A novel mitochondrial DnaJ/Hsp40 family protein BIL2 promotes plant growth and resistance against environmental stress in brassinosteroid signaling

Bekh-Ochir, Davaapurev; Shimada, Setsuko; Yamagami, Ayumi; Kanda, Satomi; Ogawa, Kenji; Nakazawa, Miki; Matsui, Minami; Sakuta, Masaaki; Osada, Hiroyuki; Asami, Tadao; Nakano, Takeshi

doi:10.1007/s00425-013-1859-3

Cited by 78 publications

(58 citation statements)

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“…Mitochondria are a major source of ROS and act as signaling organelles that coordinate plant growth and defense (Huang, et al, 2013;Nie et al, 2015). Mitochondria dysfunction interferes with 9-LOX and BR signaling (Bekh-Ochir et al, 2013;Vellosillo et al, 2013) and might unbalance ROS production, a key process in the control of plant development and plant defense. Recent studies indicate BR pathway involvement in plant immunity and its role in balancing defense versus growth (Belkhadir et al, 2014;Fan et al, 2014).…”

Section: Discussionmentioning

confidence: 99%

9-Lipoxygenase-derived oxylipins activate brassinosteroid signaling to promote cell wall-based defense and limit pathogen infection

et al. 2015

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The oxylipins, a large family of oxygenated lipid derivatives, regulate plant development and immunity. Two members of the 9-lipoxygenase (9-LOX) oxylipin pathway, 9-hydroxyoctadecatrienoic acid and 9-ketooctadecatrienoic acid, control root development and plant defense. Studies in Arabidopsis (Arabidopsis thaliana) using a series of 9-hydroxyoctadecatrienoic acidand 9-ketooctadecatrienoic acid-insensitive nonresponding to oxylipins (noxy) mutants showed the importance of the cell wall as a 9-LOX-induced defense component and the participation of NOXY proteins in signaling cell wall damage. Here, we examined 9-LOX signaling using the mutants lox1lox5, which lacks 9-LOX activity, and noxy2-2, which shows oxylipin insensitivity and mitochondrial dysfunction. Mutants in brassinosteroids (BRs), a class of plant hormones necessary for normal plant growth and the control of cell wall integrity, were also analyzed. Several lines of evidence indicated that 9-LOX-derived oxylipins induce BR synthesis and signaling to activate cell wall-based responses such as callose deposition and that constitutive activation of BR signaling in bri1-EMS-suppressor 1-D (bes1-D) plants enhances this response. We found that constitutive BR signaling in bes1-D and brassinolide-resistant 1-1D (bzr1-1D) mutants conferred resistance to Pseudomonas syringae. bes1-D and bzr1-1D showed increased resistance to Golovinomyces cichoracearum, an obligate biotrophic fungus that penetrates the cell wall for successful infection, whereas susceptibility was enhanced in lox1lox5 and noxy2-2. Our results indicate a sequential action of 9-LOX and BR signaling in activating cell wall-based defense, and this response prevents pathogen infection. These results show interaction between the 9-LOX and BR pathways and help to clarify their role in modulating plant defense.

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Section: Discussionmentioning

confidence: 99%

9-Lipoxygenase-derived oxylipins activate brassinosteroid signaling to promote cell wall-based defense and limit pathogen infection

et al. 2015

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“…The plasma membrane-type ATPase AHA1 (for Arabidopsis plasma membrane H + -ATPase) is a BR receptor binding protein that regulates cell wall expansion (Caesar et al, 2011). Our recent study determined that the mitochondrial protein BIL2, which is a potential homolog of DnaJ, increased the ATP concentration in the cell and elongated hypocotyl in the presence of Brz (Bekh-Ochir et al, 2013). The regulation of the cellular ATP concentration by BR might change the cytosolic redox conditions and affect the formation of the BSS1/BOP1 complex.…”

Section: Discussionmentioning

confidence: 99%

“…Given that large protein complexes and cellular organelles can be precipitated by ultracentrifugation (Yanagawa et al, 1999;Hagiwara et al, 2003;Nishikiori et al, 2006), we performed ultracentrifugation experiments using protein extracts from BSS1-GFP transformants and mitochondrial protein BIL2-GFP transformants (Bekh-Ochir et al, 2013), which both present punctate GFP fluorescence signals in the cytosol. Pellets from the first ultracentrifugation were treated with the detergent CHAPS, Nonidet P-40, or Triton X-100.…”

