Xu Ruirui, Jiang Shuna, Ge Hongjuan, Zhang Buhang, Shu Jing, Zhang Tianpeng, Cao Lijun, Zhang Shizhong
College of Biology and Oceanography, Weifang University, Weifang, 261061, Shandong, China.
College of Life Sciences, Shandong Agricultural University, Taian, 271018, Shandong, China.
Plant Cell Rep. 2025 Apr 30;44(5):110. doi: 10.1007/s00299-025-03492-z.
MhIDA small peptides promote apple root growth by enhancing auxin synthesis and cell wall remodeling gene expression, revealing a peptide-based strategy to improve root architecture. Although small peptides have been well documented as crucial regulators of plant growth and development, the molecular mechanisms underlying lateral root morphogenesis in Malus hupehensis remain poorly understood. In this research, exogenous application of 1 µM MhIDA-Like family peptides increased primary root (PR) length by 14.31-19.96% and lateral root (LR) number by 124.54-149.08%. MhIDA, predominant expression in the root tip and lateral root primordium, demonstrated the most substantial promoting effects on PR elongation, LR number and density when the treatment concentration reached 1 µM. Furthermore, similar effects were found in MhIDA-overexpression transgenic apple seedlings, with the number and density of transgenic LRs increase by 80.52 and 126.86%, respectively, compared with wild-type seedlings. More importantly, 1 µM MhIDA treatment induced significant hormonal alterations, with the content of auxin, salicylic acid and gibberellic acid increasing by 1.5-fold, 1.4-fold, and 2.1-fold, respectively, compared to control. The qRT-PCR results showed that MhIDA could induce the expression of auxin synthesis genes (MhTAA1 and MhYUCC1) that were up-regulated by about twofold, and the cell wall remodeling-related genes (MhEXP17, MhXTR6, MhPGAZAT and MhPGLR) were upregulated by about 2- to 4-fold after 1 µM MhIDA treatment, thereby regulating LR emergence and formation of Malus hupehensis. Overall, these findings suggested the MhIDA peptide can promote the growth and development of roots, laying the foundation for cultivating apple rootstocks with strong roots and higher resistance to abiotic stress.
MhIDA小肽通过增强生长素合成和细胞壁重塑基因表达促进苹果根系生长，揭示了一种基于肽的改善根系结构的策略。尽管小肽已被充分证明是植物生长发育的关键调节因子，但湖北海棠侧根形态发生的分子机制仍知之甚少。在本研究中，外源施加1 μM MhIDA样家族肽可使主根长度增加14.31%-19.96%，侧根数量增加124.54%-149.08%。MhIDA在根尖和侧根原基中大量表达，当处理浓度达到1 μM时，对主根伸长、侧根数量和密度的促进作用最为显著。此外，在MhIDA过表达转基因苹果幼苗中也发现了类似的效果，与野生型幼苗相比，转基因侧根的数量和密度分别增加了80.52%和126.86%。更重要的是，1 μM MhIDA处理引起了显著的激素变化，与对照相比，生长素、水杨酸和赤霉素的含量分别增加了1.5倍、1.4倍和2.1倍。qRT-PCR结果表明，MhIDA可诱导生长素合成基因（MhTAA1和MhYUCC1）的表达上调约两倍，在1 μM MhIDA处理后，细胞壁重塑相关基因（MhEXP17、MhXTR6、MhPGAZAT和MhPGLR）上调约2至4倍，从而调控湖北海棠侧根的发生和形成。总体而言，这些发现表明MhIDA肽可以促进根系的生长发育，为培育具有强大根系和更高抗非生物胁迫能力的苹果砧木奠定了基础。
