The MADS domain transcription factor AGAMOUS-LIKE 15 suppresses resistance against Botryosphaeria dothidea in apple

AGL (AGAMOUS-LIKE) transcription factors are key regulators of plant growth and development, but their function in plant defense against pathogenic fungi is less studied. Apple (Malus × domestica) ring rot, caused by Botryosphaeria dothidea, is an important disease affecting apple production. In this study, we systematically analyzed the function and regulatory mechanism of the transcription factor MdAGL15 in apple resistance to B. dothidea. The results showed that overexpression of MdAGL15 in apple calli and fruits significantly enhanced susceptibility to B. dothidea, as evidenced by the enlargement of lesion area and the intensification of pathogen infection. Further mechanistic studies showed that the expression of key genes in the jasmonic acid (JA) biosynthesis and signal transduction pathways was significantly suppressed in MdAGL15-overexpressing material after inoculation with B. dothidea. Meanwhile, MdAGL15 also affected the basal immune response of plants by regulating reactive oxygen species (ROS) accumulation. This study reveals the molecular mechanism by which AGL transcription factors impair resistance to B. dothidea by negatively regulating the JA signaling pathway and ROS accumulation in apple. These findings not only expand the functional knowledge of AGL transcription factors in plant immunity but also provide a potential theoretical basis and gene targets for disease resistance breeding in apple.

The online version contains supplementary material available at 10.1007/s11032-026-01675-4.