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Piotr Rozpądek, Agnieszka M Domka, Michał Nosek, Rafał Ważny, Roman J Jędrzejczyk, Monika Wiciarz, Katarzyna Turnau
Over the last years the role of fungal endophytes in plant biology has been extensively studied. A number of species were shown to positively affect plant growth and fitness, thus attempts have been made to utilize these microorganisms in agriculture and phytoremediation. Plant-fungi symbiosis requires multiple metabolic adjustments of both of the interacting organisms. The mechanisms of these adaptations are mostly unknown, however, plant hormones seem to play a central role in this process. The plant hormone strigolactone (SL) was previously shown to activate hyphae branching of mycorrhizal fungi and to negatively affect pathogenic fungi growth...
2018: Frontiers in Microbiology
Kaori Yoneyama, Narumi Mori, Tomoyasu Sato, Akiyoshi Yoda, Xiaonan Xie, Masanori Okamoto, Masashi Iwanaga, Toshiyuki Ohnishi, Hisashi Nishiwaki, Tadao Asami, Takao Yokota, Kohki Akiyama, Koichi Yoneyama, Takahito Nomura
Strigolactones (SLs) are a class of plant hormones which regulate shoot branching and function as host recognition signals for symbionts and parasites in the rhizosphere. However, steps in SL biosynthesis after carlactone (CL) formation remain elusive. This study elucidated the common and diverse functions of MAX1 homologs which catalyze CL oxidation. We have reported previously that ArabidopsisMAX1 converts CL to carlactonoic acid (CLA), whereas a rice MAX1 homolog has been shown to catalyze the conversion of CL to 4-deoxyorobanchol (4DO)...
June 2018: New Phytologist
Zsuzsanna Kolbert
Both strigolactones (SLs) and nitric oxide (NO) are regulatory signals with diverse roles during plant development and stress responses. This review aims to discuss the so far available data regarding SLs-NO interplay in plant systems. The majority of the few articles dealing with SL-NO interplay focuses on the root system and it seems that NO can be an upstream negative regulator of SL biosynthesis or an upstream positive regulator of SL signaling depending on the nutrient supply. From the so far published results it is clear that NO modifies the activity of target proteins involved in SL biosynthesis or signaling which may be a physiologically relevant interaction...
February 26, 2018: Physiologia Plantarum
Yaqing Zhang, Zunjian Zhang, Rui Song
BACKGROUND AND OBJECTIVES: Rhubarb-Radix scutellariae is a classic herb pair, which is commonly used to clear away heat and toxin in clinic. The aim of this study was to investigate the influence of compatibility of Rhubarb and Radix scutellariae on the pharmacokinetic behaviors of anthraquinones and flavonoids in rat plasma. METHODS: Eighteen rats were randomly divided into three groups, and were orally administered Rhubarb and/or Radix scutellariae extracts. A sensitive and rapid UPLC-MS/MS method was developed and validated to determine the concentrations of baicalin, baicalein, wogonside, wogonin, rhein, and emodin in rat plasma...
November 14, 2017: European Journal of Drug Metabolism and Pharmacokinetics
Ourania Lantzouni, Carina Klermund, Claus Schwechheimer
The phytohormones gibberellin (GA) and strigolactone (SL) are involved in essential processes in plant development. Both GA and SL signal transduction mechanisms employ α/β-hydrolase-derived receptors that confer E3 ubiquitin ligase-mediated protein degradation processes. This suggests a common evolutionary origin of these pathways and possibly a molecular interaction between them. One such indication stems from rice, where the DELLA protein of the GA pathway was reported to interact with the SL receptor...
October 4, 2017: Plant Journal: for Cell and Molecular Biology
Katelyn Nagy-Smith, Peter J Beltramo, Eric Moore, Robert Tycko, Eric M Furst, Joel P Schneider
Hydrogels prepared from self-assembling peptides are promising materials for medical applications, and using both l- and d-peptide isomers in a gel's formulation provides an intuitive way to control the proteolytic degradation of an implanted material. In the course of developing gels for delivery applications, we discovered that a racemic mixture of the mirror-image β-hairpin peptides, named MAX1 and DMAX1, provides a fibrillar hydrogel that is four times more rigid than gels formed by either peptide alone-a puzzling observation...
June 28, 2017: ACS Central Science
Kumi Otori, Masahiro Tamoi, Noriaki Tanabe, Shigeru Shigeoka
We previously demonstrated that transgenic tobacco plants expressing cyanobacterial fructose-1,6-/sedoheptulose-1,7-bisphosphatase in the cytosol increased the number of lateral shoots and leaves at elevated CO2 levels. These findings suggest that alterations in carbon partitioning affect the development of shoot branching. In order to elucidate the underlying mechanisms at the molecular level, we generated transgenic Arabidopsis plants overexpressing cyanobacterial fructose-1,6-bisphosphatase-II in the cytosol (AcF)...
