The Inheritance of Aliphatic Glucosinolates in Brassica napus

The inheritance of aliphatic glucosinolates was studied in crosses between synthetic B. napus lines and oilseed rape cultivars. Six unlinked loci are described which determine the aliphatic glucosinolate profile of B. napus. One locus regulates the presence or absence of propyl glucosinolates, while another regulates the expression of pentyl glucosinolates. Two loci regulate the removal of the terminal H₃CS-group from the amino acid derivative to produce alkenyl glucosinolates as opposed to methylthioalkyl and methylsulphinylalkyl glucosinolates, regardless of the length of the alkyl chain. Likewise, another two loci regulate the hydroxylation of both butenyl and pentenyl glucosinolates. The functional alleles at one of the hydroxylation loci results in significantly more hydroxylation than those at the other locus. The large number of aliphatic glucosinolates which have been described in Brassica thus results from an interaction between genes which regulate side chain elongation and genes which modify the structure of the side chain, regardless of its length. The implications of this study for the biosynthesis of aliphatic glucosinolates, the origin of B. napus and the potential to manipulate the leaf and seed glucosinolate profile of oilseed rape are discussed.     

Moth sex-pheromone biosynthesis is inhibited by the herbicide diclofop

Pheromones of nocturnal moths are derived from fatty acids produced as a result of the activity of acetyl-CoA carboxylase. This timely production is initiated in nocturnal moths by a tropic peptide, pheromone biosynthesis activating neuropeptide released into the hemolymph. In monocotyledonous plants, specific plastid acetyl-CoA carboxylase is inhibited by herbicides that target the eukaryotic form of the enzyme. We report evidence that these herbicides can also target pheromone biosynthesis by a moth, thereby implicating the acetyl-CoA carboxylase as a key regulatory enzyme in the pheromone biosynthetic pathway. These findings, whilst indicating the possible action of such herbicides on non-target organisms, also suggest a novel alternative method of insect pest management, which precludes sex-pheromone production and mating success, thereby reducing insect population growth.     

Genome Mining as an Alternative Way for Screening the Marine Organisms for Their Potential to Produce UV-Absorbing Mycosporine-like Amino Acid

Mycosporine-like amino acids (MAAs) are small molecules with robust ultraviolet (UV)-absorbing capacities and a huge potential to be used as an environmentally friendly natural sunscreen. MAAs, temperature, and light-stable compounds demonstrate powerful photoprotective capacities and the ability to capture light in the UV-A and UV-B ranges without the production of damaging free radicals. The biotechnological uses of these secondary metabolites have been often limited by the small quantities restored from natural resources, variation in MAA expression profiles, and limited success in heterologous expression systems. Overcoming these obstacles requires a better understanding of MAA biosynthesis and its regulatory processes. MAAs are produced to a certain extent via a four-enzyme pathway, including genes encoding enzymes dehydroquinate synthase, enzyme O-methyltransferase, adenosine triphosphate grasp, and a nonribosomal peptide synthetase. However, there are substantial genetic discrepancies in the MAA genetic pathway in different species, suggesting further complexity of this pathway that is yet to be fully explored. In recent years, the application of genome-mining approaches allowed the identification of biosynthetic gene clusters (BGCs) that resulted in the discovery of many new compounds from unconventional sources. This review explores the use of novel genomics tools for linking BGCs and secondary metabolites based on the available omics data, including MAAs, and evaluates the potential of using novel genome-mining tools to reveal a cryptic potential for new bioproduct screening approaches and unrevealing new MAA producers.     

几种经济红藻中茉莉酸合成途径的关键物质

为研究几种经济红藻中茉莉酸合成途径的关键物质,实验采用液相色谱—质谱联用技术(LC-MS)对茉莉酸生物合成途径相关物质建立检测方法,并对龙须菜、坛紫菜受到机械损伤时各物质的变化情况进行检测。以100%甲醇提取茉莉酸(JA)、茉莉酸甲酯(MeJA)、12-氧-植物二烯酸(12-OPDA)和13-氢过氧化亚麻酸(13-HpOTE),利用XBridge TM C18色谱柱,以甲醇/水为流动相分离4种物质。优化条件下4种物质得到良好分离,加标回收率为81.23%～90.25%,检测限为0.04～0.56 ng/mL,灵敏度高。坛紫菜、龙须菜和真江蓠3种红藻中,坛紫菜中未检测到JA和13-HpOTE,4种物质均在另外2种藻中检测到。龙须菜受机械损伤胁迫后,4种物质在短时间内得到积累,其中13-HpOTE响应迅速。研究表明,红藻中可能存在类似于植物的茉莉酸合成途径,并参与对损伤的胁迫响应。     

Identification,Characteristics and Function of Phosphoglucomutase (PGM) in the Agar Biosynthesis and Carbon Flux in the Agarophyte Gracilariopsis lemaneiformis (Rhodophyta)

Agar is widely applied across the food, pharmaceutical and biotechnology industries, owing to its various bioactive functions. To better understand the agar biosynthesis in commercial seaweed Gracilariopsis lemaneiformis, the activities of four enzymes participating in the agar biosynthesis were detected, and phosphoglucomutase (PGM) was confirmed as highly correlated with agar accumulation. Three genes of PGM (GlPGM1, GlPGM2 and GlPGM3) were identified from the G. lemaneiformis genome. The subcellular localization analysis validated that GlPGM1 was located in the chloroplast and GlPGM3 was not significantly distributed in the organelles. Both the GlPGM1 and GlPGM3 protein levels showed a remarkable consistency with the agar variations, and GlPGM3 may participate in the carbon flux between (iso)floridoside, floridean starch and agar synthesis. After treatment with the PGM inhibitor, the agar and floridean starch contents and the activities of floridean starch synthase were significantly decreased; products identified in the Calvin cycle, the pentose phosphate pathway, the Embden-Meyerhof-Parnas pathway and the tricarboxylic acid cycle were depressed; however, lipids, phenolic acids and the intermediate metabolites, fructose-1,6-phosphate were upregulated. These findings reveal the essential role of PGM in regulating the carbon flux between agar and other carbohydrates in G. lemaneiformis, providing a guide for the artificial regulation of agar accumulation.     

