Cheung Kyle W, Razeq Fakhria M, Sauder Connie A, James Tracey, Martin Sara L
Eastern Cereal and Oilseed Research Centre, 960 Carling Ave., Ottawa, ON, K1A 0C6, Canada.
J Plant Res. 2015 May;128(3):469-80. doi: 10.1007/s10265-015-0702-2. Epub 2015 Feb 20.
With transgenic crop development it is important to evaluate the potential for transgenes to escape into populations of wild, weedy relatives. Ethiopian mustard (Brassica carinata, BBCC) is easily transformed and is being investigated for uses from biodiesel fuels to biopharmaceuticals. However, little work has been done evaluating its ability to cross with relatives such as wild mustard (Sinapsis arvensis, SrSr), an abundant, cosmopolitan weedy relative. Here we conducted bidirectional crosses with Ethiopian mustard as a maternal parent in 997 crosses and paternal parent in 1,109 crosses. Hybrids were confirmed using flow cytometry and species-specific ITS molecular markers and indicate a high hybridization rate of 6.43 % between Ethiopian mustard (♀) and wild mustard (♂) and a lower, but not insignificant, hybridization rate of 0.01 % in the reverse direction. The majority of the hybrids were homoploid (BCSr) with less than 1 % of pollen production of their parents and low seed production (0.26 seeds/pollination) in crosses and backcrosses indicating a potential for advanced generation hybrids. The accession used had a significant effect on hybrid seed production with different accessions of Ethopian mustard varying in their production of hybrid offspring from 2.69 to 16.34 % and one accession of wild mustard siring almost twice as many hybrid offspring per flower as the other. One pentaploid (BBCCSr) and one hexaploid (BBCCSrSr) hybrid were produced and had higher pollen viability, though no and low seed production, respectively. As wild mustard is self-incompatible and the outcrossing rate of Ethiopian mustard has been estimated as 30 % potential for hybrid production in the wild appears to be high, though the hybridization rate found here represents a worst case scenario as it does not incorporate pre-pollination barriers. Hybridization in the wild needs to be directly evaluated as does the propensity of Ethiopian mustard to volunteer.
随着转基因作物的发展，评估转基因逃逸到野生杂草近缘种群中的可能性非常重要。埃塞俄比亚芥（Brassica carinata，BBCC）易于转化，正被研究用于从生物柴油燃料到生物制药等多个领域。然而，对于它与诸如野生芥菜（Sinapsis arvensis，SrSr）等近缘种杂交能力的评估工作做得很少，野生芥菜是一种广泛分布且数量众多的杂草近缘种。在这里，我们以埃塞俄比亚芥作为母本进行了997次双向杂交，作为父本进行了1109次双向杂交。利用流式细胞术和物种特异性ITS分子标记对杂种进行了鉴定，结果表明埃塞俄比亚芥（♀）与野生芥菜（♂）之间的杂交率高达6.43%，而反向杂交率较低，但并非微不足道，为0.01%。大多数杂种为同倍体（BCSr），其花粉产量不到亲本的1%，在杂交和回交中的种子产量较低（0.26粒种子/授粉），这表明存在产生高代杂种的可能性。所用的种质对杂种种子产量有显著影响，不同种质的埃塞俄比亚芥产生杂种后代的比例在2.69%至16.34%之间变化，一种野生芥菜种质每朵花产生的杂种后代数量几乎是另一种的两倍。产生了一个五倍体（BBCCSr）杂种和一个六倍体（BBCCSrSr）杂种，它们的花粉活力较高，不过分别没有种子产生和种子产量较低。由于野生芥菜是自交不亲和的，且埃塞俄比亚芥的异交率估计为30%，因此在野外产生杂种的可能性似乎很高，不过这里发现的杂交率代表了最坏的情况，因为它没有考虑授粉前的障碍。需要直接评估野外的杂交情况以及埃塞俄比亚芥自然生长的倾向。
