Endogenous biosynthesis of docosahexaenoic acid(DHA)regulates fish oocyte maturation by promoting pregnenolone production

Omega-3 polyunsaturated fatty acids(n-3 PUFAs),particularly docosahexaenoic acid(22:6n-3,DHA),play crucial roles in the reproductive health of vertebrates,including humans.Nevertheless,the underlying mechanism related to this phenomenon remains largely unknown.In this study,we employed two zebrafish genetic models,i.e.,elovl2^(-/-)mutant as an endogenous DHAdeficient model and fat1(omega-3 desaturase encoding gene)transgenic zebrafish as an endogenous DHA-rich model,to investigate the effects of DHA on oocyte maturation and quality.Results show that the elovl2^(-/-)mutants had much lower fecundity and poorer oocyte quality than the wild-type controls,while the fat1 zebrafish had higher fecundity and better oocyte quality than wildtype controls.DHA deficiency in elovl2^(-/-)embryos led to defects in egg activation,poor microtubule stability,and reduced pregnenolone levels.Further study revealed that DHA promoted pregnenolone synthesis by enhancing transcription of cyp11a1,which encodes the cholesterol side-chain cleavage enzyme,thereby stabilizing microtubule assembly during oogenesis.In turn,the hypothalamic-pituitary-gonadal axis was enhanced by DHA.In conclusion,using two unique genetic models,our findings demonstrate that endogenously synthesized DHA promotes oocyte maturation and quality by promoting pregnenolone production via transcriptional regulation of cyp11a1.

Appropriate Supply of Ammonium Nitrogen and Ammonium Nitrate Reduces Cadmium Content in Rice Seedlings by Inhibiting Cadmium Uptake and Transport

Reasonable nitrogen(N) application is a promising strategy for reducing crop cadmium(Cd) toxicity. However, the specific form of N and the required amount that affect Cd tolerance and accumulation in rice remain unclear. This study explored the influence of different N-fertilizer forms(NH_(4)NO_(3), NH_4Cl, and KNO_(3)) and dosages on Cd tolerance and uptake in Cd-stressed N-sensitive and N-insensitive indica rice accessions. The results indicated that the Cd tolerance of N-sensitive indica accessions is more robust than that of N-insensitive ones. Furthermore, the shoot Cd content and Cd translocation rate in both N-sensitive and N-insensitive indica accessions decreased with an appropriate supply of NH_(4)NO_(3) and NH_4Cl, whereas they were comparable or slightly increased with increased KNO_(3). Unfortunately, we did not find significant and regular differences in Cd accumulation or translocation between N-sensitive and N-insensitive rice accessions. Consistent with the reduction of shoot Cd content, the addition of NH_(4)NO_(3) and NH_4Cl also inhibited the instantaneous root Cd^(2+) uptake. The expression changes of Cd transport-related genes under different N forms and dosages suggested that the decreased shoot Cd content, caused by the increased supply of NH_(4)NO_(3) and NH_4Cl, is likely achieved by reducing the transcription of OsNRAMP1 and OsIRT1. In summary, our findings reveal that an appropriate supply of NH_(4)NO_(3) and NH_4Cl could reduce Cd uptake and transport in rice seedlings, suggesting that rational N management could reduce the Cd risk in rice production.

foxl2l is a germ cell-intrinsic gatekeeper of oogenesis in zebrafish

Zebrafish serve as a valuable model organism for studying germ cell biology and reproductive processes.The AB strain of zebrafish is proposed to exhibit a polygenic sex determination system,where most males initially develop juvenile ovaries before committing to male fate.In species with chromosomal sex determination,gonadal somatic cells are recognized as key determinants of germ cell fate.Notably,the loss of germ cells in zebrafish leads to masculinization,implying that germ cells harbor an intrinsic feminization signal.However,the specific signal triggering oogenesis in zebrafish remains unclear.In the present study,we identified foxl2l as an oocyte progenitor-specific gene essential for initiating oogenesis in germ cells.Results showed that foxl2l-knockout zebrafish bypassed the juvenile ovary stage and exclusively developed into fertile males.Further analysis revealed that loss of foxl2l hindered the initiation of oocyte-specific meiosis and prevented entry into oogenesis,leading to premature spermatogenesis during early gonadal development.Furthermore,while mutation of the pro-male gene dmrt1 led to fertile female differentiation,simultaneous disruption of foxl2l in dmrt1 mutants completely blocked oogenesis,with a large proportion of germ cells arrested as germline stem cells,highlighting the crucial role of foxl2l in oogenesis.Overall,this study highlights the unique function of foxl2l as a germ cell-intrinsic gatekeeper of oogenesis in zebrafish.