橡胶树树皮中ACC氧化酶基因(HbACO7)的表达特性及功能探究

天然橡胶是重要的工业原材料,主要来自橡胶树树皮中的乳管。乙烯能促进橡胶树乳管产胶和排胶,在树皮上施用乙烯利（一种乙烯释放剂）或乙烯可显著提高胶乳产量。基于本课题组前期获得的橡胶树基因组和转录组数据,克隆橡胶树中乙烯合成通路关键酶——1-氨基环丙烷基-1-羧酸（ACC）氧化酶基因家族（HbACOs）的全部8个家族基因,研究其组织表达模式。结果表明：在分析的7种组织中,尽管HbACO基因存在不同程度的冗余表达,但每种基因的组织表达模式具有明显的特异性,其中HbACO7是树皮中表达量最高的家族基因。HbACO7基因的表达在割胶季节的不同月份发生明显变化,其中在8月的表达量最高。成功构建了HbACO7基因的原核表达载体,实现其在大肠杆菌BL21中的诱导表达。纯化后的HbACO7重组蛋白具有明显的ACO酶催化活性,成功地催化了乙烯的体外合成。该结果将为后续橡胶树树皮中的乙烯生物合成调控机制研究提供参考。     

棉铃虫性信息素生物合成研究进展

性信息素是昆虫两性通讯的化学信号, 在物种繁衍中担当着重要的角色。以性信息素为基础的害虫诱杀和交配干扰等防治手段具有灵敏度高、选择性强、对天敌安全、不污染环境等优点, 在害虫综合治理和绿色防控体系应用中深受青睐。棉铃虫 Helicoverpa armigera 是一种世界性农业害虫, 具有适应能力强和寄主广泛的特点, 条件适宜时常大面积暴发成灾。以棉铃虫为代表的醛类性信息素的生物合成和调控过程, 是目前研究较早也较为透彻的一类性信息素。本研究概述了棉铃虫性信息素的组分和功能, 生物合成时的信号转导途径和调控机制, 以及性信息素前体的生成和特异性组分的碳链修饰过程, 并总结了当前研究的不足, 旨在为今后的基础研究和生产应用提供指导。     

Fungal Bergamotane Sesquiterpenoids—Potential Metabolites: Sources,Bioactivities, and Biosynthesis

The marine environment represents the largest ecosystem on the Earth’s surface. Marine-derived fungi are of remarkable importance as they are a promising pool of diverse classes of bioactive metabolites. Bergamotane sesquiterpenoids are an uncommon class of terpenoids. They possess diverse biological properties, such as plant growth regulation, phototoxic, antimicrobial, anti-HIV, cytotoxic, pancreatic lipase inhibition, antidiabetic, anti-inflammatory, and immunosuppressive traits. The current work compiles the reported bergamotane sesquiterpenoids from fungal sources in the period ranging from 1958 to June 2022. A total of 97 compounds from various fungal species were included. Among these metabolites, 38 compounds were derived from fungi isolated from different marine sources. Furthermore, the biological activities, structural characterization, and biosynthesis of the compounds are also discussed. The summary in this work provides a detailed overview of the reported knowledge of fungal bergamotane sesquiterpenoids. Moreover, this in-depth and complete review could provide new insights for developing and discovering new valuable pharmaceutical agents from these natural metabolites.     

1株能够分解木质素的泛菌的分离与鉴定

木质素紧密结合在纤维素外层,由于其结构的复杂性和稳定性,是纤维素资源利用中的一大障碍.目前微生物降解木质素的研究主要集中在以白腐菌为代表的真菌上,细菌在木质素降解中的作用有待研究.试验从洋葱腐烂茎秆中取土样,经过碱木质素为唯一碳源的限制性筛选和继代培养,并以愈创木酚为唯一碳源的培养基进行显色反应,最终得到了一株具有木质素分解能力的细菌.通过16S rDNA和gyrB基因测序对该菌株进行鉴定,发现该细菌属于泛菌属.与泛菌属的植物病原菌不同,该细菌不具备致病性,可用于进一步的木质素的细菌分解以及纤维素的综合利用研究.     

Secondary Metabolites and Biosynthetic Gene Clusters Analysis of Deep-Sea Hydrothermal Vent-Derived Streptomyces sp. SCSIO ZS0520

Streptomyces sp. SCSIO ZS0520 is a deep-sea hydrothermal vent-derived actinomycete. Our previous metabolism investigation showed that Streptomyces sp. SCSIO ZS0520 is a producer of cytotoxic actinopyrones. Here, another four types of secondary metabolites were identified, including six salinomycin isomers (2–7), the macrolide elaiophylin (8), the triterpene N-acetyl-aminobacteriohopanetriol (9), and the pyrone minipyrone (10). Among them, compounds 2–6 and 10 are new compounds. To understand the biosynthetic pathway of these compounds, a bioinformatic analysis of the whole genome was carried out, which identified 34 secondary metabolite biosynthetic gene clusters. Next, the biosynthetic pathways responsive to four types of products were deduced on the basis of gene function predictions and structure information. Taken together, these findings prove the metabolite potential of ZS0520 and lay the foundations to solve the remaining biosynthetic issues in four types of marine natural products.