Exogenous Application of Brassinosteroid 24-Norcholane 22(S)-23-Dihydroxy Type Analogs to Enhance Water Deficit Stress Tolerance in Arabidopsis thaliana

Abstract

Brassinosteroids (BRs) are plant hormones that play an essential role in plant development and have the ability to protect plants against various environmental stresses, such as low and high temperature, drought, heat, salinity, heavy metal toxicity, and pesticides. Mitigation of stress effects are produced through independent mechanisms or by interaction with other important phytohormones. However, there are few studies in which this property has been reported for BRs analogs. Thus, in this work, the enhancement of drought stress tolerance of A. thaliana was assessed for a series of 2-deoxybrassinosteroid analogs. In addition, the growth-promoting activity in the Rice Lamina Inclination Test (RLIT) was also evaluated. The results show that analog 1 exhibits similar growth activity as brassinolide (BL; used as positive control) in the RLIT bioassay. Interestingly, both compounds increase their activities by a factor of 1.2–1.5 when they are incorporated to polymer micelles formed by Pluronic F-127. On the other hand, tolerance to water deficit stress of Arabidopsis thaliana seedlings was evaluated by determining survival rate and dry weight of seedlings after the recovery period. In both cases, the effect of analog 1 is higher than that exhibited by BL. Additionally, the expression of a subset of drought stress marker genes was evaluated in presence and absence of exogenous applied BRs. Results obtained by qRT-PCR analysis, indicate that transcriptional changes of AtDREBD2A and AtNCED3 genes were more significant in A. thaliana treated with analog 1 in homogeneous solution than in that treated with BL. These changes suggest the activation of alternative pathway in response to water stress deficit. Thus, exogenous application of BRs synthetic analogs could be a potential tool for improvement of crop production under stress conditions.

Foliar brassinosteroid analogue (DI-31) sprays increase drought tolerance by improving plant growth and photosynthetic efficiency in lulo plants

“…For this reason, foliar BRs analogue (DI-31) sprays constitute a suitable crop management technique since this molecule can stimulate the production of growth-promoting hormones (auxins and gibberellins). The application of this analogue can also induce differentially expressed genes related to drought tolerance, enhancing physiological and biochemical responses under drought conditions (Jiroutova et al, 2018;Huang et al, 2020;Díaz et al, 2021). Foliar DI-31 applications increased the tolerance (low DQE and high RTI) of lulo plants and enhanced the physiological and biochemical responses of plants subjected to drought stress conditions.…”

Molecular Aspects of MicroRNAs and Phytohormonal Signaling in Response to Drought Stress: A Review

“…Brassinosteroids (BRs) belong to a novel group of steroidal plant hormones that play role in morphological and physiological changes of plant by altering their growth and development [ 90 , 91 ]. Plant BRs are synthesized in immature seeds, pollens, flowers and roots and play indirect role to modulate the drought by stimulating the H 2 O 2 level of plants [ 92 , 93 ].…”

“…BRs interact with other plant hormones, such as ABA, to reduce the severity of drought stress in tomato plants [ 91 ]. BR precursor’s 24-Epibrassinosteroid and 28-homobrassinolide include favorable modifications in Arabidopsis , brassica, purple mustard, and pepper ( Capsicum annuum ) plants’ photosynthetic antioxidant system during restricted water stress [ 90 , 96 ]. Overexpression of the Arabidopsis BR biosynthesis gene AtDWF4 in canola boosted growth, yield, and water stress tolerance, according to research [ 97 ].…”

“…[ 91 , 95 ]. The genes AtDREBD2A and AtNCED3 were elevated in Arabidopsis plants after exogenous BR treatment [ 90 ]. Various phytohormones that regulate drought responsive genes are listed in Table 1 .…”

A Brassinosteroids-BES1 Regulatory Module Manipulate Thermomemory in Arabidopsis thaliana

“…), improved functioning of PSII was observed under HS upon 24-epibrassinolide (EBR) application (Janeczko, Okleková, Pociecha, Kocielniak, & Mirek, 2011). In rice (Oryza sativa ), EBR or 7,8-dihydro-8-20-hydroxyecdysone (DHECD) application improves photosynthetic efficiency and raises the rice yield under HS (Diaz et al, 2021). In tomato, epi-brassinolide (EBL) induces thermotolerance and peroxidase (POD) activity (Mazorra, Holton, Bishop, & Nunez, 2011).…”