Dissecting the genetic architecture of glucosinolate compounds for quality improvement in flowering stalk tissues of Brassica napus

Glucosinolates(GSLs) and their hydrolytic products contribute to the quality traits of rapeseed flowering stalk tissues, such as taste, flavor and anticarcinogenic properties(Glucoraphanin). However, little is known about the genetic mechanisms of GSL accumulation in rapeseed flowering stalks. In this study, the variation and genetic architecture of GSL metabolites in flowering stalk tissues were investigated for the first time among a panel of 107 accessions. All GSL compounds exhibited continuous and wide variations in the present population. Progoitrin,glucobrassicanapin and gluconapin were the most abundant GSL compounds. Five quantitative trait loci(QTL) significantly associated with three GSL compounds were identified by genome-wide association study. GRA_C04 was under selected during modern breeding, in which the ratio of lower GSL haplotype(HAP2) in the accessions bred before 1990(52.56%) was significantly lower than that after 1990(78.95%). Four candidate genes, BnaA01. SOT16, BnaA06. SOT17, Bna A06. MYB51a, and Bna A06. MYB51b, were identified in the GTL_A01 and 4OH_A06 regions.These findings provide new insights into GSL biosynthesis in flowering stalk tissues and facilitate quality improvement in rapeseed flowering stalks.

Transcriptome analysis reveals genes expression pattern of seed response to heat stress in Brassica napus L.

Seeds might deteriorate,and lose the ability to germinate when stored under high temperature and high humidity.Brassica napus is one of the most important oil crops in China.However,B.napus seeds were generally stored through summer season with high ambient temperature,which lead to seed viability loss.In order to understand the mechanism of seed response to heat stress and improve seed heat tolerance,B.napus seeds were treated with high temperature(40℃)and ultra-high temperature(60℃)for 4 h.The germination of heatstressed seeds were obviously slower,the germination index and vigor index decreased with temperature increase from 40 to 60℃,and the 40℃ pretreatment could improve the seed tolerance to 60℃ heat stress.Transcriptomics results showed that 442 differentially expressed genes(DEGs)were identified in seeds after heat stress.Gene ontology and KEGG pathway enrichment analysis revealed that some of the genes were involved in posttranslational modification,protein turnover,chaperones and carbohydrate transport,metabolic pathways and secondary metabolites biosynthesis pathway.Among these DEGs,sHSP and transcription factors genes were involved in heat stress tolerance.Thirty-two overlapping genes under different high temperature stress(40℃ and 60℃)were enriched in biological processes of response to oxidative stress and abiotic stimulus.The expression trends of 12 genes randomly selected from the RNA-seq data were almost consistent with the results of qRT-PCR.Our results revealed several potential candidate genes and pathways related to heat responsive by high temperature,which is beneficial for further improving the heat tolerance in B.napus seeds.

Wnt/b-catenin signaling plays an ever-expanding role in stem cell self-renewal,tumorigenesis and cancer chemoresistance

Wnt signaling transduces evolutionarily conserved pathways which play important roles in initiating and regulating a diverse range of cellular activities,including cell proliferation,calcium homeostasis,and cell polarity.The role of Wnt signaling in controlling cell proliferation and stem cell self-renewal is primarily carried out through the canonical pathway,which is the best-characterized the multiple Wnt signaling branches.The past 10 years has seen a rapid expansion in our understanding of the complexity of this pathway,as many new components of Wnt signaling have been identified and linked to signaling regulation,stem cell functions,and adult tissue homeostasis.Additionally,a substantial body of evidence links Wnt signaling to tumorigenesis of cancer types and implicates it in the development of cancer drug resistance.Thus,a better understanding of the mechanisms by which dysregulation of Wnt signaling precedes the development and progression of human cancer may hasten the development of pathway inhibitors to augment current therapy.This review summarizes and synthesizes our current knowledge of the canonical Wnt pathway in development and disease.We begin with an overview of the components of the canonical Wnt signaling pathway and delve into the role this pathway has been shown to play in stemness,tumorigenesis,and cancer drug resistance.Ultimately,we hope to present an organized collection of evidence implicating Wnt signaling in tumorigenesis and chemoresistance to facilitate the pursuit of Wnt pathway modulators that may improve outcomes of cancers in which Wnt signaling contributes to aggressive disease and/or treatment resistance.

