马铃薯枯萎病和干腐病药剂防治筛选试验报告

马铃薯产业是宁夏“1+4”特色优势产业,是西吉县所有农作物中种植面积最大、涉及农户最多、比较效益最高的农民脱贫致富的主导产业。近年来西吉县马铃薯产业由商品薯种植大县向种薯繁育大县的转变,推动了农业增效,农民增收的快速发展。但各类土传性病害的发生影响了马铃薯产业的发展,同时磋商了农民种植的积极性。为了测定筛选出对马铃薯枯萎病和干腐病防治效果好、成本较低药剂,为大田防治提供科学依据。     

超表达OsPR1A增强了Xa21介导的水稻对白叶枯病的抗性反应

【背景】前期研究发现,水稻病程相关蛋白质OsPR1A的表达受上游抗病基因Xa21调控,接菌后早期启动Xa21介导的OsPR1A较高水平表达对水稻抵抗白叶枯病菌至关重要。同时OsPR1A也受到水稻白叶枯病菌（Xanthomonas oryzae pv. oryzae,Xoo）的诱导表达。对于OsPR1A的研究绝大部分是作为抗性反应发生的标志基因佐证其他基因或途径在抗性中的作用,缺乏直接的证据证实OsPR1A本身的生物学功能。【目的】通过获得OsPR1a-OX超表达转基因植株,调查其表型及农艺性状,并明确OsPR1A蛋白质表达与抗性的关系,为鉴定OsPR1A功能提供依据。【方法】通过农杆菌介导法,将构建的OsPR1a-OX转化载体转入到水稻受体4021中,利用PCR和免疫印迹（western blot,WB）技术分别在基因水平和蛋白质水平上筛选并鉴定OsPR1A超表达阳性纯合株系。在成熟期,调查OsPR1A超表达转基因植株的表型及农艺性状（株高、穗长、分蘖数、结实率和籽粒大小等）。在31℃条件下,将生长2周的水稻幼苗TP309、4021和OsPR1A超表达转基因植株接种水稻白叶枯病菌,并在接菌0、2、4、6、8、10和12 d时测量病斑长度。在接菌0、4和6 d时,收集TP309、4021和OsPR1A超表达转基因植株的水稻叶片,提取蛋白质,利用WB技术检测OsPR1A的表达特征。【结果】构建了OsPR1a-OX转化载体,并转入到受体4021中,筛选并鉴定到2个OsPR1A超表达转基因纯合株系（#704和#709）。调查了OsPR1A超表达转基因植株在成熟期的表型及农艺性状,与对照4021相比,#704和#709的株高较矮、穗长较短、分蘖数减少、结实率降低,但籽粒稍大,可能与结实率低有关。在31℃条件下,OsPR1A超表达转基因植株的病斑长度与对照4021相比明显缩短,结果具有显著性差异（P<0.05）。在接菌0、4和6 d的材料中,超表达转基因植株#704和#709中OsPR1A始终有较高水平的表达丰度,从而提高了对白叶枯病菌的抗性。【结论】采用农杆菌介导法,获得OsPR1A超表达转基因植株;超表达OsPR1A影响到水稻的正常发育过程;超表达OsPR1A后增强了Xa21介导的水稻对白叶枯病的抗性。     

Banishing barberry: The history of Berberis vulgaris prevalence and wheat stem rust incidence across Britain

Wheat stem rust, caused by the fungus Puccinia graminis f. sp. tritici (Pgt), is a notoriously damaging disease of wheat and barley. Pgt requires two hosts to complete its lifecycle; undergoing asexual reproduction on cereal crops and completing sexual reproduction on Berberis spp. The latter stage of its lifecycle is of particular importance in temperate regions such as western Europe, where asexual urediniospores are unable to survive cold winter weather. In the past, the crucial role of Berberis in the lifecycle of stem rust led to intensive eradication campaigns, initially carried out by farmers in the face of hostile scientific opinion. In the United Kingdom, common barberry (Berberis vulgaris) is today a relatively rare plant. Stem rust is, however, currently experiencing a resurgence; at the same time, there has been a general increase in the prevalence of barberry and an upsurge in its planting which, in the United Kingdom, is associated with attempts to encourage the endangered barberry carpet moth (Pareulype berberata). This article situates current developments within a broader chronological framework, examining changing attitudes towards barberry and rust in England in the past and the history of the plant's use and cultivation. It assesses how widespread B. vulgaris really was in the environment historically, and thus the scale of its eradication. We suggest that Berberis was never widely established as an archaeophyte in the United Kingdom. Current attempts to re-establish it are based on a misunderstanding of the plant's historical status and could potentially pose a serious threat to food security.     

