Brassinosteroid: Difference between revisions

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I added two functions regarding root development and oxidative stress management. This is my first edit so feedback is welcome, I hope the references are acceptable.
 
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[[File:Brassinolide2.svg|thumb|[[Brassinolide]], the first brassinosteroid isolated and shown to have biological activity]]  
[[File:Brassinolide2.svg|thumb|[[Brassinolide]], the first brassinosteroid isolated and shown to have biological activity]]  
'''Brassinosteroids''' (BRs or less commonly BS)<ref name="Khripach, VLADIMIR 2000" /> are a class of polyhydroxysteroids that have been recognized as a sixth class of
'''Brassinosteroids''' (BRs or less commonly BS)<ref name="Khripach, VLADIMIR 2000" /> are a class of polyhydroxysteroids that have been recognized as a sixth class of
[[plant hormones]] and may have utility as anticancer drugs for treating endocrine-responsive cancers by inducing apoptosis of cancer cells and inhibiting cancerous growth. These brassinosteroids were first explored during the 1970s when Mitchell et al. reported promotion in stem elongation and cell division by the treatment of organic extracts of rapeseed (''[[Brassica napus]]'') pollen.<ref name="Mitchell-et-al-1970" /> [[Brassinolide]] was the first brassinosteroid to be isolated in 1979, when  pollen from ''[[Brassica napus]]'' was shown to promote stem elongation and cell divisions, and the biologically active molecule was isolated.<ref name="10.1038/281216a0">{{cite journal | title = Brassinolide, a plant growth-promoting steroid isolated from ''Brassica napus'' pollen | journal = Nature | volume = 281 | pages = 216–217 | year = 1979 | doi = 10.1038/281216a0 | last1 = Grove | first1 = Michael D. | last2 = Spencer | first2 = Gayland F. | last3 = Rohwedder | first3 = William K. | last4 = Mandava | first4 = Nagabhushanam | last5 = Worley | first5 = Joseph F. | last6 = Warthen | first6 = J. David | last7 = Steffens | first7 = George L. | last8 = Flippen-Anderson | first8 = Judith L. | last9 = Cook | first9 = J. Carter | issue=5728 | bibcode=1979Natur.281..216G | s2cid = 4335601 }}</ref><ref name="Mitchell-et-al-1970">{{cite journal | vauthors = Mitchell JW, Mandava N, Worley JF, Plimmer JR, Smith MV | title = Brassins{{emdash}}a new family of plant hormones from rape pollen | journal = Nature | volume = 225 | issue = 5237 | pages = 1065–6 | date = March 1970 | pmid = 16056912 | doi = 10.1038/2251065a0 | bibcode = 1970Natur.225.1065M | first8 = J.L. | first9 = J.C. | s2cid = 4116426 }}</ref> The yield of brassinosteroids from 230&nbsp;kg of ''Brassica napus'' pollen was only 10&nbsp;mg. Since their discovery, over 70 BR compounds have been isolated from plants.<ref>{{cite journal | last1 = Bajguz | first1 = A. | title = Metabolism of brassinosteroids in plants | journal = Plant Physiology and Biochemistry | volume = 45 | issue = 2 | pages = 95–107 | date = February 2007 | pmid = 17346983 | doi = 10.1016/j.plaphy.2007.01.002 }}</ref>
[[plant hormones]] and may have utility as anticancer drugs for treating endocrine-responsive cancers by inducing [[apoptosis]] of cancer cells and inhibiting cancerous growth. These brassinosteroids were first explored during the 1970s when Mitchell et al. reported promotion in stem elongation and cell division by the treatment of organic extracts of rapeseed (''[[Brassica napus]]'') pollen.<ref name="Mitchell-et-al-1970" /> [[Brassinolide]] was the first brassinosteroid to be isolated in 1979, when  pollen from ''[[Brassica napus]]'' was shown to promote stem elongation and cell divisions, and the biologically active molecule was isolated.<ref name="10.1038/281216a0">{{cite journal | title = Brassinolide, a plant growth-promoting steroid isolated from ''Brassica napus'' pollen | journal = Nature | volume = 281 | pages = 216–217 | year = 1979 | doi = 10.1038/281216a0 | last1 = Grove | first1 = Michael D. | last2 = Spencer | first2 = Gayland F. | last3 = Rohwedder | first3 = William K. | last4 = Mandava | first4 = Nagabhushanam | last5 = Worley | first5 = Joseph F. | last6 = Warthen | first6 = J. David | last7 = Steffens | first7 = George L. | last8 = Flippen-Anderson | first8 = Judith L. | last9 = Cook | first9 = J. Carter | issue=5728 | bibcode=1979Natur.281..216G | s2cid = 4335601 }}</ref><ref name="Mitchell-et-al-1970">{{cite journal | vauthors = Mitchell JW, Mandava N, Worley JF, Plimmer JR, Smith MV | title = Brassins{{emdash}}a new family of plant hormones from rape pollen | journal = Nature | volume = 225 | issue = 5237 | pages = 1065–6 | date = March 1970 | pmid = 16056912 | doi = 10.1038/2251065a0 | bibcode = 1970Natur.225.1065M | first8 = J.L. | first9 = J.C. | s2cid = 4116426 }}</ref> The yield of brassinosteroids from 230&nbsp;kg of ''Brassica napus'' pollen was only 10&nbsp;mg. Since their discovery, over 70 BR compounds have been isolated from plants.<ref>{{cite journal | last1 = Bajguz | first1 = A. | title = Metabolism of brassinosteroids in plants | journal = Plant Physiology and Biochemistry | volume = 45 | issue = 2 | pages = 95–107 | date = February 2007 | pmid = 17346983 | doi = 10.1016/j.plaphy.2007.01.002 }}</ref>


