DWARF AND ROBUST PLANT regulates plant height via modulating gibberellin biosynthesis in chrysanthemum

Abstract

YABBY (YAB) genes are specifically expressed in abaxial cells of lateral organs and determine abaxial cell fate. However, most studies have focused on few model plants, and the molecular mechanisms of YAB genes are not well understood. Here, we identified a YAB transcription factor in chrysanthemum (Chrysanthemum morifolium), Dwarf and Robust Plant (CmDRP), that belongs to a distinct FILAMENTOUS FLOWER (FlL)/YAB3 sub-clade lost in Brassicaceae. CmDRP was expressed in various tissues but did not show any polar distribution in chrysanthemum. Overexpression of CmDRP resulted in a semi-dwarf phenotype with a significantly decreased active GA3 content, while reduced expression generated the opposite phenotype. Furthermore, plant height of transgenic plants was partially rescued through the exogenous application of GA3 and Paclobutrazol, and expression of the GA biosynthesis gene CmGA3ox1 was significantly altered in transgenic plants. Yeast one-hybrid, LUC, and ChIP-qPCR analyses showed that CmDRP could directly bind to the CmGA3ox1 promoter and suppress its expression. Our research reveals a nonpolar expression pattern of a YAB family gene in dicots and demonstrates it regulates plant height through the GA pathway, which will deepen the understanding of the genetic and molecular mechanisms of YAB genes.

Genetic architecture and genomic prediction of plant height-related traits in chrysanthemum

“…Recently, Zhang et al . [ 52 ] clarified that the non-polar YAB transcription factor CmDRP regulates chrysanthemum PH by directly inhibiting the expression of the GA biosynthesis gene CmGA3ox , thereby affecting the biosynthesis of GA. This study identified 32 candidate genes related to PH through GWAS, including an auxin-induced gene IAA13 ( Supplementary Data Table S4 ).…”

SlZF3 regulates tomato plant height by directly repressing SlGA20ox4 in the gibberellic acid biosynthesis pathway

“…Overexpression of CmDRP (a YAB transcription factor) resulted in a semi-dwarf phenotype with reduced bioactive GA3 level. CmDRP can directly bind to the CmGA3ox1 promoter and inhibit its expression in chrysanthemum [ 62 ]. HY5 as a master regulator is involved in many aspects of plant development and defense [ 63 ].…”

Important Factors Controlling Gibberellin Homeostasis in Plant Height Regulation

“…Similarly, overexpression of the homologous gene CmDRP (Chrysanthemum morifolium dwarf and robust plant) of CmYAB1, isolated from chrysanthemum, elicits a GA-sensitive semidwarf phenotype. 41 CmDRP inhibits the expression of CmGA3ox1 by binding the CmGA3ox1 promoter, thereby decreasing the active GA levels.…”

“…However, the effects of the indirect inhibition of Oshox4 on GA biosynthesis may be weaker than the negative feedback effects on the GA response; consequently, levels of bioactive GA in plants with Oshox4 overexpression increase and result in a GA-insensitive phenotype. Similarly, overexpression of the homologous gene CmDRP ( Chrysanthemum morifolium dwarf and robust plant) of CmYAB1 , isolated from chrysanthemum, elicits a GA-sensitive semidwarf phenotype …”