Transgenic American chestnut trees expressing a wheat gene for oxalate oxidase (OxO) can tolerate chestnut blight, but as with any new restoration material, they should be carefully evaluated before being released into the environment. Native pollinators such as bumble bees are of particular interest: Bombus impatiens use pollen for both a source of nutrition and a hive building material. Bees are regular visitors to American chestnut flowers and likely contribute to their pollination, so depending on transgene expression in chestnut pollen, they could be exposed to this novel source of OxO during potential restoration efforts. To evaluate the potential risk to bees from OxO exposure, queenless microcolonies of bumble bees were supplied with American chestnut pollen containing one of two concentrations of OxO, or a no-OxO control. Bees in microcolonies exposed to a conservatively estimated field-realistic concentration of OxO in pollen performed similarly to no-OxO controls; there were no significant differences in survival, bee size, pollen use, hive construction activity, or reproduction. A ten-fold increase in OxO concentration resulted in noticeable but non-significant decreases in some measures of pollen usage and reproduction compared to the no-OxO control. These effects are similar to what is often seen when naturally produced secondary metabolites are supplied to bees at unrealistically high concentrations. Along with the presence of OxO in many other environmental sources, these data collectively suggest that oxalate oxidase at field-realistic concentrations in American chestnut pollen is unlikely to present substantial risk to bumble bees.

表达草酸氧化酶 (OxO) 小麦基因的转基因美国板栗树可以耐受板栗枯萎病，但与任何新的修复材料一样，在释放到环境中之前应仔细评估它们。大黄蜂等原生传粉者特别令人感兴趣：凤仙花使用花粉作为营养来源和蜂巢建筑材料。蜜蜂是美国板栗花的常客，可能有助于它们的授粉，因此根据板栗花粉中的转基因表达，它们可能会在潜在的恢复工作中接触到这种新的 OxO 来源。为了评估 OxO 暴露对蜜蜂的潜在风险，为大黄蜂的无蜂王微菌落提供了含有两种 OxO 浓度之一或无 OxO 对照的美国栗花粉。暴露于保守估计的花粉中 OxO 浓度的微群落中的蜜蜂与无 OxO 对照的表现相似；在存活率、蜜蜂大小、花粉使用、蜂巢建设活动或繁殖方面没有显着差异。与无 OxO 对照相比，OxO 浓度增加 10 倍导致花粉使用和繁殖的某些测量值显着但不显着下降。这些效果类似于以不切实际的高浓度将天然产生的次级代谢物提供给蜜蜂时经常看到的效果。除了在许多其他环境来源中存在 OxO 外，这些数据共同表明，美国板栗花粉中田间实际浓度的草酸氧化酶不太可能对大黄蜂构成重大风险。