Fine mapping and validation of a stable QTL for thousand-kernel weight in wheat(Triticum aestivum L.)

Thousand-kernel weight(TKW)is a measure of grain weight,a target of wheat breeding.The object of this study was to fine-map a stable quantitative trait loci(QTL)for TKW and identify its candidate gene in a recombinant inbred line(RIL)population derived from the cross of Kenong 9204(KN9204)and Jing411(J411).On a high-density genetic linkage map,24,26 and 25 QTL were associated with TKW,kernel length(KL),and kernel width(KW),respectively.A major and stable QTL,QTkw-2D,was mapped to an8.3 cM interval on chromosome arm 2DL.By saturation of polymorphic markers in its target region,QTkw-2D was confined to a 9.13 Mb physical interval using a secondary mapping population derived from a residually heterozygous line(F6:7).This interval was further narrowed to 2.52 Mb using QTkw-2D near-isogenic lines(NILs).NILs~(KN9204)had higher fresh and dry weights than NILsJ411at various grain-filling stages.The TKW and KW of NILs~(KN9204)were much higher than those of NILsJ411in field trials.By comparison of both DNA sequence and expression between KN9204 and J411,TraesCS2D02G460300.1(TraesKN2D01HG49350)was assigned as a candidate gene for QTkw-2D.This was confirmed by RNA sequencing(RNA-seq)of QTkw-2D NILs.These results provide the basis of map-based cloning of QTkw-2D,and DNA markers linked to the candidate gene may be used in marker-assisted selection.

Overexpression of a BRASSINAZOLE RESISTANT 1 homolog attenuates drought tolerance by suppressing the expression of PLETHORA-LIKE 1 in Setaria italica

Two potential BRASSINAZOLE RESISTANT 1 (BZR1) homologs were downregulated by brassinosteroids(BRs) in Setaria italica roots.Functional analysis showed that BR regulates the dephosphorylation and nuclear localization of Si BZR1 and that Si BZR1 binds conserved BZR1-recognizing cis elements.In comparison with the wild type,Si BZR1-overexpressing S.italica seedlings were more sensitive to BR-inhibited primary root growth and drought stress,indicating that Si BZR1 is a positive regulator of BR signaling and a negative regulator of drought tolerance in S.italica.PLETHORA-LIKE 1 (Si PLT-L1) was found to be a direct target gene of Si BZR1 in S.italica roots.The expression of Si PLT-L1 was downregulated by Si BZR1.Si PLT-L1-overexpressing S.italica was less sensitive to BR-inhibited root growth and more tolerant to drought stress,possibly owing to the upregulation of drought-inducible Dehydrin-family genes.

Seasonal variations in gonad morphology and hypothalamic GnRH-I and GnIH in Eurasian Tree Sparrow,a multi-brooded passerine

The hypothalamic-pituitary-gonadal(HPG)axis ubiquitously regulates seasonal reproduction,following the rhythmicity of a suite of environmental cues.Birds display prominent seasonal variations in gonad size regulated by two hypothalamic peptides,gonadotropin-releasing hormone-1(GnRH-I)and gonadotropin-inhibiting hormone(GnIH).How multi-brooded avian species adjust GnRH-I and GnIH to regulate gonadal morphology seasonally remains largely unknown.Here,we studied the variations in the hypothalamic immunoreactivity(ir)of GnRH-I and GnIH,gonadal proliferation,and apoptosis in a typical multi-brooded species,the Eurasian Tree Sparrow(Passer montanus),across the pre-breeding(PB),first breeding(FB),second breeding(SB),pre-basic molt(PM),and wintering stages(WS).Our results showed that both sexes had higher preoptic area(POA)-GnRH-I-ir but lower paraventricular nucleus(PVN)-GnIH-ir neurons during the breeding stages(FB and SB)relative to other life-history stages,with no significant differences between two broods.The testes and ovaries were significantly larger during the breeding stages.Testicular volume increased during the two broods due to anincreased diameter of seminiferous tubules.Furthermore,there were more testicular apoptotic cells in PB and WS stages than in breeding stages,and in PB stage than in PM stage.Males had higher POA-GnRH-I expression than females during the breeding stages,but both sexes had comparable PVN-GnIH expression throughout the annual cycle.Both sexes of the sparrows may undergo a similar pattern of life-history stage-dependent variation in the hypothalamic GnRH-I,GnIH,and gonadal morphology,except that during breeding stages,males may display higher expression of POA-GnRH-I relative to females.The higher expression of POA-GnRH-I-ir in breeding male sparrows may be critical for male-dependent parental care.

