Brassinosteroid

Last updated
Brassinolide, the first brassinosteroid isolated and shown to have biological activity 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]

Contents

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.[ citation needed ]

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. [11]

BRs have been reported to counteract both abiotic and biotic stress in plants. [12] [13] 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. [14]

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. [15] 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. [15] 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 ] 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. [15]

Signalling mechanism

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. 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). [16] 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. [16]

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. [17] [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. [17] The application of BR successfully alleviate drought stress and improve wheat growth under deficit irrigation system. [18] 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." [19] 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. [20]

Related Research Articles

<span class="mw-page-title-main">Hormone</span> Biological signalling molecule

A hormone is a class of signaling molecules in multicellular organisms that are sent to distant organs by complex biological processes to regulate physiology and behavior. Hormones are required for the correct development of animals, plants and fungi. Due to the broad definition of a hormone, numerous kinds of molecules can be classified as hormones. Among the substances that can be considered hormones, are eicosanoids, steroids, amino acid derivatives, protein or peptides, and gases.

<span class="mw-page-title-main">Calmodulin</span> Messenger protein

Calmodulin (CaM) (an abbreviation for calcium-modulated protein) is a multifunctional intermediate calcium-binding messenger protein expressed in all eukaryotic cells. It is an intracellular target of the secondary messenger Ca2+, and the binding of Ca2+ is required for the activation of calmodulin. Once bound to Ca2+, calmodulin acts as part of a calcium signal transduction pathway by modifying its interactions with various target proteins such as kinases or phosphatases.

<span class="mw-page-title-main">Acetyl-CoA</span> Chemical compound

Acetyl-CoA is a molecule that participates in many biochemical reactions in protein, carbohydrate and lipid metabolism. Its main function is to deliver the acetyl group to the citric acid cycle to be oxidized for energy production.

<span class="mw-page-title-main">Germination</span> Process by which an organism grows from a spore or seed

Germination is the process by which an organism grows from a seed or spore. The term is applied to the sprouting of a seedling from a seed of an angiosperm or gymnosperm, the growth of a sporeling from a spore, such as the spores of fungi, ferns, bacteria, and the growth of the pollen tube from the pollen grain of a seed plant.

<span class="mw-page-title-main">Plant hormone</span> Chemical compounds that regulate plant growth and development

Plant hormones are signal molecules, produced within plants, that occur in extremely low concentrations. Plant hormones control all aspects of plant growth and development, including embryogenesis, the regulation of organ size, pathogen defense, stress tolerance and reproductive development. Unlike in animals each plant cell is capable of producing hormones. Went and Thimann coined the term "phytohormone" and used it in the title of their 1937 book.

<span class="mw-page-title-main">1-Aminocyclopropane-1-carboxylic acid</span> Chemical compound

1-Aminocyclopropane-1-carboxylic acid (ACC) is a disubstituted cyclic α-amino acid in which a cyclopropane ring is fused to the Cα atom of the amino acid. It is a white solid. Many cyclopropane-substituted amino acids are known, but this one occurs naturally. Like glycine, but unlike most α-amino acids, ACC is not chiral.

Self-incompatibility (SI) is a general name for several genetic mechanisms that prevent self-fertilization in sexually reproducing organisms, and thus encourage outcrossing and allogamy. It is contrasted with separation of sexes among individuals (dioecy), and their various modes of spatial (herkogamy) and temporal (dichogamy) separation.

<span class="mw-page-title-main">Plant senescence</span> Process of aging in plants

Plant senescence is the process of aging in plants. Plants have both stress-induced and age-related developmental aging. Chlorophyll degradation during leaf senescence reveals the carotenoids, such as anthocyanin and xanthophylls, which are the cause of autumn leaf color in deciduous trees. Leaf senescence has the important function of recycling nutrients, mostly nitrogen, to growing and storage organs of the plant. Unlike animals, plants continually form new organs and older organs undergo a highly regulated senescence program to maximize nutrient export.

Shade avoidance is a set of responses that plants display when they are subjected to the shade of another plant. It often includes elongation, altered flowering time, increased apical dominance and altered partitioning of resources. This set of responses is collectively called the shade-avoidance syndrome (SAS).

