拟康宁木霉Tk1的分离鉴定、拮抗作用及其生物学特性

为了分离利用高效植物病害生物防治菌株，从广东药用植物金丝皇菊根部分离获得一株木霉菌株Tk1。经过形态观察、rDNA-ITS和EF-1α序列分析明确其为拟康宁木霉Trichoderma koningiopsis。用平板对峙培养法测定，该菌株对金丝皇菊枯萎病菌（尖孢镰刀菌Fusarium oxysporum）和柑橘炭疽病菌（胶胞炭疽菌Colletotrichum gloeosporioides）的抑制率分别为68.5%和77.1%，且在后期能完全覆盖或部分覆盖病原真菌。其无菌发酵液对金丝皇菊枯萎病菌的抑制率为45.55%。该菌株营养生长和产孢的最适碳源分别为乳糖和葡萄糖，最适氮源是酵母膏；在pH 4~11的培养基上均可生长、产孢，最适pH为7；12 h交替光照条件下菌丝的生长速度最快，全光照条件下产孢数量最大；该菌株的致死温度为73℃处理10 min。     

Relationships Among the Feeding Behaviors of a Mirid Bug on Cotton Leaves of Different Ages and Plant Biochemical Substances

Apolygus lucorum (Meyer-Dür) (Hemiptera: Miridae) tends to feed on young plant tissues. To explore the relationship between stylet probing behaviors of adult A. lucorum and conditions of cotton leaves, we conducted an experiment using electropenetrography (EPG). Behaviors were recorded on four cotton varieties, in relation to thickness and biochemical traits of differently-aged leaves. Cotton leaf age had a significant effect on the probing behavior of A. lucorum but cotton variety did not. One-day-old leaves of A. lucorum received the highest mean number of stylet probes (penetrations) per insect, and longest mean durations per insect of combined stylet probing or its components, cell rupture and ingestion behaviors. All of the leaf traits (thickness and biochemical substances) were similar among these four cotton varieties. Leaf thickness had a significantly negative effect on the same four variables above. Gossypol and tannin also had a negative impact on combined probing duration. Redundancy analysis showed that the four EPG variables were closely related to nutrient substances (amino acids, sugar, and water) while they had the opposite relationship with plant defense substances (gossypol and tannin). On cotton in the seedling stages, A. lucorum fed more readily on the youngest, thinnest leaves in our no-choice EPG experiments. Nutrients and chemical resistance substances determined the probing duration of A. lucorum. Our findings can contribute to better understanding of patterns of feeding and host consumption by A. lucorum, ultimately improving cotton resistance to A. lucorum.     

Foliar lifespan,phenology and seasonal dynamics of the invasive shrub Schinus terebinthifolia

Schinus terebinthifolia is a dioecious tree native to South America that has become an invasive weed in Florida, southern California, southern Arizona, Texas and Hawaii and has been naturalised in over 20 countries. Biological control is considered a viable long-term control option for S. terebinthifolia because release from natural enemies appears to be at least partly responsible for its success in Florida. We examined leaf phenology of S. terebinthifolia over a period of 15 months at five sites in central and southern Florida to provide information that may help in predicting the impacts of potential biocontrol agents for this weed. We documented leaf lifespan, the seasonality of leaf development and abscission and the survivorship of leaves that emerged during either spring, summer or autumn. Average leaf lifespan was >4.5 months at all sites, and leaf phenology followed the seasons closely. Although S. terebinthifolia possesses leaves throughout the year, leaf production was greatest from April to September, and most leaves were abscised in February and March. Spring- and summer-emerging leaves were also longer-lived than leaves produced during autumn. These results suggest that leaves of S. terebinthifolia would be most vulnerable to herbivory during the spring and summer months when newly growing leaf tissue is most plentiful. Biocontrol agents capable of damaging these tissues during spring/summer might be an effective means of controlling this invasive weed.     

