The University of Queensland, Brisbane, Australia Sucrogen Technical Field Department, Kalamia Mill, Ayr, Queensland, Australia.
Plant Biotechnol J. 2012 Feb;10(2):217-25. doi: 10.1111/j.1467-7652.2011.00655.x. Epub 2011 Sep 5.
Transgenic sugarcane plants expressing a vacuole-targeted isomaltulose (IM) synthase in seven recipient genotypes (elite cultivars) were evaluated over 3 years at a field site typical of commercial cane growing conditions in the Burdekin district of Australia. IM concentration typically increased with internode maturity and comprised up to 217 mm (33% of total sugars) in whole-cane juice. There was generally a comparable decrease in sucrose concentration, with no overall decrease in total sugars. Sugarcane is vegetatively propagated from stem cuttings known as setts. Culture-derived plants were slower to establish and generally gave shorter and thinner stalks at harvest than those grown from field-sourced setts in the initial field generations. However, after several cycles of field propagation, selections were obtained with cane yields similar to the recipient genotypes. There was no apparent adverse effect of IM accumulation on vigour assessed by stalk height and diameter or other visual indicators including germination of setts and establishment of stools. There was some inconsistency in IM levels in juice, between samplings of the vegetatively propagated transgenic lines. Until the causes are resolved, it is prudent to selectively propagate from stalks with higher IM levels in the initial vegetative field generations. Pol/Brix ratio allowed rapid identification of lines with high IM levels, using common sugar industry instruments. Sucrose isomerase activity was low in these transgenic lines, and the results indicate strong potential to develop sugarcane for commercial-scale production of IM if higher activity can be engineered in appropriate developmental patterns.
在澳大利亚伯德金地区的一个典型商业甘蔗种植场地上，对 7 个受体基因型（优良品种）中表达液泡靶向异麦芽酮糖（IM）合酶的转基因甘蔗植物进行了 3 年的评估。IM 浓度通常随着节间成熟度的增加而增加，在整个蔗汁中可达 217mm（总糖的 33%）。蔗糖浓度通常会相应下降，总糖含量没有总体下降。甘蔗通过茎切段（称为种茎）进行营养繁殖。与从田间来源的种茎中生长的种茎相比，由培养衍生的植物在最初的田间世代中建立的速度较慢，收获时的茎秆通常较短、较细。然而，经过几轮田间繁殖，选择出的品种与受体基因型的甘蔗产量相似。IM 积累对活力的影响（通过茎秆高度和直径或包括种茎发芽和茎基建立在内的其他视觉指标评估）似乎没有明显的不利影响。在不同的取样时间点之间，转基因系的蔗汁中的 IM 水平存在一些不一致。在最初的营养繁殖田间世代中，应谨慎地从 IM 水平较高的茎秆中选择性繁殖。使用常见的糖业仪器，Pol/Brix 比值可快速识别具有高 IM 水平的品系。这些转基因系中的蔗糖异构酶活性较低，结果表明，如果能在适当的发育模式中设计出更高的活性，那么开发用于商业规模生产 IM 的甘蔗具有很大的潜力。
