Biology,invasion and management of the agricultural invader:Fall armyworm,Spodoptera frugiperda(Lepidoptera:Noctuidae)

The fall armyworm(FAW),Spodoptera frugiperda(J.E.Smith),is native to the Americas.It has rapidly invaded 47 African countries and 18 Asian countries since the first detection of invasion into Nigeria and Ghana in 2016.It is regarded as a super pest based on its host range(at least 353 host plants),its inherent ability to survive in a wide range of habitats,its strong migration ability,high fecundity,rapid development of resistance to insecticides/viruses and its gluttonous characteristics.The inherently superior biological characteristics of FAW contribute to its invasiveness.Integrated pest management(IPM)of FAW has relied on multiple applications of monitoring and scouting,agricultural control,chemical pesticides,viral insecticides,sex attractants,bio-control agents(parasitoids,predators and entomopathogens)and botanicals.Knowledge gaps remain to be filled to:(1)understand the invasive mechanisms of S.frugiperda;(2)understand how to prevent its further spread and(3)provide better management strategies.This review summarizes the biological characters of FAW,their association with its invasiveness and IPM strategies,which may provide further insights for future management.

Evolutionary genomics of structural variation in the tea plant,Camellia sinensis

Structural variants(SVs)are a type of genetic variation that contribute substantially to phenotypic diversity and evolution.Further study of SVs will help us understand the influence of SVs associated with tea quality and stress resistance and provide new insight into tea plant breeding improvement and genetic research.However,SVs have not been thoroughly discovered in the tea plant genomes.Herein,we constructed a large-scale SV map across a population of 107 resequenced genomes,including both ancient and cultivated tea plants.A total of 44,240 highconfident SVs were identified,including 34,124 DEL(deletions),4,448 DUP(duplications),2,503 INV(inversions),544 INS(insertions)and 2,621 TRA(translocations).In total,12,400 protein-coding genes were overlapped with SVs,of which 49.5%were expressed in all five tea tissues.SVbased analysis of phylogenetic relationships and population structure in tea plants showed a consistent evolutionary history with the SNP-based results.We also identified SVs subject to artificial selection and found that genes under domestication were enriched in metabolic pathways involving theanine and purine alkaloids,biosynthesis of monoterpenoid,phenylpropanoid,fatty acid,and isoflavonoid,contributing to traits of agronomic interest in tea plants.In addition,a total of 27 terpene synthase(TPS)family genes were selected during domestication.These results indicate that these SVs could provide extensive genomic information for tea quality improvement.

Host-induced silencing of MpPar6 confers Myzus persicae resistance in transgenic rape plants

Plant-mediated RNA interference(RNAi)has emerged as a promising technology for insect control.The green peach aphid,Myzus persicae,feeds on over 400 species of host plants.Brassica napus(rape)is the second most important oilseed crop worldwide.Myzus persicae is highly reproductive and causes severe damage to the rape plants due to its quite flexible life cycle.In this study,we tested the RNAi effects of transgenic rape plants on M.persicae.By in vitro feeding M.persicae with artificial diets containing double-stranded RNAs(dsRNAs)targeting seven aphid genes,we identified a new gene encoding the partitioning-defective protein 6(Par6)as the most potent RNAi target.Tissue-and stage-expression analysis of Par6 suggested this gene is highly expressed in the embryo and adult stage of M.persicae.We next generated transgenic rape plants expressing ds Par6 by Agrobacteriummediated transformation and obtained nine independent transgenic lines.Compared to wild-type control plants,transgenic rape lines expressing ds Par6 showed strong resistance to M.persicae.Feeding assays revealed that feeding transgenic rape plants to M.persicae significantly decreased MpPar6 expression and survival rate and impaired fecundity.Furthermore,we showed that the resistance levels to M.persicae are positively correlated with ds Par6 expression levels in transgenic rape plants.Our study demonstrates that transgenic rape plants expressing ds Par6 are efficiently protected from M.persicae.Interfering with the genes involved in embryo development could be the effective RNAi targets for controlling aphids and potentially other insect pests.

