Ustilaginoidea virens: A Fungus Infects Rice Flower and Threats World Rice Production

Rice false smut disease, which is caused by the fungus Ustilaginoidea virens, is currently one of the most devastating rice fungal diseases in the world. Rice false smut disease not only causes severe yield loss and grain quality reduction, but also threatens food safety due to its production of mycotoxins. In this review, the most recent progresses regarding the life cycle, infection processes, genome and genetic diversity, pathogenic gene and disease resistance in rice were summarized in order to provide theoretical basis for the control of U. virens. We also proposed some future directions and key questions that need to be addressed for a better understanding of the molecular mechanism that leads to rice false smut disease and the prospects for sustainable control of rice false smut.

The autophagy gene ATG8 affects morphogenesis and oxidative stress tolerance in Sporisorium scitamineum

The basidiomycetous fungus Sporisorium scitamineum causes sugarcane smut that leads to severe economic losses in the major sugarcane growing areas in China,India and Brazil,etc.Autophagy is a conserved pathway in eukaryotes for bulk degradation and cellular recycling,and was shown to be important for fungal cell growth,development,and pathogenicity.However,physiological function of autophagy has not been studied in S.scitamineum.In this study,we identified a conserved Atg8 protein,named as SsAtg8 and characterized its function.Our results showed that autophagy was blocked in the ssatg8Δ mutant,in nitrogen starvation.The ssatg8Δ mutant formed pseudohypha frequently and was hypersensitive to oxidative stress.However,mating or filamenation was unaffected in the ssatg8Δ mutant in vitro.Overall we demonstrate that autophagy is dispensable for S.scitamineum mating/filamentation,while critical for oxidative stress tolerance and proper morphology in sporidial stage.

Photoinduced palladium-catalyzed 1,3-diene-selective fluoroalkylamination compounds as potential bactericidal agent against Xanthomonas oryzae pv.oryzae

A series of photoinduced palladium-catalyzed 1,3-diene-selective fluoroalkylamination derivatives was rationally synthesized based on diversity-oriented synthesis via cross coupling of 1,3-dienes,amines and fluoroalkyl iodides.The reaction featured good function group tolerance and a broad substrate scope,which could be extended to the late-stage modification of bioactive molecules.Bactericidal activity of all the compounds against Xanthomonas oryzae pv.oryzae(Xoo)was evaluated.Among them,compound E14 showed significant activity against Xanthomonas oryzae pv.oryzae(Xoo)with half maximal effective concentration(EC50)value of 6.61μmol/mL.In pot experiments,the results showed that E14 could control rice bacterial blight with protective and curative efficiencies of 37.5%and 63.2%at 200μg/mL,respectively.Additionally,a plausible mechanism for antibacterial behavior of E14 was proposed by electron microscopy,flow cytometry,reactive oxygen species detection,and biofilm assay.In current work,it can promote the development of photoinduced palladium-catalyzed 1,3-diene-selective fluoroalkyl amination compounds as prospective antibacterial agent bearing an intriguing mode of action.

Evolutionary divergence of subgenomes in common carp provides insights into speciation and allopolyploid success

Hybridization and polyploidization have made great contributions to speciation,heterosis,and agricultural production within plants,but there is still limited understanding and utilization in animals.Subgenome structure and expression reorganization and cooperation post hybridization and polyploidization are essential for speciation and allopolyploid success.However,the mechanisms have not yet been comprehensively assessed in animals.Here,we produced a high-fidelity reference genome sequence for common carp,a typical allotetraploid fish species cultured worldwide.This genome enabled in-depth analysis of the evolution of subgenome architecture and expression responses.Most genes were expressed with subgenome biases,with a trend of transition from the expression of subgenome A during the early stages to that of subgenome B during the late stages of embryonic development.While subgenome A evolved more rapidly,subgenome B contributed to a greater level of expression during development and under stressful conditions.Stable dominant patterns for homoeologous gene pairs both during development and under thermal stress suggest a potential fixed heterosis in the allotetraploid genome.Preferentially expressing either copy of a homoeologous gene at higher levels to confer development and response to stress indicates the dominant effect of heterosis.The plasticity of subgenomes and their shifting of dominant expression during early development,and in response to stressful conditions,provide novel insights into the molecular basis of the successful speciation,evolution,and heterosis of the allotetraploid common carp.

Phylogenomic Insights into Deep Phylogeny of Angiosperms Based on Broad Nuclear Gene Sampling

Angiosperms(flowering plants)are the most diverse and species-rich group of plants.The vast majority(99.95%)of angiosperms form a clade called Mesangiospermae,which is subdivided into five major groups:eudicots,monocots,magnoliids,Chloranthales,and Ceratophyllales.The relationships among these Mesangiospermae groups have been the subject of long debate.In this study,we assembled a phylogenomic dataset of 1594 genes from 151 angiosperm taxa,including representatives of all five lineages,to investigate the phylogeny of major angiosperm lineages under both coalescent-and concatenationbased methods.We dissected the phylogenetic signal and found that more than half of the genes lack phylogenetic information for the backbone of angiosperm phylogeny.We further removed the genes with weak phylogenetic signal and showed that eudicots,Ceratophyllales,and Chloranthales form a clade,with magnoliids and monocots being the next successive sister lineages.Similar frequencies of gene tree conflict are suggestive of incomplete lineage sorting along the backbone of the angiosperm phylogeny.Our analyses suggest that a fully bifurcating species tree may not be the best way to represent the early radiation of angiosperms.Meanwhile,we inferred that the crown-group angiosperms originated approximately between 255.1 and 222.2 million years ago,and Mesangiospermae diversified into the five extant groups in a short time span(27 million years)at the Early to Late Jurassic.

Design and synthesis of unique thiazoloisoquinolinium thiolates and derivatives

Natural isoquinolinium alkaloids possess a wide range of biological activities.The design and synthesis of mesoionic isoquinoliniums is of great importance.This paper reports the synthesis of unique mesoionic thiazoloisoquinolinium thiolates stabilized by aromatization and 1,3-dipolarization.Such compounds can be synthesized via the three component [2 + 2 + 1] cycloaddition reaction of isoquinolines with ethyl propionate and elemental sulfur in the absence of any metal catalyst and additives.Importantly,thiazoloisoquinolinium thiolates can be transformed to thioether-containing thiazoloisoquinolinium halides.A selective [4 + 2] cycloaddition can also be used to form S-bridged fused tetracyclic compounds with a thiothiamide ring unit and two quarternary carbon centres.Compound I-1 shows good bioactivity against the chlorophyll of duckweed(Lemna minor) with inhibition rate of 51.5 mg/mL.