A transgene is a gene that has been transferred naturally, or by any of a number of genetic engineering techniques, from one organism to another. The introduction of a transgene, in a process known as transgenesis, has the potential to change the phenotype of an organism. Transgene describes a segment of DNA containing a gene sequence that has been isolated from one organism and is introduced into a different organism. This non-native segment of DNA may either retain the ability to produce RNA or protein in the transgenic organism or alter the normal function of the transgenic organism's genetic code. In general, the DNA is incorporated into the organism's germ line. For example, in higher vertebrates this can be accomplished by injecting the foreign DNA into the nucleus of a fertilized ovum. This technique is routinely used to introduce human disease genes or other genes of interest into strains of laboratory mice to study the function or pathology involved with that particular gene.

<span class="mw-page-title-main">Systemin</span> Plant peptide hormone

Systemin is a plant peptide hormone involved in the wound response in the family Solanaceae. It was the first plant hormone that was proven to be a peptide having been isolated from tomato leaves in 1991 by a group led by Clarence A. Ryan. Since then, other peptides with similar functions have been identified in tomato and outside of the Solanaceae. Hydroxyproline-rich glycopeptides were found in tobacco in 2001 and AtPeps were found in Arabidopsis thaliana in 2006. Their precursors are found both in the cytoplasm and cell walls of plant cells, upon insect damage, the precursors are processed to produce one or more mature peptides. The receptor for systemin was first thought to be the same as the brassinolide receptor but this is now uncertain. The signal transduction processes that occur after the peptides bind are similar to the cytokine-mediated inflammatory immune response in animals. Early experiments showed that systemin travelled around the plant after insects had damaged the plant, activating systemic acquired resistance, now it is thought that it increases the production of jasmonic acid causing the same result. The main function of systemins is to coordinate defensive responses against insect herbivores but they also affect plant development. Systemin induces the production of protease inhibitors which protect against insect herbivores, other peptides activate defensins and modify root growth. They have also been shown to affect plants' responses to salt stress and UV radiation. AtPEPs have been shown to affect resistance against oomycetes and may allow A. thaliana to distinguish between different pathogens. In Nicotiana attenuata, some of the peptides have stopped being involved in defensive roles and instead affect flower morphology.

Leptosphaeria maculans is a fungal pathogen of the phylum Ascomycota that is the causal agent of blackleg disease on Brassica crops. Its genome has been sequenced, and L. maculans is a well-studied model phytopathogenic fungus. Symptoms of blackleg generally include basal stem cankers, small grey lesions on leaves, and root rot. The major yield loss is due to stem canker. The fungus is dispersed by the wind as ascospores or rain splash in the case of the conidia. L. maculans grows best in wet conditions and a temperature range of 5–20 degrees Celsius. Rotation of crops, removal of stubble, application of fungicide, and crop resistance are all used to manage blackleg. The fungus is an important pathogen of Brassica napus (canola) crops.

<span class="mw-page-title-main">Brassinolide</span> Chemical compound

Brassinolide is a plant hormone. The first isolated brassinosteroid, it was discovered when it was shown that pollen from rapeseed could promote stem elongation and cell division. The biologically active component was isolated and named brassinolide.

BRI1-associated receptor kinase 1 is an important plant protein that has diverse functions in plant development.

<span class="mw-page-title-main">24-Epibrassinolide</span> Chemical compound

24-Epibrassinolide is a type of brassinosteroid, a natural occurring plant hormone. It was first discovered 1979 as a growth promoting substance in rape pollen, and was subsequently discovered in many other plant organs. 24-Epibrassinolide is essential for proper plant development growth and development, is involved in the regulation of cell elongation and division, and has been shown to improve plant functions in salt- and nickel-stressed environments, as well as increasing enzyme activity. It is sold commercially as a white powder for use in plant culture.

<span class="mw-page-title-main">Joanne Chory</span> American plant biologist

Joanne Chory is an American plant biologist and geneticist. Chory is a professor and director of the Plant Molecular and Cellular Biology Laboratory, at the Salk Institute for Biological Studies and an investigator of the Howard Hughes Medical Institute.

Feronia, also known as FER or protein Sirene, is a recognition receptor kinase found in plants. FER plays a significant part in the plant immune system as a receptor kinase which assists in immune signaling within plants, plant growth, and plant reproduction. FER is regulated by the Rapid Alkalinization Factor (RALF). FER regulates growth in normal environments but it is most beneficial in stressful environments as it helps to initiate immune signaling. FER can also play a role in reproduction in plants by participating in the communication between the female and male cells. FER is found in and can be studied in the organism Arabidopsis thaliana.