Identification of transient receptor potential channel genes and functional characterization of TRPA1 in Spodoptera frugiperda

Spodoptera frugiperda is a highly destructive pest that has become a global problem due to its robust reproductive and migratory capabilities.Transient receptor potential(TRP)channels,which constitute a vast ion channel family,play pivotal roles in sensing the external environment and maintaining internal homeostasis in insects.TRP channels have been widely investigated for their critical roles in regulating various insect behaviors in recent years.In this study,we identified 15 TRP gene loci encoding 26 transcripts in the genome of S.frugiperda and analyzed their expression profiles at different developmental stages.The results revealed that S.frugiperda possesses four TRPC genes,six TRPA genes,one TRPM gene,two TRPV genes,one TRPN gene,and one TRPML gene,while a canonical TRPP is absent.Moreover,the SfruTRPA1 was functionally characterized using the Xenopus oocyte expression system.The results showed that SfruTRPA1 is activated by temperature increases from 20 to 45℃,and there is no significant desensitization after repeated stimuli within the same temperature range.Additionally,SfruTRPA1 is activated by certain natural chemicals,including allyl isothiocyanate(AITC)and cinnamaldehyde(CA).These findings provide valuable insights to the TRP genes in S.frugiperda.

Recent omics progress in nanobiotechnology for plant abiotic stress tolerance improvement

Use of nanomaterials(NMs)to improve plant abiotic stress tolerance(AST)is a hot topic in NM-enabled agriculture.Previous studies mainly focused on the physiological and biochemical responses of plants treated with NMs under abiotic stress.To use NMs for improving plant AST,it is necessary to understand how they act on this tolerance at the omics and epigenetics levels.In this review,we summarized the knowledge of NM-improved abiotic stress tolerance in relation to omics(such as metabolic,transcriptomic,proteomic,and microRNA),DNA methylation,and histone modifications.Overall,NMs can improve plant abiotic stress tolerance through the modulation at omics and epigenetics levels.

Nanopriming with selenium doped carbon dots improved rapeseed germination and seedling salt tolerance

Soil salinity is a big environmental issue affecting crop production.Although seed nanopriming has been widely used to improve seed germination and seedling growth under salinity,our knowledge about the underlying mechanisms is still insufficient.Herein,we newly synthesized selenium-doped carbon dots nanoparticles coated with poly acrylic acid(poly acrylic acid coated selenium doped carbon dots,PAA@Se-CDs)and used it to prime seeds of rapeseeds.The TEM(transmission electron microscope)size and zeta potential of PAA@Se-CDs are 3.8±0.2 nm and-30 mV,respectively.After 8 h priming,the PAA@Se-CDs nanoparticles were detected in the seed compartments(seed coat,cotyledon,and radicle),while no such signals were detected in the NNP(no nanoparticle control)group(SeO_2 was used as the NNP).Nanopriming with PAA@Se-CDs nanoparticles increased rapeseeds germination(20%)and seedling fresh weight(161%)under saline conditions compared to NNP control.PAA@Se-CDs nanopriming significantly enhanced endo-β-mannanase activities(255%increase,21.55μmol h^(-1)g^(-1)vs.6.06μmol h^(-1)g^(-1),at DAS 1(DAS,days after sowing)),total soluble sugar(33.63 mg g^(-1)FW(fresh weight)vs.20.23 mg g^(-1)FW)and protein contents(1.96μg g^(-1)FW vs.1.0μg g^(-1)FW)to support the growth of germinating seedlings of rapeseeds under salt stress,in comparison with NNP co ntrol.The respiration rate and ATP content were increased by 76%and 607%,respectively.The oxidative damage of salinity due to the overaccumulation of reactive oxygen species(ROS)was alleviated by PAA@Se-CDs nanopriming by increasing the antioxidant enzyme activities(SOD(superoxide dismutase),POD(peroxidase),and CAT(catalase)).Another mechanism behind PAA@Se-CDs nanopriming improving rapeseeds salt tolerance at seedling stage was reducing sodium(Na^(+))accumulation and improving potassium(K^(+))retention,hence increasing the K^(+)/Na^(+)ratio under saline conditions.Overall,our results not only showed that seed nanopriming with PAA@Se-CDs could be a good approach to improve salt tolerance,but also add more knowledge to the mechanism behind nanopriming-improved plant salt tolerance at germination and early seedling growth stage.

