Bowerman Andrew F, Newberry Marcus, Dielen Anne-Sophie, Whan Alex, Larroque Oscar, Pritchard Jenifer, Gubler Frank, Howitt Crispin A, Pogson Barry J, Morell Matthew K, Ral Jean-Philippe
Agriculture Flagship, Commonwealth Science and Industrial Research Organisation, Canberra, ACT, Australia.
ARC Centre of Excellence in Plant Energy Biology, The Australian National University, Canberra, ACT, Australia.
Plant Biotechnol J. 2016 Jan;14(1):398-408. doi: 10.1111/pbi.12394. Epub 2015 May 18.
Starch phosphate ester content is known to alter the physicochemical properties of starch, including its susceptibility to degradation. Previous work producing wheat (Triticum aestivum) with down-regulated glucan, water dikinase, the primary gene responsible for addition of phosphate groups to starch, in a grain-specific manner found unexpected phenotypic alteration in grain and growth. Here, we report on further characterization of these lines focussing on mature grain and early growth. We find that coleoptile length has been increased in these transgenic lines independently of grain size increases. No changes in starch degradation rates during germination could be identified, or any major alteration in soluble sugar levels that may explain the coleoptile growth modification. We identify some alteration in hormones in the tissues in question. Mature grain size is examined, as is Hardness Index and starch conformation. We find no evidence that the increased growth of coleoptiles in these lines is connected to starch conformation or degradation or soluble sugar content and suggest these findings provide a novel means of increasing coleoptile growth and early seedling establishment in cereal crop species.
已知淀粉磷酸酯含量会改变淀粉的物理化学性质，包括其降解敏感性。先前的研究以籽粒特异性方式培育了葡聚糖、水二激酶下调的小麦（普通小麦），该基因是负责向淀粉添加磷酸基团的主要基因，结果在籽粒和生长方面发现了意外的表型改变。在此，我们报告对这些品系的进一步表征，重点关注成熟籽粒和早期生长。我们发现这些转基因品系的胚芽鞘长度增加，且与籽粒大小增加无关。在发芽过程中未发现淀粉降解速率有变化，也未发现可溶性糖水平有任何重大改变，而可溶性糖水平可能解释胚芽鞘生长的改变。我们确定了相关组织中激素的一些变化。对成熟籽粒大小、硬度指数和淀粉构象进行了检测。我们没有发现证据表明这些品系中胚芽鞘生长增加与淀粉构象、降解或可溶性糖含量有关，并表明这些发现为增加谷类作物物种的胚芽鞘生长和早期幼苗建立提供了一种新方法。
