Data from: Crossing the divide: gene flow produces intergeneric hybrid in feral transgenic creeping bentgrass population

Gene flow is the most frequently expressed public concern related to the deregulation of transgenic events (Snow 2002; Ellstrand 2003). However, assessing the potential for transgene escape is complex because it depends on the opportunities for unintended gene flow, and establishment and persistence of the transgene in the environment (Warwick et al. 2008). Creeping bentgrass (Agrostis stolonifera L.), a turfgrass species widely used on golf courses, has been genetically engineered to be resistant to glyphosate, a nonselective herbicide. Outcrossing species, such as creeping bentgrass (CB), which have several compatible species, have greater chances for gene escape and spontaneous hybridization (i.e. natural, unassisted sexual reproduction between taxa in the field), which challenges transgene containment. Several authors have emphasized the need for evidence of spontaneous hybridization to infer the potential for gene flow (Armstrong et al. 2005). Here we report that a transgenic intergeneric hybrid has been produced as result of spontaneous hybridization of a feral-regulated transgenic pollen receptor (CB) and a nontransgenic pollen donor (rabbitfoot grass, RF, Polypogon monspeliensis (L.) Desf.). We identified an off-type transgenic seedling and confirmed it to be CB × RF intergeneric hybrid. This first report of a transgenic intergeneric hybrid produced in situ with a regulated transgenic event demonstrates the importance of considering all possible avenues for transgene spread at the landscape level before planting a regulated transgenic crop in the field. Spontaneous hybridization adds a level of complexity to transgene monitoring, containment, mitigation and remediation programmes.

基因流（Gene flow）是与转基因事件（transgenic events）解除监管相关的最常见公众担忧议题（Snow等，2002；Ellstrand等，2003）。然而，评估转基因逃逸（transgene escape）的潜在风险极为复杂，因为其取决于非预期基因流发生的概率，以及转基因在环境中的定殖与存续能力（Warwick等，2008）。匍匐翦股颖（Creeping bentgrass，学名*Agrostis stolonifera* L.）是广泛应用于高尔夫球场的草坪草品种，经基因工程改造后可抗草甘膦（glyphosate）——一种非选择性除草剂（nonselective herbicide）。异交物种如匍匐翦股颖（CB）拥有多个可杂交的近缘类群，因此发生基因逃逸与自然杂交（spontaneous hybridization，即野外类群间未经人工辅助的自然有性生殖）的概率更高，这对转基因隔离防控（transgene containment）构成挑战。已有多位学者强调，需通过自然杂交的相关证据来推断基因流的发生潜力（Armstrong等，2005）。本研究报道了一项通过经监管审批的野生转基因花粉受体（匍匐翦股颖，CB）与非转基因花粉供体兔足草（rabbitfoot grass，RF，学名*Polypogon monspeliensis* (L.) Desf.）的自然杂交而产生的转基因属间杂种。本研究通过筛选获得一株非典型转基因幼苗，并经鉴定确认其为匍匐翦股颖×兔足草属间杂种。本研究首次报道了在野外原位环境下由经监管审批的转基因材料产生的转基因属间杂种，这表明在田间种植经监管审批的转基因作物前，需全面考量景观尺度下所有可能的转基因扩散途径。自然杂交会进一步提升转基因监测、隔离防控、逃逸缓解与污染修复相关项目的复杂程度。