National Key Laboratory of Wheat and Maize Crops Science, College of Agronomy, Henan Agricultural University, Zhengzhou, 450018, China.
Hubei Collaborative Innovation Center for Grain Industry, Yangtze University, Jingzhou, 433200, China.
BMC Plant Biol. 2021 Feb 26;21(1):118. doi: 10.1186/s12870-021-02890-1.
Maize (Zea mays) ear length, which is an important yield component, exhibits strong heterosis. Understanding the potential molecular mechanisms of ear-length heterosis is critical for efficient yield-related breeding.
Here, a joint netted pattern, including six parent-hybrid triplets, was designed on the basis of two maize lines harboring long (T121 line) and short (T126 line) ears. Global transcriptional profiling of young ears (containing meristem) was performed. Multiple comparative analyses revealed that 874 differentially expressed genes are mainly responsible for the ear-length variation between T121 and T126 lines. Among them, four key genes, Zm00001d049958, Zm00001d027359, Zm00001d048502 and Zm00001d052138, were identified as being related to meristem development, which corroborated their roles in the superior additive genetic effects on ear length in T121 line. Non-additive expression patterns were used to identify candidate genes related to ear-length heterosis. A non-additively expressed gene (Zm00001d050649) was associated with the timing of meristematic phase transition and was determined to be the homolog of tomato SELF PRUNING, which assists SINGLE FLOWER TRUSS in driving yield-related heterosis, indicating that Zm00001d050649 is a potential contributor to drive heterotic effect on ear length.
Our results suggest that inbred parents provide genetic and heterotic effects on the ear lengths of their corresponding F hybrids through two independent pathways. These findings provide comprehensive insights into the transcriptional regulation of ear length and improve the understanding of ear-length heterosis in maize.
玉米穗长是一个重要的产量构成要素，表现出很强的杂种优势。了解穗长杂种优势的潜在分子机制对于高效的产量相关育种至关重要。
在此，基于两个具有长穗（T121 系）和短穗（T126 系）的玉米系，设计了一个包含六个亲本-杂种三联体的联合网纹模式。对幼穗（含有分生组织）进行了全局转录谱分析。多重比较分析表明，874 个差异表达基因主要负责 T121 和 T126 系之间穗长的变化。其中，鉴定出四个关键基因 Zm00001d049958、Zm00001d027359、Zm00001d048502 和 Zm00001d052138 与分生组织发育有关，这证实了它们在 T121 系中对穗长的超加性遗传效应的作用。非加性表达模式被用来鉴定与穗长杂种优势相关的候选基因。一个非加性表达的基因（Zm00001d050649）与分生组织转换的时间有关，被确定为番茄 SELF PRUNING 的同源物，它有助于 SINGLE FLOWER TRUSS 驱动与产量相关的杂种优势，表明 Zm00001d050649 是一个潜在的驱动穗长杂种优势的基因。
我们的研究结果表明，自交系通过两条独立的途径为其相应的 F1 杂种提供穗长的遗传和杂种优势效应。这些发现为玉米穗长的转录调控提供了全面的见解，并提高了对玉米穗长杂种优势的理解。
