Gibberellin Biosynthetic Deficiency Is Responsible for Maize Dominant Dwarf11 (<i>D11</i>) Mutant Phenotype: Physiological and Transcriptomic Evidence

<div><p>Dwarf stature is introduced to improve lodging resistance and harvest index in crop production. In many crops including maize, mining and application of novel dwarf genes are urgent to overcome genetic bottleneck and vulnerability during breeding improvement. Here we report the characterization and expression profiling analysis of a newly identified maize dwarf mutant <i>Dwarf11</i> (<i>D11</i>). The <i>D11</i> displays severely developmental abnormalities and is controlled by a dominant Mendelian factor. The <i>D11</i> seedlings responds to both GA₃ and paclobutrazol (PAC) application, suggesting that dwarf phenotype of <i>D11</i> is caused by GA biosynthesis instead of GA signaling deficiency. In contrast, two well-characterized maize dominant dwarf plants <i>D8</i> and <i>D9</i> are all insensitive to exogenous GA₃ stimulation. Additionally, sequence variation of <i>D8</i> and <i>D9</i> genes was not identified in the <i>D11</i> mutant. Microarray and qRT-PCR analysis results demonstrated that transcripts encoding GA biosynthetic and catabolic enzymes <i>ent</i>-kaurenoic acid oxidase (KAO), GA 20-oxidase (GA20ox), and GA 2-oxidase (GA2ox) are up-regulated in <i>D11</i>. Our results lay a foundation for the following <i>D11</i> gene cloning and functional characterization. Moreover, results presented here may aid in crops molecular improvement and breeding, especially breeding of crops with plant height ideotypes.</p>