Putrescine Modulates Cadmium Fixation Ability of Cell Wall to Decrease Cadmium Accumulation in Rice,a Process Might Depend on Nitric Oxide

Although putrescine(PUT)has been linked to plants'responses to cadmium(Cd)stress,the exact mechanism is still elusive.In the current investigation,the endogenous PUT concentration in rice roots was enhanced by Cd stress.Exogenous PUT increased root cell wall hemicellulose levels,which in turn increased its Cd binding capacity,concurrently decreasing the transcription level of genes such as OsNRAMP1 and OsCd1 that are responsible for root Cd absorption.As a result。

Depletion of stearoyl-CoA desaturase(scd) leads to fatty liver disease and defective mating behavior in zebrafish

Stearyl coenzyme A desaturase(SCD), also known as delta-9 desaturase, catalyzes the rate-limiting step in the formation of monounsaturated fatty acids.In mammals, depletion or inhibition of SCD activity generally leads to a decrease in triglycerides and cholesteryl esters. However, the endogenous role of scd in teleost fish remains unknown. Here, we generated a zebrafish scd mutant(scd-/-) to elucidate the role of scd in lipid metabolism and sexual development. Gas chromatography-mass spectrometry(GC-MS) showed that the scd-/- mutants had increased levels of saturated fatty acids C16:0 and C18:0, and decreased levels of monounsaturated fatty acids C16:1 and C18:1. The mutant fish displayed a short stature and an enlarged abdomen during development. Unlike Scd-/ -mammals, the scd-/- zebrafish showed significantly increased fat accumulation in the whole body,especially in the liver, leading to hepatic mitochondrial dysfunction and severe cell apoptosis.Mechanistically, srebf1, a gene encoding a transcriptional activator related to adipogenesis,acc1 and acaca, genes involved in fatty acid synthesis, and dgat2, a key gene involved in triglyceride synthesis, were significantly upregulated in mutant livers to activate fatty acid biosynthesis and adipogenesis. The scd-/- males exhibited defective natural mating behavior due to defective genital papillae but possessed functional mature sperm. All defects in the scd-/- mutants could be rescued by ubiquitous transgenic overexpression of scd. In conclusion, our study demonstrates that scd is indispensable for maintaining lipid homeostasis and development of secondary sexual characteristics in zebrafish.

Jasmonic acid-mediated stress responses share the molecular mechanism underlying male sterility induced by deficiency of ZmMs33 in maize

Plant male reproduction is a fine-tuned developmental process that is susceptible to stressful environments and influences crop grain yields.Phytohormone signaling functions in control of plant normal growth and development as well as in response to external stresses,but the interaction or crosstalk among phytohormone signaling,stress response,and male reproduction in plants remains poorly understood.Cross-species comparison among 514 stress-response transcriptomic libraries revealed that ms33-6038,a genic male sterile mutant deficient in the Zm Ms33/Zm GPAT6 gene,displayed an excessive drought stress-like transcriptional reprogramming in anthers triggered mainly by disturbed jasmonic acid(JA)homeostasis.An increased level of JA appeared in Zm Ms33-deficient anthers at both meiotic and postmeiotic stages and activated genes involved in JA biosynthesis and signaling as well as genes functioning in JA-mediated drought response.Excessive accumulation of JA elevated expression level of a gene encoding a WRKY transcription factor that activated the Zm Ms33 promoter.These findings reveal a feedback loop of Zm Ms33-JA-WRKY-Zm Ms33 in controlling male sterility and JA-mediated stress response in maize,shedding light on the crosstalk of stress response and male sterility mediated by phytohormone homeostasis and signaling.

