DOI: 10.1007/978-94-007-0189-2_7 In book: Brassinosteroids: A Class of Plant Hormone, pp.193-242
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.
"RECEPTOR-LIKE KINASEs and Drought Stress 2267 PERSPECTIVE dwarf size of bri1 alleles is the result of impaired cell division and elongation in roots, shoots, and leaves (Gonzalez et al., 2010; González-García et al., 2011). Whereas many studies demonstrate a positive effect of BR application on plant tolerance to salt and drought stresses in several plant species (Krishna, 2003; Bajguz and Hayat, 2009; Gomes, 2011), only a few have evaluated the effects of altered endogenous BR content or signaling on tolerance to these stresses. In Arabidopsis, a single amino acid replacement in BRI1 that eliminates a Tyr autophosphorylation site, which negatively regulates BRI1 activity, strongly promotes shoot growth, together with increased Pro production that is normally associated with water stress (Oh et al., 2011). "
[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. DOI:10.1105/tpc.112.096677 · 9.34 Impact Factor
"In particular, it would be essential to investigate the specific action of the different compounds. Even when all the parameters mentioned above are considered, it appears that the responsiveness to BRs can vary significantly depending on plant species, developmental stage, organ/tissue, and environmental conditions (Gomes, 2011). This variability in the results, together with the high cost of synthetic BR analogs, has discouraged the use of exogenous BRs in agriculture and horticulture (Khripach et al., 2000). "
[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. DOI:10.1105/tpc.111.094912 · 9.34 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Salt stress is among the major abiotic stresses that adversely affect the global crop production and its adverse impacts are getting more serious in the regions where saline water is used for irrigation. It induces reactive oxygen species, alters the activity of antioxidant system and adversely affects the process of photosynthesis. Various strategies have been employed to mitigate the deleterious effects of salt stress. Presently, the recommended strategies to overcome the adverse effects of salt stress include the use of tolerant cultivars, ameliorative water management and diverse cultural practices. However, none of these approaches have been found to be fully effective under salt stress conditions. An alternative and technically simpler approach to induce salt stress tolerance is the exogenous application of plant growth regulators (PGRs). This technique has gained significant importance during the past decade. PGRs have been implicated to regulate a wide range of metabolic and physiological activities in plants, ranging from cell division and organogenesis to protection against biotic and abiotic stresses. One of the important factors for enhanced plant productivity by PGRs is their efficiency to overcome the salt-induced stress conditions. Recent findings on the effects of brassinosteroids and polyamines on the salt stress tolerance of crops open new avenues to address the salinity problems. This review enlightens the role of brassinosteroids and polyamines in different plant processes like their role in regulation of photosynthesis, antioxidant systems and other related aspects, thereby improving overall performance of plants.
Acta Physiologiae Plantarum 07/2013; 35(7). DOI:10.1007/s11738-013-1263-4 · 1.58 Impact Factor
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