Effects of maltogenic amylase from Lactobacillus plantarum on retrogradation of bread

Maltogenic amylase originated from Lactobacillus plantarum (LpMA) was studied to investigate its applicability as an antistaling enzyme. The differential scanning calorimetry (DSC) results demonstrated that the bread treated with purified LpMA exhibited a retrogradation peak that was 65% that of the control bread. Then, for the purpose of practically using L. plantarum as an antistaling agent, the expression of LpMA in L. plantarum was enhanced by growth on a modified medium; the LpMA expression of L. plantarum grown on De Man, Rogosa and Sharpe (MRS) medium supplemented with an additional 6% glucose was 54 times higher than that of L. plantarum grown on the original MRS medium. The side chain length distribution analysis showed that the cell extract of L. plantarum (CELP) tended to prefer to hydrolyzes the long side chains of amylopectin (>30). During storage for 9 days at 4 °C, the bread treated with CELP exhibited a 25% slower retrogradation rate and 63% lower hardness relative to the control bread, indicating that the CELP is a potential candidate for use as an antistaling agent.     

Enriching novel Glu-Ax alleles and significantly strengthening gluten properties of common wheat through wide hybridization with wild emmer

Two hybrids, BAd7-209 and BAd7-210, were obtained by wide hybridization between wild emmer D97 and weak gluten cultivar CN16. They had a genetic background of common wheat, resulting from continuous selfing over nine times. These hybrids were better than CN16 in dough quality and processing quality tests. BAd7-210 was better than medium gluten wheat cultivar MM37, and BAd7-209 was far better than moderate to strong gluten wheat cultivar SM482. Through chromosome engineering, BAd7-210 possessed the 1Ax2.2 of male D97, and BAd7-209 had the 1Ax1.2 which was caused by complex variation because of cross-parents’ genomic asymmetry. The open reading frames (ORFs) of two novel active Glu-Ax alleles 1Ax2.2 and 1Ax1.2 were 2496 bp and 2514 bp, encoding 830 and 836 amino acid residues, respectively. The 1Ax1.2 was the second longest Glu-Ax gene discovered to date, and it had two deletions and one insertion besides many single nucleotide polymorphisms (SNPs) compared with the 1Ax2.2 and 1Ax1. The longer polypeptide of 1Ax1.2 should explain why BAd7-209 has better processing quality than BAd7-210. Therefore, wild emmer could be effectively utilized to enrich the 1Ax alleles of common wheat through direct cross transferring and generating novel allele variation, which could significantly enhance the gluten strength.     

Identification of genotyping-by-sequencing sequence tags associated with milling performance and end-use quality traits in hard red spring wheat (Triticum aestivum L.)

Genotyping-by-sequencing (GBS) utilizes Next-Generation sequencing to genetically and physically map traits of interest. Here we use GBS to identify QTLs and SNP markers associated with milling and end-use quality traits in an hard red spring wheat recombinant inbred line (RIL) population. The RIL population and parents were phenotyped for eleven milling and end-use quality traits, and genotyped using GBS technology, simple sequence repeat (SSR) and allele specific sequence tagged site markers. A genetic map comprising 696 markers was used to map the end-use quality traits. Multiple QTL mapping identified 79 QTLs, 19 of which were declared ‘major’ as they explained greater than 15% of the phenotypic variance each. Transgressive segregants were observed for all phenotypes and co-locating QTLs controlling multiple quality traits were confirmed on chromosomes 1BL, 5AS, 7AS, 7AL and 7BS. To date, no GBS analysis to locate end-use quality QTLs in wheat has been conducted, thus the reporting and validation of these GBS sequence tags and their associated QTLs will shed light on the genetic architecture underlying these quantitative traits and assist wheat breeders in developing cultivars with favorable alleles through the use of marker assisted selection.     