Physiological and Biochemical Characteristics and Response Patterns of Salinity Stress Responsive Genes (SSRGs) in Wild Quinoa (Chenopodium quinoa L.)

Cultivating salt-tolerant crops is a feasible way to effectively utilize saline-alkali land and solve the problem of underutilization of saline soils.Quinoa,a protein-comprehensive cereal in the plant kingdom,is an exceptional crop in terms of salt stress tolerance level.It seems an excellent model for the exploration of salt-tolerance mechanisms and cultivation of salt-tolerant germplasms.In this study,the seeds and seedlings of the quinoa cultivar Shelly were treated with different concentrations of NaCl solution.The physiological,biochemical characteristics and agronomic traits were investigated,and the response patterns of three salt stress-responsive genes(SSRGs)in quinoa were determined by real-time PCR.The optimum level of stress tolerance of quinoa cultivar Shelly was found in the range of 250–350 mM concentration of NaCl.Salt stress significantly induced expression of superoxide dismutase(SOD),peroxidase(POD),and particularly betaine aldehyde dehydrogenase(BADH).BADH was discovered to be more sensitive to salt stress and played an important role in the salt stress tolerance of quinoa seedlings,particularly at high NaCl concentrations,as it displayed upregulation until 24 h under 100 mM salt treatment.Moreover,it showed upregulation until 12 h under 250 mM salt stress.Taken together,these results suggest that BADH played an essential role in the salt-tolerance mechanism of quinoa.Based on the expression level and prompt response induced by NaCl,we suggest that the BADH can be considered as a molecular marker for screening salt-tolerant quinoa germplasm at the early stages of crop development.Salt treatment at different plant ontogeny or at different concentrations had a significant impact on quinoa growth.Therefore,an appropriate treatment approach needs to be chosen rationally in the process of screening salt-tolerant quinoa germplasm,which is useful to the utilization of saline soils.Our study provides a fundamental information to deepen knowledge of the salt tolerance mechanism of quinoa for the development of salt-tolerant germplasm in crop breeding programs.

Regulation of soybean stem growth habit:A ten-year progress report

Stem growth habit dictates plant architecture and influences flowering and podding(seed setting),making it an essential morphological and breeding agronomic trait of soybean(Glycine max).Stem growth habit in soybean is affected by photoperiod and environment and is determined by genetic variation at major genes.Classical genetic analysis identified two critical loci,designated Determinacy 1(Dt1)and Determinacy 2(Dt2).Dt1 is an ortholog of Arabidopsis thaliana TERMINAL FLOWER1(TFL1)and specifies an indeterminate stem growth habit,whereas Dt2 specifies a semi-determinate growth habit.MADS-box proteins,including Dt2,SUPPRESSOR OF OVEREXPRESSION OF CO1(GmSOC1)and MADS-box genes downregulated by E1(GmMDE),repress Dt1 expression.Photoreceptors encoded by the E3 and E4 loci regulate the expression of soybean FLOWERING LOCUS T(GmFT)orthologs via circadian clock genes and E1,and GmFTs compete with Dt1 to regulate stem growth habit.Study of the molecular mechanism underlying the regulation of stem growth habit in soybean has focused on the repression of Dt1 expression.Here we provide an overview of progress made in elucidating the genetic and molecular bases of stem growth habit in soybean,with emphasis on the molecular components responsible for integrating photoperiodic flowering and stem growth habit.

WPA1 encodes a vWA domain protein that regulates wheat plant architecture

Plant height,spike,leaf,stem and grain morphologies are key components of plant architecture and related to wheat yield.A wheat(Triticum aestivum L.)mutant,wpa1,displaying temperaturedependent pleiotropic developmental anomalies,was isolated.The WPA1 gene,encoding a von Willebrand factor type A(vWA)domain protein,was located on chromosome arm 7DS and isolated by map-based cloning.The functionality of WPA1 was validated by multiple independent EMS-induced mutants and gene editing.Phylogenetic analysis revealed that WPA1 is monocotyledon-specific in higher plants.The identification of WPA1 provides opportunity to study the temperature regulated wheat development and grain yield.