<span class="mw-page-title-main">Brassinosteroid insensitive-1</span>

Brassinosteroid insensitive 1 (BRI1) is the major receptor of the plant hormone brassinosteroid. It plays very important roles in plant development, especially in the control of cell elongation and for the tolerance of environmental stresses. BRI1 enhances cell elongation, promotes pollen development, controls vasculature development and promotes chilling and freezing tolerance. BRI1 is one of the most well studied hormone receptors and it acts a model for the study of membrane-bound receptors in plants.

<i>Sweet potato leaf curl virus</i> Species of virus

Sweet potato leaf curl virus is commonly abbreviated SPLCV. Select isolates are referred to as SPLCV followed by an abbreviation of where they were isolated. For example, the Brazilian isolate is referred to as SPLCV-Br.

<span class="mw-page-title-main">Ethylene (plant hormone)</span> Alkene gas naturally regulating the plant growth

Ethylene (CH
2=CH
2) is an unsaturated hydrocarbon gas (alkene) acting as a naturally occurring plant hormone. It is the simplest alkene gas and is the first gas known to act as hormone. It acts at trace levels throughout the life of the plant by stimulating or regulating the ripening of fruit, the opening of flowers, the abscission (or shedding) of leaves and, in aquatic and semi-aquatic species, promoting the 'escape' from submergence by means of rapid elongation of stems or leaves. This escape response is particularly important in rice farming. Commercial fruit-ripening rooms use "catalytic generators" to make ethylene gas from a liquid supply of ethanol. Typically, a gassing level of 500 to 2,000 ppm is used, for 24 to 48 hours. Care must be taken to control carbon dioxide levels in ripening rooms when gassing, as high temperature ripening (20 °C; 68 °F) has been seen to produce CO2 levels of 10% in 24 hours.

