MRUNet:A two-stage segmentation model for small insect targets in complex environments

Online automated identification of farmland pests is an important auxiliary means of pest control.In practical applications,the online insect identification system is often unable to locate and identify the target pest accurately due to factors such as small target size,high similarity between species and complex backgrounds.To facilitate the identification of insect larvae,a two-stage segmentation method,MRUNet was proposed in this study.Structurally,MRUNet borrows the practice of object detection before semantic segmentation from Mask R-CNN and then uses an improved lightweight UNet to perform the semantic segmentation.To reliably evaluate the segmentation results of the models,statistical methods were introduced to measure the stability of the performance of the models among samples in addition to the evaluation indicators commonly used for semantic segmentation.The experimental results showed that this two-stage image segmentation strategy is effective in dealing with small targets in complex backgrounds.Compared with existing state-of-the-art semantic segmentation methods,MRUNet shows better stability and detail processing ability under the same conditions.This study provides a reliable reference for the automated identification of insect larvae.

基于文献计量的农作物基因组研究领域发展态势分析

基因组学研究是近年来世界上发展最为迅速的研究领域之一。农作物基因组学研究的发展,对于有效利用现代分子生物学手段进行物种的遗传改良发挥了重要作用。目前国内外科学家已经对诸如水稻、小麦、玉米、大豆、油菜、棉花等重要农作物的基因组进行了测序,并在此基础上克隆和鉴定了控制重要农艺性状的基因。科技文献客观地记录了各个学科或知识领域的发展概貌,基于文献计量学的学科发展态势分析,可以系统地总结领域研究现状与热点问题、评价研究机构科研实力与成果产出。本研究综合利用文献定量分析和专家定性分析相结合的方法,通过对中美自然科学基金项目资助情况及SCI论文收录文献多维度、深层次的计量分析,全面揭示近10年农作物基因组领域的研发现状、重要国家、重要机构和热门研究主题,相关研究结果可为我国相关领域未来的研发布局和决策提供参考依据。

MmNet:Identifying Mikania micrantha Kunth in the wild via a deep Convolutional Neural Network

Mikania micrantha Kunth is an invasive alien weed and known as a plant killer around the world.Accurately and rapidly identifying M.micrantha in the wild is important for monitoring its growth status,as this helps management officials to take the necessary steps to devise a comprehensive strategy to control the invasive weed in the identified area.However,this approach still mainly depends on satellite remote sensing and manual inspection.The cost is high and the accuracy rate and efficiency are low.We acquired color images of the monitoring area in the wild environment using an Unmanned Aerial Vehicle(UAV)and proposed a novel network-MmNet-based on a deep Convolutional Neural Network(CNN)to identify M.micrantha in the images.The network consists of AlexNet Local Response Normalization(LRN),along with the GoogLeNet and continuous convolution of VGG inception models.After training and testing,the identification of 400 testing samples by MmNet is very good,with accuracy of 94.50%and time cost of 10.369 s.Moreover,in quantitative comparative analysis,the proposed MmNet not only has high accuracy and efficiency but also simple construction and outstanding repeatability.Compared with recently popular CNNs,MmNet is more suitable for the identification of M.micrantha in the wild.However,to meet the challenge of wild environments,more M.micrantha images need to be acquired for MmNet training.In addition,the classification labels need to be sorted in more detail.Altogether,this research provides some theoretical and scientific basis for the development of intelligent monitoring and early warning systems for M.micrantha and other invasive species.

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.

Stability evaluation of reference genes for real-time quantitative PCR normalization in Spodoptera frugiperda(Lepidoptera:Noctuidae)

Real-time quantitative PCR(qPCR)is a reliable and widely used technique for analyzing the expression profiles of target genes in different species,and reference genes with stable expressions have been introduced for the normalization of the data.Therefore,stability evaluation should be considered as the initial step for qPCR experiments.The fall armyworm Spodoptera frugiperda(J.E.Smith)(Lepidoptera:Noctuidae)is a polyphagous pest that consumes many plant species and seriously threatens corn production around the world.However,no studies thus far have examined the stability of reference genes in this pest.In this study,the expression profiles of the eight candidate reference genes of Actin,elongation factor 1 alpha(EF1α),elongation factor 2(EF2),glyceraldehyde-3-phosphate dehydrogenase(GAPDH),ribosomal protein L3(RPL3),ribosomal protein L13(RPL13),alpha-tubulin(α-TUB),and beta-1-tubulin(β-1-TUB)were obtained from S.frugiperda in different samples and the stability was evaluated byΔCt,BestKeeper,geNorm,NormFinder,and RefFinder methods.The results of pairwise variation(V)calculated by GeNorm indicated two reference genes could be selected for normalization.Therefore,the combinations of the most stable reference genes for different experimental conditions of S.frugiperda were shown as follows:EF2 and RPL13 for developmental stages,RPL3 andβ-1-TUB for larval tissue samples,EF2 and EF1αfor the larval samples treated with different temperatures,RPL3 and EF1αfor the larval samples under starvation stress,and RPL13 and EF1αfor all the samples.Our results lay the foundation for the normalization of qPCR analyses in S.frugiperda and could help guarantee the accuracy of subsequent research.

Identification and developmental expression of putative gene encoding juvenile hormone esterase(CpJHE-like) in codling moth, Cydia pomonella(L.)

