番木瓜性别决定及其鉴定研究新进展

番木瓜有3种基本性别类型,性别遗传较为复杂.就其植株的多型性表现、性别决定及其鉴定研究、连锁遗传图的构建、分子标记辅助选择技术和花器的发育等方面的研究进展进行了综述,并对番木瓜性别鉴定的应用前景做了展望.     

植物根系吸水模型研究进展

植物根系吸水模型是当前生态水文和陆面过程建模领域最为活跃的研究方向,是研究流域水文、生态、环境以及水资源可持续利用等科学问题中最为关键的部分,研究植物根系吸水的物理和生理机制及其影响因素,是建立植物根系吸水模型的基础.本文通过对植物根系吸水模型研究的回顾,讨论了水分和盐分胁迫在根系吸水中的作用、根系吸水的多维模型、根系吸水在陆面过程中的作用等问题,指出植物根系吸水模型发展所面临的问题并展望了未来的发展方向.     

遥感技术在昆虫生态学中的应用途径与进展

结合雷达、航空和卫星遥感本身的特点 ,从害虫本身、害虫所造成的危害、影响害虫发展的环境因子三方面介绍了遥感技术在区域性害虫的早期监测及预测中的应用途径与最新进展。针对害虫本身的个体大小、可动性和种群所在空间尺度的影响 ,作者强调应发挥不同遥感系统各自独特的优势 ,同时 ,综合应用“3S”技术和时空模型方法 ,才能够实现害虫动态的可视化、立体化、实时化和精确化监测及预测。     

Computational characterization of double reduction in autotetraploid natural populations

Population genetic theory has been well developed for diploid species, but its extension to study genetic diversity, variation and evolution in autopolyploids, a class of polyploids derived from the genome doubling of a single ancestral species, requires the incorporation of multisomic inheritance. Double reduction, which is characteristic of autopolyploidy, has long been believed to shape the evolutionary consequence of organisms in changing environments. Here, we develop a computational model for testing and estimating double reduction and its genomic distribution in autotetraploids. The model is implemented with the expectation–maximization (EM) algorithm to dissect unobservable allelic recombinations among multiple chromosomes, enabling the simultaneous estimation of allele frequencies and double reduction in natural populations. The framework fills an important gap in the population genetic theory of autopolyploids.     

肠道菌群在蜜蜂健康与疾病中的作用研究进展

蜜蜂是重要的经济昆虫,在农作物授粉和维持生态平衡等方面扮演了重要角色。随着生态环境的逐步恶化,蜜蜂极易受到寄生虫、农药、抗生素和病原微生物等的危害。肠道作为蜜蜂的重要免疫器官,在抵抗外源刺激等方面具有不可替代的作用。而肠道菌群作为肠道的重要组成部分,对蜜蜂的健康有着至关重要的影响。其拥有高度保守和专门的核心微生物群,主要由九大类细菌组成。近年来,有关肠道菌群的研究主要集中在新陈代谢、免疫防御、生长发育等方面。肠道菌群不仅可以帮助宿主消化和制造营养素,还可维持宿主体内能量稳态,其对蛋白质的代谢也使菌群丰度增加。越来越多的证据表明,肠道菌群紊乱会导致蜜蜂健康受损,其多样性对宿主健康和疾病影响甚广。因此,肠道菌群成为近年来微生物学领域研究的焦点。主要综述了蜜蜂属、熊蜂属等主要传粉蜂类肠道菌群的组成及其在健康与疾病中的作用,为深入了解传粉昆虫肠道菌群功能提供参考。     

2020年中国植物科学若干领域重要研究进展

2020年中国植物科学家在国际综合性学术期刊及植物科学主流期刊发表的论文数量比上一年显著增加, 在植物发育、耐逆、系统进化和作物生物学等领域取得了重要研究进展。其中, “小麦抗赤霉病基因 Fhb7的克隆、机理解析及育种利用”和“提高作物品种氮肥利用效率的新机制”两项成果入选2020年度“中国生命科学十大进展”。该文总结了2020年我国植物科学研究取得的成绩, 简要介绍了30项代表性的重要进展, 以帮助读者了解我国植物科学发展态势, 思考如何更好地开展下阶段的研究, 服务国家需求。     

Independent translation of ORFs in dicistronic operons,synthetic building blocks for polycistronic chloroplast gene expression

