Table_3_Establishment of in vitro regeneration system and molecular analysis of early development of somatic callus in Capsicum chinense and Capsicum baccatum.xlsx

Regeneration is extremely important to pepper genetic development; however, the molecular mechanisms of how the callus reactivates cell proliferation and promotes cell reprogramming remain elusive in pepper. In the present study, C. baccatum (HNUCB81 and HNUCB226) and C. chinense (HNUCC22 and HNUCC16) were analyzed to reveal callus initiation by in vitro regeneration, histology, and transcriptome. We successfully established an efficient in vitro regeneration system of two cultivars to monitor the callus induction of differential genotypes, and the regenerated plants were obtained. Compared to C. chinense, there was a higher callus induction rate in C. baccatum. The phenotype of C. baccatum changed significantly and formed vascular tissue faster than C. chinense. The KEGG enrichment analysis found that plant hormone transduction and starch and sucrose metabolism pathways were significantly enriched. In addition, we identified that the WOX7 gene was significantly up-regulated in HNUCB81 and HNUCB226 than that in HNUCC22 and HNUCC16, which may be a potential function in callus formation. These results provided a promising strategy to improve the regeneration and transformation of pepper plants.

再生对辣椒遗传发育至关重要，但辣椒愈伤组织如何重新激活细胞增殖并促进细胞重编程的分子机制仍未明确。本研究以辣椒属C. baccatum（材料编号HNUCB81与HNUCB226）及C. chinense（材料编号HNUCC22与HNUCC16）为研究对象，通过离体再生、组织学与转录组分析解析愈伤组织起始机制。本研究成功构建了两个品种的高效离体再生体系，用于监测不同基因型的愈伤组织诱导过程，并获得了再生植株。相较于C. chinense，C. baccatum的愈伤组织诱导率更高，其表型变化更为显著，且较C. chinense更快形成维管组织。KEGG富集分析显示，植物激素信号转导与淀粉蔗糖代谢通路显著富集。此外，本研究发现WOX7基因在HNUCB81与HNUCB226中的表达量显著高于HNUCC22与HNUCC16，该基因可能在愈伤组织形成中发挥潜在功能。上述研究结果为提升辣椒植株的再生与遗传转化效率提供了极具潜力的研究策略。