==Biosynthesis==
==Biosynthesis==


The BR is biosynthesised from [[campesterol]]. The biosynthetic pathway was elucidated  by Japanese researchers and later shown to be correct through the analysis of BR biosynthesis mutants in ''[[Arabidopsis thaliana]]'', tomatoes, and peas.<ref>{{cite journal | last1 = Fujioka | first1 = S | last2 = Sakurai | first2 = A. | year = 1997 | title = Biosynthesis and metabolism of brassinosteroids | journal = Physiologia Plantarum | volume = 100 | issue = 3| pages = 710–15 | doi = 10.1111/j.1399-3054.1997.tb03078.x }}</ref> The sites for BR synthesis in plants have not been experimentally demonstrated. One well-supported hypothesis is that all tissues produce BRs, since BR biosynthetic and signal transduction genes are expressed in a wide range of plant organs, and short distance activity of the hormones also supports this.<ref name ="Clouse">{{cite journal | last1 = Clouse | first1 = SD | last2 = Sasse | first2 = JM. | title = Brassinosteroids: Essential Regulators of Plant Growth and Development | journal = Annual Review of Plant Physiology and Plant Molecular Biology | volume = 49 | pages = 427–451 | date = June 1998 | pmid = 15012241 | doi = 10.1146/annurev.arplant.49.1.427 }}</ref><ref>{{cite journal | last1 = Li | first1 = JM | last2 = Chory | first2 = J. | title = A putative leucine-rich repeat receptor kinase involved in brassinosteroid signal transduction | journal = Cell | volume = 90 | issue = 5 | pages = 929–38 | date = September 1997 | pmid = 9298904 | doi = 10.1016/S0092-8674(00)80357-8 | doi-access = free }}</ref> Experiments have shown that long distance transport is possible and that the flow is from the base to the tips (acropetal), but it is not known if this movement is biologically relevant.<ref name ="Clouse"/>
The BR is biosynthesised from [[campesterol]]. The biosynthetic pathway was elucidated  by Japanese researchers and later shown to be correct through the analysis of BR biosynthesis mutants in ''[[Arabidopsis thaliana]]'', [[Tomato|tomatoes]], and [[Pea|peas]].<ref>{{cite journal | last1 = Fujioka | first1 = S | last2 = Sakurai | first2 = A. | year = 1997 | title = Biosynthesis and metabolism of brassinosteroids | journal = Physiologia Plantarum | volume = 100 | issue = 3| pages = 710–15 | doi = 10.1111/j.1399-3054.1997.tb03078.x }}</ref> The sites for BR synthesis in plants have not been experimentally demonstrated. One well-supported hypothesis is that all tissues produce BRs, since BR biosynthetic and signal transduction genes are expressed in a wide range of plant organs, and short distance activity of the hormones also supports this.<ref name ="Clouse">{{cite journal | last1 = Clouse | first1 = SD | last2 = Sasse | first2 = JM. | title = Brassinosteroids: Essential Regulators of Plant Growth and Development | journal = Annual Review of Plant Physiology and Plant Molecular Biology | volume = 49 | pages = 427–451 | date = June 1998 | pmid = 15012241 | doi = 10.1146/annurev.arplant.49.1.427 }}</ref><ref>{{cite journal | last1 = Li | first1 = JM | last2 = Chory | first2 = J. | title = A putative leucine-rich repeat receptor kinase involved in brassinosteroid signal transduction | journal = Cell | volume = 90 | issue = 5 | pages = 929–38 | date = September 1997 | pmid = 9298904 | doi = 10.1016/S0092-8674(00)80357-8 | doi-access = free }}</ref> Experiments have shown that long distance transport is possible and that the flow is from the base to the tips (acropetal), but it is not known if this movement is biologically relevant.<ref name ="Clouse"/>