Wnt and BMP signaling crosstalk in regulating dental stem cells:Implications in dental tissue engineering

Tooth is a complex hard tissue organ and consists of multiple cell types that are regulated by important signaling pathways such as Wnt and BMP signaling.Serious injuries and/or loss of tooth or periodontal tissues may significantly impact aesthetic appearance,essential oral functions and the quality of life.Regenerative dentistry holds great promise in treating oral/dental disorders.The past decade has witnessed a rapid expansion of our understanding of the biological features of dental stem cells,along with the signaling mechanisms governing stem cell self-renewal and differentiation.In this review,we first summarize the biological characteristics of seven types of dental stem cells,including dental pulp stem cells,stem cells from apical papilla,stem cells from human exfoliated deciduous teeth,dental follicle precursor cells,periodontal ligament stem cells,alveolar bone-derived mesenchymal stem cells(MSCs),and MSCs from gingiva.We then focus on how these stem cells are regulated by bone morphogenetic protein(BMP)and/or Wnt signaling by examining the interplays between these pathways.Lastly,we analyze the current status of dental tissue engineering strategies that utilize oral/dental stem cells by harnessing the interplays between BMP and Wnt pathways.We also highlight the challenges that must be addressed before the dental stem cells may reach any clinical applications.Thus,we can expect to witness significant progresses to be made in regenerative dentistry in the coming decade.

Transition to resistance:An unexpected role of the EMT in cancer chemoresistance

Two recent studies provide intriguing evidence that challenges the role of the epithelialemesenchymal transition(EMT)as a critical mediator of cancer metastasis,while revealing an unexpected role in cancer drug resistance.1,2 While these findings may not settle the EMT’s role in metastasis,these studies suggest that targeting the EMT may inhibit both cancer metastasis and chemoresistance.

Beclin-1/LC3-II dependent macroautophagy was uninfluenced in ischemia-challenged vascular endothelial cells

Autophagy has been extensively studied and occurs in many biological settings.However,a question remains as to whether ischemia enhances Beclin-1/LC3-II-dependent macroautophagy in vascular endothelial cells,as has been previously thought.Furthermore,the effect of the level of autophagy on cell or skin flap survival still requires elucidation.We created a lethal ischemia model in human umbilical vascular endothelial cells(HUVECs),performed quantitative proteomics and bioinformatics analyses,and verified the autophagic status and effect both in vitro and in vivo.The significantly upregulated proteins encoded by autophagy-related genes(ATGs)included ATG2A,ATG3,ATG4B,ATG5,ATG7,ATG9A,ATG12,ATG16,and ATG101.The significantly enhanced lysosomal proteins were cathepsin B,cathepsin D,lysosome-associated membrane protein 1(LAMP1),and LAMP2.However,the differentially expressed proteins excluded Beclin-1,microtubule-associated protein light chain 3(LC3)-I,and LC3-II.Western blot analyses verified that the protein expression levels of Beclin-1,LC3-I,and LC3-II were neither upregulated nor downregulated in ischemia-challenged HUVECs.The autophagic status was not enhanced by rapamycin in ischemic HUVECs but appeared to be inhibited by chloroquine.Our in vivo study on rats showed that a downregulation in autophagic status jeopardized skin flap survival.In conclusion,Ischemia neither enhanced nor inhibited Beclin-1/LC3-II-dependent canonical macroautophagy both in vitro and in vivo,in contradiction to previous studies.An appropriate autophagic homeostasis can minimize cell or skin flap damage.

SATB2:A versatile transcriptional regulator of craniofacial and skeleton development,neurogenesis and tumorigenesis,and its applications in regenerative medicine

SATB2(special AT-rich sequence-binding protein 2)is a member of the special AT-rich binding protein family.As a transcription regulator,SATB2 mainly integrates higher-order chromatin organization.SATB2 expression appears to be tissue-and stage-specific,and is governed by several cellular signaling molecules and mediators.Expressed in branchial arches and osteoblast-lineage cells,SATB2 plays a significant role in craniofacial pattern and skeleton development.In addition to regulating osteogenic differentiation,SATB2 also displays versatile functions in neural development and cancer progression.As an osteoinductive factor,SATB2 holds great promise in improving bone regeneration toward bone defect repair.In this review,we have summarized our current understanding of the physiological and pathological functions of SATB2 in craniofacial and skeleton development,neurogenesis,tumorigenesis and regenerative medicine.