Juvenile hormone esterase(JHE) is a key enzyme for insects,playing an important role in the regulation of insect growth,development,diapause and reproduction.We identified a complete putative JHE of Cydia pomonella(CpJHE-like) which is comprised of a 1 761 bp coding sequence(CDS) encoding 587 amino acid residues from the transcriptome data.The deduced protein sequence of CpJHE-like showed the highest identity of 60.44% with the Adoxophyes honmai JHE(AhJHE) and the minimal identity of 25.81% with Aedes aegypti JHE(AaJHE).CpJHE-like exhibited all the seven typical motifs of the functional JHEs and had the highly consistent tertiary structure with Manduca sexta JHE(MsJHE).Phylogenetic analysis showed that the CpJHE-like was close to two JHEs from the family Tortricidae.The CpJHE-like transcript level take a leap in the 3-day-old fifth instar larva,increased about 300-fold compared to the basal level.Tissue-specific expression profile showed that the CpJHE-like transcript was expressed mainly in the fat body.This study indicates that the CpJHE-like is the functional JHE,which may play vital roles in the development and reproduction of C.pomonella.

InvasionDB: A genome and gene database of invasive alien species

Invasive alien species(IAS) are species whose introduction to areas outside of their native range cause harm to economics, biodiversity, and the environment. Understanding the genetic basis of invasiveness is critical for preventing invasion by an alien species and managing IAS with eco-friendly control methods. In addition, uncovering the genomic features of IAS is essential for accurately predicting invasiveness. However, even though increasing efforts have been devoted to sequencing the genomes of IAS, there is still not an integrated genome database for the invasive biology community. Here, we first determined a list of invasive plants and animals by mining references and databases. Then, we retrieved the genomic and gene data of these IAS, and constructed a database, Invasion DB. Invasion DB encompasses 131 IAS genomes, 76 annotated IAS assemblies, and links these data to conventional functions such as searching for gene coding sequences and Pfam, KEGG, NR annotations, BLAST server, JBrowse, and downloads services. Next, we analyzed 19 invasivenessrelated gene families which confer invasiveness in insects. To study the roles of noncoding RNA in invasiveness, we also annotated 135 494 mi RNAs, 89 294 r RNAs, and 2 671 941 t RNAs from these IAS. In summary, Invasion DB is useful for studying the invasiveness at the genomic level, and thus helps to develop novel management strategies to control IAS.

China launches the “IAS1000 Project”

1. IAS1000 Project The rapid development of omics provides new technologies andmethodologiesforthestudyofinvasionbiology.Agricultural Genomics Institute at Shenzhen (CAAS-AGIS)andInstituteofPlantProtection,ChineseAcademyof AgriculturalSciences(CAAS-IPP)initiatedthe"IAS1000Project"-A genome project of 1 000 invasive alien species,and established the "IAS1000 Alliance" in Shenzhen, China,on November 14, 2018.Via deep-mining of omics data,theprojectaimsforbetterunderstandingtheecological processesandmolecularmechanismsofbiological invasion, and developing new technologies and products for prevention and management of invasive alien species.Up

昆虫滞育诱导的分子调控机制

滞育是昆虫长期适应不利环境的重要对策之一,对昆虫的生存、繁衍和进化都具有重要意义。滞育一般分为滞育前期、滞育期和滞育后期3个阶段,其中,滞育前期包括滞育诱导期和滞育准备期,是确保昆虫顺利进入滞育的重要时期。本文首先简要概括了光周期、温度、湿度、食料等外界环境因素在不同昆虫滞育诱导中的作用;然后系统综述了滞育激素、保幼激素、蜕皮激素、促前胸腺激素和胰岛素等内分泌激素,生物钟通路的节律基因,以及DNA甲基化、小RNA和组蛋白修饰等表观遗传修饰在昆虫滞育过程,尤其是滞育诱导调控中的作用,并以黑腹果蝇Drosophila melanogaster的生殖滞育为例,总结了昆虫滞育诱导调控的分子通路;最后就目前昆虫滞育诱导调控研究中亟待解决的问题和后续重点研究方向进行了探讨,展望了将昆虫滞育研究应用于害虫防控实践的主要策略和前景。

鳞翅目昆虫模式识别受体的研究进展

昆虫虽然缺乏适应性免疫系统,却进化出一套高效复杂的先天免疫系统来保护机体免受多种病原感染。昆虫先天免疫系统能够识别入侵病原体并迅速启动以消除潜在的威胁。免疫反应的第一步依赖于种系编码的模式识别受体,模式识别受体可以检测并结合入侵病原体表面的病原相关分子模式,进而激活下游免疫反应。到目前为止,在鳞翅目昆虫中已经鉴定到多种模式识别受体,如肽聚糖识别蛋白、β-1,3-葡聚糖识别蛋白和C型凝集素等。多种模式识别受体分工协作,共同参与复杂而精细的免疫应答。生物化学、遗传学和分子生物学等研究发现,不同种类的模式识别受体具有结合特异性和适应性进化。本文将重点总结模式识别受体相关基因家族的起源、结构特征以及在鳞翅目模式昆虫的生理功能和进化等方面的研究进展,为进一步研究其它鳞翅目昆虫的免疫系统,探索免疫基因与宿主生态适应性的关系提供参考。