–silica gel columns.Instrumental analyses were carried out using gas chromatography-triple quadrupole mass spectrometry,highresolution gas chromatography coupled with high-resolution mass spectrometry,and gas chromatography coupled with quadrupole time-of-flight mass spectrometry,respectively.The proposed method was validated for linearity,sensitivity,precision,accuracy,and matrix effects.Method detection limits for NBFRs,OPEs,PCNs,SCCPs,and MCCPs were 4.6×10^(–4)–8.6×10^(–2),4.3×10^(–3)–1.3,1.1×10^(–5)–1.0×10^(–4),1.5,and 9.0×10–1 ng/mL,respectively.Matrix spike recoveries ranged from 73%–122%,71%–124%,75%–129%,92%–126%,and 94%–126%for NBFRs,OPEs,PCNs,SCCPs,and MCCPs,respectively.The analytical method was applied for detection of real human serum.CPs were the dominant FRs in serum,indicating CPs were widely presented in human serum and should be pay more attention for their health risk.