Virus-induced gene complementation reveals a transcription factor network in modulation of tomato fruit ripening

Plant virus technology, in particular virus-induced gene silencing, is a widely used reverse- and forward-genetics tool in plant functional genomics. However the potential of virus technology to express genes to induce phenotypes or to complement mutants in order to understand the function of plant genes is not well documented. Here we exploit Potato virus X as a tool for virus-induced gene complementation (VIGC). Using VIGC in tomato, we demonstrated that ectopic viral expression of LeMADS-RIN, which encodes a MADS-box transcription factor (TF), resulted in functional complementation of the non-ripening rin mutant phenotype and caused fruits to ripen. Comparative gene expression analysis indicated that LeMADS-RIN up-regulated expression of the SBP-box (SQUAMOSA promoter binding protein-like) gene LeSPL-CNR, but down-regulated the expression of LeHB-1, an HD-Zip homeobox TF gene. Our data support the hypothesis that a transcriptional network may exist among key TFs in the modulation of fruit ripening in tomato

Cinnamon Oil Inhibits Penicillium expansum Growth by Disturbing the Carbohydrate Metabolic Process

Penicillium expansum is a major postharvest pathogen that mainly threatens the global pome fruit industry and causes great economic losses annually. In the present study, the antifungal effects and potential mechanism of cinnamon oil against P. expansum were investigated. Results indicated that 0.25 mg L−1 cinnamon oil could efficiently inhibit the spore germination, conidial production, mycelial accumulation, and expansion of P. expansum. In addition, it could effectively control blue mold rots induced by P. expansum in apples. Cinnamon oil could also reduce the expression of genes involved in patulin biosynthesis. Through a proteomic quantitative analysis, a total of 146 differentially expressed proteins (DEPs) involved in the carbohydrate metabolic process, most of which were down-regulated, were noticed for their large number and functional significance. Meanwhile, the expressions of 14 candidate genes corresponding to DEPs and the activities of six key regulatory enzymes (involving in cellulose hydrolyzation, Krebs circle, glycolysis, and pentose phosphate pathway) showed a similar trend in protein levels. In addition, extracellular carbohydrate consumption, intracellular carbohydrate accumulation, and ATP production of P. expansum under cinnamon oil stress were significantly decreased. Basing on the correlated and mutually authenticated results, we speculated that disturbing the fungal carbohydrate metabolic process would be partly responsible for the inhibitory effects of cinnamon oil on P. expansum growth. The findings would provide new insights into the antimicrobial mode of cinnamon oil

Changes in physiology and quality of Laiyang pear in long time storage

Physiological disorders easily occur in Laiyang pear (Pyrus bretschneideri cv. Laiyang) fruit after harvest and result in quality deterioration and short postharvest life. In this paper, we mainly investigated the effects of 1-methylcyclopropene (1-MCP) treatment and controlled atmosphere (CA) with 2% O-2 plus 2% CO2 on quality of Laiyang pear and storage time. The results indicated that 1-MCP treatment and CA were effective in maintaining quality and prolonging storage time of Laiyang pear fruit, because 1-MCP and CA could significantly delay fruit senescence via limiting ethylene production, reducing fruit respiration rate, regulating anti-oxidant enzymes and membrane permeability. We consider that the major action modes of 1-MCP and CA, that can maintain harvested quality of Laiyang pear fruit, may be greatly contributed to inhibiting ethylene biosynthesis and regulating anti-oxidant pathways. (C) 2012 Elsevier B.V. All rights reserved

Antimicrobial evaluation of the crude extract of symbiotic fungi from marine sponge Reniera japonica

Marine sponge-derived microbes are one of the rich sources of bioactive natural products with a broad spectrum of bioactivities. The present work focuses on the isolation and antimicrobial screening of the marine sponge-associated fungi from Reniera japonica MNP-2016. The results indicated that five fungi (L1-2, L2-1, L4, L8-1 and L14) were successfully isolated. Bioassay tests showed that only strain L14 had strong inhibitory effect on the pathogens, Staphyloccocus aureus, Escherichia coli and Candida albicans. 18S rDNA sequence analysis indicated that strain L14 was ascribed to Aspergillus genus. To the best of our knowledge, this work was the first report on the isolation and antimicrobial evaluation of fungi from R. japonica. Video Clip of Methodology: 1 min 13 sec:   Full Screen   Alternat

Optimization of the Microwave-Assisted Extraction of Polyphenols from Red Pitaya Peel using Response Surface Methodology

419-424In order to maximizing extraction yield of polyphenols from red pitaya (Hylocereus undatus) peel, an agro-industrial byproduct in pitaya juice processing, the present work firstly focused on optimization of the microwave-assisted extraction (MAE) using response surface methodology (RSM). A Box-Behnken design (BBD) was used to monitor effects of five MAE factors on the polyphenols yield, including extraction time, ratio of solvent to raw material, microwave power, extraction temperature, and ethanol concentration. The optimal conditions were extraction time of 20.3 min, ratio of solvent to raw material 33.4:1 (mL:g), microwave power 497 W, extraction temperature 43.3oC and ethanol concentration 64.9%. Validation tests suggested that the actual yield of polyphenols was (463.8±1.1) mg gallic acid equivalents (GAE) per 100 g dry pitaya peel with the relative standard deviation (RSD) of 2.15% (n = 5) under the optimized conditions, which was in good agreement with the predicated yield. Antioxidant assays suggested that the ethanol extract from red pitaya peel had stronger DPPH, hydroxyl and superoxide free-radical scavenging capabilities than vitamin C at 1.0 mg/mL. These results provide an alternative way to make good use of red pitaya peel to produce natural antioxidant

Mechanism of Penicillium expansum in response to exogenous nitric oxide based on proteomics analysis

Penicillium expansurn is an important fungal pathogen, which causes blue mold rot in various fruits and produces a mycotoxin (patulin) with potential damage to public health. Here, we found that nitric oxide (NO) donor could significantly inhibit germinability of P. expansum spores, resulting in lower virulence to apple fruit. Based on two dimension electrophoresis (2-DE) and mass spectrometry (MS) analysis, we identified ten differentially expressed proteins in response to exogenous NO in P. expansum. Among of them, five proteins, such as glutamine synthetase (GS), amidohydrolase, nitrilases, nitric oxide dioxygenase (NOD) and heat shock protein 70, were up-regulated. Others including tetratricopeptide repeat domain, UDP-N-acetylglucosamine pyrophosphorylase, enolase (Eno), heat shock protein 60 and K homology RNA-binding domain were down-regulated. The expression of three genes associated with the identified proteins (GS, NOD, and Eno) was evaluated at the mRNA level by RT-PCR. Our results provide the novel evidence for understanding the mechanism, by which NO regulates growth of P. expansum and its virulence. Biological significance Crop diseases caused by fungal pathogens lead to huge economic losses every year in the world. Application of chemical fungicides to control diseases brings the concern about food and environmental safety. Screening new antimicrobial compounds and exploring involved mechanisms have great significance to development of new disease management strategies. Nitric oxide (NO), as an important intracellular signaling molecule, has been proved to be involved in many physiological processes and defense responses during plant pathogen interactions. In this study, we firstly found that NO at high concentration could distinctly delay spore germination and significantly reduce virulence of P. expansum to fruit host, identified some important proteins in response to NO stress and characterized the functions of these proteins. These results provide novel evidence for understanding the mechanism of NO regulating virulence of the fungal pathogen, but are beneficial for screening new targets of antifungal compounds. (c) 2014 Elsevier B.V. All rights reserved