The ZAT17-PRL1 module engages in the miRNA synthesis in Arabidopsis

MicroRNAs (miRNAs) affect the expression of target mRNAs post-transcriptionally or inhibit their translation, thus controlling plant growth and stress response. Pleiotropic Regulatory Locus 1 (PRL1) plays a crucial role in the process of miRNA synthesis. However, the regulators of PRL1 downstream signaling remain largely unknown. A previous study reported that sup8 (suppressor of prl1-2) can partially compensate for the development and cadmium (Cd) sensitivity of prl1-2 mutant. The mutant gene in sup8 encodes C2H2-type zinc finger protein ZAT17. Our research revealed that sup8 restored the defect in miRNA expression in prl1-2. Through RNA-seq analysis, we discovered that ZAT17 negatively modulated the transcription of specific MIR genes and might affect specific biological processes, such as starch and sucrose metabolism, circadian rhythm, glycerolipid metabolism, and amino acid metabolism, via modulating the accumulation levels of particular miRNAs. Furthermore, we characterized the alternative splicing (AS) defects of MIR171b and MIR172b in prl1-2 that were restored by ZAT17. Consistent with ZAT17's involvement in miRNA production, we found that ZAT17 interacts with the components of the pri-miRNA Dicer complex. These findings broaden our understanding of miRNA biosynthetic pathways and provide promising candidate targets for breeding programs aimed at enhancing plant growth and stress tolerance.