Genome-wide association study identifies 12 new genetic loci associated with growth traits in pigs

Growth traits are among the most important economic traits in pigs and are regulated by polygenes with complex regulatory mechanisms.As the major indicators of growth performance,the backfat thickness(BFT),loin eye area(LEA),and days to 100 kg(D100)traits are commonly used to the genetics improvement in pigs.However,the available genetic markers for these traits are limited.To uncover novel loci and candidate genes associated with growth performance,we collected the phenotypic information of BFT,LEA,and D100 in 1,186 pigs and genotyped all these individuals using the Neogen GGP porcine 80K BeadChip.We performed a genome-wide association study(GWAS)using 4 statistical models,including mixed linear models(MLM),fixed and random model circulating probability unification(FarmCPU),settlement of MLM under progressively exclusive relationships(SUPER),Bayesian-information and linkage-disequilibrium Iteratively nested keyway(Blink),and identified 5,3,and 6 high-confidence single nucleotide polymorphisms(SNPs)associated with BFT,LEA,and D100,respectively.Variant annotation and quantitative trait locus(QTL)mapping analysis suggested that6 genes(SKAP2,SATB1,PDE7B,PPP1R16B,WNT3,and WNT9B)were potentially associated with growth performance in pigs.Transcriptome analysis suggested that the expression of Src Kinase Associated Phosphoprotein 2(SKAP2)was higher in prenatal muscles than in postnatal muscles,and the expression of Phosphodiesterase 7B(PDE7B)continuously increased during the prenatal stages and gradually decreased after birth,implying their potential roles in prenatal skeletal muscle development.Overall,this study provides new candidate loci and genes for the genetic improvement of pigs.

Whole-genome analysis reveals distinct adaptation signatures to diverse environments in Chinese domestic pigs

Background Long-term natural and artificial selection has resulted in many genetic footprints within the genomes of pig breeds across distinct agroecological zones.Nevertheless,the mechanisms by which these signatures contribute to phenotypic diversity and facilitate environmental adaptation remain unclear.Results Here,we leveraged whole-genome sequencing data from 82 individuals from 6 domestic pig breeds originating in tropical,high-altitude,and frigid regions.Population genetic analysis suggested that habitat isolation significantly shaped the genetic diversity and contributed to population stratification in local Chinese pig breeds.Analysis of selection signals revealed regions under selection for adaptation in tropical(55.5 Mb),high-altitude(43.6 Mb),and frigid(17.72 Mb)regions.The potential functions of the selective sweep regions were linked to certain complex traits that might play critical roles in different geographic environments,including fat coverage in frigid environments and blood indicators in tropical and high-altitude environments.Candidate genes under selection were significantly enriched in biological pathways involved in environmental adaptation.These pathways included blood circulation,protein degradation,and inflammation for adaptation to tropical environments;heart and lung development,hypoxia response,and DNA damage repair for high-altitude adaptation;and thermogenesis,cold-induced vasodilation(CIVD),and the cell cycle for adaptation to frigid environments.By examining the chromatin state of the selection signatures,we identified the lung and ileum as two candidate functional tissues for environmental adaptation.Finally,we identified a mutation(chr1:G246,175,129A)in the cis-regulatory region of ABCA1 as a plausible promising variant for adaptation to tropical environments.Conclusions In this study,we conducted a genome-wide exploration of the genetic mechanisms underlying the adaptability of local Chinese pig breeds to tropical,high-altitude,and frigid environments.Our findings shed light on the prominent role of cis-regulatory elements in environmental adaptation in pigs and may serve as a valuable biological model of human plateau-related disorders and cardiovascular diseases.

