Multiple determinants influence root colonization and induction of induced systemic resistance by Pseudomonas chlororaphis O6

Colonization of the roots of tobacco by Pseudomonas chlororaphis O6 induces systemic resistance to the soft-rot pathogen, Erwinia carotovora ssp. carotovara SCC1. A screen of the transposon mutants of P. chlororaphis O6 showed mutants with about a fivefold reduction in ability to induce systemic resistance to the soft-rot disease. These mutations disrupted genes involved in diverse functions: a methyl-accepting chemotaxis protein, biosynthesis of purines, phospholipase C, transport of branched-chain amino acids and an ABC transporter. Additional mutations were detected in the intergenic spacer regions between genes encoding a GGDEF protein and fumarate dehydratase, and in genes of unknown function. The mutants in the ABC transporters did not display reduced root colonization. However, the other mutants had up to 100-fold reduced colonization levels. Generally the production of metabolites important for interactions in the rhizosphere, phenazines and siderophores, was not altered by the mutations. A reduced induction of systemic resistance by a purine biosynthesis mutant with a disrupted purM gene correlated with poor growth rate, lesser production of phenazines and siderophore and low levels of root colonization. These studies showed that multiple determinants are involved in the induction of systemic resistance, with there being a requirement for strong root colonization.     

Morphological evolutionary trends and their implications for the phylogenetic analysis of metendosternite in Chinese dung beetles (Coleoptera, Scarabaeidae)

后胸叉骨是昆虫胸部的内骨骼,是重要的肌肉联结点,在昆虫运中起着不可替代的作用.该结构在鞘翅目高级阶元系统发育关系重建中扮演了重要角色,但由于其在低级阶元间的差异较小以及在形态分析中使用困难等因素限制,致使后胸叉骨的研究并未受到广泛重视.国内学者对于甲虫后胸叉骨的研究非常少,甚至长期以来没有中文名称,相关内容只零星散布于教科书和学位论文中,针对蜣螂后胸叉骨形态学研究尚未见报道.本文对金龟科蜣螂亚科9族65种的后胸叉骨进行了详细的比较形态学研究,归纳了族级形态特征,进而探究蜣螂后胸叉骨形态演化趋势及其在系统发育分析中的意义.此外,还对利用现代形态学和几何形态学等方法研究后胸叉骨功能形态的前景进行了阐述.     

绿盲蝽雄虫体外挥发物研究

采用气质联用和嗅觉仪对分部解剖的绿盲蝽Apolygus lucorum(Meyer-Dür)雄虫体外挥发物进行鉴定和生测。结果表明:绿盲蝽雄虫浸提物中的主要组分有13种,包括醇类、酸类和酯类。相对含量较高的依次有丁酸己酯、反-2-丁酸己烯酯和己醇。绿盲蝽雄虫从交配不活跃期进入活跃期,其体内的丁酸己酯、反-2-丁酸己烯酯和己醇的含量都明显变化,其中丁酸己酯和反-2-丁酸己烯酯明显增加,而己醇的含量减少,表明绿盲蝽雄虫在交配活跃期,可能有大量的丁酸己酯和反-2-丁酸己烯酯释放到体外。比较绿盲蝽雄虫的不同部位的浸提物的含量,发现丁酸己酯、反-2-丁酸己烯酯和己醇主要存在于虫体胸部。嗅觉反应测试中绿盲蝽雌虫对丁酸己酯和反-2-丁酸己烯酯有明显的趋性,同时含量很少的丁酸庚酯对雌虫有明显引诱作用。因此推测丁酸己酯、反-2-丁酸己烯酯和丁酸庚酯可能是绿盲蝽雄虫释放到体外的挥发性引诱成分,并主要由胸部内的腺体分泌。     

蜣螂后胸叉骨形态演化趋势及其在系统发育分析中的意义(鞘翅目:金龟科)

后胸叉骨是昆虫胸部的内骨骼,是重要的肌肉联结点,在昆虫运动中起着不可替代的作用。该结构在鞘翅目高级阶元系统发育关系重建中扮演了重要角色,但由于其在低级阶元间的差异较小以及在形态分析中使用困难等因素限制,致使后胸叉骨的研究并未受到广泛重视。国内学者对于甲虫后胸叉骨的研究非常少,甚至长期以来没有中文名称,相关内容只零星散布于教科书和学位论文中,针对蜣螂后胸叉骨形态学研究尚未见报道。本文对金龟科蜣螂亚科9族65种的后胸叉骨进行了详细的比较形态学研究,归纳了族级形态特征,进而探究蜣螂后胸叉骨形态演化趋势及其在系统发育分析中的意义。此外,还对利用现代形态学和几何形态学等方法研究后胸叉骨功能形态的前景进行了阐述。     

Identification of the gene MdSOD3 and its role in resisting heavy metal stress in housefly (Musca domestica)

