Bigelow Patrick J, Loescher Wayne, Hancock James F, Grumet Rebecca
Graduate Program in Plant Breeding, Genetics and Biotechnology Michigan State University East Lansing MI USA.
Evol Appl. 2018 Mar 5;11(6):950-962. doi: 10.1111/eva.12610. eCollection 2018 Jul.
Reducing crop losses due to abiotic stresses is a major target of agricultural biotechnology that will increase with climate change and global population growth. Concerns, however, have been raised about potential ecological impacts if transgenes become established in wild populations and cause increased competitiveness of weedy or invasive species. Potential risks will be a function of transgene movement, population sizes, and fitness effects on the recipient population. While key components influencing gene flow have been extensively investigated, there have been few studies on factors subsequent to transgene movement that can influence persistence and competitiveness. Here, we performed multiyear, multigenerational, assessment to examine fitness effects and persistence of three mechanistically different abiotic stress tolerance genes: and . Transgenic overexpressing these genes were grown in pure populations and in competition with wild-type (WT) parents for six generations spanning a range of field environment conditions. Growth, development, biomass, seed production, and transgene frequency were measured at each generation. Seed planted for each generation was obtained from the previous generation as would occur during establishment of a new genotype in the environment. The three transgenes exhibited different fitness effects and followed different establishment trajectories. In comparison with pure populations, lines exhibited reduced dry weight, seed yield, and viable seed yield, relative to WT background. In contrast, overexpression of and did not significantly impact productivity measures in pure populations. In competition with WT, negative fitness effects were magnified. Transgene frequencies were significantly reduced for and while frequencies of appeared to be subject to genetic drift. These studies demonstrate the importance of fitness effects and intergenotype competition in influencing persistence of transgenes conferring complex traits.
减少非生物胁迫造成的作物损失是农业生物技术的一个主要目标，随着气候变化和全球人口增长，这一目标将变得更加重要。然而，如果转基因在野生种群中得以确立并导致杂草或入侵物种的竞争力增强，人们就会对其潜在的生态影响表示担忧。潜在风险将取决于转基因的传播、种群规模以及对受体种群的适合度影响。虽然影响基因流动的关键因素已得到广泛研究，但对于转基因传播后可能影响其持久性和竞争力的因素，却鲜有研究。在此，我们进行了多年、多代评估，以检验三种机制不同的非生物胁迫耐受性基因的适合度影响和持久性。过表达这些基因的转基因植株在纯合种群中生长，并与野生型（WT）亲本竞争，历经六代，涵盖一系列田间环境条件。每一代均测量其生长、发育、生物量、种子产量和转基因频率。每一代种植的种子均从上一代获得，就如同在环境中建立新基因型时的情况一样。这三种转基因表现出不同的适合度影响，并遵循不同的建立轨迹。与纯合种群相比，[具体基因1]品系相对于野生型背景，干重、种子产量和有活力种子产量均降低。相比之下，[具体基因2]和[具体基因3]的过表达在纯合种群中并未显著影响生产力指标。在与野生型竞争时，负面适合度影响被放大。[具体基因1]和[具体基因2]的转基因频率显著降低，而[具体基因3]的频率似乎受到遗传漂变的影响。这些研究证明了适合度影响和基因型间竞争在影响赋予复杂性状的转基因持久性方面的重要性。