Biology of Hippo signaling pathway:Skeletal muscle development and beyond

Global demand for farm animals and their meat products i.e.,pork,chicken and other livestock meat,is steadily incresing.With the ongoing life science research and the rapid development of biotechnology,it is a great opportunity to develop advanced molecular breeding markers to efficiently improve animal meat production traits.Hippo is an important study subject because of its crucial role in the regulation of organ size.In recent years,with the increase of research on Hippo signaling pathway,the integrative application of multi-omics technologies such as genomics,transcriptomics,proteomics,and metabolomics can help promote the in-depth involvement of Hippo signaling pathway in skeletal muscle development research.The Hippo signaling pathway plays a key role in many biological events,including cell division,cell migration,cell proliferation,cell differentiation,cell apoptosis,as well as cell adhesion,cell polarity,homeostasis,maintenance of the face of mechanical overload,etc.Its influence on the development of skeletal muscle has important research value for enhancing the efficiency of animal husbandry production.In this study,we traced the origin of the Hippo pathway,comprehensively sorted out all the functional factors found in the pathway,deeply analyzed the molecular mechanism of its function,and classified it from a novel perspective based on its main functional domain and mode of action.Our aim is to systematically explore its regulatory role throughout skeletal muscle development.We specifically focus on the Hippo signaling pathway in embryonic stem cell development,muscle satellite cell fate determination,myogenesis,skeletal muscle meat production and organ size regulation,muscle hypertrophy and atrophy,muscle fiber formation and its transformation between different types,and cardiomyocytes.The roles in proliferation and regeneration are methodically summarized and analyzed comprehensively.The summary and prospect of the Hippo signaling pathway within this article will provide ideas for further improving meat production and muscle deposition and developing new molecular breeding technologies for livestock and poultry,which will be helpful for the development of animal molecular breeding.

The evolution and diurnal expression patterns of photosynthetic pathway genes of the invasive alien weed,Mikania micrantha

Mikania micrantha is a fast-growing global invasive weed species that causes severe damage to natural ecosystems and very large economic losses of forest and crop production.It has advantages in photosynthesis,including a similar net photosynthetic rate as C4 plants and a higher carbon fixation capacity.We used a combination of genomics and transcriptomics approaches to study the evolutionary mechanisms and circadian expression patterns of M.micrantha.In M.micrantha,16 positive selection genes focused on photoreaction and utilization of photoassimilates.In different tissues,98.1%of the genes associated with photoresponse had high expression in stems,and more than half of the genes of the C4 cycle had higher expression in stems than in leaves.In stomatal opening and closing,2 genes of carbonic anhydrase(CAs)had higher expression at 18:00 than at 8:00,and the slow anion channel 1(SLAC1)and high-leaf-temperature 1 kinase(HT1)genes were expressed at low levels at 18:00.In addition,genes associated with photosynthesis had higher expression levels at 7:00 and 17:00.We hypothesized that M.micrantha may undergo photosynthesis in the stem and flower organs and that some stomata of the leaves were opening at night by CO_(2)signals.In addition,its evolution may attenuate photoinhibition at high light intensities,and enhance more efficient of photosynthesis during low light intensity.And the tissue-specific photosynthetic types and different diurnal pattern of photosynthetic-related genes may contribute to its rapid colonization of new habitats of M.micrantha.

