Systematic identification and characterization of candidate genes for the regulation of plant height in maize

Abstract

Plant height, which is an important trait for maize breeding because of its relationship with lodging resistance and yield production, is reportedly determined by multiple qualitative and quantitative genes. However, only a few plant height-related genes have been cloned or characterized in maize. In the present study, previously characterized genes involved in the regulation of plant height were collected from maize, Arabidopsis thaliana, Oryza sativa and sorghum. A collinearity analysis was subsequently performed to identify homologs in the maize genome. A total of 82 new homologous genes were identified as possibly influencing plant height in maize. Interestingly, most of the candidates were involved in the synthesis or signaling of various phytohormones, particularly gibberellin (GA), implying that phytohormones are critical for regulating plant height. Moreover, in a comprehensive analysis of the expression patterns for these genes, substantial variability was observed across tissues and developmental stages, and each tissue exhibited diverse gene expression patterns. An RNA-sequencing analysis of tall and dwarf inbred lines revealed that 15 candidates were differentially expressed, among which six (40.0%) genes were functionally characterized as affecting various phytohormone pathways. Furthermore, the expression of candidate genes potentially involved in the GA signaling pathway was strongly induced by an exogenous GA treatment. This increased expression may have contributed to the observed faster growth rate of the GA-treated plants compared with the mock controls. Our results indicate that the spatial or temporal expression of genes involved in various phytohormone pathways may be associated with the regulation of plant height in maize.