The red queen in the corn: agricultural weeds as models of rapid adaptive evolution

Abstract

Weeds are among the greatest pests of agriculture, causing billions of dollars in crop losses each year. As crop field management practices have changed over the past 12 000 years, weeds have adapted in turn to evade human removal. This evolutionary change can be startlingly rapid, making weeds an appealing system to study evolutionary processes that occur over short periods of time. An understanding of how weeds originate and adapt is needed for successful management; however, relatively little emphasis has been placed on genetically characterizing these systems. Here, we review the current literature on agricultural weed origins and their mechanisms of adaptation. Where possible, we have included examples that have been genetically well characterized. Evidence for three possible, non-mutually exclusive weed origins (from wild species, crop-wild hybrids or directly from crops) is discussed with respect to what is known about the microevolutionary signatures that result from these processes. We also discuss what is known about the genetic basis of adaptive traits in weeds and the range of genetic mechanisms that are responsible. With a better understanding of genetic mechanisms underlying adaptation in weedy species, we can address the more general process of adaptive evolution and what can be expected as we continue to apply selective pressures in agroecosystems around the world.

Introductory Chapter: Actual Issues (Moments) in Herbicide Resistance Weeds and Crops

“…They have always been a component of agriculture and have successfully thwarted all attempts by humans to eliminate them from interfering with crop production [2]. Weeds result in a 34% loss of crop yield, on an average, worldwide.…”

Molecular Mechanisms of Herbicide Resistance

“…Guidelines for transcriptome-based analysis of NTSR in weeds have been proposed (Délye 2013). Yet, this approach is still in its infancy Vigueira et al 2013), and only a few attempts have been made to date (e.g., Gaines et al 2013;Gardin et al 2013). …”

“…The recent rise of the NGS technologies has also opened the possibility to study weed adaptive traits with a complex genetic determinism involving both structural and regulatory mutations (Vigueira et al 2013), such as NTSR (Délye 2013;Yuan et al 2007). An approach of choice for this purpose is quantitative transcriptome sequencing, also known as RNA sequencing or RNAseq.…”

“…NGS technologies are thus of interest if sequencing a few genes or amplicons in a massive number of plants or of weed populations is required. Another use of NGS techniques is to gain access to the sequence of genes of interest in a weed species where no or few genomic data are available (Vigueira et al 2013). This can be achieved by sequencing and assembling the transcriptome or a draft of the genome of the species of interest (e.g., Riggins et al 2010).…”

Determination of Morphological and Genetic Diversity of ALS (Acetolactate Synthase)- Herbicide-Resistant Echinochloa oryzoides Biotypes in Rice

“…Natural selection, genetic flow and genetic drift are the forces that cause an evolution in both the natural environments and weeds (Vigueira et al, 2013). Many weed species display differences in terms of their genetic characteristics due to different growth patterns and morphological characteristics, depending on the area in which they grow (Yabuno, 1996;Michishita and Yamaguchi, 2003;Claerhout et al, 2015;Karn and Jasieniuk, 2017).…”