Transcriptomic analysis on cucumber tendril reveals GLRs play important roles in thigmotropism and thigmomorphogenesis

Thigmotropism and thigmomorphogenesis are two related and pervasive processes that play crucial roles in plant adaptation to the environment.However,there have been few investigations into the molecular regulatory mechanisms of these phenomena.Cucumber(Cucumis sativus L.)tendrils are ideal material for studying thigmotropism and thigmomorphogenesis because they display a combination of the two processes.Here,we generated the transcriptome profiles of cucumber tendrils at the young,stretch,and coiling stages.Genes related to receptor proteins,transmembrane transport,and ion transport were significantly enriched among those differentially expressed between stages.Pharmacological assays illustrated that three GLUTAMATE RECEPTOR(GLR)genes might play a vital function in perceiving or transducing touch stimulation signals.Comparing the transcriptomes of tendrils and roots after touch stimulation,we found that genes related to extracellular stimulus and xyloglucan metabolism might have conserved functions in the regulation of thigmomorphogenesis.The transcriptome atlas of thigmotropism and thigmomorphogenesis of cucumber tendrils constructed in this study will help further elucidate the molecular mechanisms behind these processes.

Transcriptome and morphological analyses of double flower formation in Dianthus chinensis

The double flower developmental process is regulated via a complex transcriptional regulatory network.To understand this highly dynamic and complex developmental process of Dianthus spp.,we performed a comparative analysis of floral morphology and transcriptome dynamics in simple flowers and double flowers.We found that the primordium of double flowers of‘X’was larger in size compared to that of simple flowers of‘L’in Dianthus chinensis.RNA-seq and Weighted Gene Co-expression Network Analysis(WGCNA)during flower development,identified stage-specific gene network modules.Expression analysis by RNA-seq indicated that a group of genes related to floral meristem identity,primordia position and polarity were highly expressed in double flowers genotypes compared to simple flowers genotypes,suggesting their roles in double-petal formation.A total of 21 DEGs related to petal number were identified between simple and double flowers.The experiments of in situ hybridization revealed that DcaAP2L,DcaLFY and DcaUFO genes were expressed in the intra-sepal boundary and petal boundary.We proposed a potential transcriptional regulatory network for simple and double flower development.This study provides novel insights into the molecular mechanism underlying double flower formation in Dianthus spp.

Two nanobody‑based immunoassays to differentiate antibodies against genotype 1 and 2 porcine reproductive and respiratory syndrome virus

Porcine reproductive and respiratory syndrome virus(PRRSV)infection causes significant economic loss to the global pig industry.Genotype 1 and 2 PRRSV(PRRSV-1 and-2)infections have been reported in China,Europe and America.For accurate prevention,nanobodies were first used as diagnostic reagents for PRRSV typing.In this study three nanobodies targeting both PRRSV-1 and-2,two targeting PRRSV-1 and three targeting PRRSV-2,were screened and produced.To develop two competitive ELISAs(cELISAs),the g1-2-PRRSV-Nb3-HRP nanobody was chosen for the g1-2-cELISA,to detect common antibodies against PRRSV-1 and-2,and the g1-PRRSV-Nb136-HRP nanobody was chosen for the g1-cELISA,to detect anti-PRRSV-1 antibodies.The two cELISAs were developed using PRRSV-1-N protein as coating antigen,and the amounts for both were 100 ng/well.The optimized dilution of testing pig sera was 1:20,the optimized reaction times were 30 min,and the colorimetric reaction times were 15 min.Then,the cut-off values of the g1-2-cELISA and g1-cELISA were 26.6%and 35.6%,respectively.Both of them have high sensitivity,strong specificity,good repeatability,and stability.In addition,for the 1534 clinical pig sera,an agreement rate of 99.02%(Kappa values=0.97)was determined between the g1-2-cELISA and the commercial IDEXX ELISA kit.For the g1-cELSIA,it can specifically detect anti-PRRSV-1 antibodies in the clinical pig sera.Importantly,combining two nanobody-based cELISAs can differentially detect antibodies against PRRSV-1 and-2.

