# Multi-Omics Analysis Reveals Differential Molecular Responses of RNA Polymerase Common Subunit ZmRPABC5b for Seedling Development in Maize

## TL;DR

This study shows that the ZmRPABC5b gene is crucial for maize seedling development, as its loss causes growth delays and affects multiple metabolic and gene expression pathways.

## Contribution

The study reveals the novel role of the RNA polymerase subunit ZmRPABC5b in regulating maize seedling development through multi-omics analysis.

## Key findings

- Loss of ZmRPABC5b function leads to reduced stem and root length, as well as lower fresh and dry weight in maize seedlings.
- Transcriptomic analysis identified over 8000 differentially expressed genes related to RNA biosynthesis, hormone stimulus, and metabolism.
- Metabolomic analysis found 501 altered metabolites, mainly in amino acid, carbohydrate, and lipid metabolism pathways.

## Abstract

The normal development of maize (Zea mays) seedling is a prerequisite for achieving high crop yields. Although numerous molecular pathways regulate seedling development, the role of RNA polymerases (RNAPs) in this process remains largely unclear, and the function of common RNAP subunits in plants are not well understood. Here, we characterized the loss-of-function mutant of common subunit ZmRPABC5b, defective kernel 701 (dek701), which displays delayed seedling development. To elucidate the role of ZmRPABC5b in maize seedling growth, we conducted transcriptomic and metabolomic analyses. This study found that the loss of ZmRPABC5b function severely impaired early seedling growth, leading to significant reductions in stem length, root length, as well as fresh and dry weight. Transcriptome analysis identified 3780 upregulated and 4385 downregulated differentially expressed genes (DEGs) in dek701 seedlings compared to wild type. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses of DEGs revealed that significant enrichment in pathways related to RNA biosynthesis, carbohydrate metabolic, hormone stimulus, cellular transporter and ribosome activity. Metabolome analysis identified 501 differentially expressed metabolites (DEMs) in dek701 seedlings, which were significantly enriched in the amino acid metabolism, secondary metabolites, carbohydrate metabolism, lipid metabolism, transport and translation. These findings provide substantial insight into the ZmRPABC5b regulatory network, positioning it as a central hub for regulating seedling development in maize.