Birds and plastic pollution:recent advances

Plastic waste and debris have caused substantial environmental pollution globally in the past decades,and they have been accumulated in hundreds of terrestrial and aquatic avian species.Birds are susceptible and vulnerable to external environments;therefore,they could be used to estimate the negative effects of environmental pollution.In this review,we summarize the effects of macroplastics,microplastics,and plastic-derived additives and plastic-absorbed chemicals on birds.First,macroplastics and microplastics accumulate in different tissues of various aquatic and terrestrial birds,suggesting that birds could suffer from the macroplastics and microplastics-associated contaminants in the aquatic and terrestrial environments.Second,the detrimental effects of macroplastics and microplastics,and their derived additives and absorbed chemicals on the individual survival,growth and development,reproductive output,and physiology,are summarized in different birds,as well as the known toxicological mechanisms of plastics in laboratory model mammals.Finally,we identify that human commensal birds,long-life-span birds,and model bird species could be utilized to different research objectives to evaluate plastic pollution burden and toxicological effects of chronic plastic exposure.

Rice Curled Its Leaves Either Adaxially or Abaxially to Combat Drought Stress

Leaf rolling(LR)is one of the defensive mechanisms that plants have developed against adverse environmental conditions.LR is a typical drought response,promoting drought resistance in various gramineae species,including wheat,maize,and rice.Rice cultivation faces the formidable challenge of water deprivation because of its high water requirements,which leads to drought-related symptoms in rice.LR is an important morphological characteristic that plays a key role in controlling water loss during water insufficiency,thereby regulating leaf area and stature,which are crucial agronomic traits determining yield criteria.Bulliform,sclerenchyma,mesophyll,and vascular bundles are the cells that engage in LR and commonly exhibit adaxial or abaxial types of rolling in rice.The specific genes linked to rolling,either adaxially or abaxially,are discussed here.In addition to the factors influencing LR,here is a short review of the morphological,physiological and molecular responses of this adaptation under drought stress.Moreover,this review highlights how LR combats the consequences of drought stress.The eco-physiological and molecular mechanisms underlying this morphological adaptation in rice should be further explored,as they might be useful in dealing with various degrees of drought tolerance.

Boosting wheat functional genomics via an indexed EMS mutant library of KN9204

A better understanding of wheat functional genomics can improve targeted breeding for better agronomic traits and environmental adaptation.However,the lack of gene-indexed mutants and the low transformation efficiency of wheat limit in-depth gene functional studies and genetic manipulation for breeding.In this study,we created a library for KN9204,a popular wheat variety in northern China,with a reference genome,transcriptome,and epigenome of different tissues,using ethyl methyl sulfonate(EMS)mutagenesis.This library contains a vast developmental diversity of critical tissues and transition stages.Exome capture sequencing of 2090 mutant lines using KN9204 genome-designed probes revealed that 98.79%of coding genes had mutations,and each line had an average of 1383 EMS-type SNPs.We identified new allelic variations for crucial agronomic trait-related genes such as Rht-D1,Q,TaTB1,and WFZP.We tested 100 lines with severemutations in 80 NAC transcription factors(TFs)under drought and salinity stress and identified 13 lines with altered sensitivity.Further analysis of three lines using transcriptome and chromatin accessibility data revealed hundreds of direct NAC targets with altered transcription patterns under salt or drought stress,including SNAC1,DREB2B,CML16,and ZFP182,factors known to respond to abiotic stress.Thus,we have generated and indexed a KN9204 EMS mutant library that can facilitate functional genomics research and offer resources for genetic manipulation of wheat.