Construction of apricot variety search engine based on deep learning

Apricot has a long history of cultivation and has many varieties and types. The traditional variety identification methods are timeconsuming and labor-consuming, posing grand challenges to apricot resource management. Tool development in this regard will help researchers quickly identify variety information. This study photographed apricot fruits outdoors and indoors and constructed a dataset that can precisely classify the fruits using a U-net model (F-score:99%), which helps to obtain the fruit's size, shape, and color features. Meanwhile, a variety search engine was constructed, which can search and identify variety from the database according to the above features. Besides, a mobile and web application (ApricotView) was developed, and the construction mode can be also applied to other varieties of fruit trees.Additionally, we have collected four difficult-to-identify seed datasets and used the VGG16 model for training, with an accuracy of 97%, which provided an important basis for ApricotView. To address the difficulties in data collection bottlenecking apricot phenomics research, we developed the first apricot database platform of its kind (ApricotDIAP, http://apricotdiap.com/) to accumulate, manage, and publicize scientific data of apricot.

A novel Effective Panicle Number per Plant 4 haplotype enhances grain yield by coordinating panicle number and grain number in rice

Increasing effective panicle number per plant(EPN)is one approach to increase yield potential in rice.However,molecular mechanisms underlying EPN remain unclear.In this study,we integrated mapbased cloning and genome-wide association analysis to identify the EPN4 gene,which is allelic to NARROW LEAF1(NAL1).Overexpression lines containing the Teqing allele(TQ)of EPN4 had significantly increased EPN.NIL-EPN4^(TQ) in japonica(geng)cultivar Lemont(LT)exhibited significantly improved EPN but decreased grain number and flag leaf size relative to LT.Haplotype analysis indicated that accessions with EPN4-1 had medium EPN,medium grain number,and medium grain weight,but had the highest grain yield among seven haplotypes,indicating that EPN4-1 is an elite haplotype of EPN4 for positive coordination of the three components of grain yield.Furthermore,accessions carrying the combination of EPN4-1 and haplotype GNP1-6 of GNP1 for grain number per panicle showed higher grain yield than those with other allele combinations.Therefore,pyramiding of EPN4-1 and GNP1-6 could be a preferred approach to obtain high yield potential in breeding.

Glomerular organization in the antennal lobe of the oriental armyworm Mythimna separata

In insects,the number and specificity of antennal lobe glomeruli often reflect the number and diversity of expressed chemosensory genes,which are linked to its ecological niche and specific olfactory needs.The oriental armyworm,Mythimna separata,is an important and common lepidopteran pest of cereal crops.Given its reliance on the olfactory system for crucial behaviors,understanding the evolutionary potential of this system requires a thorough characterization of the anatomical structure of the primary olfactory center.Here,we systematically identified all antennal lobe glomeruli of M.separata based on synaptic antibody immunostaining and mass staining of the olfactory sensory neurons.A total of 69 glomeruli were identified in females and 65 in males,and an intuitive nomenclature based on glomerular positions was applied.Our findings uncovered some sex-specific glomeruli in this species.There were ten female-specific glomeruli and three male-specific glomeruli,except for the macroglomerular complex(MGC)units,with a notable observation that the female labial pit organ glomerulus was larger than its male counterpart.Additionally,we identified four antennal-lobe tracts(ALTs)and retrograde labeling from the calyx revealed that all glomeruli were innervated by the medial ALT projection neurons.The comparison of the olfactory system structures between M.separata and sympatric moths supports their evolutionary convergence in noctuid moths.These results collectively lay the foundation for future studies on olfactory processing in M.separata.

A CRISPR/Cas12a-based platform for rapid on-site bovine viral diarrhea virus diagnostics

Bovine viral diarrhea virus(BVDV)is a positive-sense single-stranded RNA virus,belonging to the genus Pestivirus in the Flaviviridae family(Riitho et al.2020).Currently,BVDV is divided into 3 main genotypes,BVDV-1,BVDV-2,and BVDV-3,based on the genetic differences in the 5′untranslated region(5′UTR)(Muasya et al.2022).

