Improving crop lodging resistance by adjusting plant height and stem strength

Crop height not only determines plant resistance to lodging and crowding, but also affects crop architecture, apical dominance, biomass, and mechanical harvesting. Plant height is determined by the internode elongation, regulated by genes involved in gibberellin (GA) and brassinosteroid (BR) biosynthesis or related signaling networks. Plants' genetic inability to synthesize or respond to GAs and BRs induce dwarfness. However, the signaling mechanisms of GAs and BRs for controlling plant height individually or collectively are still unclear. Since stem mechanically supports plant during the whole life span, components that affect stem physical strength are also important to crop lodging resistance. One of the major components is lignin, which forms stem structure, thus contributing to crop lodging resistance. In this review, we looked into the reported genes involved in lignin, GAs, and BRs biosynthesis and summarized the signaling networks centered by these genes. Then, we filled the knowledge gap by modifying plant height through interrupting normal GA and BR metabolism utilizing core gene inhibitors. Therefore, we highly endorsed the current approaches of using plant growth regulators (PRGs) to maintain an ideal plant height under lodging stress, and proposed possibilities of modifying crop culm strength against lodging as well.