title: Taxonomic and life history bias in herbicide resistant weeds: implications for deployment of resistant crops.
abstract: Evolved herbicide resistance (EHR) is an important agronomic problem and consequently a food security problem, as it jeopardizes herbicide effectiveness and increases the difficulty and cost of weed management. EHR in weeds was first reported in 1970 and the number of cases has accelerated dramatically over the last two decades. Despite 40 years of research on EHR, why some weeds evolve resistance and others do not is poorly understood. Here we ask whether weed species that have EHR are different from weeds in general. Comparing taxonomic and life history traits of weeds with EHR to a control group ("the world's worst weeds"), we found weeds with EHR significantly over-represented in certain plant families and having certain life history biases. In particular, resistance is overrepresented in Amaranthaceae, Brassicaceae and Poaceae relative to all weeds, and annuality is ca. 1.5 times as frequent in weeds with EHR as in the control group. Also, for perennial EHR weeds, vegetative reproduction is only 60% as frequent as in the control group. We found the same trends for subsets of weeds with EHR to acetolactate synthase (ALS), photosystem II (PSII), and 5-enolpyruvylshikimate-3-phosphate (EPSP) synthase-inhibitor herbicides and with multiple resistance. As herbicide resistant crops (transgenic or not) are increasingly deployed in developing countries, the problems of EHR could increase in those countries as it has in the USA if the selecting herbicides are heavily applied and appropriate management strategies are not employed. Given our analysis, we make some predictions about additional species that might evolve resistance.
authors.affiliation: Department of Botany and Plant Sciences, University of California Riverside, Riverside, California, United States of America.
authors.forename: Jodie S
authors.initials: JS
authors.lastname: Holt
authors.forename: Shana R
authors.initials: SR
authors.lastname: Welles
authors.forename: Katia
authors.initials: K
authors.lastname: Silvera
authors.forename: Ian M
authors.initials: IM
authors.lastname: Heap
authors.forename: Sylvia M
authors.initials: SM
authors.lastname: Heredia
authors.forename: Alejandra
authors.initials: A
authors.lastname: Martinez-Berdeja
authors.forename: Kai T
authors.initials: KT
authors.lastname: Palenscar
authors.forename: Lynn C
authors.initials: LC
authors.lastname: Sweet
authors.forename: Norman C
authors.initials: NC
authors.lastname: Ellstrand
mesh_terms: D005075:Biological Evolution; D018556:Crops, Agricultural / Q000187:drug effects* / Q000235:genetics; D004791:Enzyme Inhibitors / Q000494:pharmacology; D053209:Herbicide Resistance; D006540:Herbicides / Q000494:pharmacology*; D019684:Magnoliopsida / Q000187:drug effects / Q000235:genetics; D010641:Phenotype; D010802:Phylogeny; D010940:Plant Proteins / Q000037:antagonists & inhibitors / Q000235:genetics; D057685:Plant Weeds / Q000187:drug effects* / Q000235:genetics
chemical_list: D004791:Enzyme Inhibitors; D006540:Herbicides; D010940:Plant Proteins
references.citation: Annu Rev Entomol. 2007;52:231-53
references.pmid: 16925478
references.citation: Proc Natl Acad Sci U S A. 1996 Oct 15;93(21):11746-50
references.pmid: 8876208
references.citation: J Theor Biol. 1978 Dec 7;75(3):349-71
references.pmid: 745447
references.citation: Pest Manag Sci. 2008 Apr;64(4):319-25
references.pmid: 18273882
references.citation: Annu Rev Plant Biol. 2010;61:317-47
references.pmid: 20192743
references.citation: Trends Plant Sci. 2007 Jan;12(1):6-13
references.pmid: 17161644
references.citation: J Insect Sci. 2010;10:102
references.pmid: 20874389