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Brassinosteroids are a group of plant hormones that play important roles in various physiological processes such as cell elongation, division, and differentiati...
Brassinosteroids are a group of plant hormones that play important roles in various physiological processes such as cell elongation, division, and differentiation. They are known to be involved in the regulation of plant growth, development, and stress responses. Brassinosteroids also help plants to cope with various environmental stresses such as drought, salinity, and extreme temperatures. They are chemically similar to animal steroid hormones and are believed to have potential applications in agriculture for improving crop yield and stress tolerance.
Brassinosteroids are classified as a type of steroidal phytohormone, and they are structurally similar to the class of hormones found in animals. They were first discovered in pollen of rapeseed plants, and since then, they have been found to be present in a wide range of plant species.
These plant hormones have been found to have a multitude of effects on plant growth and development. They are known to promote cell elongation, regulate vascular differentiation, and stimulate the division of cells in the roots. Additionally, they have been found to be involved in the regulation of various stress responses, such as drought and salt stress.
In agriculture, there is increasing interest in using brassinosteroids to improve crop yield and stress tolerance. They have been found to promote the growth of various crops and help them withstand environmental stresses, which could be beneficial for increasing agricultural productivity. However, further research is needed to fully understand their potential application in agriculture.
Có một số ứng dụng tiềm năng của brassinosteroids trong nông nghiệp. Ví dụ, sự ổn định của cây trồng dưới điều kiện thời tiết bất lợi, chống lại sâu bệnh và hạn chế hại của cỏ dại.
Ngoài ra, brassinosteroids có thể giúp cải thiện sự hấp thụ và sử dụng dinh dưỡng của cây trồng, góp phần tăng cường sản lượng cây trồng. Hơn nữa, chúng cũng có khả năng giúp thúc đẩy quá trình mầm non và phục hồi cây trồng sau khi bị tổn thương.
Tuy nhiên, việc ứng dụng brassinosteroids trong nông nghiệp cần được nghiên cứu kỹ lưỡng để đảm bảo tính hiệu quả và an toàn, cũng như tối ưu hóa công nghệ áp dụng.
BZR1 Is a Transcriptional Repressor with Dual Roles in Brassinosteroid Homeostasis and Growth Responses American Association for the Advancement of Science (AAAS) - Tập 307 Số 5715 - Trang 1634-1638 - 2005
Brassinosteroid (BR) homeostasis and signaling are crucial for normal growth and development of plants. BR signaling through cell-surface receptor kinases and intracellular components leads to dephosphorylation and accumulation of the nuclear protein BZR1. How BR signaling regulates gene expression, however, remains unknown. Here we show that BZR1 is a transcriptional repressor that has a previously unknown DNA binding domain and binds directly to the promoters of feedback-regulated BR biosynthetic genes. Microarray analyses identified additional potential targets of BZR1 and illustrated, together with physiological studies, that BZR1 coordinates BR homeostasis and signaling by playing dual roles in regulating BR biosynthesis and downstream growth responses.
Biosynthesis and Metabolism of Brassinosteroids Annual Review of Plant Biology - Tập 54 Số 1 - Trang 137-164 - 2003
Brassinosteroids (BRs) are steroid hormones that regulate the growth and development of plants. Detailed study of the biosynthesis of brassinolide, a C28BR, revealed that two parallel routes, the early and late C-6 oxidation pathways, are connected at multiple steps and also are linked to the early C-22 oxidation pathway. Thus, BR biosynthetic pathways are highly networked. Furthermore, the biosynthesis of C27BRs was shown to proceed in a similar way to that of C28BRs. Information on enzymes and genes involved in the BR biosynthesis, as well as their regulation, has been obtained using BR-deficient and BR-insensitive mutants. In addition, the biosynthesis of sterols, which were recently recognized not only as precursors of BRs and membrane constituents, but also as modulators of plant development, is discussed. Various metabolic reactions of BRs including epimerization, oxidation, and conjugation are also summarized.
Brassinosteroid functions in a broad range of disease resistance in tobacco and rice Plant Journal - Tập 33 Số 5 - Trang 887-898 - 2003
SummaryBrassinolide (BL), considered to be the most important brassinosteroid (BR) and playing pivotal roles in the hormonal regulation of plant growth and development, was found to induce disease resistance in plants. To study the potentialities of BL activity on stress responding systems, we analyzed its ability to induce disease resistance in tobacco and rice plants. Wild‐type tobacco treated with BL exhibited enhanced resistance to the viral pathogen tobacco mosaic virus (TMV), the bacterial pathogen Pseudomonas syringae pv. tabaci (Pst), and the fungal pathogen Oidium sp. The measurement of salicylic acid (SA) in wild‐type plants treated with BL and the pathogen infection assays using NahG transgenic plants indicate that BL‐induced resistance does not require SA biosynthesis. BL treatment did not induce either acidic or basic pathogenesis‐related (PR) gene expression, suggesting that BL‐induced resistance is distinct from systemic acquired resistance (SAR) and wound‐inducible disease resistance. Analysis using brassinazole 2001, a specific inhibitor for BR biosynthesis, and the measurement of BRs in TMV‐infected tobacco leaves indicate that steroid hormone‐mediated disease resistance (BDR) plays part in defense response in tobacco. Simultaneous activation of SAR and BDR by SAR inducers and BL, respectively, exhibited additive protective effects against TMV and Pst, indicating that there is no cross‐talk between SAR‐ and BDR‐signaling pathway downstream of BL. In addition to the enhanced resistance to a broad range of diseases in tobacco, BL induced resistance in rice to rice blast and bacterial blight diseases caused by Magnaporthe grisea and Xanthomonas oryzae pv. oryzae, respectively. Our data suggest that BDR functions in the innate immunity system of higher plants including dicotyledonous and monocotyledonous species.
Brassinosteroids Regulate Dissociation of BKI1, a Negative Regulator of BRI1 Signaling, from the Plasma Membrane American Association for the Advancement of Science (AAAS) - Tập 313 Số 5790 - Trang 1118-1122 - 2006
Brassinosteroids, the steroid hormones of plants, are perceived at the plasma membrane by a leucine-rich repeat receptor serine/threonine kinase called BRI1. We report a BRI1-interacting protein, BKI1, which is a negative regulator of brassinosteroid signaling. Brassinosteroids cause the rapid dissociation of BKI1–yellow fluorescent protein from the plasma membrane in a process that is dependent on BRI1-kinase. BKI1 is a substrate of BRI1 kinase and limits the interaction of BRI1 with its proposed coreceptor, BAK1, suggesting that BKI1 prevents the activation of BRI1.
Perception of Brassinosteroids by the Extracellular Domain of the Receptor Kinase BRI1 American Association for the Advancement of Science (AAAS) - Tập 288 Số 5475 - Trang 2360-2363 - 2000
An assay was developed to study plant receptor kinase activation and signaling mechanisms. The extracellular leucine-rich repeat (LRR) and transmembrane domains of the
Arabidopsis
receptor kinase BRI1, which is implicated in brassinosteroid signaling, were fused to the serine/threonine kinase domain of XA21, the rice disease resistance receptor. The chimeric receptor initiates plant defense responses in rice cells upon treatment with brassinosteroids. These results, which indicate that the extracellular domain of BRI1 perceives brassinosteroids, suggest a general signaling mechanism for the LRR receptor kinases of plants. This system should allow the discovery of ligands for the LRR kinases, the largest group of plant receptor kinases.