References

  1. 1 2 3 4 Khripach, Vladimir; Zhabinskiia, Vladimir; de Groot, Aede (2000). "Twenty Years of Brassinosteroids: Steroidal Plant Hormones Warrant Better Crops for the XXI Century". Annals of Botany (86th ed.). 86 (3): 441–47. doi: 10.1006/anbo.2000.1227 . JSTOR   42766031. S2CID   49561922.
  2. 1 2 Mitchell JW, Mandava N, Worley JF, Plimmer JR, Smith MV (March 1970). "Brassins—a new family of plant hormones from rape pollen". Nature. 225 (5237): 1065–6. Bibcode:1970Natur.225.1065M. doi:10.1038/2251065a0. PMID   16056912. S2CID   4116426.
  3. ↑ Grove, Michael D.; Spencer, Gayland F.; Rohwedder, William K.; Mandava, Nagabhushanam; Worley, Joseph F.; Warthen, J. David; Steffens, George L.; Flippen-Anderson, Judith L.; Cook, J. Carter (1979). "Brassinolide, a plant growth-promoting steroid isolated from Brassica napus pollen". Nature. 281 (5728): 216–217. Bibcode:1979Natur.281..216G. doi:10.1038/281216a0. S2CID   4335601.
  4. ↑ Bajguz, A. (February 2007). "Metabolism of brassinosteroids in plants". Plant Physiology and Biochemistry. 45 (2): 95–107. doi:10.1016/j.plaphy.2007.01.002. PMID   17346983.
  5. ↑ Fujioka, S; Sakurai, A. (1997). "Biosynthesis and metabolism of brassinosteroids". Physiologia Plantarum. 100 (3): 710–15. doi:10.1111/j.1399-3054.1997.tb03078.x.
  6. 1 2 3 4 5 6 Clouse, SD; Sasse, JM. (June 1998). "Brassinosteroids: Essential Regulators of Plant Growth and Development". Annual Review of Plant Physiology and Plant Molecular Biology. 49: 427–451. doi:10.1146/annurev.arplant.49.1.427. PMID   15012241.
  7. ↑ Li, JM; Chory, J. (September 1997). "A putative leucine-rich repeat receptor kinase involved in brassinosteroid signal transduction". Cell. 90 (5): 929–38. doi: 10.1016/S0092-8674(00)80357-8 . PMID   9298904.
  8. ↑ Nemhauser, Jennifer L.; Mockler, Todd C.; Chory, Joanne (September 2004). "Interdependency of brassinosteroid and auxin signaling in Arabidopsis". PLOS Biology. 2 (9): E258. doi: 10.1371/journal.pbio.0020258 . PMC   509407 . PMID   15328536.
  9. ↑ Caño-Delgado, A; Yin, Y; Yu, C; Vafeados, D; Mora-Garcia, S; Cheng, JC; Nam, KH; Li, J; Chory, J (November 2004). "BRL1 and BRL3 are novel brassinosteroid receptors that function in vascular differentiation in Arabidopsis". Development. 131 (21): 5341–51. doi: 10.1242/dev.01403 . hdl: 11336/43673 . PMID   15486337.
  10. ↑ Hewitt, FR; Hough, T; O'Neill, P; Sasse, JM; Williams, EG; Rowan, KS (1985). "Effect of brassinolide and other growth regulators on the germination and growth of pollen tubes of "Prunus avium" using a multiple hanging drop assay". Aust. J. Plant Physiol. 12 (2): 201–11. doi:10.1071/PP9850201.
  11. ↑ Sondhi, N.; Bhardwaj, R.; Kaur, S.; Singh, B.; Kumar, N. (2008). "Isolation of 24-epibrassinolide from leaves of "Aegle marmelos" and evaluation of its antigenotoxicity potential employing Allium cepa chromosomal aberration assay". Plant Growth Regul. 54 (3): 217–224. doi:10.1007/s10725-007-9242-7. S2CID   34251037.
  12. ↑ Sharma, P.; Bhardwaj, R. (2007). "Effects of 24-Epibrassinolide on growth and metal uptake in "Brassica juncea" L. under copper metal stress". Acta Physiologiae Plantarum. 29 (3): 259–263. doi:10.1007/s11738-007-0032-7. S2CID   20183878.
  13. ↑ Sharma, P; Bhardwaj, R; Arora, HK; Arora, N; Kumar, A. (2008). "Effects of 28-homobrassinolide on nickel uptake, protein content and antioxidative defence system in "Brassica juncea". Biol. Plant. 52 (4): 767–770. doi:10.1007/s10535-008-0149-6. S2CID   33850414.
  14. ↑ Xiao Jian, Xia; Zhang, Y; Wu, JX; Wang, JT; Zhou, YH; Shi, K; Yu, YL; Yu, JQ (September 2009). "Brassinosteroids promote metabolism of pesticides in cucumber". Journal of Agricultural and Food Chemistry. 57 (18): 8406–13. doi:10.1021/jf901915a. PMID   19694443.
  15. 1 2 3 Anuradha, S; S Seeta Ram Rao (May 2003). "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". Plant Growth Regulation. 40 (1): 29–32. doi:10.1023/A:1023080720374. S2CID   34266295.
  16. 1 2 Belkhadir, Youssef; Jaillais, Yvon (April 2015). "The molecular circuitry of brassinosteroid signaling". The New Phytologist. 206 (2): 522–540. doi: 10.1111/nph.13269 . ISSN   1469-8137. PMID   25615890.
  17. 1 2 Kang YY, Guo SR (2011). "Role of brassinosteroids on horticultural crops". In Hayat S, Ahmad A (eds.). Brassinosteroids: A Class of Plant Hormone . Dordrecht, Netherlands: Springer. pp. 269–288. doi:10.1007/978-94-007-0189-2_9. ISBN   978-94-007-0189-2.
  18. ↑ Lalarukh, Irfana; Amjad, S.F.; Mansoora, N. (2022). "Integral effects of brassinosteroids and timber waste biochar enhances the drought tolerance capacity of wheat plant". Scientific Reports. 12 (1): 12842. Bibcode:2022NatSR..1212842L. doi: 10.1038/s41598-022-16866-0 . PMC   9329315 . PMID   35896783. S2CID   245162092.
  19. ↑ Kim, Seong-Ki; Abe, Hiroshi; Little, C. H. Anthony; Pharis, Richard P. (December 1990). "Identification of Two Brassinosteroids from the Cambial Region of Scots Pine (Pinus silverstris) by Gas Chromatography-Mass Spectrometry, after Detection Using a Dwarf Rice Lamina Inclination Bioassay". Plant Physiology. 94 (4): 1709–13. doi:10.1104/pp.94.4.1709. PMC   1077442 . PMID   16667906.
  20. ↑ Tossi, Vanesa E.; Acebedo, Sofía L.; Cassia, Raúl O.; Lamattina, Lorenzo; Galagovsky, Lydia R.; Ramírez, Javier A. (October 2015). "A bioassay for brassinosteroid activity based on the in vitro fluorimetric detection of nitric oxide production". Steroids. 102: 46–52. doi:10.1016/j.steroids.2015.07.003. hdl: 11336/13281 . PMID   26209812. S2CID   43227975.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.