August 2017: Bioscience, Biotechnology, and Biochemistry
Eva L Decker, Adrian Alder, Stefan Hunn, Jenny Ferguson, Mikko T Lehtonen, Bjoern Scheler, Klaus L Kerres, Gertrud Wiedemann, Vajiheh Safavi-Rizi, Steffen Nordzieke, Aparna Balakrishna, Lina Baz, Javier Avalos, Jari P T Valkonen, Ralf Reski, Salim Al-Babili
In seed plants, strigolactones (SLs) regulate architecture and induce mycorrhizal symbiosis in response to environmental cues. SLs are formed by combined activity of the carotenoid cleavage dioxygenases (CCDs) 7 and 8 from 9-cis-β-carotene, leading to carlactone that is converted by cytochromes P450 (clade 711; MAX1 in Arabidopsis) into various SLs. As Physcomitrella patens possesses CCD7 and CCD8 homologs but lacks MAX1, we investigated if PpCCD7 together with PpCCD8 form carlactone and how deletion of these enzymes influences growth and interactions with the environment...
March 6, 2017: New Phytologist
Bruno Guillotin, Mohammad Etemadi, Corinne Audran, Mondher Bouzayen, Guillaume Bécard, Jean-Philippe Combier
Root colonization by arbuscular mycorrhizal (AM) fungi is a complex and finely tuned process. Previous studies have shown that, among other plant hormones, auxin plays a role in this process but the specific involvement of Aux/IAAs, the key regulators of auxin responses, is still unknown. In this study, we addressed the role of the tomato Sl-IAA27 during AM symbiosis by using Sl-IAA27-RNAi and pSL-IAA27::GUS stable tomato lines. The data show that Sl-IAA27 expression is up-regulated by the AM fungus and that silencing of Sl-IAA27 has a negative impact on AM colonization...
February 2017: New Phytologist
Philip B Brewer, Kaori Yoneyama, Fiona Filardo, Emma Meyers, Adrian Scaffidi, Tancred Frickey, Kohki Akiyama, Yoshiya Seto, Elizabeth A Dun, Julia E Cremer, Stephanie C Kerr, Mark T Waters, Gavin R Flematti, Michael G Mason, Georg Weiller, Shinjiro Yamaguchi, Takahito Nomura, Steven M Smith, Koichi Yoneyama, Christine A Beveridge
Strigolactones are a group of plant compounds of diverse but related chemical structures. They have similar bioactivity across a broad range of plant species, act to optimize plant growth and development, and promote soil microbe interactions. Carlactone, a common precursor to strigolactones, is produced by conserved enzymes found in a number of diverse species. Versions of the MORE AXILLARY GROWTH1 (MAX1) cytochrome P450 from rice and Arabidopsis thaliana make specific subsets of strigolactones from carlactone...
May 31, 2016: Proceedings of the National Academy of Sciences of the United States of America
Gavin R Flematti, Adrian Scaffidi, Mark T Waters, Steven M Smith
Plants produce strigolactones with different structures and different stereospecificities which provides the potential for diversity and flexibility of function. Strigolactones (SLs) typically comprise a tricyclic ABC ring system linked through an enol-ether bridge to a butenolide D-ring. The stereochemistry of the butenolide ring is conserved but two alternative configurations of the B-C ring junction leads to two families of SLs, exemplified by strigol and orobanchol. Further modifications lead to production of many different strigolactones within each family...
June 2016: Planta
Mark Bruno, Salim Al-Babili
The β-carotene isomerase OsDWARF27 is stereo- and double bond-specific. It converts bicyclic carotenoids with at least one unsubstituted β-ionone ring. OsDWARF27 may contribute to the formation of α-carotene-based strigolactone-like compounds. Strigolactones (SLs) are synthesized from all-trans-β-carotene via a pathway involving the β-carotene isomerase DWARF27, the carotenoid cleavage dioxygenases 7 and 8 (CCD7, CCD8), and cytochrome P450 enzymes from the 711 clade (MAX1 in Arabidopsis). The rice enzyme DWARF27 was shown to catalyze the reversible isomerization of all-trans- into 9-cis-β-carotene in vitro...
June 2016: Planta
Shinsaku Ito, Ken Ito, Naoko Abeta, Ryo Takahashi, Yasuyuki Sasaki, Shunsuke Yajima
Strigolactones (SLs) are a group of terpenoid lactones found in plants that regulate diverse developmental phenomena. SLs are thought to be involved in the maintenance of phosphate homeostasis. In addition, SL signaling is required for the regulation of shoot branching by nitrogen supply in Arabidopsis. In this study, we evaluated the effects of SLs on nitrogen deficient-inducing phenomena (leaf senescence and reduction of plant weight) in Arabidopsis. SL-biosynthesis (max1-1) and SL-insensitive (atd14-1) mutants showed altered responses to nitrogen deficient in comparison with wild-type (WT) plants...