马铃薯镰刀菌干腐病研究进展及防控手段

马铃薯是世界第四大粮食作物。马铃薯干腐病是一种重要的马铃薯收获后真菌病害,在我国各马铃薯产区内广泛发生,导致马铃薯块茎的商品薯率大幅下降,对马铃薯的产量造成严重经济损失。本文针对马铃薯干腐病的症状、发生与危害、病原菌种类以及综合防控手段进行综述,以期为病害的研究及防治提供参考。     

Influence of temperature,humidity duration and growth stage on the infection and mycotoxin production by Fusarium langsethiae and Fusarium poae in oats

High occurrence of Fusarium poae (FP) and Fusarium langsethiae (FL) and their mycotoxins nivalenol (NIV) and T-2/HT-2 have been observed in Swiss oats. Early prediction of mycotoxin levels is important for farmers and the cereal industry to minimize the risk of contaminated food and feed. Therefore, climate chamber experiments were conducted to investigate the influence of different temperatures (10, 15, 20 °C) and durations (4, 8, 12 h) at 99% relative humidity (RH) on the infection of oats with FP and FL. In addition, to discover the most susceptible period of oats, artificial FL inoculations were conducted at different growth stages. Field experiments were performed to observe the dispersal of these fungal species within the field and to investigate the weather conditions that influence the dispersal. The climate chamber experiments revealed higher contamination with NIV and T-2/HT-2 in the 10 °C treatments and with a prolonged humidity duration of 12 h 99% RH. Inoculations of oat plants at early (DC 61) and mid (DC 65) anthesis, led to higher FL infection and T-2/HT-2 accumulation in the grains compared with treatments at earlier growth stages, which might be due to an increased susceptibility during anthesis. No indication for spore dispersal was observed in the field experiments. The results obtained, together with the cropping factors that influence infection and mycotoxin production, could be used as a first step in developing forecasting models to predict the contamination of oats with the mycotoxins NIV and T-2/HT-2.     

红枣提取物对虹鳟血清指标和头肾免疫相关基因表达的影响

为了探讨添加红枣提取物对促进虹鳟(Oncorhynchus mykiss)机体健康的可能性,选取体长为7.2~8.4 cm的健康虹鳟,随机分成4个试验组,分别投喂红枣提取物添加量为0%(对照组)、0.25%、0.50%和1.00%的等氮等脂饲料,饲养56 d,养殖结束后测定12项血清生化指标和头肾的6个免疫相关基因mRNA表达量。结果显示:与对照组相比较,血清中肌酐(CREA)和尿素氮(BUN)含量三个红枣提取物组均出现极显著下降;谷丙转氨酶(GPT)活性在0.50%和1.00%组极显著下降,谷草转氨酶(GOT)活性也在0.50%和1.00%组出现了一定程度下降,但差异不显著;酸性磷酸酶(ACP)和碱性磷酸酶(AKP)活性无显著变化;总蛋白(TP)和白介素6(IL-6)含量在0.25%组出现显著增加;溶菌酶(LZM)活性三个红枣提取物组均显著升高;超氧化物歧化酶(SOD)活性在0.50%组极显著增加;补体4(C4)和肿瘤坏死因子(TNF-α)含量在0.25%和0.50%组均极显著增加。在头肾中,与对照组相比,SOD、白介素1β(IL-1β)和补体3(C3)基因表达量在0.50%和1.00%组均为显著或极显著上调;Factor H基因表达量在0.50%组显著上调;过氧化氢酶(CAT)和LZM基因表达量在0.50%和1.00%组仅出现差异不显著上调。上述结果表明,在虹鳟饲料中添加一定量的红枣提取物,可以起到促进肾功能,保护肝脏和提高其非特异性免疫功能的作用。     

Combining ability of yield and yield components among Fusarium oxysporum f.sp. strigae-compatible and Striga-resistant sorghum genotypes

ABSTRACT

Use of sorghum [Sorghum bicolor (L.) Moench] cultivars with partial resistance to Striga spp. and Fusarium oxysporum f.sp. strigae (FOS) represents a novel strategy to control Striga. This study aimed to identify the nature of gene action controlling grain yield and yield components and to select promising sorghum crosses possessing both FOS compatibility and Striga resistance, along with good combining ability effects. One-hundred hybrids, developed from pairwise matings among 10 FOS compatible, high-yielding female lines and 10 Striga-resistant male lines, were evaluated with and without FOS inoculation. The F₁s were field evaluated at three locations in Tanzania known for their severe Striga infestation, using an alpha lattice design with two replications. General (GCA) and specific combining ability (SCA) variances were significant for grain yield per plant, hundred-seed weight, plant height, flowering time and the number of Striga plants. The study demonstrated FOS inoculation to be an effective means of controlling Striga. Families 675?×?672, AS435?×?3993 and 4643?×?AS436 displaying large SCA effects for grain yield, and 4567?×?AS429, 3424?×?AS430 and 3424?×?AS436 with small SCA effects for Striga counts should be useful genetic resources for breeding and integrated Striga management.     

