MhWRKY46 gene as a positive regulator under iron deficiency stress in Malus halliana

WRKY transcription factors play critical roles in plant hormone signaling and in responses to various abiotic and biotic stresses. However, research on the relationship between WRKY transcription factors and iron deficiency in apple trees is limited. This study adopted real-time quantitative PCR (RT-qPCR) to detect WRKY gene expression in Malus halliana. The results revealed that the MhWRKY46 gene exhibited the highest expression level in response to iron deficiency stress. Furthermore, the precise regulatory mechanisms governing its role in iron deficiency stress are not yet fully elucidated. Accordingly, MhWRKY46 was selected for subsequent functional verification. Transgenic Arabidopsis thaliana plants overexpressing the MhWRKY46 gene demonstrated improved tolerance to iron deficiency stress. Additionally, overexpression in apple calli significantly enhanced growth under iron-deficient conditions compared with wild type. Physiological measurements indicated that the overexpression of the MhWRKY46 gene not only enhanced the tolerance of Arabidopsis thaliana to iron deficiency stress by promoting chlorophyll production, but also increased the resilience of apple calli to iron deficiency by lowering pH levels, enhancing the activity of antioxidant enzymes, and increasing iron content. In conclusion,the overexpression of the MhWRKY46 gene significantly improved the tolerance of both Arabidopsis thaliana and apple calli to iron deficiency stress.

The online version contains supplementary material available at https://doi.org/10.1007/s12298-026-01791-7.