Auxin response factors (ARFs) differentially regulate rice antiviral immune response against rice dwarf virus

There are 25 auxin response factors (ARFs) in the rice genome, which play critical roles in regulating myriad aspects of plant development, but their role (s) in host antiviral immune defense and the underneath mechanism remain largely unknown. By using the rice-rice dwarf virus (RDV) model system, here we report that auxin signaling enhances rice defense against RDV infection. In turn, RDV infection triggers increased auxin biosynthesis and accumulation in rice, and that treatment with exogenous auxin reduces OsIAA10 protein level, thereby unleashing a group of OsIAA10-interacting OsARFs to mediate downstream antiviral responses. Strikingly, our genetic data showed that loss-of-function mutants of osarf12 or osarf16 exhibit reduced resistance whereas osarf11 mutants display enhanced resistance to RDV. In turn, OsARF12 activates the down-stream OsWRKY13 expression through direct binding to its promoter, loss-of-function mutants of oswrky13 exhibit reduced resistance. These results demonstrated that OsARF 11, 12 and 16 differentially regulate rice antiviral defense. Together with our previous discovery that the viral P2 protein stabilizes OsIAA10 protein via thwarting its interaction with OsTIR1 to enhance viral infection and pathogenesis, our results reveal a novel auxin-IAA10-ARFs-mediated signaling mechanism employed by rice and RDV for defense and counter defense responses.     

Five months of daily standardized exercise for sedentary monkeys

A system to physically exercise rhesus monkeys is described, based on their natural capacity to climb. It is composed of an enclosure where a motor-driven rope is continually going down. The two stage training to this task is easily performed. The total work of each run, evaluated with the weight of the animal and the distance climbed, may be very stable. It was used to provide five sedentary monkeys with daily physical training for five months.     

Effects of Anoectochilus formosanus Hayata extract and glucocorticoid on lung maturation in preterm rats.

We investigated the effects of maternal administration of Anoectochilus formosanus extract and dexamethasone on lung maturation in preterm rats. A. formosanus group mothers were tube-fed A. formosanus extract (300 mg/kg body wt./day) for 7 days from days 12-18 of gestation. Dexamethasone group mothers were injected intraperitoneally with dexamethasone (0.2 mg/kg body wt.) in saline on day 18 of gestation. Control group mothers were similarly injected with saline alone. On day 19 of gestation, fetuses were delivered by cesarean section. A. formosanus treatment significantly increased the fetal lung/body weight ratio, as compared to dexamethasone treatment. Saturated phosphatidylcholine levels in fetal lung tissue and growth hormone levels in maternal serum were significantly increased in the A. formosanus- and dexamethasone-treated groups as compared to controls. The histological appearance of preterm rat lungs revealed extensive branching of intermediate airways, denser mesenchyme, and more epithelial tubules in the dexamethasone and A. formosanus groups as compared with the control group. These results suggest that antenatal A. formosanus treatment may play a role in accelerating fetal rat lung maturation.     

MicroRNA-520b inhibits growth of hepatoma cells by targeting MEKK2 and cyclin D1

Growing evidence indicates that the deregulation of microRNAs (miRNAs) contributes to the tumorigenesis. We previously revealed that microRNA-520b (miR-520b) was involved in the complement attack and migration of breast cancer cells. In this report, we show that miR-520b is an important miRNA in the development of hepatocellular carcinoma (HCC). Our data showed that the expression levels of miR-520b were significantly reduced in clinical HCC tissues and hepatoma cell lines. We observed that the introduction of miR-520b dramatically suppressed the growth of hepatoma cells by colony formation assays, 5-ethynyl-2-deoxyuridine (EdU) incorporation assays and 3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays. Moreover, ectopic expression of miR-520b was able to inhibit the growth of hepatoma cells in nude mice. Further studies revealed that the mitogen-activated protein kinase kinase kinase 2 (MEKK2) and cyclin D1 were two of direct target genes of miR-520b. Silencing of MEKK2 or cyclin D1 was able to inhibit the growth of hepatoma cells in vitro and in vivo, which is consistent with the effect of miR-520b overexpression on the growth of hepatoma cells. In addition, miR-520b significantly decreased the phosphorylation levels of c-Jun N-terminal kinase (p-JNK, a downstream effector of MEKK2) or retinoblastoma (p-Rb, a downstream effector of cyclin D1). In conclusion, miR-520b is able to inhibit the growth of hepatoma cells by targeting MEKK2 or cyclin D1 in vitro and in vivo. Our findings provide new insights into the role of miR-520b in the development of HCC, and implicate the potential application of miR-520b in cancer therapy.     

