Mechanisms of natural and transgenic auxinic herbicide resistance

除草剂（例如2，4-D、麦草畏）是最早开发的选择性有机除草剂，并且已经在农业中使用超过60年，主要用于选择性控制谷类作物中的阔叶杂草。他们彻底改变了现代农业。如果由于严重的杂草抗药性而停止使用，加拿大农民的总经济损失估计超过3.5亿美元/年，其中约2.5亿美元是由于作物损失，1亿美元是更换除草剂的额外费用。消费者的成本将是。第一年3000万至3300万美元，第六年增加到3亿美元。这些除草剂被归类为吲哚-3-乙酸（IAA）的模拟物，IAA是一种天然植物激素，也称为生长素。生长素几乎涉及植物生长和发育的所有方面。生长素类除草剂抗性的发生率有所增加。最具抗性的杂草之一是野生芥菜（S。arvensis L.）在用生长素除草剂处理超过10年的马尼托巴田地中发现的生物型。我的小组是第一个在生理学、生物化学和遗传学上表征这种抗性（R）生物型的小组，从而进一步加深了我们对生长素除草剂作用机制的理解，从而进一步理解了生长素的作用机制。本研究的主要目的有两个：（1）鉴定野生芥菜（S。arvensis），和（2）在烟草和拟南芥植物中开发基于抗体（Ab）的生长素除草剂抗性，以及用于生长素免疫调节的抗IAA Ab的表达。 从这项研究中获得的知识可能会确定一个新的生长素受体类，可能会提供战略，以打击生长素-除草剂抗性，允许开发新的除草剂抗性机制的作物植物和新的选择标记用于生产转基因植物，和新的生理试剂用于研究更全面的了解生长素除草剂和生长素。 此外，在植物中表达抗小分子抗体可以允许开发这种机制作为一种实用的模型，用于在植物中产生基于抗体的环境污染物抗性，用于污染场地的生物修复。

Auxinic herbicides (e.g. 2,4-D, dicamba) were the first selective organic herbicides developed and have been used in agriculture for over 60 years primarily for the selective control of broadleaf weeds in cereal crops. They have revolutionized modern agriculture. If their use was eliminated because of severe weed resistance the total economic loss to Canadian farmers is estimated to be over $350 M/year, consisting of approximately $250 M due to crop loss and $100 M for the additional cost of replacement herbicides. The cost to consumers would be ca. $30-33 M in the first year, increasing to $300 M by year six. These herbicides are classified as mimics of indole-3-acetic acid (IAA), the natural plant hormone also known as auxin. Auxin has been implicated in virtually all aspects of plant growth and development. The incidence of auxinic herbicide resistance has increased. One of the most resistant weeds is a wild mustard (S. arvensis L.) biotype found in a Manitoba field treated with auxinic herbicides for over 10 years. My group was the first to characterize this resistant (R) biotype physiologically, biochemically, and genetically, thus furthering our understanding of the mechanism(s) of action of auxinic herbicides, and hence the mechanisms of action of auxin. The major goals of this research proposal are twofold: (1) identification of the gene responsible for auxinic herbicide resistance in wild mustard (S. arvensis), and (2) develop antibody (Ab)-based auxinic herbicide resistance, and expression of an anti-IAA Ab for auxin immunomodulation, in tobacco and Arabidopsis plants.  Knowledge gained from this research may identify a new auxin receptor class, may provide strategies to combat auxinic-herbicide resistance, allow development of novel herbicide resistance mechanisms for crop plants and new selectable markers for use in the production of transgenic plants, and novel physiological reagents for use in research towards a more complete understanding of auxinic herbicides and auxins.  Furthermore, expression of Abs against small molecules in plants may allow development of this mechanism as a practical model for creating Ab-based environmental contaminant resistance in plants for bioremediation of contaminated sites.