Symbiotic Association of Aphids: Biochemical Role of the Procaryotic Endosymbiont

蚜虫的共生关联：原核内共生体的生化作用

• 批准号: 9201285
• 负责人: Paul Baumann
• 金额: $ 15万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-09-01 至 1994-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9201285&HistoricalAwards=false
• 关键词: Symbiotic; Association; Aphids; Biochemical; Role

Aphids are small syringe-like insects which penetrate plants and suck up plant juices for nutrients. Acting like unsterilized needles these insects transmit a variety of agriculturally important plant diseases. Within the body cavity of aphids are specialized cells which contain gram-negative bacteria (endosymbionts) which cannot be cultured outside the host cells. The aphid is dependent on the endosymbionts, their elimination by treatment with antibiotics results in sterility or death of the host. Plant sap is deficient in a variety of amino acids which insects cannot synthesize and evidence suggests that the endosymbionts supply these amino acids for the aphid host. Perhaps the best available evidence is for the overproduction of tryptophan by the endosymbiont; there is also evidence that some endosymbionts may overproduce cysteine. Our study involves the cloning and sequencing of genes coding for enzymes of tryptophan and cysteine biosynthesis, the overproduction of selected key enzymes and a study of their kinetic properties. These results may indicate that the two key amino acids, tryptophan and cysteine are overproduced by the endosymbiont and utilized by the aphid host. This information will establish a function for the endosymbiont and may suggest approaches for the controlling of aphid pests by the elimination of their endosymbionts.

蚜虫是一种小的昆虫，像蜜蜂一样侵入植物， 吸取植物汁液作为营养 就像没消毒过一样 针这些昆虫传播各种农业 重要植物病害。 在蚜虫的体腔内 含有革兰氏阴性菌的特殊细胞 （内共生体），其不能在宿主细胞外培养。 蚜虫依赖于内共生体，它们被 用抗生素治疗会导致不育或死亡， 主持人 植物汁液缺乏多种氨基酸， 昆虫不能合成，有证据表明， 内共生体为蚜虫宿主提供这些氨基酸。 也许 最好的证据是色氨酸的过量生产 也有证据表明， 内共生体可过量产生半胱氨酸。 我们的研究涉及 色氨酸酶编码基因的克隆和测序 和半胱氨酸生物合成，过量生产选定的关键 酶及其动力学性质的研究。 这些结果可能 表明两种关键氨基酸色氨酸和半胱氨酸 被内共生体过度生产并被蚜虫宿主利用。 这些信息将建立内共生体的功能， 可以建议的方法来控制蚜虫害虫的 消除它们的内共生体。