Basal defense is enhanced in a wheat cultivar resistant to Fusarium head blight

Fusarium head blight(FHB),mainly caused by the fungal pathogen Fusarium graminearum,is one of the most destructive wheat diseases.Besides directly affecting the yield,the mycotoxin residing in the kernel greatly threatens the health of humans and livestock.Xinong 979(XN979)is a widely cultivated wheat elite with high yield and FHB resistance.However,its resistance mechanism remains unclear.In this study,we studied the expression of genes involved in plant defense in XN979 by comparative transcriptomics.We found that the FHB resistance in XN979 consists of two lines of defense.The first line of defense,which is constitutive,is knitted via the enhanced basal expression of lignin and jasmonic acid(JA)biosynthesis genes.The second line of defense,which is induced upon F.graminearum infection,is contributed by the limited suppression of photosynthesis and the struggle of biotic stress-responding genes.Meanwhile,the effective defense in XN979 leads to an inhibition of fungal gene expression,especially in the early infection stage.The formation of the FHB resistance in XN979 may coincide with the breeding strategies,such as selecting high grain yield and lodging resistance traits.This study will facilitate our understanding of wheat-F.graminearum interaction and is insightful for breeding FHB-resistant wheat.

Turning gas hydrate nucleation with oxygen-containing groups on size-selected graphene oxide flakes

Gas hydrate is a promising alternative for gas capture and storage due to its high gas storage capacity achieved with only structured water molecules.Nucleation is the critical controlling step in gas hydrate formation.Adding an alien solid surface is an effective approach to regulate gas hydrate nucleation.However,how the solid surface compositions control the gas hydrate nucleation remains unclear.Benefiting from the fact that the surface compositions of graphene oxide(GO)can be finely tuned,we report the effect of functional groups of size-selected GO flakes on methane hydrate nucleation.The carbonyl and carboxyl of GO flakes showed a more prominent promotion for methane hydrate nucleation than the hydroxyl of GO flakes.Surface energy,zeta potential,Raman spectra,and molecular dynamics simulation analysis were used to reveal the regulation mechanism of the functional groups of size-selected GO flakes on methane hydrate nucleation.The GO flakes with abundant carbonyl and carboxyl exhibited higher charge density than those enriched in hydroxyl.The negatively charged GO flakes can induce water molecules to form an ordered hydrogen-bonded arrangement via charge-dipole interactions.Therefore,the water molecules surrounding the carboxyl and carbonyl showed a more ordered hydrogen-bonded structure than those around the hydroxyl of GO flakes.The ordered water arrangement,similar to methane hydrate cages,significantly accelerated methane hydrate nucleation.Our study shows how the surface chemistry of solids control gas hydrate nucleation and sheds light on the design of effective heterogeneous nucleators for gas hydrate.

癌性厌食发病机制和临床诊疗的研究进展

癌性厌食(cancer-related anorexia,CA)可贯穿癌症患者疾病全程且易被忽略,发病率为40%~80%。CA会导致患者摄食量减少、营养不良、体质量下降,最终导致癌症厌食恶病质综合征(cancer anorexia cachexia syndrome,CACS)。CA的发病机制复杂,评估标准尚存争议,缺乏可靠有效的治疗药物。因此,CA发病机制的阐述,规范化食欲评估标准的制定及相关药物的研发,对于癌症治疗疗效、提高患者生存质量极为重要。本文旨在阐述CA的发病机制、临床常用评估方法及治疗进展。

Wheat adaptation to environmental stresses under climate change:Molecular basis and genetic improvement

Wheat(Triticum aestivum)is a staple food for about 40%of the world’s population.As the global population has grown and living standards improved,high yield and improved nutritional quality have become the main targets for wheat breeding.However,wheat production has been compromised by global warming through the more frequent occurrence of extreme temperature events,which have increased water scarcity,aggravated soil salinization,caused plants to be more vulnerable to diseases,and directly reduced plant fertility and suppressed yield.One promising option to address these challenges is the genetic improvement of wheat for enhanced resistance to environmental stress.Several decades of progress in genomics and genetic engineering has tremendously advanced our understanding of the molecular and genetic mechanisms underlying abiotic and biotic stress responses in wheat.These advances have heralded what might be considered a“golden age”of functional genomics for the genetic improvement of wheat.Here,we summarize the current knowledge on the molecular and genetic basis of wheat resistance to abiotic and biotic stresses,including the QTLs/genes involved,their functional and regulatory mechanisms,and strategies for genetic modification of wheat for improved stress resistance.In addition,we also provide perspectives on some key challenges that need to be addressed.

Deletion of all three MAP kinase genes results in severe defects in stress responses and pathogenesis in Fusarium graminearum

Mitogen-activated protein kinase(MAPK)cascades are activated by external stimuli and convert signals to cellular changes.Individual MAPKs have been characterized in a number of plant pathogenic fungi for their roles in pathogenesis and responses to biotic or abiotic stresses.However,mutants deleted of all the MAPK genes have not been reported in filamentous fungi.To determine the MAPK-less effects in a fungal pathogen,in this study we generated and characterized mutants deleted of all three MAPK genes in the wheat scab fungus Fusarium graminearum.The Gpmk1 mgv1 Fghog1 triple mutants had severe growth defects and was non-pathogenic.It was defective in infection cushion formation and DON production.Conidiation was reduced in the triple mutant,which often produced elongated conidia with more septa than the wild-type conidia.The triple mutant was blocked in sexual reproduction due to the loss of female fertility.Lack of any MAPKs resulted in an increased sensitivity to various abiotic stress including cell wall,osmotic,oxidative stresses,and phytoalexins,which are likely related to the defects of the triple mutant in environmental adaptation and plant infection.The triple mutant also had increased sensitivity to the biocontrol bacterium Bacillus velezensis and fungus Clonostachys rosea.In co-incubation assays with B.velezensis,the Gpmk1 mgv1 Fghog1 mutant had more severe growth limitation than the wild type and was defective in conidium germination and germ tube growth.In confrontation assays,the triple mutant was defective in defending against mycoparasitic activities of C.rosea and the latter could grow over the mutant but not wild-type F.graminearum.RNA-seq and metabolomics analyses showed that the MAPK triple mutant was altered in the expression of many ATP-binding cassette(ABC)and major facilitator superfamily(MFS)transporter genes and the accumulation of metabolites related to arachidonic acid,linoleic acid,and alpha-linolenic acid metabolisms.Overall,as the first study on mutants deleted of all three MAPKs in fungal pathogens,our results showed that although MAPKs are not essential for growth and asexual reproduction,the Gpmk1 mgv1 Fghog1 triple mutant was blocked in plant infection and sexual reproductions.It also had severe defects in responses to various abiotic stresses and bacterial-or fungal-fungal interactions.