Sharma Shrikant, Friberg Martin, Vogel Paul, Turesson Helle, Olsson Niklas, Andersson Mariette, Hofvander Per
Department of Plant Breeding, Swedish University of Agricultural Sciences, Alnarp, Sweden.
Front Plant Sci. 2023 Aug 9;14:1220973. doi: 10.3389/fpls.2023.1220973. eCollection 2023.
Reserve starch from seeds and tubers is a crucial plant product for human survival. Much research has been devoted to quantitative and qualitative aspects of starch synthesis and its relation to abiotic factors of importance in agriculture. Certain aspects of genetic factors and enzymes influencing carbon assimilation into starch granules remain elusive after many decades of research. Starch phosphorylase (Pho) can operate, depending on metabolic conditions, in a synthetic and degradative pathway. The plastidial form of the enzyme is one of the most highly expressed genes in potato tubers, and the encoded product is imported into starch-synthesizing amyloplasts. We identified that the genomic locus of a Pho1a-type starch phosphorylase is duplicated in potato. Our study further shows that the enzyme is of importance for a normal starch granule phenotype in tubers. Null mutants created by genome editing display rounded starch granules in an increased number that contained a reduced ratio of apparent amylose in the starch.
种子和块茎中的储备淀粉是人类生存至关重要的植物产物。许多研究致力于淀粉合成的定量和定性方面及其与农业中重要非生物因素的关系。经过数十年的研究，影响碳同化为淀粉颗粒的遗传因素和酶的某些方面仍然难以捉摸。淀粉磷酸化酶（Pho）可根据代谢条件在合成和降解途径中发挥作用。该酶的质体形式是马铃薯块茎中表达量最高的基因之一，其编码产物被导入合成淀粉的造粉体中。我们发现马铃薯中Pho1a型淀粉磷酸化酶的基因组位点是重复的。我们的研究进一步表明，该酶对块茎中正常淀粉颗粒表型很重要。通过基因组编辑产生的无效突变体显示出圆形淀粉颗粒数量增加，且淀粉中表观直链淀粉比例降低。
