Fitness cost and competitive ability of transgenic herbicide-tolerant rice expressing a protoporphyrinogen oxidase gene

Abstract

The expression of transgenic traits in genetically modified crops is sometimes associated with decreases in crop performanceor fitness. These decreases in performance or fitness of transgenic plants in unfavourable conditions may providevaluable information about the ecological consequences of transgene escape. In a glasshouse trial, we tested the costassociated with resistance to herbicides by comparing the growth, yield, and competitive ability of transgenic rice withits parental non-transgenic line. This new line was developed for constitutive overexpression of protoporphyrinogen oxidase(PPO) to increase resistance to herbicides. We evaluated nine agronomic traits of transgenic and non-transgenic ricegrown in a replacement series design over four densities. Competitive ability was also assessed between transgenic andnon-transgenic plants by analyzing their relative yields based on biomass and seed weight data. Our results indicated thatnon-transgenic plants showed greater performance than did the transgenic plants when those genotypes were grownin mixtures. The non-transgenic rice plants exhibited superior competitive ability at certain combinations of plantingdensities and genotype proportions. These results suggest that PPO-herbicide resistance incurs some costs in plant performanceand competitive ability

Different Mutations Endowing Resistance to Acetyl-CoA Carboxylase Inhibitors Results in Changes in Ecological Fitness of Lolium rigidum Populations

“…TS resistance to various herbicide MOAs had been reported to be associated with reduction in competition abilities, which can affect plants ecological fitness (e.g., Chun et al, 2013 ; Shergill et al, 2016 ). Here, plants from TS-resistant and -sensitive populations of L. rigidum were tested for their inter-population and intra-species (with wheat) competition abilities.…”