2016: Plant Signaling & Behavior
Päivi L H Rinne, Laju K Paul, Jorma Vahala, Raili Ruonala, Jaakko Kangasjärvi, Christiaan van der Schoot
Tree architecture develops over time through the collective activity of apical and axillary meristems. Although the capacity of both meristems to form buds is crucial for perennial life, a comparative analysis is lacking. As shown here for hybrid aspen, axillary meristems engage in an elaborate process of axillary bud (AXB) formation, while apical dominance prevents outgrowth of branches. Development ceased when AXBs had formed an embryonic shoot (ES) with a predictable number of embryonic leaves at the bud maturation point (BMP)...
November 2015: Journal of Experimental Botany
Katelyn Nagy-Smith, Eric Moore, Joel Schneider, Robert Tycko
Most, if not all, peptide- and protein-based hydrogels formed by self-assembly can be characterized as kinetically trapped 3D networks of fibrils. The propensity of disease-associated amyloid-forming peptides and proteins to assemble into polymorphic fibrils suggests that cross-β fibrils comprising hydrogels may also be polymorphic. We use solid-state NMR to determine the molecular and supramolecular structure of MAX1, a de novo designed gel-forming peptide, in its fibrillar state. We find that MAX1 adopts a β-hairpin conformation and self-assembles with high fidelity into a double-layered cross-β structure...
August 11, 2015: Proceedings of the National Academy of Sciences of the United States of America
Elisabeth Stes, Stephen Depuydt, Annick De Keyser, Cedrick Matthys, Kris Audenaert, Koichi Yoneyama, Stefaan Werbrouck, Sofie Goormachtig, Danny Vereecke
Leafy gall syndrome is the consequence of modified plant development in response to a mixture of cytokinins secreted by the biotrophic actinomycete Rhodococcus fascians. The similarity of the induced symptoms with the phenotype of plant mutants defective in strigolactone biosynthesis and signalling prompted an evaluation of the involvement of strigolactones in this pathology. All tested strigolactone-related Arabidopsis thaliana mutants were hypersensitive to R. fascians. Moreover, treatment with the synthetic strigolactone mixture GR24 and with the carotenoid cleavage dioxygenase inhibitor D2 illustrated that strigolactones acted as antagonistic compounds that restricted the morphogenic activity of R...
August 2015: Journal of Experimental Botany
Salim Al-Babili, Harro J Bouwmeester
Strigolactones (SLs) are carotenoid-derived plant hormones and signaling molecules. When released into the soil, SLs indicate the presence of a host to symbiotic fungi and root parasitic plants. In planta, they regulate several developmental processes that adapt plant architecture to nutrient availability. Highly branched/tillered mutants in Arabidopsis, pea, and rice have enabled the identification of four SL biosynthetic enzymes: a cis/trans-carotene isomerase, two carotenoid cleavage dioxygenases, and a cytochrome P450 (MAX1)...
2015: Annual Review of Plant Biology
Yifat Miller, Buyong Ma, Ruth Nussinov
Hydrogels are proving to be an excellent class of materials for biomedical applications. The molecular self-assembly of designed MAX1 β-hairpin peptides into fibrillar networks has emerged as a novel route to form responsive hydrogels. Herein, computational modeling techniques are used to investigate the relative arrangements of individual hairpins within the fibrils that constitute the gel. The modeling provides insight into the morphology of the fibril network, which defines the gel's mechanical properties...
January 15, 2015: Journal of Physical Chemistry. B
Satoko Abe, Aika Sado, Kai Tanaka, Takaya Kisugi, Kei Asami, Saeko Ota, Hyun Il Kim, Kaori Yoneyama, Xiaonan Xie, Toshiyuki Ohnishi, Yoshiya Seto, Shinjiro Yamaguchi, Kohki Akiyama, Koichi Yoneyama, Takahito Nomura
Strigolactones (SLs) stimulate seed germination of root parasitic plants and induce hyphal branching of arbuscular mycorrhizal fungi in the rhizosphere. In addition, they have been classified as a new group of plant hormones essential for shoot branching inhibition. It has been demonstrated thus far that SLs are derived from carotenoid via a biosynthetic precursor carlactone (CL), which is produced by sequential reactions of DWARF27 (D27) enzyme and two carotenoid cleavage dioxygenases CCD7 and CCD8. We previously found an extreme accumulation of CL in the more axillary growth1 (max1) mutant of Arabidopsis, which exhibits increased lateral inflorescences due to SL deficiency, indicating that CL is a probable substrate for MAX1 (CYP711A1), a cytochrome P450 monooxygenase...
December 16, 2014: Proceedings of the National Academy of Sciences of the United States of America
Benjun Zhou
Kinetics of chromium (VI) reduction and phenol biodegradation by a pure culture of Pseudomonas sp. JF122 was studied. High inoculum (volume) increased both chromium (VI) reduction and phenol biodegradation velocity, which are ascribable to shorter acclimation period requirement for cell growth. Haldane's kinetics model adequately described the substrate kinetics with kinetic constants μ(max1) =0.113 h⁻¹, K(s1) = 0.4009 mM, K(i1) =5.165 mM for chromium (VI) reduction and μ(max2) =0.3081 h⁻¹, K(s2) =7...
November 2014: Pakistan Journal of Pharmaceutical Sciences
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