Smart horticulture as an emerging interdisciplinary field combining novel solutions:Past development,current challenges,and future perspectives

Horticultural products such as fruits,vegetables,and tea offer a range of important nutrients such as protein,carbohydrates,vitamins and lipids.However,the present yield and quality do not meet the requirements of the rapid population growth associated with global climate change,the decline in horticultural practitioners,poor automation,and epidemic diseases such as COVID-19.In this context,smart horticulture is expected to greatly improve the land output rates,resource-use efficiency,and productivity,all of which should facilitate the sustainable development of the horticulture industry.Emerging technologies,such as artificial intelligence,big data,the Internet of Things,and cloud computing,play an important role.This paper reviews past developments and current challenges,offering future perspectives for horticultural chain management.We expect that the horticulture industry would benefit from integration with smart technologies.This requires the use of novel solutions to build a new advanced system encompassing smart breeding,smart cultivation,smart transportation,and smart sales.Finally,a new development approach combining precise perception,smart operation,and smart control should be instituted in the horticulture industry.Within 30 years,we expect that the industry will embrace mechanical,automatic,and informational production to transform into a smart industry.

Preparation and interaction mechanism analysis of single‑chain fragment variables against phenylethanolamine A

This is the first report on the screening,expression,and recognition mechanism analysis of single-chain fragment variable(scFv)against phenylethanolamine A(PEAA),a newly emergedβ-adrenergic agonist illegally used as a feed additive for growth promotion.The PEAA-specific scFv scFv,called scFv-32,was screened from hybridoma cell lines by phage display and was found to be optimally expressed in the E.coli system.The ic-ELISA results revealed an IC_(50)value of 10.34μg/L for scFv-32 and no cross-reactivity with otherβ-adrenergic agonists.Homology modeling and molecular docking revealed the key binding sites VAL178,TYP228,and ASP229.One hydrogen bond,two pisigma bonds,and one pi-pi bond maintain the formation of the antibody‒drug complex.Alanine scanning mutagenesis of the three predicted key binding sites showed that the mutants completely lost their recognition activity,which confirmed the accuracy of the theoretical analysis.These results are valuable for the preparation of scFvs and the analysis of the molecular recognition mechanism of antigen-antibodies.

Utilizing resequencing big data to facilitate Brassica vegetable breeding:tracing introgression pedigree and developing highly specific markers for clubroot resistance

Clubroot caused by Plasmodiophora brassicae is a devastating disease of Cruciferous crops.Developing cultivars with clubroot resistance(CR)is the most effective control measure.For the two major Brassica vegetable species B.rapa and B.oleracea,several commercial cultivars with unclear CR pedigrees have been intensively used as CR donors in breeding.However,the continuous occurrence of CR-breaking makes the CR pedigree underlying these cultivars one of the breeders'most urgent concerns.The complex intraspecific diversity of these two major Brassica vegetables has also limited the applicability of CR markers in different breeding programs.Here we first traced the pedigree underlying two kinds of CR that have been widely applied in breeding by linkage and introgression analyses based on public resequencing data.In B.rapa,a major locus CRzi8 underlying the CR of the commercial CR donor‘DegaoCR117’was identified.CRzi8 was further shown to have been introgressed from turnip(B.rapa ssp.rapifera)and that it carried a potential functional allele of Crr1a.The turnip introgression carried CRb^(c),sharing the same coding sequence with the CRb that was also identified from chromosome C07 of B.oleracea CR cultivars with different morphotypes.Within natural populations,variation analysis of linkage intervals of CRzi8,PbBa8.1,CRb,and CRb^(c)yielded easily resolved InDel markers(>20 bp)for these fundamental CR genes.The specificity of these markers was tested in diverse cultivars panels,and each exhibited high reliability in breeding.Our research demonstrates the value of the practice of applying resequencing big data to solve urgent concerns in breeding programs.