National Key Laboratory of Crop Genetic Improvement, Hongshan Laboratory, Huazhong Agricultural University, Wuhan 430070, China.
Key Laboratory of Crop Physiology, Ecology and Genetic Breeding, Ministry of Education, Jiangxi Agricultural University, Nanchang 330045, China.
Int J Mol Sci. 2021 Nov 18;22(22):12450. doi: 10.3390/ijms222212450.
Temperature-sensitive male sterility is a heritable agronomic trait affected by genotype-environment interactions. In rapeseed (), Polima () temperature-sensitive cytoplasmic male sterility (TCMS) is commonly used for two-line breeding, as the fertility of TCMS lines can be partially restored at certain temperatures. However, little is known about the underlying molecular mechanism that controls fertility restoration. Therefore, we aimed to investigate the fertility conversion mechanism of the TCMS line at two different ambient temperatures (16 °C and 25 °C). Our results showed that the anthers developed and produced vigorous pollen at 16 °C but not at 25 °C. In addition, we identified a novel co-transcript of in the mitochondria that might lead to fertility conversion of the TCMS line. RNA-seq analysis showed that 1637 genes were significantly differentially expressed in the fertile flowers of 596-L when compared to the sterile flower of 1318 and 596-H. Detailed analysis revealed that differentially expressed genes were involved in temperature response, ROS accumulation, anther development, and mitochondrial function. Single-molecule long-read isoform sequencing combined with RNA sequencing revealed numerous genes produce alternative splicing transcripts at high temperatures. Here, we also found that alternative oxidase, type II NAD(P)H dehydrogenases, and transcription factor might play a crucial role in male fertility under the low-temperature condition. RNA sequencing and bulked segregant analysis coupled with whole-genome sequencing identified the candidate genes involved in the post-transcriptional modification of . Overall, our study described a putative mechanism of fertility restoration in a TCMS line controlled by ambient temperature that might help utilise TCMS in the two-line breeding of crops.
温度敏感型雄性不育是一种受基因型-环境互作影响的可遗传农艺性状。在油菜（）中，Polima（）温度敏感细胞质雄性不育（TCMS）通常用于两系育种，因为 TCMS 系的育性可以在某些温度下部分恢复。然而，对于控制育性恢复的潜在分子机制知之甚少。因此，我们旨在研究 TCMS 系在两种不同环境温度（16°C 和 25°C）下的育性转换机制。我们的研究结果表明，在 16°C 时，花药发育并产生活力旺盛的花粉，但在 25°C 时则不然。此外，我们在粒体中鉴定到一个可能导致 TCMS 系育性转换的新的共转录本。RNA-seq 分析表明，与 1318 和 596-H 的不育花相比，在 596-L 的可育花中，有 1637 个基因的表达存在显著差异。详细分析表明，差异表达基因参与了温度响应、ROS 积累、花药发育和线粒体功能。单分子长读长异构体测序与 RNA 测序相结合，揭示了许多基因在高温下产生可变剪接转录本。在这里，我们还发现，在低温条件下，替代氧化酶、Ⅱ型 NAD(P)H 脱氢酶和转录因子 可能在雄性育性中发挥关键作用。RNA 测序和混池分离分析与全基因组测序相结合，鉴定了参与 的转录后修饰的候选基因。总的来说，我们的研究描述了一个由环境温度控制的 TCMS 系育性恢复的假说机制，这可能有助于在油菜作物的两系育种中利用 TCMS。
