Centre for Nutrition and Food Sciences, Queensland Alliance for Agriculture & Food Innovation (QAAFI), The University of Queensland, Brisbane, Australia.
Centre for Horticulture Science, QAAFI, The University of Queensland, Brisbane, Australia.
Sci Rep. 2023 Jan 19;13(1):1050. doi: 10.1038/s41598-023-28083-4.
The existence of purple-pericarp super-sweetcorn based on the supersweet mutation, shrunken2 (sh2), has not been previously reported, due to its extremely tight genetic linkage to a non-functional anthocyanin biosynthesis gene, anthocyaninless1 (a1). Generally, pericarp-pigmented starchy purple corn contains significantly higher anthocyanin. The development of purple-pericarp super-sweetcorn is dependent on breaking the a1-sh2 tight genetic linkage, which occurs at a very low frequency of < 1 in 1000 meiotic crossovers. Here, to develop purple-pericarp super-sweetcorn, an initial cross between a male purple-pericarp maize, 'Costa Rica' (A1Sh2.A1Sh2) and a female white shrunken2 super-sweetcorn, 'Tims-white' (a1sh2.a1sh2), was conducted. Subsequent self-pollination based on purple-pericarp-shrunken kernels identified a small frequency (0.08%) of initial heterozygous F3 segregants (A1a1.sh2sh2) producing a fully sh2 cob with a purple-pericarp phenotype, enabled by breaking the close genetic linkage between the a1 and sh2 genes. Resulting rounds of self-pollination generated a F6 homozygous purple-pericarp super-sweetcorn (A1A1.sh2sh2) line, 'Tim1'. Genome sequencing revealed a recombination break between the a1 and yz1 genes of the a1-yz1-x1-sh2 multigenic interval. The novel purple-pericarp super-sweetcorn produced a similar concentration of anthocyanin and sugar as in its purple-pericarp maize and white super-sweetcorn parents, respectively, potentially adding a broader range of health benefits than currently exists with standard yellow/white sweetcorn.
基于超甜突变体 shrunken2(sh2)的紫皮超甜玉米的存在以前没有报道过，因为它与一个无功能的花青素生物合成基因 anthocyaninless1(a1)紧密连锁。一般来说，果皮着色的粉质紫玉米含有明显更高的花青素。紫皮超甜玉米的开发依赖于打破 a1-sh2 紧密的遗传连锁，这种连锁在 1000 个减数分裂交叉中发生的频率非常低，<1/1000。在这里，为了开发紫皮超甜玉米，首先进行了一个雄性紫皮玉米“哥斯达黎加”(A1Sh2.A1Sh2)和一个雌性白色 shrunken2 超甜玉米“Tims-white”(a1sh2.a1sh2)之间的杂交。随后，根据紫皮缩粒进行自交，鉴定出一小部分初始杂合 F3 分离体(A1a1.sh2sh2)，它们产生的完全 sh2 穗轴具有紫皮表型，这是由于打破了 a1 和 sh2 基因之间的紧密遗传连锁。随后的自交产生了一个 F6 纯合紫皮超甜玉米(A1A1.sh2sh2)系，“Tim1”。基因组测序揭示了 a1-yz1-x1-sh2 多基因间隔的 a1 和 yz1 基因之间的重组断裂。新产生的紫皮超甜玉米产生的花青素和糖浓度与紫皮玉米和白色超甜玉米亲本相似，可能比目前标准的黄/白甜玉米具有更广泛的健康益处。