Protein regulation mechanism of cold tolerance in Haemaphysalis longicornis

Ticks are external parasitic arthropods that can transmit a variety of pathogens by sucking blood.Low-temperature tolerance is essential for ticks to survive during the cold winter.Exploring the protein regulation mechanism of low-temperature tolerance of Haemaphysalis longicornis could help to explain how ticks survive in winter.In this study,the quantitative proteomics of several tissues of H.longicornis exposed to low temperature were studied by data independent acquisition technology.Totals of 3699,3422,and 1958 proteins were identified in the salivary gland,midgut,and ovary,respectively.The proteins involved in energy metabolism,cell signal transduction,protein synthesis and repair,and cytoskeleton synthesis changed under low-temperature stress.The comprehensive analysis of the protein regulation of multiple tissues of female ticks exposed to low temperature showed that maintaining cell homeostasis,maintaining cell viability,and enhancing cell tolerance were the most important means for ticks to maintain vital signs under low temperature.The expression of proteins involved in and regulating the above cell activities was the key to the survival of ticks under low temperatures.Through the analysis of a large amount of data,we found that the expression levels of arylamine N-acetyltransferase,inositol polyphosphate multikinase,and dual-specificity phosphatase were up-regulated under low temperature.We speculated that they might have important significance in low-temperature tolerance.Then,we performed RNA interference on the mRNA of these 3 proteins,and the results showed that the ability of female ticks to tolerate low temperatures decreased significantly.

The emerging role of furin in neurodegenerative and neuropsychiatric diseases

Furin is an important mammalian proprotein convertase that catalyzes the proteolytic maturation of a variety of prohormones and proproteins in the secretory pathway. In the brain, the substrates of furin include the proproteins of growth factors, receptors and enzymes. Emerging evidence, such as reduced FURIN mRNA expression in the brains of Alzheimer’s disease patients or schizophrenia patients, has implicated a crucial role of furin in the pathophysiology of neurodegenerative and neuropsychiatric diseases. Currently, compared to cancer and infectious diseases, the aberrant expression of furin and its pharmaceutical potentials in neurological diseases remain poorly understood. In this article, we provide an overview on the physiological roles of furin and its substrates in the brain, summarize the deregulation of furin expression and its effects in neurodegenerative and neuropsychiatric disorders, and discuss the implications and current approaches that target furin for therapeutic interventions. This review may expedite future studies to clarify the molecular mechanisms of furin deregulation and involvement in the pathogenesis of neurodegenerative and neuropsychiatric diseases, and to develop new diagnosis and treatment strategies for these diseases.

Hibernation with rhythmicity:the circadian clock and hormonal adaptations of the hibernating Asiatic toads(Bufo gargarizans)

Hibernation is one of the fundamental strategies in response to cold environmental temperatures.During hibernation,the endocrine and circadian systems ensure minimal expenditure of energy for survival.The circadian rhythms of key hormones,melatonin(MT),corticosterone(CORT),triiodothyronine(T3),and thyroxine(T4),and the underlying molecular regulatory mechanisms of hibernation have been well determined in mammals but not in ectotherms.Here,a terrestrial hibernating species,Asiatic toad(Bufo gargarizans),was employed to investigate the plasma CORT,MT,T3,and T4;and the retina,brain,and liver mRNA expression of the core clock genes,including circadian locomotor output cycles kaput(Clock),brain and muscle ARNT-like 1(Bmal1),cryptochrome(Cry)1 and 2,and period(Per)1 and 2,at 7-time points over a 24-h period under acute cold(1 day at 4℃),and hibernation(45 days at 4℃).Our results showed that the circadian rhythms of the core clock genes were rather unaffected by acute cold exposure in the retina,unlike the brain and liver.In contrast,during hibernation,the liver clock genes displayed significant circadian oscillations,while those in the retina and brain stopped ticking.Furthermore,plasma CORT expressed circadian oscillations in both groups,and T3 in acute cold exposure group,whereas T4 and MT did not.Our results reveal that the plasma CORT and the liver sustain rhythmicity when the brain was not,indicating that the liver clock along with the adrenal clock synergistically maintains the metabolic requirements to ensure basic survival in hibernating Asiatic toads.

