【原】每日三篇植物相关最新文献推送：MOS1联系免疫与细胞周期；水稻砷E3 ligase; GA与SL的共同机制的探索

1Plant J: MOS1 functions closely with TCP transcription factors to modulate immunity and cell cycle in Arabidopsis. PCF1（TCP）转录因子TCP15及其同系物是介导MOS1功能的免疫应答和可能的细胞周期控制。

Authors

• Zhang N ^1,2 ,Wang Z ^1,2 ,Bao Z ² ,Yang L ² ,Wu D ¹ ,Shu X ¹ ,Hua J ^2,3

• 1 State Key Laboratory of Rice Biology, Institute of Nuclear AgriculturalSciences, Zhejiang University, Hangzhou, 310029, P.R, China.

• 2 School of Integrated Plant Science, Plant Biology Section, Cornell University,Ithaca, NY, 14853, USA.

• 3 State Key Laboratory of Crop Genetics and Germplasm Enhancement, NanjingAgricultural University, Nanjing, 210095, China.

    新出现的证据表明细胞周期进程与植物免疫反应之间有着密切的联系。在拟南芥中，snc1-1（MOS1）的调节子调节许多过程，包括内部复制和植物抗病性，但是这种调节的分子机制还不完全清楚。在这里，我们提供生化和遗传证据，TEOSINTE BRANCHED 1，CYCLOIDEA，PCF1（TCP）转录因子TCP15及其同系物是介导MOS1功能的免疫应答和可能的细胞周期控制。发现MOS1和TCP蛋白具有直接的物理相互作用。它们都与npr1-1，本体1（SNC1）的免疫受体基因SUPRESSOR的启动子结合并调节其表达，从而调节免疫应答。 MOS1和TCP15均影响细胞周期调控中可能介导MOS1功能的细胞周期基因D型CYCLIN3; 1（CYCD3; 1）的表达。有趣的是，CYCD3; 1过度表达上调免疫反应。因此，本研究揭示了MOS1通过TCP15及其同系物在转录调控中的作用，并提示在多个水平上协调细胞周期进程和植物免疫应答。

Abstract:Emerging evidence indicates a close connection between cell cycle progression and plant immune responses. In Arabidopsis, MODIFIER OF snc1-1 (MOS1) modulates a number of processes including endoreduplication and plant disease resistance, but the molecular mechanism underlying this modulation was not fully understood. Here, we provide biochemical and genetic evidence that TEOSINTE BRANCHED 1, CYCLOIDEA, PCF1 (TCP) transcription factors TCP15 and its homologs are mediators of MOS1 function in immune response and likely cell cycle control as well. MOS1 and TCP proteins are found to have direct physical interaction. They both bind to the promoter of the immune receptor gene SUPRESSOR OF npr1-1, CONSTITUTIVE 1 (SNC1) and modulate its expression and consequently immune responses. MOS1 and TCP15 both affect the expression of cell cycle genes D-type CYCLIN 3;1 (CYCD3;1), which likely mediate the function of MOS1 in cell cycle modulation. Intriguingly, CYCD3;1 overexpression upregulates immune responses. Therefore, this work reveals a role of MOS1 in transcriptional regulation through TCP15 and its homologs and suggests a coordination of cell cycle progression and plant immune responses at multiple levels. This article is protected by copyright. All rights reserved.

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2Molecular characterization of rice arsenic-induced RING finger E3 ligase 2 (OsAIR2) and its heterogeneous overexpression in Arabidopsis thaliana. OsAIR2在拟南芥中的异源过表达提高了砷胁迫条件下的种子萌发和根长 Hwang SG,et al Physiol Plant  2017 Nov

Authors

• Hwang SG ¹ ,Chapagain S ¹ ,Han AR ¹ ,Park YC ¹ ,Park HM ¹ ,Kim H ²,JangCS ¹

• 1 Plant Genomics Laboratory, Department of Applied Plant Sciences, KangwonNational University, Chuncheon, 24341, South Korea.

• 2 Department of Crop Science and Biotechnology, Dankook University, Cheonan,31116, South Korea.

