A multi-omics approach to maize (Zea mays) tassel development

The development of the male inflorescence in maize (Zea mays) is a complex and highly regulated process that is essential for reproductive success and yield. To gain a comprehensive understanding of the regulatory programs involved in tassel formation, including the initial specification of anther cell types, the transcriptomes, small RNAs (sRNAs), and proteomes were profiled at four developmental stages (0.5-2.0 cm). The RNA-seq analysis indicates dynamic shifts in gene expression underlying the transition from indeterminate meristems to organ initiation and germinal cell determination by 2.0 cm. Complementing these data, sRNA sequencing uncovered 182 microRNAs (miRNAs) with distinct temporal patterns. A core set of 126 miRNAs was expressed throughout tassel development, while others displayed strong stage-specific enrichment. Notably, families of miRNAs that target auxin signaling were dynamically regulated, suggesting fine-tuning of hormone signaling in relation to meristem activity. Later stages were enriched for miR2275 and miR11969, which previously have both been associated with meiocytes, indicating the onset of reproductive sRNA pathways during the early stages of anther differentiation. One factor identified in the transcriptomic and proteomic analyses was GASA (Gibberellic Acid-Stimulated Arabidopsis)-like 4 (GSL4). Further tests indicated that GSL4 could influence tassel branch length. Together, these data provide a broad overview of tassel development and enrich existing RNA-seq and single-cell RNA-seq datasets of specific steps in tassel and initial anther development. They also offer the opportunity to identify novel developmental factors, such as GSL4, while adding new data on small RNA (sRNA) expression.