中国西部地区归化植物时空分布特征研究

归化是外来植物越过一系列障碍成为入侵植物的基本前提,对归化植物的种类组成及分布规律进行研究,有助于预防和管控植物入侵.该文基于文献报道和标本记录,对中国西部地区共12省(区)126个地级市的归化植物进行统计(包含所有维管束植物),并分析了这些植物的组成和时空分布特征.结果表明:(1)西部地区共有归化植物826种,分属1...     

Dominant and pleiotropic effects of a GAI gene in wheat results from a lack of interaction between DELLA and GID1

Dominance, semidominance, and recessiveness are important modes of Mendelian inheritance. The phytohormone gibberellin (GA) regulates many plant growth and developmental processes. The previously cloned semidominant GA-insensitive (GAI) genes Reduced height1 (Rht1) and Rht2 in wheat (Triticum aestivum) were the basis of the Green Revolution. However, no completely dominant GAI gene has been cloned. Here, we report the molecular characterization of Rht-B1c, a dominant GAI allele in wheat that confers more extreme characteristics than its incompletely dominant alleles. Rht-B1c is caused by a terminal repeat retrotransposons in miniature insertion in the DELLA domain. Yeast two-hybrid assays showed that Rht-B1c protein fails to interact with GA-INSENSITIVE DWARF1 (GID1), thereby blocking GA responses and resulting in extreme dwarfism and pleiotropic effects. By contrast, Rht-B1b protein only reduces interaction with GID1. Furthermore, we analyzed its functions using near-isogenic lines and examined its molecular mechanisms in transgenic rice. These results indicated that the affinity between GID1 and DELLA proteins is key to regulation of the stability of DELLA proteins, and differential interactions determine dominant and semidominant gene responses to GA.     

The Global Phosphoproteome of Chlamydomonas reinhardtii Reveals Complex Organellar Phosphorylation in the Flagella and Thylakoid Membrane

