利用甲基磺酸乙酯(EMS)对玉米自交系郑58进行诱变，获得一个可以稳定遗传的小粒突变体mn7 (miniature 7)。mn7成熟籽粒表现为体积变小、籽粒偏白、胚乳发育缓慢，百粒重降低60.2%，粒长、粒宽、粒厚均极显著降低。mn7突变体的籽粒在授粉后15d即可观察到明显小于野生型的籽粒。对其自交后代和回交后代的遗传分析表明，该性状受隐性单基因控制。用mn7纯合体与自选玉米自交系19HL3012杂交构建的包含348个个体的F2分离群体，将该基因定位于玉米第7染色体上bin7.02区域内分子标记umc2327和SYM232之间5.8cM的范围内，距umc2327为4.4cM，距SYM232为1.4cM。初步的生物信息学分析表明，mn7可能是一个新基因或新等位基因。该结果为进一步克隆和解析mn7基因调控玉米籽粒发育的分子机制奠定了基础。

In this study, a stable miniature kernel mutant, named mn7 (miniature 7), was generated by ethylmethane sulfonate (EMS) mutagenesis with a inbred line Zheng58 in maize. Compared with wild type, the mature kernels of mutant mn7 showed smaller volume, whiter, slow endosperm development, 100-kernel weight decreased by 60.2%, and kernel length, width and thickness were all significantly reduced. The kernel of the mn7 mutant were significantly smaller than that of the wild type at 15 days after pollination (DAP). Genetic analysis of its inbred progeny and backcross progeny showed that the mutant trait is controlled by a single recessive gene. A F2 segregation population consisting of 348 individuals derived from 19HL3012×mn7 was used as mapping population and the mn7 gene was located in a region of 5.8 centi Morgan(cM) flanked by the molecular markers umc2327 and SYM232 in the bin 7.02 on chromosome 7. The genetic distance from mn7 to umc2327 was 4.4cM and it was 1.4cM from mn7 to SYM232. Bioinformatics analysis indicated that mn7 might be a new gene or allele. These results laid a foundation for further cloning and analysing of the molecular mechanism of regulating maize kernel development of mn7 gene.

科技部“十三五”国家重点研发计划课题(2017YFD0102001)。