BPG4 regulates chloroplast development and homeostasis by suppressing GLK transcription factors and involving light and brassinosteroid signaling

葉緑体の発達を適正に制御する新しい因子を発見. 京都大学プレスリリース. 2024-01-23.Chloroplast development adapts to the environment for performing suitable photosynthesis. Brassinosteroids (BRs), plant steroid hormones, have crucial effects on not only plant growth but also chloroplast development. However, the detailed molecular mechanisms of BR signaling in chloroplast development remain unclear. Here, we identify a regulator of chloroplast development, BPG4, involved in light and BR signaling. BPG4 interacts with GOLDEN2-LIKE (GLK) transcription factors that promote the expression of photosynthesis-associated nuclear genes (PhANGs), and suppresses their activities, thereby causing a decrease in the amounts of chlorophylls and the size of light-harvesting complexes. BPG4 expression is induced by BR deficiency and light, and is regulated by the circadian rhythm. BPG4 deficiency causes increased reactive oxygen species (ROS) generation and damage to photosynthetic activity under excessive high-light conditions. Our findings suggest that BPG4 acts as a chloroplast homeostasis factor by fine-tuning the expression of PhANGs, optimizing chloroplast development, and avoiding ROS generation

通所型介護予防事業修了者の運動に関する介護予防プログラム継続に関わる要因と行政に求められる支援

【目的】通所型介護予防事業修了者の運動に関する介護予防プログラム継続の状況と要因を明らかにし、行政に求められる支援について考察する。 【方法】前橋市の平成23年度通所型介護予防事業修了生で事業に７回以上出席した479人に郵送調査を実施した。 【結果】352名（73.5％）から有効回答が得られ、230名（65.3％）が現在も、運動に関する介護予防プログラムを継続して実施していた。継続群は［以前からの運動習慣］があり、［運動は大切］と認識し、［それ以外の運動］も行っていた。事業に参加して［楽しかった］［仲間ができた］［体調に良い変化がみられた］［大変ではなかった］と感じ、［まわりの人にも勧めたい］と思う傾向があった。修了時には、［続けて行う場所の案内］や［近所の集まりへの誘い］があり、［介護予防サポーターを知っている］人の割合が高かった。 【考察】通所型介護予防事業修了者の運動に関する介護予防プログラム継続の要因として「楽しい」「負担でない」「仲間ができる」「身体に良いと実感できる」教室運営、教室修了時/後の「身近な開催場所の案内」と「次の集まりへの誘い」、「卒業後の受け皿がある」こと、普段からの「運動 習慣の定着」が明らかになった。行政の役割として、今回の調査から得られた介護予防プログラム継続の要因を踏まえた教室運営と、介護予防サポーターの育成及び活動支援を含む受け皿づくりの支援が求められる。また、広く若者から高齢者まで運動習慣を作る健康づくりへの支援が大切である

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

Funding Information: Acknowledgments We thank Dr. Tsuyoshi Nakagawa (Shimane University) for the gift of the gateway vectors, pGWB2, pGWB80, pGWB5, and pGWB3. This work was supported in part by funding from the Program for Promotion of Basic Research Activities for Innovation Bioscience (PROBRAIN) to T.N. and T.A., and CREST, Japan Science and Technology Agency to T.N. and T.A.Plant steroid hormones, brassinosteroids, are essential for growth, development and responses to environmental stresses in plants. Although BR signaling proteins are localized in many organelles, i.e., the plasma membrane, nuclei, endoplasmic reticulum and vacuole, the details regarding the BR signaling pathway from perception at the cellular membrane receptor BRASSINOSTEROID INSENSITIVE 1 (BRI1) to nuclear events include several steps. Brz (Brz220) is a specific inhibitor of BR biosynthesis. In this study, we used Brz-mediated chemical genetics to identify Brz-insensitive-long hypocotyls 2-1D (bil2-1D). The BIL2 gene encodes a mitochondrial-localized DnaJ/Heat shock protein 40 (DnaJ/Hsp40) family, which is involved in protein folding. BIL2-overexpression plants (BIL2-OX) showed cell elongation under Brz treatment, increasing the growth of plant inflorescence and roots, the regulation of BR-responsive gene expression and suppression against the dwarfed BRI1-deficient mutant. BIL2-OX also showed resistance against the mitochondrial ATPase inhibitor oligomycin and higher levels of exogenous ATP compared with wild-type plants. BIL2 participates in resistance against salinity stress and strong light stress. Our results indicate that BIL2 induces cell elongation during BR signaling through the promotion of ATP synthesis in mitochondria.Peer reviewe