Section: Bss1/bop1 Forms Punctate Protein Complexes Under Br-deficienmentioning

confidence: 99%

Formation and Dissociation of the BSS1 Protein Complex Regulates Plant Development via Brassinosteroid Signaling

et al. 2015

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JapanBrassinosteroids (BRs) play important roles in plant development and the response to environmental cues. BIL1/BZR1 is a master transcription factor in BR signaling, but the mechanisms that lead to the finely tuned targeting of BIL1/BZR1 by BRs are unknown. Here, we identified BRZ-SENSITIVE-SHORT HYPOCOTYL1 (BSS1) as a negative regulator of BR signaling in a chemical-biological analysis involving brassinazole (Brz), a specific BR biosynthesis inhibitor. The bss1-1D mutant, which overexpresses BSS1, exhibited a Brz-hypersensitive phenotype in hypocotyl elongation. BSS1 encodes a BTB-POZ domain protein with ankyrin repeats, known as BLADE ON PETIOLE1 (BOP1), which is an important regulator of leaf morphogenesis. The bss1-1D mutant exhibited an increased accumulation of phosphorylated BIL1/BZR1 and a negative regulation of BRresponsive genes. The number of fluorescent BSS1/BOP1-GFP puncta increased in response to Brz treatment, and the puncta were diffused by BR treatment in the root and hypocotyl. We show that BSS1/BOP1 directly interacts with BIL1/BZR1 or BES1. The large protein complex formed between BSS1/BOP1 and BIL1/BZR1 was only detected in the cytosol. The nuclear BIL1/BZR1 increased in the BSS1/BOP1-deficient background and decreased in the BSS1/BOP1-overexpressing background. Our study suggests that the BSS1/BOP1 protein complex inhibits the transport of BIL1/BZR1 to the nucleus from the cytosol and negatively regulates BR signaling.

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“…Brassinazole (Brz), a specifi c inhibitor of BR biosynthesis, was used in experiments performed by Bekh-Ochir et al ( 2013 ) to identify Brz-insensitive-long hypocotyls 2-1D ( bil2-1D ) mutant of Arabidopsis . The BIL2 gene encodes a mitochondrial-localised DnaJ/heat-shock protein 40 (DnaJ/Hsp40) family, which is involved in protein folding.…”

Section: A Class Of Brassinosteroid-activated Transcription Factors Amentioning

confidence: 99%

Brassinosteroids Implicated in Growth and Stress Responses

Bajguz

Piotrowska‐Niczyporuk

2014

Phytohormones: A Window to Metabolism, Signaling and Biotechnological Applications

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Brassinosteroids (BRs) are steroidal hormones essential for plant growth and development. They are implicated in plant responses to abiotic environmental stresses such as low and high temperature, drought, salt, infection, pesticides, and heavy metals. BR-regulated stress response is a result of a complex sequence of biochemical reactions such as activation or suppression of key enzymatic reactions, induction of protein synthesis, and the production of various chemical defence compounds. However, the molecular mechanism of BR-induced plant abiotic stress tolerance remains poorly understood. The BR signalling is initiated by a ligandinduced kinase activation followed by receptor oligomerisation. The signal transduction in the cell is mediated through phosphorylation and transcription factors which directly bind to promoters of BR-responsive genes to regulate their expression. BRs that are biosynthesised using sterols as precursors are structurally similar to the cholesterol-derived, human steroid hormones and insect moulting hormones. The biosynthetic pathway of BRs is divided into multiple subunits. Depending on C-22 hydroxylation at campesterol, the BR pathway is further divided into the early and late C-22 oxidation pathways. Similarly, the C-6 position can be oxidised at campestanol or later at 6-deoxocathasterone stage, and thus these are called the early and late C-6 oxidation pathways, respectively. The pathways of BR biosynthesis in plants are well studied. Nevertheless, in order to understand properly the role of BRs during plant development under stress conditions, it seems essential to summarise the experimental data, focusing on the biosynthesis and signal transduction.

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A novel mitochondrial DnaJ/Hsp40 family protein BIL2 promotes plant growth and resistance against environmental stress in brassinosteroid signaling

Cited by 78 publications

References 44 publications

9-Lipoxygenase-derived oxylipins activate brassinosteroid signaling to promote cell wall-based defense and limit pathogen infection

9-Lipoxygenase-derived oxylipins activate brassinosteroid signaling to promote cell wall-based defense and limit pathogen infection

Formation and Dissociation of the BSS1 Protein Complex Regulates Plant Development via Brassinosteroid Signaling

Brassinosteroids Implicated in Growth and Stress Responses

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