超氧化物歧化酶(SOD)是一种重要的抗氧化酶,在昆虫抗氧化保护过程中起着重要作用.本研究通过RTPCR技术鉴定了家蝇Musca domestica MdSOD3基因(GenBank登录号为JQ408979),cDNA序列817 bp,开放阅读框534 bp,推导的多肽序列含有177个氨基酸.同源性分析及NJ法系统分析表明MdSOD3与其他物种的Cu/ZnSOD关系较近.荧光定量PCR检测该基因在家蝇幼虫脂肪体、肠、表皮和血细胞中不存在差异表达;在受到不同浓度重金属Cd2+刺激时,MdSOD3基因呈诱导性表达,5 mmol/L时表达量最高.通过RNAi策略技术成功敲低MdSOD3表达水平.将RNA干扰60h的幼虫置于5 mmol/L Cd2+处理24h后死亡率明显升高,并且出现中毒表象.NBT活性染色检测到体外重组表达的MdSOD3具有明显的酶活性.结果提示MdSOD3基因可能在家蝇抗逆防御过程中起着重要作用.     

Variability and adaptability of Miscanthus species evaluated for energy crop domestication

A growing body of evidence indicates that second‐generation energy crops can play an important role in the development of renewable energy and the mitigation of climate change. However, dedicated energy crops have yet to be domesticated in order to fully realize their productive potential under unfavorable soil and climatic conditions. To explore the possibility of domesticating Miscanthus crops in northern China where marginal and degraded land is abundant, we conducted common garden experiments at multiple locations to evaluate variation and adaptation of three Miscanthus species that are likely to serve as the wild progenitors of the energy crops. A total of 93 populations of Miscanthus sinensis, Miscanthus sacchariflorus, and Miscanthus lutarioriparius were collected across their natural distributional ranges in China and grown in three locations that represent temperate grassland with cold winter, the semiarid Loess Plateau, and relatively warm and wet central China. Evaluated with growth traits such as plant height, tiller number, tiller diameter, and flowering time, the Miscanthus species showed high levels of genetic variation within and between species. There were significant site × population interactions for almost all traits of M. sacchariflorus and M. sinensis, but not M. lutarioriparius. The northern populations of M. sacchariflorus had the highest establishment rates at the most northern site owing to their strong cold tolerance. An endemic species in central China, M. lutarioriparius, produced not only the highest biomass of the three species but also higher biomass at the Loess Plateau than the southern site near its native habitats. These results demonstrated that the wild species harbored a high level of genetic variation underlying traits important for crop establishment and production at sites that are colder and drier than their native habitats. The natural variation and adaptive plasticity found in the Miscanthus species indicated that they could provide valuable resources for the development of second‐generation energy crops.     

二氧化氯浸泡对双孢蘑菇褐变的抑制效应及其机理分析

以‘W2000’双孢蘑菇为试验材料,设清水(CK)和ClO2浸泡(120mg·L-1)2个处理,研究ClO2浸泡处理在低温贮藏条件下对双孢蘑菇采后品质、生理及相关酶活性的影响。结果显示:ClO2浸泡处理配合0℃低温贮藏可显著降低双孢蘑菇的呼吸强度,推迟呼吸高峰的出现时间,呼吸强度较CK降低29.2%,并使呼吸高峰推迟5d出现;同时能够有效抑制子实体多酚氧化酶(PPO)和过氧化物酶(POD)的活性,控制酚类氧化产物的积累,减缓子实体褐化进程,贮藏20d时,处理的总酚含量仅为0.81μmol/mg。另外,ClO2处理还可延缓子实体硬度的下降,保持其可溶性固形物的含量,并抑制开伞,有效延长双孢蘑菇的贮藏期。研究表明,ClO2处理+低温贮藏对双孢蘑菇具有较理想的保鲜效应,可有效保持双孢蘑菇的外观和营养品质,提高商品价值,具有一定的实际应用价值。     

STUDY OF THE PEPPER PEST GENUS, LANKA MAULIK, AND DESCRIPTIONS OF TWO NEW SPECIES FROM CHINA (COLEOPTERA,CHRYSOMELIDAE, ALTICINAE)

突顶跳甲属L.anka Maulik此前已知17种,分布于中国云南,台湾及日本,越南,泰国,老挝,斯里兰卡和印度,是一个典型的东洋区分布属,在印度是胡椒属植物的重要害虫.又记述2新种:栗褐突顶跳甲Lanka puncticolla Wang et Ge,sp.nov.,产自云南西双版纳;律点突顶跳甲Lanka regularia Wang et Ge,sp.nov..产自西藏墨脱.至此,该属已知种增至19种,其中中国5种.列出了全部已知种名录、产地、寄主、检索表、部分种的雄虫阳茎图,记述了新种,绘制其整体图和特征图等.新种模式标本保存于中国科学院动物研究所.