Thymol attenuates allergic airway inflammation in ovalbumin (OVA)-induced mouse asthma

Thymol, a naturally occurring monocyclic phenolic compound derived from Thymus vulgaris (Lamiaceae), has been reported to exhibit anti-inflammatory property in vivo and vitro. However, the mechanism of thymol is not clear. The aim of the present study was to investigate the effects of thymol on allergic inflammation in OVA-induced mice asthma and explore its mechanism. The model of mouse asthma was established by the induction of OVA. Thymol was orally administered at a dose of 4, 8, and 16 mg/kg body weight 1 h before OVA challenge. At 24 h after the last challenge, mice were sacrificed, and the data were collected by various experimental methods. The results revealed that pretreatment with thymol reduced the level of OVA-specific IgE, inhibited recruitment of inflammatory cells into airway, and decreased the levels of IL-4, IL-5, and IL-13 in BALF. Moreover, the pathologic changes of lung tissues were obviously ameliorated and goblet cell hyperplasia was effectively inhibited by the pretreatment of thymol. In addition, thymol reduced the development of airway hyperresponsiveness and blocked the activation of NF-κB pathway. All data suggested that thymol ameliorated airway inflammation in OVA-induced mouse asthma, possibly through inhibiting NF-κB activation. These findings indicated that thymol may be used as an alternative agent for treating allergic asthma.     

Turnip crinkle virus with nonviral gene cancels the effect of silencing suppressors of P19 and 2b in Arabidopsis thaliana

In plants, green fluorescent protein (GFP) has become a preferred molecular marker for gene expression and cellular localization, and plant viral vectors are valuable tools for heterologous gene expression. Some plant viruses have been used for expression of GFP, and the activities of these viruses are barely affected by the extra GFP gene. In contrast, the packaging and the length of Turnip crinkle virus (TCV) genome is strictly limited when foreign genes are inserted into the coding sequences of TCV genome. In this report, we removed the silencing suppressor p38 from TCV, and constructed GFP derivatives of TCV. Then the resulting TCV mutants were used to infect Arabidopsis plants containing mutations in key silencing pathway genes, including triple dcl2/dcl3/dcl4, dcl2, dcl4 and ago mutant plants. Our results demonstrate that the activity of TCV is affected by nonviral GFP insert in Arabidopsis plants, and RNA silencing appears not play an important role. AGOs appear to be more efficient at slicing RNAs of viral origin, especially AGO2 and AGO7. Although the viral suppressors of RNA silencing (VSRs) P19 and 2b can enhance the accumulation of viral RNAs, neither P19 nor 2b can significantly increase the expression of TCV mutants with nonviral genes. TCV is an example of an RNA virus that is recalcitrant to add nonviral gene sequences.     

安徽药用牡丹炭疽病病原菌鉴定

<正>牡丹(Paeonia suffruticosa Andr.)是芍药科植物,为多年生落叶灌木,具有很高的观赏和药用价值。因其风姿华丽、色彩艳丽、品种繁多、深受大家喜爱,是中国传统名花和世界著名花卉之一。其根皮也被称为丹皮,具有抗炎、抑制血小板、止痛、清热等作用,是六味地黄丸等著名中成药的主要配方,也是饮片中的常用品[1-2]。近年来,随着牡丹种植面积的不断扩大,造成牡丹病害的大面积发生,已给牡丹生产带来严重影响。     

Incubation of ovine scrapie with environmental matrix results in biological and biochemical changes of PrPSc over time

Ovine scrapie can be transmitted via environmental reservoirs. A pool of ovine scrapie isolates were incubated on soil for one day or thirteen months and eluted prion was used to challenge tg338 mice transgenic for ovine PrP. After one-day incubation on soil, two PrP^Sc phenotypes were present: G₃₃₈ or Apl₃₃₈ii. Thirteen months later some divergent PrP^Sc phenotypes were seen: a mixture of Apl₃₃₈ii with either G₃₃₈ or P_338, and a completely novel PrP^Sc deposition, designated Cag₃₃₈. The data show that prolonged ageing of scrapie prions within an environmental matrix may result in changes in the dominant PrP^Sc biological/biochemical properties.