Wang Yaping, Wang Hao, Bao Wenquan, Sui Mingming, Bai Yu E
College of Forestry, Inner Mongolia Agricultural University, Huhhot 010019, China.
Curr Issues Mol Biol. 2023 Jun 21;45(7):5232-5247. doi: 10.3390/cimb45070332.
is a rare tree species in China, which is of great significance in combating desertification and improving the harsh ecological environment. Due to the low rate of natural regeneration, high mortality, and susceptibility to pests and cold springs, has gradually become extinct. At present, somatic embryogenesis (SE) is the most effective method of micro-proliferation in conifers, but the induction rate of embryogenic callus (EC) is low, and EC is difficult to differentiate from non-embryonic callus (NEC). Therefore, the EC and NEC of were compared from the morphology, histological, physiological, and transcriptional levels, respectively. Morphological observation showed that the EC was white and transparent filamentous, while the NEC was compact and brownish-brown lumpy. Histological analyses showed that the NEC cells were large and loosely arranged; the nuclei attached to the edge of the cells were small; the cytoplasm was low; and the cell gap was large and irregular. In the EC, small cells, closely arranged cells, and a large nucleus and nucleolus were observed. Physiological studies showed significant differences in ROS-scavenging enzymes between the EC and NEC. Transcriptome profiling revealed that 13,267 differentially expressed genes (DEGs) were identified, 3682 were up-regulated, and 9585 were down-regulated. In total, 63 GO terms had significant enrichment, 32 DEGs in plant hormone signal transduction pathway were identified, and 502 different transcription factors (TFs) were characterized into 38 TF families. Meanwhile, we identified significant gene expression trends associated with somatic embryo development in plant hormones (/, , , etc.), stress (, , , etc.), phenylpropanoid metabolism (, , , etc.), and transcription factors (/, MYB, , etc.). In addition, nine genes were chosen for RT-qPCR, and the results were consistent with RNA-Seq data. This study revealed the changes in morphology, histology, physiology, and gene expression in the differentiation of NEC into EC and laid the foundation for finding the key genes to promote EC formation.
是中国的一种珍稀树种，在防治荒漠化和改善恶劣生态环境方面具有重要意义。由于自然更新率低、死亡率高以及易受病虫害和倒春寒影响，已逐渐灭绝。目前，体细胞胚胎发生（SE）是针叶树微繁殖最有效的方法，但胚性愈伤组织（EC）的诱导率低，且EC难以与非胚性愈伤组织（NEC）区分。因此，分别从形态学、组织学、生理学和转录水平对的EC和NEC进行了比较。形态学观察表明，EC为白色透明丝状，而NEC为致密的棕褐色块状。组织学分析表明，NEC细胞大且排列松散；附着在细胞边缘的细胞核小；细胞质少；细胞间隙大且不规则。在EC中，观察到细胞小、排列紧密、细胞核和核仁大。生理学研究表明，EC和NEC之间的活性氧清除酶存在显著差异。转录组分析显示，共鉴定出13267个差异表达基因（DEG），其中3682个上调，9585个下调。共有63个基因本体（GO）术语显著富集，鉴定出植物激素信号转导途径中的32个DEG，502个不同的转录因子（TF）被归类为38个TF家族。同时，我们确定了与植物激素（/、、、等）、胁迫（、、、等）、苯丙烷代谢（、、、等）和转录因子（/、MYB、、等）中体细胞胚胎发育相关的显著基因表达趋势。此外，选择了9个基因进行RT-qPCR，结果与RNA-Seq数据一致。本研究揭示了NEC分化为EC过程中形态学、组织学、生理学和基因表达的变化，为寻找促进EC形成的关键基因奠定了基础。