==Functions==
==Functions==
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BRs have been shown to be involved in numerous plant processes:
BRs have been shown to be involved in numerous plant processes:
*Promotion of cell expansion and cell elongation;<ref name ="Clouse"/> work with [[auxin]]s to do so.<ref name = "plos">{{cite journal | last1 = Nemhauser | first1 = Jennifer L. | last2 = Mockler | first2 = Todd C. | last3 = Chory | first3 = Joanne | title = Interdependency of brassinosteroid and auxin signaling in Arabidopsis | journal = PLOS Biology | volume = 2 | issue = 9 | pages = E258 | date = September 2004 | pmid = 15328536 | pmc = 509407 | doi = 10.1371/journal.pbio.0020258 | doi-access = free }}</ref>
*Promotion of cell expansion and cell elongation;<ref name ="Clouse"/> work with [[auxin]]s to do so.<ref name = "plos">{{cite journal | last1 = Nemhauser | first1 = Jennifer L. | last2 = Mockler | first2 = Todd C. | last3 = Chory | first3 = Joanne | title = Interdependency of brassinosteroid and auxin signaling in Arabidopsis | journal = PLOS Biology | volume = 2 | issue = 9 | pages = E258 | date = September 2004 | pmid = 15328536 | pmc = 509407 | doi = 10.1371/journal.pbio.0020258 | doi-access = free }}</ref>
*Regulating different aspects of root development including root meristem size, and lateral root initiation and development.<ref> Wei, Z., & Li, J. (2016). Brassinosteroids regulate root growth, development, and symbiosis. Molecular plant, 9(1), 86-100. https://doi.org/10.1016/j.molp.2015.12.003</ref>
*It has an unclear role in cell division and cell wall regeneration.<ref name ="Clouse"/>
*It has an unclear role in cell division and cell wall regeneration.<ref name ="Clouse"/>
*Promotion of [[vascular bundle|vascular]] differentiation; BR [[signal transduction]] has been studied during vascular differentiation.<ref>{{cite journal | last1 = Caño-Delgado | first1 = A | last2 = Yin | first2 = Y | last3 = Yu | first3 = C | last4 = Vafeados | first4 = D | last5 = Mora-Garcia | first5 = S | last6 = Cheng | first6 = JC | last7 = Nam | first7 = KH | last8 = Li | first8 = J | last9 = Chory | first9 = J | title = BRL1 and BRL3 are novel brassinosteroid receptors that function in vascular differentiation in Arabidopsis | journal = Development | volume = 131 | issue = 21 | pages = 5341–51 | date = November 2004 | pmid = 15486337 | doi = 10.1242/dev.01403 | doi-access = free | hdl = 11336/43673 | hdl-access = free }}</ref>
*Promotion of [[vascular bundle|vascular]] differentiation; BR [[signal transduction]] has been studied during vascular differentiation.<ref>{{cite journal | last1 = Caño-Delgado | first1 = A | last2 = Yin | first2 = Y | last3 = Yu | first3 = C | last4 = Vafeados | first4 = D | last5 = Mora-Garcia | first5 = S | last6 = Cheng | first6 = JC | last7 = Nam | first7 = KH | last8 = Li | first8 = J | last9 = Chory | first9 = J | title = BRL1 and BRL3 are novel brassinosteroid receptors that function in vascular differentiation in Arabidopsis | journal = Development | volume = 131 | issue = 21 | pages = 5341–51 | date = November 2004 | pmid = 15486337 | doi = 10.1242/dev.01403 | doi-access = free | hdl = 11336/43673 | hdl-access = free }}</ref>
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*Acceleration of [[senescence]] in dying [[Tissue (biology)|tissue]] [[cell culture|cultured cells]]; delayed senescence in BR mutants supports that this action may be biologically relevant.<ref name ="Clouse"/>
*Acceleration of [[senescence]] in dying [[Tissue (biology)|tissue]] [[cell culture|cultured cells]]; delayed senescence in BR mutants supports that this action may be biologically relevant.<ref name ="Clouse"/>
*Can provide some protection to plants during chilling and drought stress.<ref name ="Clouse"/>
*Can provide some protection to plants during chilling and drought stress.<ref name ="Clouse"/>
*Promoting activity of [[reactive oxygen species]] (ROS) detoxifying enzymes such as [[superoxide dismutase]] (SOD) and [[catalase]] (CAT). These [[antioxidants]] reduce oxidative damage caused by ROS, which is essential for [[oxidative stress]] management in plants.<ref>Vardhini, B. V., & Anjum, N. A. (2015). Brassinosteroids make plant life easier under abiotic stresses mainly by modulating major components of antioxidant defense system. Frontiers in Environmental Science, 2, 67. https://doi.org/10.3389/fenvs.2014.00067</ref><ref>Talaat, N. B., & Shawky, B. T. (2012). 24-Epibrassinolide ameliorates the saline stress and improves the productivity of wheat (Triticum aestivum L.). Environmental and Experimental Botany, 82, 80-88. https://doi.org/10.1111/ppl.13237</ref><ref>Guerrero, Y.R., González, L.M., DellAmico, J., Núñez, M., Pieters, A.J. (2015). Reversion of deleterious effects of salt stress by activation of ROS detoxifying enzymes via foliar application of 24-epibrassinolide in rice seedlings. Theoretical and Experimental Plant Physiology 27, 31-40. https://doi.org/10.1007/s40626-014-0029-8</ref>