Androgen signaling inhibits de novo lipogenesis to alleviate lipid deposition in zebrafish

Testosterone is closely associated with lipid metabolism and known to affect body fat composition and muscle mass in males.However,the mechanisms by which testosterone acts on lipid metabolism are not yet fully understood,especially in teleosts.In this study,cyp17a1-/-zebrafish(Danio rerio)exhibited excessive visceral adipose tissue(VAT),lipid content,and up-regulated expression and activity of hepatic de novo lipogenesis(DNL)enzymes.The assay for transposase accessible chromatinwithsequencing(ATAC-seq)results demonstrated that chromatin accessibility of DNL genes was increased in cyp17a1-/-fish compared to cyp17a1+/+male fish,including stearoyl-CoA desaturase(scd)and fatty acid synthase(fasn).Androgen response element(ARE)motifs in the androgen signaling pathway were significantly enriched in cyp17a1+/+male fish but not in cyp17a1-/-fish.Both androgen receptor(ar)-/-and wildtype(WT)zebrafish administered with Ar antagonist flutamide displayed excessive visceral adipose tissue,lipid content,and up-regulated expression and activity of hepatic de novo lipogenesis enzymes.The Ar agonist BMS-564929 reduced the content of VAT and lipid content,and down-regulated acetyl-CoA carboxylase a(acaca),fasn,and scd expression.Mechanistically,the rescue effect of testosterone on cyp17a1-/-fish in terms of phenotypes was abolished when ar was additionally depleted.Collectively,these findings reveal that testosterone inhibits lipid deposition by down-regulating DNL genes via Ar in zebrafish,thus expanding our understanding of the relationship between testosterone and lipid metabolism in teleosts.

The impact of high-temperature stress on rice: Challenges and solutions

Heat stress (HS) caused by rapidly warming climate has become a serious threat to global food security.Rice (Oryza sativa L.) is a staple food crop for over half of the world’s population,and its yield and quality are often reduced by HS.There is an urgent need for breeding heat-tolerant rice cultivars.Rice plants show various morphological and physiological symptoms under HS.Precise analysis of the symptoms(phenotyping) is essential for the selection of elite germplasm and the identification of thermotolerance genes.In response to HS,rice plants trigger a cascade of events and activate complex transcriptional regulatory networks.Protein homeostasis under HS is especially important for rice thermotolerance,which is affected by protein quality control,effective elimination of toxic proteins,and translational regulation.Although some agronomic and genetic approaches for improving heat tolerance have been adopted in rice,the molecular mechanisms underlying rice response to HS are still elusive,and success in engineering rice thermotolerance in breeding has been limited.In this review,we summarize HS-caused symptoms in rice and progress in heat-stress sensing and signal cascade research,and propose approaches for improving rice thermotolerance in future.

Successful Production of an All-Female Common Carp (Cyprinus carpio L.) Population Using cyp17a1-Deficient Neomale Carp

Due to sexual dimorphism in the growth of certain cultured fish species,the production of monosex fishes is desirable for the aquaculture industry.Nowadays,the most widely practiced technique available for the mass production of monosex fish populations is sex steroid-induced sex reversal.Here,a novel strategy for the successful production of all-female(AF)common carp(Cyprinus carpio L.),to take advantage of the sexual dimorphism in growth documented in this species,has been developed using genetic engineering via single gene-targeting manipulation without any exogenous hormone treatments.Male and female heterozygous cyp17a1-deficient common carp were first obtained using the clustered regularly interspaced short palindromic repeats/CRISPR-associated endonuclease 9(CRISPR/Cas9)technique.An all-male phenotype for homozygous cyp17a1-deficient carp,regardless of the individuals’sexdetermination genotypes(XY or XX),has been observed.A male-specific DNA marker newly identified in our laboratory was used to screen the neomale carp population with the XX genotype from the cyp17a1-deficient carp.These neomale carp develop a normal testis structure with normal spermatogenesis and sperm capacity.The neomale common carp were then mated with wild-type(WT)females(cyp17a1^(+/+)XX genotype)using artificial fertilization.All the AF offspring sample fish from the neomale-WT female mating were confirmed as having the cyp17a^(1+/-)XX genotype,and normal development of gonads to ovaries was observed in 100.00%of this group at eight months post-fertilization(mpf).A total of 1000 carp fingerlings,500 from the WT male and female and 500 from the neomale and WT female mating,were mixed and reared in the same pond.The average body weight of cyp17a1^(+/-)XX females was higher by 6.60%(8 mpf)and 32.66%(12 mpf)than that of the control common carp.Our study demonstrates the first successful production of a monosex teleost population with the advantages of sexual dimorphism in growth using genetic manipulation targeting a single locus.