Brassinosteroids regulate outer ovule integument growth in part via the control of INNER NO OUTER by BRASSINOZOLE‐RESISTANT family transcription factors

Brassinosteroids(BRs)play important roles in regulating plant reproductive processes.BR signaling or BR biosynthesis null mutants do not produce seeds under natural conditions,but the molecular mechanism underlying this infertility is poorly understood.In this study,we report that outer integument growth and embryo sac development were impaired in the ovules of the Arabidopsis thaliana BR receptor null mutant bri1-116.Gene expression and RNA-seq analyses showed that the expression of INNER NO OUTER(INO),an essential regulator of outer integument growth,was significantly reduced in the bri1-116 mutant.Increased INO expression due to overexpression or increased transcriptional activity of BRASSINAZOLE-RESISTANT 1(BZR1)in the mutant alleviated the outer integument growth defect in bri1-116 ovules,suggesting that BRs regulate outer integument growth partially via BZR1-mediated transcriptional regulation of INO.Meanwhile,INO expression in bzr-h,a null mutant for all BZR1 family genes,was barely detectable;and the outer integument of bzr-h ovules had much more severe growth defects than those of the bri1-116 mutant.Together,our findings establish a new role for BRs in regulating ovule development and suggest that BZR1 family transcription factors might regulate outer integument growth through both BRI1-dependent and BRI1-independent pathways.

Molecular mechanisms governing plant responses to high temperatures

The increased prevalence of high temperatures （HTs） around the world is a major global concern, as they dramatically affect agronomic productivity. Upon HT exposure, plants sense the temperature change and initiate cellular and metabolic responses that enable them to adapt to their new environmental conditions.Decoding the mechanisms by which plants cope with HT will facilitate the development of molecular markers to enable the production of plants with improved thermotolerance. In recent decades, genetic, physiological, molecular, and biochemical studies have revealed a number of vital cellular components and processes involved in thermoresponsive growth and the acquisition of thermo- tolerance in plants. This review summarizes the major mechanisms involved in plant HT responses, with a special focus on recent discoveries related to plant thermosensing, heat stress signaling, and HT-regulated gene expression networks that promote plant adaptation to elevated environmental temperatures.

BZR1 Family Transcription Factors Function Redundantly and Indispensably in BR Signaling but Exhibit BRI1-Independent Function in Regulating Anther Development in Arabidopsis

BRASSINAZOLE-RESISTANT 1 family proteins(BZRs)are central transcription factors that govern brassinosteroid(BR)-regulated gene expression and plant growth.However,it is unclear whether there exists a BZR-independent pathway that mediates BR signaling.In this study,we found that disruption of all BZRs in Arabidopsis generated a hextuple mutant(bzr-h)displaying vegetative growth phenotypes that were almost identical to those of the null mutant of three BR receptors,bri1brl1brl3(bri-t).By RNA sequencing,we found that global gene expression in bzr-h was unaffected by 2 h of BR treatment.The anthers of bzr-h plants were loculeless,but a similar phenotype was not observed in bri-t,suggesting that BZRs have a BR signaling-independent regulatory role in anther development.By real-time PCR and in situ hybridization,we found that the expression of SPOROCYTELESS(SPL),which encodes a transcription factor essential for anther locule development,was barely detectable in bzr-h,suggesting that BZRs regulate locule development by affecting SPL expression.Our findings reveal that BZRs are indispensable transcription factors required for both BR signaling and anther locule development,providing new insight into the molecular mechanisms underlying the microsporogenesis in Arabidopsis.

Ferrodifferentiation regulates neurodevelopment via ROS generation

Iron is important for life,and iron deficiency impairs development,but whether the iron level regulates neural differentiation remains elusive.In this study,with iron-regulatory proteins(IRPs)knockout embryonic stem cells(ESCs)that showed severe iron deficiency,we found that the Pax6-and Sox2-positive neuronal precursor cells and Tuj1 fibers in IRP1^(-/-)IRP2^(-/-)ESCs were significantly decreased after inducing neural differentiation.Consistently,in vivo study showed that the knockdown of IRP1 in IRP2^(-/-)fetal mice remarkably affected the differentiation of neuronal precursors and the migration of neurons.These findings suggest that low intracellular iron status significantly inhibits neurodifferentiation.When supplementing IRP1^(-/-)IRP2^(-/-)ESCs with iron,these ESCs could differentiate normally.Further investigations revealed that the underlying mechanism was associated with an increase in reactive oxygen species(ROS)production caused by the substantially low level of iron and the downregulation of iron-sulfur cluster protein ISCU,which,in turn,affected the proliferation and differentiation of stem cells.Thus,the appropriate amount of iron is crucial for maintaining normal neural differentiation that is termed ferrodifferentiation.