A new insight into arable weed adaptive evolution: mutations endowing herbicide resistance also affect germination dynamics and seedling emergence
A new insight into arable weed adaptive evolution: mutations endowing herbicide resistance also affect germination dynamics and seedling emergence
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DOI：
10.1093/aob/mct018
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发表时间：
2013-04-01
期刊：
影响因子：
4.2
通讯作者：
Le Corre, Valerie
中科院分区：
文献类型：
--
作者：
Delye, Christophe;Menchari, Yosra;Le Corre, Valerie
农业对可耕地杂草种群施加的选择压力促进了适应性性状的进化。发芽和出苗动态和除草剂抗性是关键的适应性性状。除草剂抗性等位基因对杂草的生活史具有多效性。本研究探讨了赋予除草剂抗性的三个乙酰辅酶A羧化酶（ACCase）等位基因对禾本科杂草大穗看麦娘生活史种子到植株部分的多效性效应。在两个系列实验中，A.以Leu 1781、Asn 2041和Gly 2078 ACCase突变体为分离基因，采用均质化遗传背景的大尾轮虫种群，比较了野生型、杂合型和纯合型ACCase突变体种子的发芽动态、土壤存活率和出苗前生长情况。Gly 2078 ACC酶的主要作用是共显性加速种子萌发（对于纯合和杂合突变体胚，达到50萌发（T-50）的时间分别减少125倍和110倍）。在一系列实验中观察到对纯合突变胚的分离畸变或致死性发芽的共显性增加。Leu 1781 ACCase的主要效应是共显性延迟种子萌发（纯合和杂合突变胚的T-50分别增加141倍和122倍）与致死性发芽的显著共显性降低相关。携带Leu 1781或Gly 2078 ACC酶的植物具有分别增强或抵消的除草剂抗性赋予的适合度优势，通过对植物物候的直接多效性效应。与除草剂抗性突变相关的多效性效应无疑在杂草种群除草剂抗性的进化动态中起着重要作用。突变ACCase等位基因也应该证明是有用的，以调查种子贮藏脂质在控制种子休眠和萌发中所发挥的作用。
Selective pressures exerted by agriculture on populations of arable weeds foster the evolution of adaptive traits. Germination and emergence dynamics and herbicide resistance are key adaptive traits. Herbicide resistance alleles can have pleiotropic effects on a weeds life cycle. This study investigated the pleiotropic effects of three acetyl-coenzyme A carboxylase (ACCase) alleles endowing herbicide resistance on the seed-to-plant part of the life cycle of the grass weed Alopecurus myosuroides.In each of two series of experiments, A. myosuroides populations with homogenized genetic backgrounds and segregating for Leu1781, Asn2041 or Gly2078 ACCase mutations which arose independently were used to compare germination dynamics, survival in the soil and seedling pre-emergence growth among seeds containing wild-type, heterozygous and homozygous mutant ACCase embryos.Asn2041 ACCase caused no significant effects. Gly2078 ACCase major effects were a co-dominant acceleration in seed germination (125- and 110-fold decrease in the time to reach 50 germination (T-50) for homozygous and heterozygous mutant embryos, respectively). Segregation distortion against homozygous mutant embryos or a co-dominant increase in fatal germination was observed in one series of experiments. Leu1781 ACCase major effects were a co-dominant delay in seed germination (141- and 122-fold increase in T-50 for homozygous and heterozygous mutant embryos, respectively) associated with a substantial co-dominant decrease in fatal germination.Under current agricultural systems, plants carrying Leu1781 or Gly2078 ACCase have a fitness advantage conferred by herbicide resistance that is enhanced or counterbalanced, respectively, by direct pleiotropic effects on the plant phenology. Pleiotropic effects associated with mutations endowing herbicide resistance undoubtedly play a significant role in the evolutionary dynamics of herbicide resistance in weed populations. Mutant ACCase alleles should also prove useful to investigate the role played by seed storage lipids in the control of seed dormancy and germination.