Exploration of rice yield potential: Decoding agronomic and physiological traits

Rice grain yield is determined by three major"visible"morphological traits:grain weight,grain number per panicle,and effective tiller number,which are affected by a series of"invisible"physiological factors including nutrient use efficiency and photosynthetic efficiency.In the past few decades,substantial progress has been made on elucidating the molecular mechanisms underlying grain yield formation,laying a solid foundation for improving rice yield by molecular breeding.This review outlines our current understanding of the three morphological yield-determining components and summarizes major progress in decoding physiological traits such as nutrient use efficiency and photosynthetic efficiency.It also discusses the integration of current knowledge about yield formation and crop improvement strategies including genome editing with conventional and molecular breeding.

Contribution to our knowledge of Aleurocybotus Quaintance&Baker(Hemiptera:Aleyrodidae)

The genus Aleurocybotus Quaintance&Baker(Hemiptera:Aleyrodidae)is a newly recorded genus in China.This new record species Aleurocybotus occiduus Russell is redescribed with morphological illustrations and photographs from a scanning electron microscope(SEM).Its distribution and host plant are also provided.It is compared with A.cereus Martin and A.graminicolus(Quaintance)and the geographical distribution of Aleurocybotus are noted.An identification key to Aleurocybotus species is provided.

Contribution to the knowledge of Tetraleurodes Cockerell(Hemiptera: Aleyrodidae) in China

Five species in the genus Tetraleurodes Cockerell(Hemiptera:Aleyrodidae)known to occur in China were studied.Tetraleurodes thenmozhiae Jesudasan and David is recognized as a newly recorded species to China and is redescribed with morphological illustrations and photographs taken with a scanning electron microscope(SEM).Comments on the other four species,T.acaciae(Quaintance),T.neemani Bink-Moenen,T.graminis Takahashi and T.oplismeni Takahashi are provided.An identification key to the puparia of Chinese Tetraleurodes species is given.Specimens are deposited in the Insect Collection of Zhejiang Agriculture&Forestry University,Hangzhou,China.

Evaluation of Tung Oil(Vernicia fordii(Hemsl.))for Controlling Termites

In worldwide,the use of chemical pesticides to protect wood has been greatly restricted.In recent years,a large number of researchers devoted to the search for natural,safe and non-polluting bioactive chemical compounds from plants as an alternative to synthetic organic chemical preservative.In Chinese folk,tung oil can be used as paint for wooden furniture to protect them from pests.This study aimed to evaluate the chemical compositions of raw and heated tung oil and their activity against termite.In choice bioassays,weight loss of wood treated with 5%raw or heated tung oil after 4 weeks was significantly less than that of the control group.In no-choice bioassays,there was a significant difference in termite survival and wood weight loss on raw and heated tung oil-treated wood.When tung oil-treatment concentrations increased to 5%,wood weight loss was less than 10%.There was no significant difference in termite survival and wood weight loss between raw and heated tung oil-treated wood.Survival of termites in both tung oil wood treatments was significantly lower than that in the starvation control after 4 weeks.Raw and heated tung oil significantly improved the resistance of pine wood to termites,and have the potential for the development of natural wood preservatives.

