Chapter

Physiological effects related to brassinosteroid application in plants

DOI: 10.1007/978-94-007-0189-2_7

ABSTRACT Brassinosteroids are plant hormones whose functions have been discovered in the past years. In order to confirm scientifically
the biological effects caused exclusively by these compounds, different tools can be used, such as BRdeficient or BR-perceptive
mutants, molecular studies, biological assays, application of brassinosteroid biosynthesis inhibitors, endogenous quantification
and exogenous application. This work aims at relating the physiological effects in plants when exposed to different dosages
and analogues of brassinosteroids during different phases of development (germination, flowering, fructification) and when
submitted to biotic and abiotic stress (pathogens, water stress, saline stress, hypoxia, temperature, heavy metals and pesticides)
as well as the particularities related to tropisms, circadian rhythms and interactions with other plant hormones. The use
of brassinosteroids with the objective of increasing crop yield in the field and to improve the quality of the seedlings has
also received attention in recent papers. The main objective of this chapter is to discuss the physiological effects that
occur in cells, tissue or whole plants when submitted to brassinosteroid applications, taking into account the possible mechanism
of action of these compounds and their practical use in agriculture, describing the analogues and the dosages used in field
and laboratory experiments during the last 10 years.

Key wordsbrassinosteroid concentration-brassinosteroid analogue-germination-flowering-plant tissue culture-plant stress

3 Bookmarks
 · 
398 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Brassinosteroids (BRs) are steroidal hormones that play pivotal roles during plant development. In addition to the characterization of BR deficient mutants, specific BR biosynthesis inhibitors played an essential role in the elucidation of BR function in plants. However, high costs and limited availability of common BR biosynthetic inhibitors constrain their key advantage as a species-independent tool to investigate BR function. We studied propiconazole (Pcz) as an alternative to the BR inhibitor brassinazole (Brz). Arabidopsis seedlings treated with Pcz phenocopied BR biosynthetic mutants. The steady state mRNA levels of BR, but not gibberellic acid (GA), regulated genes increased proportional to the concentrations of Pcz. Moreover, root inhibition and Pcz-induced expression of BR biosynthetic genes were rescued by 24epi-brassinolide, but not by GA(3) co-applications. Maize seedlings treated with Pcz showed impaired mesocotyl, coleoptile, and true leaf elongation. Interestingly, the genetic background strongly impacted the tissue specific sensitivity towards Pcz. Based on these findings we conclude that Pcz is a potent and specific inhibitor of BR biosynthesis and an alternative to Brz. The reduced cost and increased availability of Pcz, compared to Brz, opens new possibilities to study BR function in larger crop species.
    PLoS ONE 01/2012; 7(5):e36625. · 3.73 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Plant sterols and steroid hormones, the brassinosteroids (BRs), are compounds that exert a wide range of biological activities. They are essential for plant growth, reproduction, and responses to various abiotic and biotic stresses. Given the importance of sterols and BRs in these processes, engineering their biosynthetic and signaling pathways offers exciting potentials for enhancing crop yield. In this review, we focus on how alterations in components of sterol and BR metabolism and signaling or application of exogenous steroids and steroid inhibitors affect traits of agronomic importance. We also discuss areas for future research and identify the fine-tuning modulation of endogenous BR content as a promising strategy for crop improvement.
    The Plant Cell 03/2012; 24(3):842-57. · 9.25 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Global climate change and a growing population require tackling the reduction in arable land and improving biomass production and seed yield per area under varying conditions. One of these conditions is suboptimal water availability. Here, we review some of the classical approaches to dealing with plant response to drought stress and we evaluate how research on RECEPTOR-LIKE KINASES (RLKs) can contribute to improving plant performance under drought stress. RLKs are considered as key regulators of plant architecture and growth behavior, but they also function in defense and stress responses. The available literature and analyses of available transcript profiling data indeed suggest that RLKs can play an important role in optimizing plant responses to drought stress. In addition, RLK pathways are ideal targets for nontransgenic approaches, such as synthetic molecules, providing a novel strategy to manipulate their activity and supporting translational studies from model species, such as Arabidopsis thaliana, to economically useful crops.
    The Plant Cell 06/2012; 24(6):2262-78. · 9.25 Impact Factor