    砷（As）积累对植物的生长和生产力产生不利影响，对人类健康和粮食安全构成严重威胁。在这项研究中，我们确定了一个As（RING）E3泛素连接酶基因从水稻根组织。我们将其命名为Oryza sativa As-Induced RING E3连接酶2（OsAIR2）。在各种非生物胁迫条件下（包括热，盐，干旱和砷暴露）诱导OsAIR2的表达。体外泛素化测定的结果显示OsAIR2具有E3连接酶活性。在细胞内，OsAIR2被发现定位于高尔基体。使用酵母双杂交（Y2H）测定，3-酮脂酰辅酶A硫解酶（KAT）蛋白质被鉴定为相互作用伙伴。我们发现O. sativa KAT1（OsKAT1）定位于细胞质和过氧化物酶体。此外，体外pull-down试验验证了OsAIR2和OsKAT1之间的物理相互作用。有趣的是，体外泛素化测定和体内蛋白酶体降解测定表明，OsAIR2泛素化OsKAT1并通过26S蛋白酶体降解途径促进OsKAT1的降解。 OsAIR2在拟南芥中的异源过表达提高了砷胁迫条件下的种子萌发和根长。因此，这些结果表明，OsAIR2可能与植物对As胁迫的反应有关，并作为As胁迫耐受性的正调控因子。

Abstract

Arsenic (As) accumulation adversely affects the growth and productivity of plants and poses a serious threat to human health and food security. In this study, we identified one As-responsive Really Interesting New Gene (RING) E3 ubiquitin ligase gene from rice root tissues during As stress. We named it Oryza sativa As-Induced RING E3 ligase 2 (OsAIR2). Expression of OsAIR2 was induced under various abiotic stress conditions, including heat, salt, drought and As exposure. Results of an in vitro ubiquitination assay showed that OsAIR2 possesses an E3 ligase activity. Within the cell, OsAIR2 was found to be localized to the Golgi apparatus. Using yeast two-hybrid (Y2H) assay, the 3-ketoacyl-CoA thiolase (KAT) protein was identified as an interaction partner. We found that the O. sativa KAT1 (OsKAT1) is localized to the cytosol and peroxisomes. Moreover, in vitro pull-down assay verified the physical interaction between OsAIR2 and OsKAT1. Interestingly, in vitro ubiquitination assay and in vivo proteasomal degradation assay revealed that OsAIR2 ubiquitinates OsKAT1 and promotes the degradation of OsKAT1 via the 26S proteasome degradation pathway. Heterogeneous overexpression of OsAIR2 in Arabidopsis improved the seed germination and increased the root length under arsenate stress conditions. Therefore, these results suggest that OsAIR2 may be associated with the plant response to As stress and acts as a positive regulator of As stress tolerance.

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3Largely additive effects of gibberellin and strigolactone on gene expression in Arabidopsis thaliana seedlings.GA和拟南芥幼苗中的rac-GR24信号在一个共同基因集合的转录水平上会聚。Lantzouni O,et al Plant J 2017 Dec

    植物激素赤霉素（GA）和独脚金内酯（SL）参与植物发育的基本过程。 GA和SL信号转导机制都使用赋予E3泛素连接酶介导的蛋白质降解过程的α/β水解酶衍生的受体。这表明这些途径有一个共同的进化起源，可能是它们之间的分子相互作用。这可以在水稻中得到印证，其中GA途径的DELLA蛋白被报道与SL受体相互作用。在这里，我们通过分析GA（ga1）和SL生物合成（max1和max3）突变体来检查两种途径之间的生理相互作用。在ga1 max双突变体中，当检查几种表型读数时，我们发现仅适用于加性相互作用的迹象。我们进一步通过在ga1 max1中对poly-adenylated RNAs（RNA-seq）进行新一代测序来鉴定对GA和合成的SL rac-GR24的短期转录反应。值得注意的是，这两种激素导致基本上重叠的一组基因主要是加性转录变化。仅有少数基因的表达以协同方式改变，但有趣的是，这些包括编码GA分解代谢酶GA2 OXIDASE2（GA2ox2）以及SL途径调节剂BRANCHED1（BRC1）和抑制剂max2 1-LIKE8（ SMXL8）。我们得出这样的结论：GA和拟南芥幼苗中的rac-GR24信号在一个共同基因集合的转录水平上会聚。

Abstract

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. Here, we examine the physiological interaction between both pathways through the analysis of GA (ga1) and SL biosynthesis (max1 and max3) mutants. In ga1 max double mutants, we find indications only for additive interactions when examining several phenotypic readouts. We further identify short-term transcriptional responses to GA and the synthetic SL rac-GR24 through next-generation sequencing of poly-adenylated RNAs (RNA-seq) in ga1 max1. Remarkably, both hormones lead to predominantly additive transcriptional changes of a largely overlapping set of genes. The expression of only a few genes was altered in a synergistic manner but, interestingly, these include the genes encoding the GA catabolic enzyme GA2 OXIDASE2 (GA2ox2) as well as the SL pathway regulators BRANCHED1 (BRC1) and SUPPRESSOR OF max2 1-LIKE8 (SMXL8). We conclude that GA and rac-GR24 signaling in Arabidopsis seedlings converge at the level of transcription of a common gene-set.

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