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Nematode Community Structure and Effects on Peanut Production Systems.

机译：线虫群落结构及其对花生生产系统的影响。

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摘要

Understanding the total nematode community in agronomic systems and its impact on crop health may provide insight into more sustainable management strategies. In this study the focus was on management of the peanut root-knot nematode, Meloidogyne arenaria race 1 and the aflatoxigenic fungi Aspergillus flavus and A. parasiticus, a toxic food contaminate that poses a threat to humans and animals, to increase peanut yields while lowering toxins. The overall approach of management is to suppress plant-parasitic nematodes that facilitate invasion of the toxin producing fungi through manipulation of free-living nematode populations that act to increase plant health. The objectives of this research were (1) evaluate nematode consensus primers and Denaturing Gradient Gel Electrophoresis (DGGE) techniques for effectiveness in identification of nematode populations and monitoring community shifts; (2) develop nematode genetic profiles of selected soil samples, using DGGE fingerprinting, from different rotation sequences: continuous peanut, continuous bahiagrass, peanut/cotton, and peanut/corn, to determine if any factors exist that result in nematode population shifts; and (3) identify individual populations in the nematode community and determine their relationship with peanut yields and aflatoxin contamination. Nematode populations were established through various methods including in vitro culturing methods, after which total genomic DNA was extracted from each species to evaluate the specificity of nematode consensus primers. The primers amplified a wide trophic range of nematode DNA and fungal DNA, showing that the primers may be universal to all eukaryotes. DGGE techniques were then evaluated by amplifying a portion of the 18S rDNA per species collected and subsequently separating the species through denaturing gradient gel electrophoresis. The DGGE technique successfully separated nematodes at the generic level. Nematode genetic profiles were created from peanut soils under different cropping sequences which revealed individual banding patterns, indicating population shifts between rotation sequences and shifts between sampling periods. Free-living nematodes accounted for the majority of sequences recovered from profiles, although plant-parasitic, animal-parasitic, and entomopathogenic nematodes, as well as nematophagus fungi were identified in recovered sequences. Bahiagrass rotations supported higher population levels of microbivore nematodes and significantly lower levels of aflatoxins when planted in rotation with peanuts. Negative correlations occurred between microbivore populations and total aflatoxin levels, suggesting that free-living nematodes may play a role in the suppression of aflatoxin contamination in peanuts.
机译：了解农艺系统中的整个线虫群落及其对作物健康的影响，可以为更可持续的管理策略提供见识。在这项研究中，重点在于花生根结线虫，Meloidogyne沙参种族1和黄曲霉毒素真菌黄曲霉和寄生曲霉的管理，这是一种对人和动物构成威胁的有毒食品，可增加花生产量，同时降低花生产量。毒素。管理的总体方法是通过操纵自由活动的线虫种群来抑制植物寄生的线虫，这些线虫通过促进植物健康的活动来促进毒素生产真菌的入侵。这项研究的目的是：（1）评估线虫共有引物和变性梯度凝胶电泳（DGGE）技术，以鉴定线虫种群并监测群落转移。 （2）利用DGGE指纹图谱，从不同的轮换序列（连续的花生，连续的Bahiagrass，花生/棉和花生/玉米）开发选定土壤样品的线虫遗传图谱，以确定是否存在导致线虫种群迁移的因素; （3）确定线虫群落中的单个种群，并确定它们与花生产量和黄曲霉毒素污染的关系。通过各种方法，包括体外培养方法，建立了线虫种群，然后从每个物种中提取总基因组DNA，以评估线虫共有引物的特异性。该引物扩增了广泛的线虫DNA和真菌DNA的营养序列，表明该引物可能对所有真核生物都是通用的。然后，通过对收集到的每个物种的一部分18S rDNA进行扩增，然后通过变性梯度凝胶电泳分离该物种，来评估DGGE技术。 DGGE技术成功地在一般水平上分离了线虫。线虫的遗传图谱是在不同种植顺序下从花生土壤中产生的，揭示了个体的带状分布模式，表明轮作序列之间的种群转移和采样周期之间的转移。自生线虫占从图谱中回收的大部分序列，尽管在回收的序列中鉴定出了植物寄生，动物寄生和昆虫致病线虫以及食道真菌。当与花生一起轮作种植时，Bahiagrass轮作可支持较高种群的微食虫线虫和低水平的黄曲霉毒素。微生物种群与总黄曲霉毒素水平之间存在负相关关系，这表明自由活动的线虫可能在抑制花生中的黄曲霉毒素污染中起作用。

著录项

  • 作者

    Conner, Kassie N.;

  • 作者单位

    Auburn University.;

  • 授予单位 Auburn University.;
  • 学科 Agriculture Agronomy.;Agriculture Plant Pathology.
  • 学位 Ph.D.
  • 年度 2010
  • 页码 121 p.
  • 总页数 121
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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