Snyman Sandy J, Komape Dennis M, Khanyi Hlobisile, van den Berg Johnnie, Cilliers Dirk, Lloyd Evans Dyfed, Barnard Sandra, Siebert Stefan J
Crop Biology Resource Centre, South African Sugarcane Research Institute, Mount Edgecombe, South Africa.
Department of Biology, School of Life Sciences, University of KwaZulu-Natal, Westville, South Africa.
Front Bioeng Biotechnol. 2018 Jun 7;6:72. doi: 10.3389/fbioe.2018.00072. eCollection 2018.
Pre-commercialization studies on environmental biosafety of genetically modified (GM) crops are necessary to evaluate the potential for sexual hybridization with related plant species that occur in the release area. The aim of the study was a preliminary assessment of factors that may contribute to gene flow from sugarcane ( hybrids) to indigenous relatives in the sugarcane production regions of Mpumalanga and KwaZulu-Natal provinces, South Africa. In the first instance, an assessment of wild relatives was conducted based on existing phylogenies and literature surveys. The prevalence, spatial overlap, proximity, distribution potential, and flowering times of wild relatives in sugarcane production regions based on the above, and on herbaria records and field surveys were conducted for , and species. Eleven species were selected for spatial analyses based on their presence within the sugarcane cultivation region: four species in the Saccharinae and seven in the Sorghinae. Secondly, fragments of the nuclear internal transcribed spacer (ITS) regions of the 5.8s ribosomal gene and two chloroplast genes, ribulose-bisphosphate carboxylase (), and maturase K () were sequenced or assembled from short read data to confirm relatedness between hybrids and its wild relatives. Phylogenetic analyses of the ITS cassette showed that the closest wild relative species to commercial sugarcane were , and was found to be more distantly related to than previously described. Based on the phylogeny described in our study, the only species to highlight in terms of evolutionary divergence times from are those within the genus , most especially , and which are only 3 million years divergent from . Field assessment of pollen viability of 13 commercial sugarcane cultivars using two stains, iodine potassium iodide (IKI) and triphenyl tetrazolium chloride, showed decreasing pollen viability (from 85 to 0%) from the north to the south eastern regions of the study area. Future work will include other aspects influencing gene flow such as cytological compatibility and introgression between sugarcane and species.
对转基因作物进行商业化前的环境生物安全研究，对于评估其与释放区域内相关植物物种发生有性杂交的可能性是必要的。本研究的目的是初步评估可能导致基因从甘蔗（杂交种）流向南非姆普马兰加省和夸祖鲁 - 纳塔尔省甘蔗产区本土近缘种的因素。首先，基于现有的系统发育学和文献调查对野生近缘种进行了评估。根据上述内容以及植物标本记录和实地调查，对甘蔗产区野生近缘种的发生率、空间重叠、 proximity、分布潜力和开花时间进行了调查，涉及 种、 种和 种。基于它们在甘蔗种植区域内的存在情况，选择了11个物种进行空间分析：其中4个属于甘蔗亚族，7个属于高粱亚族。其次，对5.8s核糖体基因的核内转录间隔区（ITS）片段以及两个叶绿体基因，核酮糖 - 1,5 - 二磷酸羧化酶（ ）和成熟酶K（ ）进行测序，或从短读数据中组装，以确认甘蔗杂交种与其野生近缘种之间的亲缘关系。ITS盒的系统发育分析表明，与商业甘蔗最接近的野生近缘种是 ，并且发现 与 的亲缘关系比之前描述的更远。根据我们研究中描述的系统发育，就与 进化分歧时间而言，唯一需要突出的物种是 属内的那些物种，尤其是 ，它们与 的分歧时间仅为300万年。使用碘碘化钾（IKI）和氯化三苯基四氮唑两种染色剂对13个商业甘蔗品种的花粉活力进行田间评估，结果显示从研究区域的北部到东南部地区，花粉活力逐渐降低（从85%降至0%）。未来的工作将包括影响基因流动的其他方面，如甘蔗与 物种之间的细胞学兼容性和渐渗。 （注：原文中“proximity”未翻译完整，可能是有遗漏信息，此处保留英文）