Organized and Sustainable Education Program for Drug Abuse Prevention by Yogo-teachers

　学校における喫煙・飲酒・薬物乱用防止教育の充実には，問題行動が顕在化する中学校期だけでなく小学校期 における指導の推進が重要であり，系統的な指導計画を立て，指導者や時間の確保，教材作成などに組織的に取 組み，継続可能なプログラム開発を行う必要がある。そこで，地区内12 校の養護教諭が協働して，発達段階に応 じた系統的・組織的かつ継続可能な地区共通の指導計画を開発し，各校の教育課程・年間計画に位置付けた実践 研究を行った。その結果，指導計画の実施状況は，小学校11 校中，学級活動10 校，ミニ保健指導10 校，長期 休業前指導6 校，広報活動9 校となり，特別支援学校1 校では広報活動のみを行うことができた。小学校におけ る喫煙・飲酒・薬物乱用防止教育の推進には，学校保健活動の中核的役割を担う養護教諭が専門性を活かし協働 して，系統的な指導計画を各校の教育課程に位置付け組織的で継続可能なプログラムとする取組が有効であった

Fenarimol, a Pyrimidine-Type Fungicide, Inhibits Brassinosteroid Biosynthesis

The plant steroid hormone brassinosteroids (BRs) are important signal mediators that regulate broad aspects of plant growth and development. With the discovery of brassinoazole (Brz), the first specific inhibitor of BR biosynthesis, several triazole-type BR biosynthesis inhibitors have been developed. In this article, we report that fenarimol (FM), a pyrimidine-type fungicide, exhibits potent inhibitory activity against BR biosynthesis. FM induces dwarfism and the open cotyledon phenotype of Arabidopsis seedlings in the dark. The IC50 value for FM to inhibit stem elongation of Arabidopsis seedlings grown in the dark was approximately 1.8 ± 0.2 μM. FM-induced dwarfism of Arabidopsis seedlings could be restored by brassinolide (BL) but not by gibberellin (GA). Assessment of the target site of FM in BR biosynthesis by feeding BR biosynthesis intermediates indicated that FM interferes with the side chain hydroxylation of BR biosynthesis from campestanol to teasterone. Determination of the binding affinity of FM to purified recombinant CYP90D1 indicated that FM induced a typical type II binding spectrum with a Kd value of approximately 0.79 μM. Quantitative real-time PCR analysis of the expression level of the BR responsive gene in Arabidopsis seedlings indicated that FM induces the BR deficiency in Arabidopsis

Discovery of a nonsteroidal brassinolide-like compound, NSBR1

Fourteen compounds screened from 5 million compounds in silico were submitted to bioassay to find brassinolide (BL) agonists/antagonists against Arabidopsis thaliana. Of these, two N-benzoyl-N′-phenylpiperazine (NBNPP)-type compounds showed antagonistic activity; however, none showed agonistic activity against A. thaliana. The substituents at the benzoyl moiety of NBNPP were changed to OH groups to derive N-(3, 4-dihydroxybenzoyl)-N′-(4-butanoyl-2-fluorophenyl)pyrazine, which was named NSBR1. NSBR1 was rationally designed based on docking simulations and molecular dynamics. NSBR1 significantly suppressed the gene expression of CPD and BR6-ox2, which are known as marker genes for the action of BL. This novel NSBR1 was also effective in the rice lamina inclination assay (RLIA), and the activity in terms of the 50% effective dose (ED₅₀) was determined as 0.79 nmol/plant from the dose–response curve for RLIA