Laboratory of Fruit Tree Biotechnology, College of Horticulture, Nanjing Agricultural University, Nanjing, Jiangsu, China.
College of Horticulture, Zhongkai University of Agriculture and Engineering, Guangzhou, Guangdong, China.
BMC Biol. 2024 Aug 26;22(1):184. doi: 10.1186/s12915-024-01985-z.
Grafting with dwarf rootstock is an efficient method to control plant height in fruit production. However, the molecular mechanism remains unclear. Our previous study showed that plants with Prunus mume (mume) rootstock exhibited a considerable reduction in plant height, internode length, and number of nodes compared with Prunus persica (peach) rootstock. The present study aimed to investigate the mechanism behind the regulation of plant height by mume rootstocks through transcriptomic and metabolomic analyses with two grafting combinations, 'Longyan/Mume' and 'Longyan/Peach'.
There was a significant decrease in brassinolide levels in plants that were grafted onto mume rootstocks. Plant hormone signal transduction and brassinolide production metabolism gene expression also changed significantly. Flavonoid levels, amino acid and fatty acid metabolites, and energy metabolism in dwarf plants decreased. There was a notable upregulation of PmLBD3 gene expression in plant specimens that were subjected to grafting onto mume rootstocks. Auxin signalling cues promoted PmARF3 transcription, which directly controlled this upregulation. Through its binding to PmBAS1 and PmSAUR36a gene promoters, PmLBD3 promoted endogenous brassinolide inactivation and inhibited cell proliferation.
Auxin signalling and brassinolide levels are linked by PmLBD3. Our findings showed that PmLBD3 is a key transcription factor that regulates the balance of hormones through the auxin and brassinolide signalling pathways and causes dwarf plants in stone fruits.
利用矮化砧木进行嫁接是控制水果生产中植物高度的有效方法。然而，其分子机制尚不清楚。我们之前的研究表明，与桃砧木相比，用李砧木嫁接的植物在株高、节间长度和节点数量方面都有显著减少。本研究旨在通过对两种嫁接组合“龙延/李”和“龙延/桃”的转录组和代谢组分析，研究李砧木调控植物高度的机制。
在嫁接到李砧木上的植物中，油菜素内酯水平显著降低。植物激素信号转导和油菜素内酯生物合成代谢基因的表达也发生了显著变化。矮化植物中的类黄酮水平、氨基酸和脂肪酸代谢物以及能量代谢物降低。在嫁接到李砧木上的植物标本中，PmLBD3 基因的表达显著上调。生长素信号线索促进了 PmARF3 的转录，这直接控制了这种上调。通过与 PmBAS1 和 PmSAUR36a 基因启动子结合，PmLBD3 促进内源性油菜素内酯失活并抑制细胞增殖。
生长素信号和油菜素内酯水平通过 PmLBD3 相互关联。我们的研究结果表明，PmLBD3 是一种关键的转录因子，通过生长素和油菜素内酯信号通路调节激素平衡，导致核果类矮化植物。