贝莱斯芽孢杆菌XC1的筛选、鉴定及其对苹果连作障碍的影响

从连作苹果园健康苹果树根际土壤中筛选出1株对苹果连作障碍镰孢属病原菌具有较强拮抗作用的细菌XC1,该菌对尖孢镰孢菌的抑菌率最高,达到79.83%。根据其形态、生理生化特征和基于16S rDNA、gyrA基因的系统发育分析,鉴定该菌为贝莱斯芽孢杆菌(Bacillus velezensis)。目前菌株XC1已保藏于中国微生物菌种保藏管理委员会普通微生物中心,保藏号为CGMCC No.20057。苹果连作土盆栽试验表明,XC1菌肥处理能显著促进平邑甜茶(Malus hupehensis Rehd.)幼苗的生长,其株高、地径、鲜质量和干质量分别比对照提高了54.8%、34.8%、121.1%和96.0%;显著提高连作土壤中的蔗糖酶、脲酶、过氧化氢酶和中性磷酸酶的活性,分别为对照的1.57倍、2.71倍、1.21倍和1.79倍;显著减少连作土壤中真菌的数量,提高细菌和放线菌的数量,且对尖孢镰孢菌(Fusarium oxysporum)有很好的抑制作用,尖孢镰孢菌的基因拷贝数比对照降低了76.4%。这说明贝莱斯芽孢杆菌抑制连作障碍病原菌的效果明显,可改善土壤环境,促进平邑甜茶幼苗的生长,能在一定程度上减轻苹果连作障碍。     

Y型网式过滤器堵塞过程对有机肥浓度的响应研究

为研究水肥一体化设备中用于过滤有机肥的Y型网式过滤器的堵塞规律,对Y型网式过滤器在初始流量500 L/h、水源压力117.6 k Pa下,设置25、30、40、50 g/L共4种黄腐酸钾有机肥肥液质量浓度,进行了过滤器堵塞试验,分析了Y型网式过滤器的局部水头损失与单个滤孔滤网清洁度(单个滤孔有效过水断面面积与孔隙总面积比值) S/S0的关系,并利用XRD分析了过滤器内堵塞物质的成分。结果表明:肥液质量浓度对过滤器滤网清洁度影响显著,建议肥液质量浓度不超过40 g/L;过滤器局部水头损失在S/S0减小到10%后才逐渐开始增大,过滤器局部水头损失与滤网清洁度、肥液质量浓度有关,利用多项式拟合给出了过滤器滤网清洁度与肥液质量浓度、施肥持续时间的关系式及局部水头损失与肥液质量浓度、滤网清洁度的关系式;滤网堵塞物质主要成分为硫酸钙、草酸钙。本研究结果可为水肥一体化设备中过滤器的选择提供理论参考。     

High vegetative compatibility diversity of Cryphonectria parasitica infecting sweet chestnut (Castanea sativa) in Britain indicates multiple pathogen introductions

Chestnut blight, caused by Cryphonectria parasitica, was identified in Devon, UK, in December 2016. Intensive surveys detected the disease at further sites in Devon (seven), Berkshire (one), Dorset (one), Derbyshire (four) and a cluster of eight sites in southeast London. Over 570 survey samples were tested, and 227 were positive for C. parasitica by isolation and real-time PCR. A total of 227 isolates were tested for mating type, and 197 screened for vegetative compatibility group (VCG) and compared with VCGs known from mainland Europe. The same isolates were also screened for the presence of Cryphonectria hypovirus 1 (CHV-1). Eleven VCGs were identified within the UK population. Five corresponded to already known European VCGs but six were unique. The European VCGs mainly came from the Devon, Dorset, Berkshire and Derbyshire disease outbreaks, whilst unique VCGs were almost exclusively from the southeast London cluster. Both mating types were detected, but only one mating type was present at each site, with the exception of a single Devon site. Perithecia of C. parasitica were never observed at any site. CHV-1 was found in seven isolates from three different locations and was always subtype-I, which has limited hypovirulence. Therefore, although CHV-1 is associated with C. parasitica at some outbreaks, it probably has limited impact on virulence. The diversity of VCGs and their distribution at outbreak sites, together with findings of CHV-1, suggests C. parasitica has been introduced to the UK multiple times over at least two decades through international plant trade.