Development of small intestinal barrier function and underlying mechanism in Chinese indigenous and Duroc piglets during suckling and weaning periods

This study explored the developmental changes in small intestinal barrier function and the potential regulatory roles of intestinal microbiota and metabolites in different breeds of piglets during suckling and weaning periods.Taoyuan black(TB),Xiangcun black(XB),and Duroc(DR)piglets(10 litters per breed;half male and half female)were selected for sampling to evaluate the intestinal barrier-related indexes and intestinal microbiota and metabolites at 1,10,21(weaned),and 24(3 d after weaning)d old.The results showed that weaning led to severe shedding of small intestinal microvilli and sparse microvilli arrangement.D-lactate level in the ileum of TB and XB piglets during suckling and weaning periods was lower(P<0.01)than that of DR piglets,as well as the ileal diamine oxidase level at 1 d old.The expression level of mucin 1 was higher(P<0.05)in the ileum of TB and XB piglets than that of DR piglets,and it was the highest in the ileum of TB piglets at 21 d old.The expression levels of mucin 2 and mucin 13 were higher(P<0.10)in TB and XB piglets than those of DR piglets at 21 d old,whereas mucin2 and mucin 13 in the ileum of TB and XB piglets were higher(P<0.05)than those of DR piglets at 24 d old.TB and XB piglets had a lower relative abundance of Escherichia_Shigella at 21 and 24 d old,but they had higher Streptococcus at 1 and 24 d old than DR piglets(P<0.01).Differential metabolites between the three breeds of piglets were mainly related to oxidative phosphorylation,steroid biosynthesis,and bile acid synthesis.Collectively,these findings suggest that different pig breeds present differences in the development of the small intestinal barrier function.Compared with DR piglets,TB and XB piglets had higher intestinal permeability during the suckling period and a stronger intestinal mechanical barrier after weaning.Moreover,intestinal microbiota and metabolites are the key factors for developing small intestinal barrier functions in different breeds of piglets.

A Gγallele makes alkaline tolerance real

Along with the increase in the population,the requirements for increased human food and animal feed production have been boosted worldwide.Such an urgent food demand requires more arable land for crop productions.To cope with these urgent needs,saline and/or alkaline lands could be used as alternatives for crop production.

HvMPK4 phosphorylates HvWRKY1 to enhance its suppression of barley immunity to powdery mildew fungus

Mitogen-activated protein kinase(MAPK)cascades play important roles in disease resistance in model plant species.However,the functions of MAPK signaling pathways in crop disease resistance are largely unknown.Here we report the function of HvMKK1-HvMPK4-HvWRKY1 module in barley immune system.HvMPK4 is identified to play a negative role in barley immune response against Bgh,as virus-induced gene silencing of HvMPK4 results in enhanced disease resistance whilst stably overexpressing HvMPK4 leads to super-susceptibility to Bgh infection.Furthermore,the barley MAPK kinase HvMKK1 is found to specifically interact with HvMPK4,and the activated HvMKK1^(DD) variant specifically phosphorylates HvMPK4 in vitro.Moreover,the transcription factor HvWRKY1 is identified to be a downstream target of HvMPK4 and phosphorylated by HvMPK4 in vitro in the presence of HvMKK1^(DD).Phosphorylation assay coupled with mutagenesis analyses identifies S122,T284,and S347 in HvWRKY1 as the major residues phosphorylated by HvMPK4.HvWRKY1 is phosphorylated in barley at the early stages of Bgh infection,which enhances its suppression on barley immunity likely due to enhanced DNA-binding and transcriptional repression activity.Our data suggest that the HvMKK1-HvMPK4 kinase pair acts upstream of HvWRKY1 to negatively regulate barley immunity against powdery mildew.

Unraveling the stereoscopic gene transcriptional landscape of zebrafish using Fish SED,a fish spatial expression database with multispecies scalability

Dear Editor,The expression profile demonstrates how each gene was expressed in the target tissue or cell at a given time.Cell heterogeneity is a biological concept characterized by the presence of numerous cells with varying functions and expression profiles within organ/tissue samples.There is also cell-to-cell signaling,which implies that the extracellular environment and spatial location influence intracellular transcription,resulting in spatial heterogeneity of gene expression within the same cell type.