Extract from the plant ''Lychnis viscaria'' contains a relatively high amount of Brassinosteroids. ''[[Lychnis viscaria]]'' increases the disease resistance of surrounding plants.{{citation needed|date=April 2014}}
Extract from the plant ''Lychnis viscaria'' contains a relatively high amount of Brassinosteroids. ''[[Lychnis viscaria]]'' increases the disease resistance of surrounding plants.{{citation needed|date=April 2014}}


[[24-Epibrassinolide]] (EBL), a brassinosteroid isolated from ''[[Aegle marmelos]]'' Correa (Rutaceae), was further evaluated for the antigenotoxicity against [[maleic hydrazide]] (MH)-induced [[genotoxicity]] in ''[[Allium cepa]]'' chromosomal aberration assay. It was shown that the percentage of chromosomal aberrations induced by maleic hydrazide (0.01%) declined significantly with 24-epibrassinolide treatment.<ref>{{cite journal | last1 = Sondhi | first1 = N. | last2 = Bhardwaj | first2 = R. | last3 = Kaur | first3 = S. | last4 = Singh | first4 = B. | last5 = Kumar | first5 = N. | year = 2008 | title = Isolation of 24-epibrassinolide from leaves of "Aegle marmelos" and evaluation of its antigenotoxicity potential employing ''Allium cepa'' chromosomal aberration assay | journal = Plant Growth Regul | volume = 54 | issue = 3| pages = 217–224 | doi = 10.1007/s10725-007-9242-7 | s2cid = 34251037 }}</ref>
[[24-Epibrassinolide]] (EBL), a brassinosteroid isolated from ''[[Aegle marmelos]]'' Correa (Rutaceae), was further evaluated for the antigenotoxicity against [[maleic hydrazide]] (MH)-induced [[genotoxicity]] in ''[[Allium cepa]]'' chromosomal aberration assay. It was shown that the percentage of chromosomal aberrations induced by maleic hydrazide (0.01%) declined significantly with 24-epibrassinolide treatment.<ref>{{cite journal | last1 = Sondhi | first1 = N. | last2 = Bhardwaj | first2 = R. | last3 = Kaur | first3 = S. | last4 = Singh | first4 = B. | last5 = Kumar | first5 = N. | year = 2008 | title = Isolation of 24-epibrassinolide from leaves of "Aegle marmelos" and evaluation of its antigenotoxicity potential employing ''Allium cepa'' chromosomal aberration assay | journal = Plant Growth Regul | volume = 54 | issue = 3| pages = 217–224 | doi = 10.1007/s10725-007-9242-7 | s2cid = 34251037 }}</ref>


