MdRZFP34a promotes plant growth and enhances biotic stress resistance in apple

Biotic stress poses a significant threat to apple growth and development, often leading to substantial economic losses in fruit production. RING-type E3 ubiquitin ligases play crucial roles in regulating various plant physiological processes, including hormone signaling, photomorphogenesis, carbohydrate metabolism, and responses to biotic stress. Notably, heterologous overexpression of CpLRR-RLK1 in Arabidopsis thaliana has been shown to enhance resistance to bacterial diseases. Transcriptomic analysis further revealed that the RING Zinc-Finger Protein 34 s (MdRZFP34a and MdRZFP34b) expression was significantly upregulated in the CpLRR-RLK1 transgenic apple lines. In this study, MdRZFP34a and MdRZFP34b were identified to contain conserved CHY zinc-finger and RING-related domains. Overexpression of MdRZFP34a significantly promoted lateral root development and vegetative growth in apple. Functional analysis demonstrated that MdRZFP34a positively regulates resistance to Colletotrichum fructicola infection and aphid colonization by enhancing the accumulation of antioxidant enzymes and the biosynthesis of secondary metabolites. These findings provide valuable insights into the biological mechanisms underlying MdRZFP34a-mediated biotic stress resistance in apple.

The online version contains supplementary material available at 10.1007/s12298-026-01763-x.