A framework is presented to consider the value and utility of molecular-based research in weed science. Four themes are used to illustrate why adopting molecular approaches might be helpful. First, the rationale for academic institutions adopting molecular approaches is outlined, including strengths, weaknesses, opportunities, and threats (SWOT) analysis. Second, research strategy and synergies developed into other functions, such as education, consultancy, and business, is considered. Third, project management as a vehicle for integrating technical and personnel skills is examined. Finally, specific examples of outputs such as the application of functional genomics for herbicide discovery are described. The adoption of molecular-based methods can have far-reaching benefits in agriculture and biotechnology. Communicating these benefits within the scientific community and beyond, particularly to end users, is of fundamental importance.

The incidence of auxinic herbicide resistance in plants has increased worldwide. Auxinic herbicides were the first selective organic herbicides developed and have been used in agriculture for over 50 yr, primarily for the selective control of broadleaf weeds in cereal crops. However, the mode of action of auxinic herbicides and the molecular basis of auxinic herbicide resistance remain unknown, although an auxin-binding protein (ABP) is proposed to be the primary target site. Using auxinic herbicide-resistant (R) and -susceptible (S) biotypes of wild mustard as a model system, we have extensively studied the mode of action of auxinic herbicides and the resistance mechanisms at the physiological, biochemical, and molecular genetic levels. There are no differences in uptake, transport, and metabolism of auxinic herbicides between the R and S biotypes. Based on these results, as well as the studies on the role of auxin-enhanced ethylene biosynthesis and calcium in mediating the auxinic herbicide resistance, we hypothesize that resistance of the R biotype to auxinic herbicides is due to an altered target site, possibly an auxin receptor. We have identified and characterized a small ABP gene family as well as their cDNAs from both R and S of wild mustard. Amino acid changes were found in the ABP of the R biotype. Functional and mutational analyses of these genes are underway to determine the role of ABP in mediating auxinic herbicide resistance. In this review, we focus on the mode of action of auxinic herbicides and the molecular basis of auxinic herbicide resistance in wild mustard.

Many advances in disciplines such as chemistry, biochemistry, plant breeding, genetics, engineering, and others have been applied in a positive manner to improve knowledge in weed science. The emerging field of genomics is likely to have a similar positive effect on our understanding of weeds and their management in various plant agriculture systems. Genomics involves the large-scale use of molecular techniques for identification and functional analysis of complete or nearly complete genomic complements of genes. Commercial application of genomics has already occurred for improvement in certain crop input and output traits, including improved quality characteristics and herbicide and insect resistance. Additional commercial applications of genomics in weed science will be identification of genes involved in a crops' competitive ability. Genes controlling early crop shoot emergence, rapid early-season leaf and root development for fast canopy closure, production of allelochemicals for natural weed control, identification of novel herbicide target sites, resistance mechanisms, and genes for safening crops against specific herbicides can and will be identified. Successful crop improvement in these areas using the tools of genomics will dramatically affect weed–crop interactions and improve crop yields while reducing weed problems. In relation to improved basic knowledge of weeds and the resulting ability to improve our weed management techniques, genomics will offer the weed science community many new and exciting research opportunities. Scientists will be able to determine the genetic composition of weed populations and how it changes over time in relation to agricultural practices. Identification of genes contributing to weediness, perennial growth habit, herbicide resistance, seed and vegetative structure dormancy, plant architecture and morphology, plant reproductive characters (outcrossing and hybridization, introgression), and allelopathy will be identified and utilized with high-throughput DNA sequencing and other genomics-based technologies. Using genomics to improve our understanding of weed biology by determining which genes function to affect the fitness, competitiveness, and adaptation of weeds in agricultural environments will allow the development of improved management strategies. This review provides a summary of the various plant genomic research methods being used. Information is provided concerning the current state of molecular research in various areas of weed science and specific genomic research currently being conducted at Purdue University using transfer DNA (T-DNA) activation tagging to generate large populations of mutated plants that can be screened for genes of importance to weed science.

The discovery of the first systemic or hormone herbicides, 2,4-D, 2,4,5-T, and MCPA, initiated an agricultural revolution and modern weed science. The finding of these herbicides was a striking case of multiple independent discovery by four groups of workers in two countries, the United Kingdom and the United States: William G. Templeman and associates at Imperial Chemical Industries; Philip S. Nutman and associates at the Rothamsted Agricultural Experiment Station; Franklin D. Jones at the American Chemical Paint Company; and Ezra Kraus, John Mitchell, and associates at the University of Chicago and the U.S. Department of Agriculture. Because of wartime and commercial secrecy, the usual procedures of scientific publication and patent disclosure were not followed; instead, the first scientific report on these herbicides occurred in a publication by workers who were not original discoverers. Considerable confusion consequently resulted concerning the discovery and the discoverers. This confusion has not been completely dispelled in subsequent years. The present report summarizes the complete story, clarifies the chronology of the discoverers and their publications, and makes the case that all four groups of workers deserve credit for this revolutionary advance. The scientific background of the discovery and events in its immediate aftermath, especially the ticklish patent situation, are also briefly chronicled.