BRs have been reported to counteract both abiotic and biotic stress in plants.<ref>{{cite journal | last1 = Sharma | first1 = P. | last2 = Bhardwaj | first2 = R. | year = 2007 | title = Effects of 24-Epibrassinolide on growth and metal uptake in "Brassica juncea" L. under copper metal stress | journal = Acta Physiologiae Plantarum | volume = 29 | issue = 3| pages = 259–263 | doi = 10.1007/s11738-007-0032-7 | s2cid = 20183878 }}</ref><ref>{{cite journal | last1 = Sharma | first1 = P | last2 = Bhardwaj | first2 = R | last3 = Arora | first3 = HK | last4 = Arora | first4 = N | last5 = Kumar | first5 = A. | year = 2008 | title = Effects of 28-homobrassinolide on nickel uptake, protein content and antioxidative defence system in "Brassica juncea | journal = Biol. Plant. | volume = 52 | issue = 4| pages = 767–770 | doi = 10.1007/s10535-008-0149-6 | s2cid = 33850414 | doi-access = free }}</ref>  Application of brassinosteroids to cucumbers was demonstrated to increase the [[metabolism]] and removal of pesticides, which could be beneficial for reducing the human ingestion of residual pesticides from non-organically grown vegetables.<ref>{{cite journal | last1 = Xiao Jian | first1 = Xia | last2 = Zhang | first2 = Y | last3 = Wu | first3 = JX | last4 = Wang | first4 = JT | last5 = Zhou | first5 = YH | last6 = Shi | first6 = K | last7 = Yu | first7 = YL | last8 = Yu | first8 = JQ | title = Brassinosteroids promote metabolism of pesticides in cucumber | journal = Journal of Agricultural and Food Chemistry | volume = 57 | issue = 18 | pages = 8406–13 | date = September 2009 | pmid = 19694443 | doi = 10.1021/jf901915a }}</ref>
BRs have been reported to counteract both abiotic and biotic stress in plants.<ref>{{cite journal | last1 = Sharma | first1 = P. | last2 = Bhardwaj | first2 = R. | year = 2007 | title = Effects of 24-Epibrassinolide on growth and metal uptake in "Brassica juncea" L. under copper metal stress | journal = Acta Physiologiae Plantarum | volume = 29 | issue = 3| pages = 259–263 | doi = 10.1007/s11738-007-0032-7 | s2cid = 20183878 }}</ref><ref>{{cite journal | last1 = Sharma | first1 = P | last2 = Bhardwaj | first2 = R | last3 = Arora | first3 = HK | last4 = Arora | first4 = N | last5 = Kumar | first5 = A. | year = 2008 | title = Effects of 28-homobrassinolide on nickel uptake, protein content and antioxidative defence system in "Brassica juncea | journal = Biol. Plant. | volume = 52 | issue = 4| pages = 767–770 | doi = 10.1007/s10535-008-0149-6 | s2cid = 33850414 | doi-access = free }}</ref>  Application of brassinosteroids to [[Cucumber|cucumbers]] was demonstrated to increase the [[metabolism]] and removal of pesticides, which could be beneficial for reducing the human ingestion of residual pesticides from non-organically grown vegetables.<ref>{{cite journal | last1 = Xiao Jian | first1 = Xia | last2 = Zhang | first2 = Y | last3 = Wu | first3 = JX | last4 = Wang | first4 = JT | last5 = Zhou | first5 = YH | last6 = Shi | first6 = K | last7 = Yu | first7 = YL | last8 = Yu | first8 = JQ | title = Brassinosteroids promote metabolism of pesticides in cucumber | journal = Journal of Agricultural and Food Chemistry | volume = 57 | issue = 18 | pages = 8406–13 | date = September 2009 | pmid = 19694443 | doi = 10.1021/jf901915a }}</ref>


BRs have also been reported to have a variety of effects when applied to rice seeds (Oryza sativa L.). Seeds treated with BRs were shown to reduce the growth inhibitory effect of salt stress.<ref name="Anuradha, S 2003">{{cite journal |author1=Anuradha, S |author2=S Seeta Ram Rao | title = Application of brassinosteroids to rice seeds (Oryza sativa L.) reduced the impact of salt stress on growth, prevented photosynthetic pigment loss and increased nitrate reductase activity. | volume = 40 | issue = 1 | pages = 29–32 | journal = Plant Growth Regulation | date = May 2003 | doi = 10.1023/A:1023080720374 | s2cid = 34266295 }}</ref> When the developed plants fresh weight was analyzed the treated seeds outperformed plants grown on saline and non-saline medium however when the dry weight was analyzed BR treated seeds only outperformed untreated plants that were grown on saline medium.<ref name="Anuradha, S 2003"/> When dealing with tomatoes (''Lycopersicon esculentum'') under salt stress the concentration of chlorophyll a and chlorophyll b were decreased and thus pigmentation was decreased as well.{{citation needed|date=November 2019}} BR treated rice seeds considerably restored the pigment level in plants that were grown on saline medium when compared to non-treated plants under the same conditions.<ref name="Anuradha, S 2003"/>
BRs have also been reported to have a variety of effects when applied to rice seeds ([[Oryza sativa|Oryza sativa L]].). Seeds treated with BRs were shown to reduce the growth inhibitory effect of salt stress.<ref name="Anuradha, S 2003">{{cite journal |author1=Anuradha, S |author2=S Seeta Ram Rao | title = Application of brassinosteroids to rice seeds (Oryza sativa L.) reduced the impact of salt stress on growth, prevented photosynthetic pigment loss and increased nitrate reductase activity. | volume = 40 | issue = 1 | pages = 29–32 | journal = Plant Growth Regulation | date = May 2003 | doi = 10.1023/A:1023080720374 | s2cid = 34266295 }}</ref> When the developed plants fresh weight was analyzed the treated seeds outperformed plants grown on saline and non-saline medium however when the dry weight was analyzed BR treated seeds only outperformed untreated plants that were grown on saline medium.<ref name="Anuradha, S 2003"/> When dealing with tomatoes (''Lycopersicon esculentum'') under salt stress the concentration of [[chlorophyll a]] and chlorophyll b were decreased and thus pigmentation was decreased as well.{{citation needed|date=November 2019}} BR treated rice seeds considerably restored the pigment level in plants that were grown on saline medium when compared to non-treated plants under the same conditions.<ref name="Anuradha, S 2003"/>