Chlamydomonas reinhardtii is the most intensively-studied and well-developed model for investigation of a wide-range of microalgal processes ranging from basic development through understanding triacylglycerol production. Although proteomic technologies permit interrogation of these processes at the protein level and efforts to date indicate phosphorylation-based regulation of proteins in C. reinhardtii is essential for its underlying biology, characterization of the C. reinhardtii phosphoproteome has been limited. Herein, we report the richest exploration of the C. reinhardtii proteome to date. Complementary enrichment strategies were used to detect 4588 phosphoproteins distributed among every cellular component in C. reinhardtii. Additionally, we report 18,160 unique phosphopeptides at <1% false discovery rate, which comprise 15,862 unique phosphosites - 98% of which are novel. Given that an estimated 30% of proteins in a eukaryotic cell are subject to phosphorylation, we report the majority of the phosphoproteome (23%) of C. reinhardtii. Proteins in key biological pathways were phosphorylated, including photosynthesis, pigment production, carbon assimilation, glycolysis, and protein and carbohydrate metabolism, and it is noteworthy that hyperphosphorylation was observed in flagellar proteins. This rich data set is available via ProteomeXchange (ID: PXD000783) and will significantly enhance understanding of a range of regulatory mechanisms controlling a variety of cellular process and will serve as a critical resource for the microalgal community.Chlamydomonas reinhardtii (C. reinhardtii)¹ is the most intensively studied and well-developed microalgal model species for investigation of a wide-range of processes ranging from basic development through understanding triacylglycerol production. C. reinhardtii is easy to culture, grows quickly, and is tolerant to varying growth conditions. Additionally, the genome of C. reinhardtii is sequenced (1) and C. reinhardtii is easily engineered at the genetic level (2), thus making it an attractive model system for investigation of a wide range of underlying biology processes, including photosynthesis, cell motility, and phototaxis, cell-wall biogenesis, and other fundamental cellular processes (3).Advances in proteomic technologies permit ever increasing breadth and depth for interrogation of protein level dynamics, and the definitive role of phosphorylation in affecting a protein''s function, activity, localization, stability, and ligand/protein interactions is well understood (4). However, compared with Arabidopsis and other plant species (5), the C. reinhardtii phosphoproteome data set is still in nascent assembly. In a series of studies, researchers investigated the effects of environmental changes on 43 phosphopeptides among thylakoid membrane-associated proteins (6–8), analysis of which provides evidence for a thylakoid protein kinase cascade. Wagner et al. (9) observed 83 phosphopeptides associated with the eyespot apparatus, including several kinases and phosphatases implicated in phosphorylation-based signaling in the eyespot. In a study of C. reinhardtii flagella, Pan et al. (10) observed 1296 spectral counts of phosphopeptides corresponding to 224 phosphoproteins involved with motility and assembly. In a similar study, Boesger et al. (11) observed 141 phosphopeptides corresponding to 32 proteins. Using whole cells, Wagner et al. (12) observed 360 phosphopeptides corresponding to 328 proteins, including several flagellar kinases, which indicates the importance of phosphorylation-based signaling for motility and assembly.Despite the importance of phosphorylation-based signaling underlying C. reinhardtii biological processes, characterization of the cellular pool of phosphopeptides has been limited. Although additional dimensions of separation that are orthogonal to online reversed-phase are routinely used in order to probe phosphopeptide species of low-abundance, this has not been implemented for probing the C. reinhardtii phosphoproteome. Hydrophilic-interaction liquid chromatography improves phosphopeptide separation and detection (13) and is more orthogonal than strong-cation exchange compared with online reversed-phase chromatography (14). Additionally, to complement the increased resolution of phosphopeptides afforded by a first-dimension separation, enrichment strategies based on the affinity of a phosphate group to a metal ion or metal oxide can further increase coverage. Currently, a single immobilized metal affinity chromatography (IMAC) scheme is the most popular choice for phosphopeptide studies using C. reinhardtii. However, conventional insoluble TiO₂ beads recover more phosphopeptides than traditional IMAC (15). Additionally, PolyMAC (polymer-based metal ion affinity capture) is a polymer-based improved analog of IMAC that uses TiO₂-functionalized soluble nanopolymers to chelate phosphopeptides in a homogeneous aqueous environment (15). Thus, use of complementary enrichment schemes based on TiO₂ and PolyMAC can yield more comprehensive results compared with a single strategy.In this study, complementary approaches using TiO₂/PolyMAC enrichment and hydrophilic-interaction liquid chromatography (HILIC) chromatography were employed to explore the C. reinhardtii phosphoproteome in significant depth. We report the detection of 4588 nonredundant phosphoproteins from 18,160 unique phosphopeptides at <1% false discovery rate. Among these peptides, we report 15,862 unique phosphosites identified with ≥95% localization probability. Nearly all reported sites are novel. Our data show many key biological pathways, including photosynthesis, chlorophyll biosynthesis, carbon assimilation, protein metabolism, and flagella assembly and motility are comprised of multiple phosphoproteins. These data provide a framework for garnering novel mechanistic insights into understanding a variety of cellular/signaling processes.