Male sterility is widely utilized for hybrid seed production. In this study, two new found male sterile mutants SauS4 and SauS5 were obtained from space flighted seeds of maize inbred line RP125. Then, genetic analysis, molecular markers identification, and cytological observation were conducted to confirm their male sterile types. For genetic analysis, the above two male sterile mutants were continuously backcrossed with two maize inbred line 18Hong and RP125, and four stable male sterile lines SauS4(18Hong), SauS5(18Hong), SauS4(RP125), SauS5(RP125) were generated by six-generation backcross. Restoring and maintaining relationship analysis showed that both Hui313 and Zifeng1 didn’t rescue the male sterility SauS4(18Hong) and SauS5(18Hong). Using CMS mitochondria-specific primers for PCR detection suggested that only a 440 bp band unique to CMS-T type was amplified in SauS4(18Hong), SauS5(18Hong), SauS4(RP125), and SauS5(RP125). Sequencing results showed that these bands sequences were identical in DNA level which compared with T-urf13. Cytological observations showed that the main abortion stages of SauS4 and SauS5 were at the middle stage of uninucleate microspores under the two nuclear backgrounds of 18Hong and RP125, exhibiting the characteristics of sporophyte sterility. All the above results pointed out the two male sterile mutants SauS4 and SauS5 belonged to the CMS-T type. Interestingly, some mitochondrial genome difference between SauS4(RP125) and SauS5(RP125) were revealed by AFLP analysis.

雄性不育被广泛用于杂交种子的生产。在这项研究中，从玉米自交系RP125的空间飞行种子中获得了两个新发现的雄性不育突变体SauS4和SauS5。然后，进行遗传分析，分子标记鉴定和细胞学观察，以确认其雄性不育类型。为了进行遗传分析，将上述两个雄性不育突变体与两个玉米自交系18Hong和RP125连续回交，并产生了四个稳定的雄性不育系SauS4（18Hong），SauS5（18Hong），SauS4（RP125），SauS5（RP125）。六代回交。恢复和维持的关系分析表明，Hui313和子丰1号都不能拯救雄性不育的SauS4（18Hong）和SauS5（18Hong）。使用CMS线粒体特异性引物进行PCR检测，表明在SauS4（18Hong），SauS5（18Hong），SauS4（RP125）和SauS5（RP125）中仅扩增了CMS-T类型独特的440 bp带。测序结果表明，这些条带序列的DNA水平与T-urf13。细胞学观察表明，在18Hong和RP125两种核背景下，SauS4和SauS5的主要流产期处于单核小孢子的中期，表现出孢子体不育的特征。以上所有结果表明，两个雄性不育突变体SauS4和SauS5属于CMS-T型。有趣的是，通过AFLP分析揭示了SauS4（RP125）和SauS5（RP125）之间的线粒体基因组差异。