College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China.
Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing 100083, China.
Int J Mol Sci. 2021 Mar 19;22(6):3138. doi: 10.3390/ijms22063138.
Ovule abortion is a common phenomenon in plants that has an impact on seed production. Previous studies of ovule and female gametophyte (FG) development have mainly focused on angiosperms, especially in . However, because it is difficult to acquire information about ovule development in gymnosperms, this remains unclear. Here, we investigated the transcriptomic data of natural ovule abortion mutants (female sterile line, STE) and the wild type (female fertile line, FER) of Carr. to evaluate the mechanism of ovule abortion during the process of free nuclear mitosis (FNM). Using single-molecule real-time (SMRT) sequencing and next-generation sequencing (NGS), 18 cDNA libraries via Illumina and two normalized libraries via PacBio, with a total of almost 400,000 reads, were obtained. Our analysis showed that the numbers of isoforms and alternative splicing (AS) patterns were significantly variable between FER and STE. The functional annotation results demonstrate that genes involved in the auxin response, energy metabolism, signal transduction, cell division, and stress response were differentially expressed in different lines. In particular, , , , and had significantly lower expression in STE, showing that auxin might be insufficient in STE, thus hindering nuclear division and influencing metabolism. Apoptosis in STE might also have affected the expression levels of these genes. To confirm the transcriptomic analysis results, nine pairs were confirmed by quantitative real-time PCR. Taken together, these results provide new insights into ovule abortion in gymnosperms and further reveal the regulatory mechanisms of ovule development.
胚珠败育是植物中一种常见的现象，对种子生产有影响。以前对胚珠和雌配子体（FG）发育的研究主要集中在被子植物上，尤其是在 。然而，由于难以获得裸子植物胚珠发育的信息，这一点尚不清楚。在这里，我们研究了 Carr. 的自然胚珠败育突变体（雌性不育系，STE）和野生型（雌性可育系，FER）的转录组数据，以评估游离核有丝分裂（FNM）过程中胚珠败育的机制。使用单分子实时（SMRT）测序和下一代测序（NGS），通过 Illumina 获得了 18 个 cDNA 文库，通过 PacBio 获得了 2 个归一化文库，总共获得了近 400,000 个读数。我们的分析表明，FER 和 STE 之间的同工型和选择性剪接（AS）模式的数量有显著差异。功能注释结果表明，参与生长素反应、能量代谢、信号转导、细胞分裂和应激反应的基因在不同的品系中差异表达。特别是，在 STE 中， 、 、 、 和 表达水平显著降低，表明 STE 中生长素可能不足，从而阻碍核分裂并影响代谢。STE 中的细胞凋亡也可能影响这些基因的表达水平。为了验证转录组分析的结果，通过定量实时 PCR 确认了 9 对。综上所述，这些结果为裸子植物胚珠败育提供了新的见解，并进一步揭示了胚珠发育的调控机制。