== Signalling mechanism ==
== Signalling mechanism ==
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==Agricultural uses==
==Agricultural uses==


BR might reveal to have a prominent interest in the role of horticultural crops. Based on extensive research BR has the ability to improve the quantity and quality of horticultural crops and protect plants against many stresses that can be present in the local environment.<ref name="ReferenceA">{{cite book | vauthors = Kang YY, Guo SR | veditors = Hayat S, Ahmad A | chapter = Role of brassinosteroids on horticultural crops | title = Brassinosteroids: A Class of Plant Hormone  | url = https://archive.org/details/brassinosteroids00haya_168 | url-access = limited | pages = 269–288 | isbn = 978-94-007-0189-2 | doi = 10.1007/978-94-007-0189-2_9 | publisher = Springer | location = Dordrecht, Netherlands | year = 2011 }}</ref><ref name="Khripach, VLADIMIR 2000">{{cite journal | first1=Vladimir | last1=Khripach | first2=Vladimir | last2=Zhabinskiia | first3=Aede | last3=de Groot | title = Twenty Years of Brassinosteroids: Steroidal Plant Hormones Warrant Better Crops for the XXI Century | edition = 86th | journal = Annals of Botany | volume = 86 | issue = 3 | date = 2000 | pages = 441–47 | doi = 10.1006/anbo.2000.1227 | doi-access = free | s2cid=49561922 | jstor=42766031}}</ref> With the many advances in technology dealing with the synthesis of more stable synthetic analogues and the genetic manipulation of cellular BR activity, using BR in the production of horticultural crops has become a more practical and hopeful strategy for improving crop yields and success.<ref name="ReferenceA"/> The application of BR successfully alleviate drought stress and improve wheat growth under deficit irrigation system.<ref name="Lalarukh et al.">{{cite journal |last1=Lalarukh |first1=Irfana |last2=Amjad |first2=S.F. |last3=Mansoora |first3=N. |title=Integral effects of brassinosteroids and timber waste biochar enhances the drought tolerance capacity of wheat plant |journal=Scientific Reports |date=2022 |volume=12 |issue=1 |page=12842 |doi=10.1038/s41598-022-16866-0 |pmid=35896783 |pmc=9329315 |bibcode=2022NatSR..1212842L |s2cid=245162092 |doi-access=free }}</ref> It had further positive impacts on increasing plant growth parameters via their integral role in decreasing oxidative stress indicators.
BR might reveal to have a prominent interest in the role of horticultural crops. Based on extensive research BR has the ability to improve the quantity and quality of horticultural crops and protect plants against many stresses that can be present in the local environment.<ref name="ReferenceA">{{cite book | vauthors = Kang YY, Guo SR | veditors = Hayat S, Ahmad A | chapter = Role of brassinosteroids on horticultural crops | title = Brassinosteroids: A Class of Plant Hormone  | url = https://archive.org/details/brassinosteroids00haya_168 | url-access = limited | pages = 269–288 | isbn = 978-94-007-0189-2 | doi = 10.1007/978-94-007-0189-2_9 | publisher = Springer | location = Dordrecht, Netherlands | year = 2011 }}</ref><ref name="Khripach, VLADIMIR 2000">{{cite journal | first1=Vladimir | last1=Khripach | first2=Vladimir | last2=Zhabinskiia | first3=Aede | last3=de Groot | title = Twenty Years of Brassinosteroids: Steroidal Plant Hormones Warrant Better Crops for the XXI Century | edition = 86th | journal = Annals of Botany | volume = 86 | issue = 3 | date = 2000 | pages = 441–47 | doi = 10.1006/anbo.2000.1227 | doi-access = free | s2cid=49561922 | jstor=42766031}}</ref> With the many advances in technology dealing with the synthesis of more stable synthetic analogues and the genetic manipulation of cellular BR activity, using BR in the production of horticultural crops has become a more practical and hopeful strategy for improving crop yields and success.<ref name="ReferenceA"/> The application of BR successfully alleviate drought stress and improve wheat growth under deficit irrigation system.<ref name="Lalarukh et al.">{{cite journal |last1=Lalarukh |first1=Irfana |last2=Amjad |first2=S.F. |last3=Mansoora |first3=N. |title=Integral effects of brassinosteroids and timber waste biochar enhances the drought tolerance capacity of wheat plant |journal=Scientific Reports |date=2022 |volume=12 |issue=1 |page=12842 |doi=10.1038/s41598-022-16866-0 |pmid=35896783 |pmc=9329315 |bibcode=2022NatSR..1212842L |s2cid=245162092 |doi-access=free }}</ref> It had further positive impacts on increasing plant growth parameters via their integral role in decreasing [[oxidative stress]] indicators.


