Carpenter Margaret A, Shaw Martin, Cooper Rebecca D, Frew Tonya J, Butler Ruth C, Murray Sarah R, Moya Leire, Coyne Clarice J, Timmerman-Vaughan Gail M
The New Zealand Institute for Plant & Food Research Limited, PO Box 4704, Christchurch, New Zealand.
USDA-ARS Western Regional Plant Introduction Station, 59 Johnson Hall, WSU Pullman, Pullman, Washington, WA 99164-6402, USA.
BMC Plant Biol. 2017 Aug 1;17(1):132. doi: 10.1186/s12870-017-1080-9.
Although starch consists of large macromolecules composed of glucose units linked by α-1,4-glycosidic linkages with α-1,6-glycosidic branchpoints, variation in starch structural and functional properties is found both within and between species. Interest in starch genetics is based on the importance of starch in food and industrial processes, with the potential of genetics to provide novel starches. The starch metabolic pathway is complex but has been characterized in diverse plant species, including pea.
To understand how allelic variation in the pea starch metabolic pathway affects starch structure and percent amylose, partial sequences of 25 candidate genes were characterized for polymorphisms using a panel of 92 diverse pea lines. Variation in the percent amylose composition of extracted seed starch and (amylopectin) chain length distribution, one measure of starch structure, were characterized for these lines. Association mapping was undertaken to identify polymorphisms associated with the variation in starch chain length distribution and percent amylose, using a mixed linear model that incorporated population structure and kinship. Associations were found for polymorphisms in seven candidate genes plus Mendel's r locus (which conditions the round versus wrinkled seed phenotype). The genes with associated polymorphisms are involved in the substrate supply, chain elongation and branching stages of the pea carbohydrate and starch metabolic pathways.
The association of polymorphisms in carbohydrate and starch metabolic genes with variation in amylopectin chain length distribution and percent amylose may help to guide manipulation of pea seed starch structural and functional properties through plant breeding.
尽管淀粉由由α-1,4-糖苷键连接的葡萄糖单元组成的大分子构成，且具有α-1,6-糖苷分支点，但在物种内部和物种之间都发现了淀粉结构和功能特性的差异。对淀粉遗传学的兴趣基于淀粉在食品和工业过程中的重要性，以及遗传学提供新型淀粉的潜力。淀粉代谢途径很复杂，但已在包括豌豆在内的多种植物物种中得到表征。
为了了解豌豆淀粉代谢途径中的等位基因变异如何影响淀粉结构和直链淀粉百分比，使用92个不同的豌豆品系组成的群体对25个候选基因的部分序列进行了多态性表征。对这些品系提取的种子淀粉的直链淀粉组成百分比和（支链淀粉）链长分布（淀粉结构的一种度量）的变异进行了表征。采用混合线性模型进行关联作图，该模型纳入了群体结构和亲缘关系，以鉴定与淀粉链长分布和直链淀粉百分比变异相关的多态性。发现七个候选基因加上孟德尔的r位点（决定圆形与皱缩种子表型）中的多态性存在关联。具有相关多态性的基因参与豌豆碳水化合物和淀粉代谢途径的底物供应、链延伸和分支阶段。
碳水化合物和淀粉代谢基因中的多态性与支链淀粉链长分布和直链淀粉百分比变异之间的关联，可能有助于通过植物育种来指导对豌豆种子淀粉结构和功能特性的操控。
