Zinc finger protein ZFP36 and pyruvate dehydrogenase kinase PDK1 function in ABA-mediated aluminum tolerance in rice

Abstract

Aluminum (Al) toxicity poses a significant constraint on field crop yields in acid soils. Zinc finger protein 36 (ZFP36) is well-documented for its pivotal role in enhancing tolerance to both drought and oxidative stress in rice. This study unveils a novel function of ZFP36 modulated by abscisic acid (ABA)-dependent mechanisms, specifically aimed at alleviating Al toxicity in rice. Under Al stress, the expression of ZFP36 significantly increased through an ABA-dependent pathway. Knocking down ZFP36 heightened Al sensitivity, while overexpressing ZFP36 conferred increased resistance to Al stress. Additionally, our investigations revealed a physical interaction between ZFP36 and pyruvate dehydrogenase kinase 1 in rice (OsPDK1). Biochemical assays further elucidated that OsPDK1 phosphorylates ZFP36 at the amino acid site 73–161. Subsequent experiments demonstrated that ZFP36 positively regulates the expression of ascorbate peroxidases (OsAPX1) and OsALS1 by binding to specific elements in their upstream segments in rice. Through genetic and phenotypic analyses, we unveiled that OsPDK1 influences ABA-triggered antioxidant defense to alleviate Al toxicity by interacting with ZFP36. In summary, our study underscores that pyruvate dehydrogenase kinase 1 (OsPDK1) phosphorylates ZFP36 to modulate the activities of antioxidant enzymes via an ABA-dependent pathway, influencing tolerance of rice to soil Al toxicity.