Data from: Crop-to-wild gene flow and spatial genetic structure in the closest wild relatives of the cultivated apple

Crop-to-wild gene flow have important evolutionary and ecological consequences and require careful consideration in conservation programs for wild genetic resources of potential use in breeding programs and in assessments of the risk of transgene escape into natural ecosystems. Using 26 microsatellites and a set of 1181 trees, we investigated the extent of introgression from the cultivated apple, Malus domestica, to its three closest wild relatives, M. sylvestris in Europe, M. orientalis in the Caucasus and M. sieversii in Central Asia. We found footprints of introgression from M. domestica to M. orientalis (3.2% of hybrids), M. sieversii (14.8%) and M. sylvestris (36.7%). Malus sieversii and M. orientalis presented weak but significant genetic structures across their geographic range. Malus orientalis displayed genetic differentiation with three differentiated populations in Turkey, Armenia and Russia. Malus sieversii consisted of a main population spread over Central Asia and a smaller population in the Tian Shan Mountains. The low Sp values suggest high dispersal capacities for the wild apple relatives. High potential for crop-to-wild gene flow in apples needs to be considered in the implementation of in situ and ex situ actions for the conservation of wild apple genetic resources potentially useful to plant breeding.

作物向野生近缘种的基因流（crop-to-wild gene flow）具有重要的进化与生态学效应，在针对可用于育种项目的野生遗传资源的保护计划，以及评估转基因逃逸进入自然生态系统的风险时，均需予以审慎考量。本研究利用26个微卫星（microsatellite）标记与1181份林木样本，探究了栽培苹果（Malus domestica）向其3种近缘野生苹果属物种的渐渗程度：欧洲的欧洲野苹果（M. sylvestris）、高加索地区的东方苹果（M. orientalis）以及中亚的塞威氏苹果（M. sieversii）。研究结果显示，栽培苹果向M. orientalis（杂交个体占比3.2%）、M. sieversii（14.8%）以及M. sylvestris（36.7%）均存在渐渗痕迹。塞威氏苹果与东方苹果在各自的地理分布范围内均呈现出微弱但显著的遗传结构。东方苹果表现出遗传分化，在土耳其、亚美尼亚与俄罗斯境内形成3个分化显著的种群。塞威氏苹果包含一个横跨中亚的广布种群，以及天山山脉内的一个小型种群。较低的Sp值表明这些野生苹果近缘种具备较强的扩散能力。苹果属作物向野生近缘种的基因流存在较高潜力，因此在制定原位（in situ）与迁地（ex situ）保护措施以保护可用于植物育种的野生苹果遗传资源时，需将该因素纳入考量范畴。