BR application has demonstrated efficacy against ''[[Phytophthora infestans]]'', [[mildew]] on [[cucumber]], [[plant virus|viral diseases]], and various others.<ref name="Khripach, VLADIMIR 2000"/>
BR application has demonstrated efficacy against ''[[Phytophthora infestans]]'', [[mildew]] on [[cucumber]], [[plant virus|viral diseases]], and various others.<ref name="Khripach, VLADIMIR 2000"/>

Latest revision as of 10:45, 3 December 2025

Template:Short description

File:Brassinolide2.svg
Brassinolide, the first brassinosteroid isolated and shown to have biological activity

Brassinosteroids (BRs or less commonly BS)[1] are a class of polyhydroxysteroids that have been recognized as a sixth class of plant hormones and may have utility as anticancer drugs for treating endocrine-responsive cancers by inducing apoptosis of cancer cells and inhibiting cancerous growth. These brassinosteroids were first explored during the 1970s when Mitchell et al. reported promotion in stem elongation and cell division by the treatment of organic extracts of rapeseed (Brassica napus) pollen.[2] Brassinolide was the first brassinosteroid to be isolated in 1979, when pollen from Brassica napus was shown to promote stem elongation and cell divisions, and the biologically active molecule was isolated.[3][2] The yield of brassinosteroids from 230 kg of Brassica napus pollen was only 10 mg. Since their discovery, over 70 BR compounds have been isolated from plants.[4]

Biosynthesis

The BR is biosynthesised from campesterol. The biosynthetic pathway was elucidated by Japanese researchers and later shown to be correct through the analysis of BR biosynthesis mutants in Arabidopsis thaliana, tomatoes, and peas.[5] The sites for BR synthesis in plants have not been experimentally demonstrated. One well-supported hypothesis is that all tissues produce BRs, since BR biosynthetic and signal transduction genes are expressed in a wide range of plant organs, and short distance activity of the hormones also supports this.[6][7] Experiments have shown that long distance transport is possible and that the flow is from the base to the tips (acropetal), but it is not known if this movement is biologically relevant.[6]

Functions

BRs have been shown to be involved in numerous plant processes:

Extract from the plant Lychnis viscaria contains a relatively high amount of Brassinosteroids. Lychnis viscaria increases the disease resistance of surrounding plants.Script error: No such module "Unsubst".

24-Epibrassinolide (EBL), a brassinosteroid isolated from Aegle marmelos Correa (Rutaceae), was further evaluated for the antigenotoxicity against maleic hydrazide (MH)-induced genotoxicity in Allium cepa chromosomal aberration assay. It was shown that the percentage of chromosomal aberrations induced by maleic hydrazide (0.01%) declined significantly with 24-epibrassinolide treatment.[15]

BRs have been reported to counteract both abiotic and biotic stress in plants.[16][17] Application of brassinosteroids to cucumbers was demonstrated to increase the metabolism and removal of pesticides, which could be beneficial for reducing the human ingestion of residual pesticides from non-organically grown vegetables.[18]

BRs have also been reported to have a variety of effects when applied to rice seeds (Oryza sativa L.). Seeds treated with BRs were shown to reduce the growth inhibitory effect of salt stress.[19] When the developed plants fresh weight was analyzed the treated seeds outperformed plants grown on saline and non-saline medium however when the dry weight was analyzed BR treated seeds only outperformed untreated plants that were grown on saline medium.[19] When dealing with tomatoes (Lycopersicon esculentum) under salt stress the concentration of chlorophyll a and chlorophyll b were decreased and thus pigmentation was decreased as well.Script error: No such module "Unsubst". BR treated rice seeds considerably restored the pigment level in plants that were grown on saline medium when compared to non-treated plants under the same conditions.[19]

Signalling mechanism

File:Brassinosteroid signal cascade.jpg
Brassinosteroid signal cascade: in the absence of BR, BKI1 blocks BRI1 activity and BIN2 inhibits transcription factors. When BR is present, BKI1 dissociates from BRI1 and the BRI1:BAK1 complex is formed. This complex promotes the inactivation of BIN2 and transcription factors can then exert their effects.

BRs are perceived at the cell membrane by a co-receptor complex, comprising brassinosteroid insensitive-1 (BRI1) and BRI1-associated receptor kinase 1 (BAK1).[20] BRI1 acts as a kinase, but in the absence of BR its action is inhibited by another protein, BRI1 kinase inhibitor 1 (BKI1). When BR binds to the BRI1:BAK1 complex, BKI1 is released, and a phosphorylation cascade is triggered which results in the de-activation of another kinase, brassinosteroid insensitive 2 (BIN2). BIN2 and its close homologues inhibit several transcription factors. The inhibition of BIN2 by BR releases these transcription factors to bind to DNA and to enact certain developmental pathways.[20]

Agricultural uses

BR might reveal to have a prominent interest in the role of horticultural crops. Based on extensive research BR has the ability to improve the quantity and quality of horticultural crops and protect plants against many stresses that can be present in the local environment.[21][1] With the many advances in technology dealing with the synthesis of more stable synthetic analogues and the genetic manipulation of cellular BR activity, using BR in the production of horticultural crops has become a more practical and hopeful strategy for improving crop yields and success.[21] The application of BR successfully alleviate drought stress and improve wheat growth under deficit irrigation system.[22] It had further positive impacts on increasing plant growth parameters via their integral role in decreasing oxidative stress indicators.

