著者

Shingo Sakamoto Taiji Nomura Yasuo Kato Shinjiro Ogita Nobutaka Mitsuda

出版者

Japanese Society for Plant Biotechnology

雑誌

Plant Biotechnology (ISSN:13424580)

巻号頁・発行日

vol.39, no.3, pp.229-240, 2022-09-25 (Released:2022-09-25)

参考文献数

44

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The secondary cell wall, which is mainly composed of cellulose, hemicellulose, and lignin, constitutes woody tissues and gives physical strength and hydrophobic properties for resistance against environmental stresses. We cloned and functionally analyzed the homologous transcription factor (TF) genes of SECONDARY WALL NAC (SWN) proteins from Hachiku bamboo (Phyllostachys nigra; PnSWNs). An RT-PCR analysis showed that PnSWNs are expressed in young tissues in bamboo. Their transcriptional activation activities were higher than that of the Arabidopsis NAC SECONDARY WALL THICKENING PROMOTING FACTOR 3 (NST3) TF, which was equivalent to SWN TFs in monocot. PnSWNs preferred to activate the genes related to secondary cell wall formation but not the genes related to programmed cell death. When PnSWNs were expressed in Arabidopsis, they highly induced secondary cell wall formation, like previously-shown rice SWN1. Dissection analysis revealed that this high activity largely depends on C-terminal domain. These results demonstrate that the cloned bamboo SWNs function as regulators of secondary cell wall formation with strong activation ability derived from C-terminal domain, and could be served as new genetic tools for secondary cell wall manipulation.

著者

Reika Hasegawa Tomoki Arakawa Kenjiro Fujita Yuichiro Tanaka Zen Ookawa Shingo Sakamoto Hironori Takasaki Miho Ikeda Ayumi Yamagami Nobutaka Mitsuda Takeshi Nakano Masaru Ohme-Takagi

出版者

Japanese Society for Plant Biotechnology

雑誌

Plant Biotechnology (ISSN:13424580)

巻号頁・発行日

vol.39, no.2, pp.209-214, 2022-06-25 (Released:2022-06-25)

参考文献数

51

被引用文献数

1

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Brassinosteroid (BR) is a phytohormone that acts as important regulator of plant growth. To identify novel transcription factors that may be involved in unknown mechanisms of BR signaling, we screened the chimeric repressor expressing plants (CRES-T), in which transcription factors were converted into chimeric repressors by the fusion of SRDX plant-specific repression domain, to identify those that affect the expression of BR inducible genes. Here, we identified a homeobox-leucine zipper type transcription factor, BRASSINOSTEROID-RELATED-HOMEOBOX 3 (BHB3), of which a chimeric repressor expressing plants (BHB3-sx) significantly downregulated the expression of BAS1 and SAUR-AC1 that are BR inducible genes. Interestingly, ectopic expression of BHB3 (BHB3-ox) also repressed the BR inducible genes and shorten hypocotyl that would be similar to a BR-deficient phenotype. Interestingly, both BHB3-sx and BHB3-ox showed pale green phenotype, in which the expression of genes related photosynthesis and chlorophyll contents were significantly decreased. We found that BHB3 contains three motifs similar to the conserved EAR-repression domain, suggesting that BHB3 may act as a transcriptional repressor. These results indicate that BHB3 might play an important role not only to the BR signaling but also the regulation of greenings.

著者

Reika Hasegawa Kenjiro Fujita Yuichiro Tanaka Hironori Takasaki Miho Ikeda Ayumi Yamagami Nobutaka Mitsuda Takeshi Nakano Masaru Ohme-Takagi

出版者

Japanese Society for Plant Biotechnology

雑誌

Plant Biotechnology (ISSN:13424580)

巻号頁・発行日

vol.39, no.2, pp.185-189, 2022-06-25 (Released:2022-06-25)

参考文献数

27

被引用文献数

2

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The brassinosteroid (BR) phytohormone is an important regulator of plant growth. To identify novel transcription factors that regulate BR responses, we screened chimeric repressor gene silencing technology (CRES-T) plants, in which transcription factors were converted into chimeric repressors by the fusion of SRDX plant-specific repression domain, with brassinazole (Brz), an inhibitor of BR biosynthesis. We identified that a line that expressed the chimeric repressor for zinc finger homeobox transcription factor, BRASSINOSTEORID-RELATED-HOMEOBOX-2 (BHB2-sx), exhibited Brz-hypersensitive phenotype with shorter hypocotyl under dark, dwarf and round and dark green leaves similar to BR-deficient phenotype. Similar to BHB2-sx plants, bhb2 knockout mutant also exhibited Brz hypersensitive phenotype. In contrast, ectopic expression of BHB2 (BHB2-ox) showed hypocotyl elongation phenotype (BR excessive), showing decrease to Brz sensitivity. The expression of the DWF4 and CPD BR biosynthesis genes was repressed in BHB2-sx plants, whereas it was enhanced in BHB2-ox plants. The BR deficient-like phenotype of BHB2-sx plants was partially restored by treatment with brassinolide (BL), indicating that the BR deficient phenotype of BHB2-sx plant may be due to suppression of BR biosynthesis. Our results indicate that BHB2 is a positive regulator of BR response may be due to the promotion of BR biosynthesis genes.

著者

Sumire Fujiwara Keiko Kigoshi Nobutaka Mitsuda Kaoru Suzuki Masaru Ohme-Takagi

出版者

Japanese Society for Plant Cell and Molecular Biology

雑誌

Plant Biotechnology (ISSN:13424580)

巻号頁・発行日

pp.14.0121a, (Released:2014-03-20)

参考文献数

58

被引用文献数

5 7

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Proper gene expression regulated by transcription factors is essential for plants to achieve proper growth and development. However, the biological functions of many transcription factors remain largely unknown. Furthermore, although there are transcription factors which possess a plant-specific repression domain(s), their biological functions and whether such transcription factors function as transcriptional repressors are unclear. Thus, aiming for searching clues to understand their functions, we generated transgenic plants in which a putative transcriptional repressor fused with a VP16 viral trans-activation domain was expressed constitutively. Several plants with strong morphological phenotypes such as leaf and flower development defects were isolated from those lines expressing potential transcriptional repressors with unknown functions, giving the clue to reveal the yet-to-be analyzed functions of each protein. Reversal of function of the well-known transcriptional and floral repressor SHORT VEGETATIVE PHASE by VP16 fusion was observed, exemplifying successful functional reversion by this system. Plants constitutively expressing VP16 fused WUSCHEL, which is known to function both as a transcriptional activator and repressor, showed both phenotypes reported in its overexpression and loss-of-function lines. Taken together, our data provide examples showing the efficacy of VP16 fusion to provide helpful information to uncover the unknown functions of potential transcriptional repressors. This technique could also be effective to produce “super plants” which obtained strong and useful traits for application by strongly activating genes which are usually silent.