We designed a dicistronic plastid marker system that relies on the plastid's ability to translate polycistronic mRNAs. The identification of transplastomic clones is based on selection for antibiotic resistance encoded in the first open reading frame (ORF) and accumulation of the reporter gene product in tobacco chloroplasts encoded in the second ORF. The antibiotic resistance gene may encode spectinomycin or kanamycin resistance based on the expression of aadA or neo genes, respectively. The reporter gene used in the study is the green fluorescent protein (GFP). The mRNA level depends on the 5′‐untranslated region of the first ORF. The protein output depends on the strengths of the ribosome binding, and is proportional with the level of translatable mRNA. Because the dicistronic mRNA is not processed, we could show that protein output from the second ORF is independent from the first ORF. High‐level GFP accumulation from the second ORF facilitates identification of transplastomic events under ultraviolet light. Expression of multiple proteins from an unprocessed mRNA is an experimental design that enables predictable protein output from polycistronic mRNAs, expanding the toolkit of plant synthetic biology.     

2019年中国植物科学若干领域重要研究进展

2019年中国植物科学家在国际综合性学术期刊及植物科学主流期刊发表的论文数量大幅增加, 在光生物学、植物抗逆和分子进化等若干领域取得了重要成果。其中, 硅藻光合膜蛋白超分子结构和功能研究入选2019年度中国科学十大进展和中国生命科学十大进展; 植物抗病小体的结构与功能研究入选2019年度中国生命科学十大进展。该文评述了2019年中国科学家在植物科学若干领域取得的重要研究进展, 以期追踪和报道当前中国植物科学领域发展的前沿和热点及展示中国科学家所取得的辉煌成果。     

Rapid identification of an Arabidopsis NLR gene as a candidate conferring susceptibility to Sclerotinia sclerotiorum using time‐resolved automated phenotyping

The broad host range necrotrophic fungus Sclerotinia sclerotiorum is a devastating pathogen of many oil and vegetable crops. Plant genes conferring complete resistance against S. sclerotiorum have not been reported. Instead, plant populations challenged by S. sclerotiorum exhibit a continuum of partial resistance designated as quantitative disease resistance (QDR). Because of their complex interplay and their small phenotypic effect, the functional characterization of QDR genes remains limited. How broad host range necrotrophic fungi manipulate plant programmed cell death is for instance largely unknown. Here, we designed a time‐resolved automated disease phenotyping pipeline enabling high‐throughput disease lesion measurement with high resolution, low footprint at low cost. We could accurately recover contrasted disease responses in several pathosystems using this system. We used our phenotyping pipeline to assess the kinetics of disease symptoms caused by seven S. sclerotiorum isolates on six A. thaliana natural accessions with unprecedented resolution. Large effect polymorphisms common to the most resistant A. thaliana accessions identified highly divergent alleles of the nucleotide‐binding site leucine‐rich repeat gene LAZ5 in the resistant accessions Rubezhnoe and Lip‐0. We show that impaired LAZ5 expression in laz5.1 mutant lines and in A. thaliana Rub natural accession correlate with enhanced QDR to S. sclerotiorum. These findings illustrate the value of time‐resolved image‐based phenotyping for unravelling the genetic bases of complex traits such as QDR. Our results suggest that S. sclerotiorum manipulates plant sphingolipid pathways guarded by LAZ5 to trigger programmed cell death and cause disease.     

Kmasker plants – a tool for assessing complex sequence space in plant species

Many plant genomes display high levels of repetitive sequences. The assembly of these complex genomes using short high‐throughput sequence reads is still a challenging task. Underestimation or disregard of repeat complexity in these datasets can easily misguide downstream analysis. Detection of repetitive regions by k‐mer counting methods has proved to be reliable. Easy‐to‐use applications utilizing k‐mer counting are in high demand, especially in the domain of plants. We present Kmasker plants, a tool that uses k‐mer count information as an assistant throughout the analytical workflow of genome data that is provided as a command‐line and web‐based solution. Beside its core competence to screen and mask repetitive sequences, we have integrated features that enable comparative studies between different cultivars or closely related species and methods that estimate target specificity of guide RNAs for application of site‐directed mutagenesis using Cas9 endonuclease. In addition, we have set up a web service for Kmasker plants that maintains pre‐computed indices for 10 of the economically most important cultivated plants. Source code for Kmasker plants has been made publically available at https://github.com/tschmutzer/kmasker . The web service is accessible at https://kmasker.ipk-gatersleben.de .