BR application has demonstrated efficacy against Phytophthora infestans, mildew on cucumber, viral diseases, and various others.[1]

BR could also help bridge the gap of the consumers' health concerns and the producers need for growth. A major benefit of using BR is that it does not interfere with the environment because they act in a natural way. Since it is a “plant strengthening substance” and it is natural, BR application would be more favorable than pesticides and does not contribute to the co-evolution of pests.[1]

In Germany, extract from the plant is allowed for use as a "plant strengthening substance."_authors=Udo_Roth,_Annette_Friebe,_Heide_Schnabl_|_title=Resistance_Induction_in_Plants_by_a_Brassinosteroid-Containing_Extract_of_''Lychnis_viscaria''_L._|_doi=10.1515/znc-2000-7-813_|_journal=[[Zeitschrift_für_Naturforschung_C]]|_year=2000_|_volume=55_|_issue=7–8_|_pages=552–559_|_s2cid=39948194_|_doi-access=free_}}_==Detection_and_chemical_analysis==_BRs_can_be_detected_by_[[Gas_chromatography–mass_spectrometry|gas_chromatography_mass_spectrometry]]_and_[[bioassay]]s.<ref-23|[23] There are some bioassays that can detect BRs in the plant such as the bean second internode elongation assay and the rice leaf lamina inclination test.[24]

References

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  1. ↑ a b c d Script error: No such module "Citation/CS1".
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  6. ↑ a b c d e f Script error: No such module "Citation/CS1".
  7. ↑ Script error: No such module "Citation/CS1".
  8. ↑ Script error: No such module "Citation/CS1".
  9. ↑ Wei, Z., & Li, J. (2016). Brassinosteroids regulate root growth, development, and symbiosis. Molecular plant, 9(1), 86-100. https://doi.org/10.1016/j.molp.2015.12.003
  10. ↑ Script error: No such module "Citation/CS1".
  11. ↑ Script error: No such module "Citation/CS1".
  12. ↑ Vardhini, B. V., & Anjum, N. A. (2015). Brassinosteroids make plant life easier under abiotic stresses mainly by modulating major components of antioxidant defense system. Frontiers in Environmental Science, 2, 67. https://doi.org/10.3389/fenvs.2014.00067
  13. ↑ Talaat, N. B., & Shawky, B. T. (2012). 24-Epibrassinolide ameliorates the saline stress and improves the productivity of wheat (Triticum aestivum L.). Environmental and Experimental Botany, 82, 80-88. https://doi.org/10.1111/ppl.13237
  14. ↑ Guerrero, Y.R., González, L.M., DellAmico, J., Núñez, M., Pieters, A.J. (2015). Reversion of deleterious effects of salt stress by activation of ROS detoxifying enzymes via foliar application of 24-epibrassinolide in rice seedlings. Theoretical and Experimental Plant Physiology 27, 31-40. https://doi.org/10.1007/s40626-014-0029-8
  15. ↑ Script error: No such module "Citation/CS1".
  16. ↑ Script error: No such module "Citation/CS1".
  17. ↑ Script error: No such module "Citation/CS1".
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  19. ↑ a b c Script error: No such module "Citation/CS1".
  20. ↑ a b Script error: No such module "Citation/CS1".
  21. ↑ a b Script error: No such module "citation/CS1".
  22. ↑ Script error: No such module "Citation/CS1".
  23. _authors=Udo_Roth,_Annette_Friebe,_Heide_Schnabl_|_title=Resistance_Induction_in_Plants_by_a_Brassinosteroid-Containing_Extract_of_''Lychnis_viscaria''_L._|_doi=10.1515/znc-2000-7-813_|_journal=[[Zeitschrift_für_Naturforschung_C]]|_year=2000_|_volume=55_|_issue=7–8_|_pages=552–559_|_s2cid=39948194_|_doi-access=free_}}_==Detection_and_chemical_analysis==_BRs_can_be_detected_by_[[Gas_chromatography–mass_spectrometry|gas_chromatography_mass_spectrometry]]_and_[[bioassay]]s.<ref_23-0|↑ Script error: No such module "Citation/CS1".
  24. ↑ Script error: No such module "Citation/CS1".

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External links

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