Deng Xuan, Ahmad Bilal, Deng Jing, Liu Lianlian, Lu Xiuping, Fan Zelin, Zha Xingfu, Pan Yu
State Key Laboratory of Resource Insects, Southwest University, Chongqing, China.
State Key Laboratory of Tropical Crop Breeding, Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China.
Front Plant Sci. 2023 Aug 21;14:1229811. doi: 10.3389/fpls.2023.1229811. eCollection 2023.
Mulberry holds significant economic value. However, during the ripening stage of its fruit, the phenomenon of abscission, resulting in heavy fruit drop, can severely impact the yield. The formation of off-zone structures is a critical factor in the fruit abscission process, and this process is regulated by multiple transcription factors. One such key gene that plays a significant role in the development of the off-zone in the model plant tomato is , which promotes the expression of abscission-related genes and regulates the differentiation of abscission zone tissue cells. However, there is a lack of information about fruit abscission mechanism in mulberry. Here, we analyzed the promoter and identified the upstream regulators MaABF1 and MaABI5. These two regulators showed binding with promoter MaABF1 (the ABA Binding Factor/ABA-Responsive Element Binding Proteins) activated the expression of , while MaABI5 (ABSCISIC ACID-INSENSITIVE 5) inhibited the expression of . Finally, the differentially expressed genes (DEGs) were analyzed by transcriptome sequencing to investigate the expression and synergistic relationship of endogenous genes in mulberry during abscission. GO classification and KEGG pathway enrichment analysis showed that most of the DEGs were concentrated in MAPK signaling pathway, flavonoid biosynthesis, citric acid cycle, phytohormone signaling, amino acid biosynthesis, and glycolysis. These results provide a theoretical basis for subsequent in-depth study of physiological fruit abscission in mulberry.
桑树具有重要的经济价值。然而，在其果实成熟阶段，脱落现象会导致大量落果，这会严重影响产量。离区结构的形成是果实脱落过程中的一个关键因素，并且这个过程受多种转录因子调控。在模式植物番茄中，一个在离区发育中起重要作用的关键基因是 ，它促进脱落相关基因的表达并调节离区组织细胞的分化。然而，关于桑树果实脱落机制的信息却很匮乏。在此，我们分析了 启动子，并鉴定出上游调控因子MaABF1和MaABI5。这两个调控因子与 启动子结合，MaABF1（脱落酸结合因子/脱落酸响应元件结合蛋白）激活 的表达，而MaABI5（脱落酸不敏感5）抑制 的表达。最后，通过转录组测序分析差异表达基因（DEGs），以研究桑树在脱落过程中内源基因的表达及协同关系。基因本体（GO）分类和京都基因与基因组百科全书（KEGG）通路富集分析表明，大多数DEGs集中在丝裂原活化蛋白激酶（MAPK）信号通路、类黄酮生物合成、柠檬酸循环、植物激素信号传导、氨基酸生物合成和糖酵解中。这些结果为后续深入研究桑树生理性落果提供了理论依据。
