College of Horticulture, Hunan Agricultural University, Changsha 410128, China.
Int J Mol Sci. 2024 Jul 17;25(14):7812. doi: 10.3390/ijms25147812.
The research is aimed to elucidate the role of plant hormones in regulating the development of hybrid embryos in . Fruits from the intraspecific cross of 'Otaksa' × 'Coerulea' were selected at the globular, heart, and torpedo stages of embryo development. Transcriptome sequencing and differential gene expression analysis were conducted. The results showed that fruit growth followed a single "S-shaped growth curve, with globular, heart, and torpedo embryos appearing at 30, 40, and 50 d post-pollination, respectively, and the embryo maintaining the torpedo shape from 60 to 90 d. A total of 12,933 genes was quantified across the three developmental stages, with 3359, 3803, and 3106 DEGs in the S1_vs_S2, S1_vs_S3, and S2_vs_S3 comparisons, respectively. Among these, 133 genes related to plant hormone biosynthesis and metabolism were differentially expressed, regulating the synthesis and metabolism of eight types of plant hormones, including cytokinin, auxin, gibberellin, abscisic acid, and jasmonic acid. The pathways with the most differentially expressed genes were cytokinin, auxin, and gibberellin, suggesting these hormones may play crucial roles in embryo development. In the cytokinin pathway, (Hma1.2p1_0579F.1_g182670.gene, Hma1.2p1_1194F.1_g265700.gene, and NewGene_12164) genes were highly expressed during the globular embryo stage, promoting rapid cell division in the embryo. In the auxin pathway, (Hma1.2p1_0271F.1_g109005.gene and Hma1.2p1_0271F.1_g109020.gene) genes were progressively up-regulated during embryo growth; the early response factor (Hma1.2p1_0760F.1_g214260.gene) was down-regulated, while the later transcriptional activator (NewGene_21460, NewGene_21461, and Hma1.2p1_0209F.1_g089090.gene) was up-regulated, sustaining auxin synthesis and possibly preventing the embryo from transitioning to maturity. In the gibberellin pathway, (Hma1.2p1_0129F.1_g060100.gene) expression peaked during the heart embryo stage and then declined, while the negative regulator (Hma1.2p1_0020F.1_g013915.gene) showed the opposite trend; and the gibberellin signaling repressor (Hma1.2p1_1054F.1_g252590.gene) increased over time, potentially inhibiting embryo development and maintaining the torpedo shape until fruit maturity. These findings preliminarily uncover the factors affecting the development of hybrid embryos, laying a foundation for further research into the regulatory mechanisms of hybrid embryo development.
本研究旨在阐明植物激素在调控杂种胚发育中的作用。选择在球状、心形和鱼雷形胚发育阶段的 'Otaksa'×'Coerulea' 种内杂交果实。进行了转录组测序和差异基因表达分析。结果表明，果实生长遵循单一的“S”形生长曲线，授粉后 30、40 和 50 天分别出现球状、心形和鱼雷形胚，60 至 90 天的胚胎保持鱼雷形。在三个发育阶段共定量了 12933 个基因，S1_vs_S2、S1_vs_S3 和 S2_vs_S3 比较中分别有 3359、3803 和 3106 个差异表达基因。其中，133 个与植物激素生物合成和代谢相关的基因差异表达，调节八种类型植物激素的合成和代谢，包括细胞分裂素、生长素、赤霉素、脱落酸和茉莉酸。差异表达基因最多的途径是细胞分裂素、生长素和赤霉素，表明这些激素可能在胚胎发育中发挥关键作用。在细胞分裂素途径中，（Hma1.2p1_0579F.1_g182670.gene、Hma1.2p1_1194F.1_g265700.gene 和 NewGene_12164）基因在球状胚阶段高度表达，促进胚胎快速细胞分裂。在生长素途径中，（Hma1.2p1_0271F.1_g109005.gene 和 Hma1.2p1_0271F.1_g109020.gene）基因在胚胎生长过程中逐渐上调；早期反应因子（Hma1.2p1_0760F.1_g214260.gene）下调，而后期转录激活因子（NewGene_21460、NewGene_21461 和 Hma1.2p1_0209F.1_g089090.gene）上调，维持生长素的合成，并可能防止胚胎进入成熟阶段。在赤霉素途径中，（Hma1.2p1_0129F.1_g060100.gene）在心脏胚阶段表达达到峰值，然后下降，而负调节因子（Hma1.2p1_0020F.1_g013915.gene）则呈现相反的趋势；赤霉素信号抑制剂（Hma1.2p1_1054F.1_g252590.gene）随时间增加，可能抑制胚胎发育并保持鱼雷形，直到果实成熟。这些发现初步揭示了影响杂种胚发育的因素，为进一步研究杂种胚发育的调控机制奠定了基础。
