National Key Laboratory of Plant Molecular Genetics, Chinese Academy of Sciences Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China.
University of the Chinese Academy of Sciences, Beijing 100049, China.
Plant Cell. 2019 Jun;31(6):1238-1256. doi: 10.1105/tpc.18.00966. Epub 2019 Apr 8.
Cell number is a critical factor that determines kernel size in maize (). Rapid mitotic divisions in early endosperm development produce most of the cells that make up the starchy endosperm; however, the mechanisms underlying early endosperm development remain largely unknown. We isolated a maize mutant that shows a varied-kernel-size phenotype (). encodes ZmKIN11, which belongs to the kinesin-14 subfamily and is predominantly expressed in early endosperm development. VKS1 dynamically localizes to the nucleus and microtubules and plays key roles in the migration of free nuclei in the coenocyte as well as in mitosis and cytokinesis in early mitotic divisions. Absence of VKS1 has relatively minor effects on plants but causes deformities in spindle assembly, sister chromatid separation, and phragmoplast formation in early endosperm development, thereby resulting in reduced cell proliferation. Severities of aberrant mitosis and cytokinesis within individual endosperms differ, thereby resulting in varied kernel sizes. Our discovery highlights VKS1 as a central regulator of mitosis in early maize endosperm development and provides a potential approach for future yield improvement.
细胞数量是决定玉米子粒大小的关键因素。早期胚乳发育中的快速有丝分裂产生了构成淀粉胚乳的大部分细胞；然而，早期胚乳发育的机制在很大程度上仍然未知。我们分离到一个玉米突变体，其表现出不同大小的子粒表型。该基因编码 ZmKIN11，属于驱动蛋白-14 亚家族，在早期胚乳发育中表达旺盛。VKS1 在细胞核和微管上动态定位，并在合胞体中游离核的迁移以及早期有丝分裂和胞质分裂过程中的有丝分裂中发挥关键作用。VKS1 的缺失对植物的影响相对较小，但会导致早期胚乳发育中纺锤体装配、姐妹染色单体分离和胞质分裂板形成的缺陷，从而导致细胞增殖减少。个别胚乳中异常有丝分裂和胞质分裂的严重程度不同，导致子粒大小不同。我们的发现强调了 VKS1 作为早期玉米胚乳发育中有丝分裂的核心调节剂的作用，并为未来的产量提高提供了一种潜在的方法。
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