Designed Manipulation of the Brassinosteroid Signal to Enhance Crop Yield

Abstract

Brassinosteroid (BR), a plant steroid hormone, plays crucial role in modulating plant growth and development, which affect crop architecture and yield. However, BR application cannot highly benefit to agricultural production as expectation, because it regulates multiple processes in different tissues and leads to side effect. In addition, accurately modifying BR signal at transcriptional level is difficult. Effective manipulation of the BR signal and avoidance of side effects are required to enhance yield in different crops. Application of BR by spraying at specific developmental stages can enhance crop yield, but this method is impractical for use on a large scale. The accurate molecular design of crops would be much more helpful to manipulate the BR signal in specific organs and/or at particular developmental stages to enhance crop yield. This minireview summarizes the BR regulation of yield in different crops, especially horticultural crops, and the strategies used to regulate the BR signal to enhance crop yield. One popular strategy is to directly modulate the BR signal through modifying the functions of important components in the BR signal transduction pathway. Another strategy is to identify and modulate regulators downstream of, or in crosstalk with, the BR signal to manipulate its role in specific processes and increase crop yield. Efforts to accurately design a BR manipulation strategy will ultimately lead to effective control of the BR signal to avoid side effects and enhance crop yield.

Brassinosteroids (BRs) Role in Plant Development and Coping with Different Stresses

“…BRs are steroid hormones that play various roles in the growth and development of plants [32][33][34] (Figure 1). BRs regulate various developmental and physiological processes in plants, such as expansion, cell division, stem cell maintenance, vascular development, elongation of different cell types, and floral transition [35][36][37][38].…”

“…BRs have the ability to activate the cell cycle during seed germination [50], regulate cell cycle progression [51], control leaf cells' proliferation [52], and induce excessive growth in hydroponically grown plants [53]. BRs also regulate the abiotic and biotic stress responses and stomata development [7,34,54]. Moreover, BR plays a vital role in regulating male and female fertility in crops [55,56].…”

Impact of Drought Exerted during Spike Development on Tillering, Yield Parameters and Grain Chemical Composition in Semi-Dwarf Barley Mutants Deficient in the Brassinosteroid Metabolism

“…An overall increase in the BR content frequently results in larger lamina joints and increased plant height which result in decreased lodging resistance and planting density [42]. These negative side-effects may preclude utility of exogenous BR application for agricultural production [38,43]. Interestingly, the biomass and grain yield in the semi-dwarf rice dwarf4-1 mutant, defective in the BR biosynthesis, are…”

“…An overall increase in the BR content frequently results in larger lamina joints and increased plant height which result in decreased lodging resistance and planting density [42]. These negative side-effects may preclude utility of exogenous BR application for agricultural production [38,43]. Interestingly, the biomass and grain yield in the semi-dwarf rice dwarf4-1 mutant, defective in the BR biosynthesis, are increased compared with those in reference cultivar under the high-density planting conditions even without extra fertilizer, as the mutant shows erect leaves and normal reproductive development [24].…”

Low‐dose prestorage 24‐epibrassinolide spray enhances postharvest chilling tolerance in zucchini squash ( Cucurbita pepo L.) by eliciting peroxidase and phenolic antioxidants

“…Not surprisingly, early works focused on applying BRs to improve plant stress responses in the field (Nolan et al, 2020). Based on that, the manipulation of brassinosteroid metabolism has been suggested as a strategy to enhance crop yield (Lin, 2020). Studies in the last few years aimed at expanding brassinosteroid use for harvested products (Aghdam et al, 2016; Hussain et al, 2020).…”