Brassinosteroid-Mediated Stress Responses

Abstract

Brassinosteroids (BRs) are a group of naturally occurring plant steroidal compounds with wide-ranging biological activity that offer the unique possibility of increasing crop yields through both changing plant metabolism and protecting plants from environmental stresses. In recent years, genetic and biochemical studies have established an essential role for BRs in plant development, and on this basis BRs have been given the stature of a phytohormone. A remarkable feature of BRs is their potential to increase resistance in plants to a wide spectrum of stresses, such as low and high temperatures, drought, high salt, and pathogen attack. Despite this, only a few studies aimed at understanding the mechanism by which BRs promote stress resistance have been undertaken. Studies of the BR signaling pathway and BR gene-regulating properties indicate that there is cross-talk between BRs and other hormones, including those with established roles in plant defense responses such as abscisic acid, jasmonic acid, and ethylene. Recent studies aimed at understanding how BRs modulate stress responses suggest that complex molecular changes underlie BR-induced stress tolerance in plants. Analyses of these changes should generate exciting results in the future and clarify whether the ability of BRs to increase plant resistance to a range of stresses lies in the complex interactions of BRs with other hormones. Future studies should also elucidate if BRI1, an essential component of the BR receptor, directly participates in stress response signaling through interactions with ligands and proteins involved in plant defense responses.

Effect of 24-epibrassinolide treatment on the metabolism of eggplant fruits in relation to development of pulp browning under chilling stress

“…Brassinosteroids (BRs), a group of naturally occurring plant hormones, exhibit unique biological effects on plant growth and development and resistance to biotic and abiotic stresses (Bajguz and Tretyn 2003;Kagale et al 2007;Bajguz and Hayat 2009;Krishna 2003). Recently, BRs have also attracted much attention in the preservation of postharvest horticultural products.…”

Signalling Cascades Involved in Induced Resistance

“…Cross-communication between these pathways provides a powerful regulatory potential that allows the plant to fine-tune its defence responses. Other plant hormones, such as abscisic acid (ABA), brassinosteroids and auxins have been reported to also play a role in induced defence against pathogens, but their significance is understood less well (Jameson, 2000;Audenaert et al, 2002a;Krishna, 2003;Nakashita et al, 2003;Thaler & Bostock, 2004;Ton & Mauch-Mani, 2004;Ton et al, 2005).…”

Effects of brassinosteroids on prosperity of Scots pine seedlings

“…Research studies dealing with brassinosteroids revealed that these hormones are able to elicit a broad spectrum of both positive and undesirable physiological and morphological responses in plants, including stem elongation, leaf bending and epinasty (Krishna 2003;Bajguz, Hayat 2009;Bajguz 2011), floral initiation, development of flowers and fruits (Hayat, Ahmad 2003), induction of ethylene biosynthesis and proton pump activation, synthesis of nucleic acids and proteins, regulation of carbohydrate assimilation and allocation and activation of photosynthesis (Bajguz, Hayat 2009;Bajguz 2011).…”

“…Brassinosteroids play a crucial role in plant development and can also promote the tolerance to a range of abiotic stresses, including salt and drought stress, temperature extremes and pathogen attacks (Clouse, Sasse 1998;Krishna 2003;Divi et al 2010). Although much has been learned about their role in plant development, the mechanisms by which BRs control plant stress responses and regulate stressresponsive gene expression are not fully explained (Divi et al 2010).…”

“…The effects of external brassinosteroid application are now studied and used particularly in agriculture (Vardhini, Rao 1997, 2003Annuradha, Rao 2001;Hradecká et al 2009;Divi et al 2010). The practical application of BRs is being done in Japan, where these hormones are used in large agricultural areas to improve the yield of crops such as wheat and rice (Brosa 1999).…”