Maize ZmEREB130 transcription factor negatively regulates growth and seed size

Abstract

The APETALA2/Ethylene Response Element Binding Protein (AP2/EREBP) is a kind of plant-specific transcription factor and plays a pivotal role in governing plant growth, ontogenesis, and stress acclimation processes. However, the AP2 members modulating plant height and seed morphogenesis remain largely unelucidated. In the present study, the maize ZmEREB130 gene was cloned and functionally validated in modulating growth and seed size development. Our findings demonstrated that ZmEREB130 protein harbors two conserved AP2 domains, localized to the nucleus, exhibits no self-activation activity, and is a canonical AP2 transcription factor. The results of Y2H, BiFC, and split-LUC assays revealed that ZmEREB130 undergoes homodimerization via its AP2 domain, and interacts with ZmFdx1/5. The ZmEREB130 exhibited predominant expression in maize seeds. Heterologous expression of ZmEREB130 in Arabidopsis resulted in the suppression of plant growth and reduction of seed dimensions. Phenotypic analyses demonstrated that five transgenic lines manifested reduced seedling size, diminished biomass accumulation, delayed flowering, decreased plant height, and significantly reductions in seed length, width, and weight compared to wild type plants. The results of RNA-seq, qRT-PCR, and dual-LUC assays implied that ZmEREB130 binds to the promoters of development-associated genes, modulating their transcription and ultimately impeding growth and ontogenesis of transgenic Arabidopsis. This study provides evidence that ZmEREB130 functions as a negative regulator of plant growth and development, thereby presenting a novel candidate gene for maize genetic improvements aiming to achieve high-yield traits via genome-editing technologies.