Elimination of common scab sensitive progeny from a potato breeding population using thaxtomin A as a selective agent

Common scab is one of the most important soil‐borne diseases of potato and is difficult to control. Selection of potato breeding lines for resistance to common scab is also cumbersome due to environmental factors influencing symptom development and an erratic spatial distribution of the scab pathogens (Streptomyces spp.) in the field. The bacterial phytotoxin thaxtomin A, which causes scab symptoms, can be used to screen large numbers of potato seedlings for tolerance in vitro, but few studies have investigated whether the results correspond to resistance to common scab observed in the field. In this study, 120 F1 potato progeny from a single cross were screened in vitro by exposing the seedlings to thaxtomin A added to the culture medium. Eighteen genotypes were selected based on high sensitivity or tolerance using shoot growth as the criterion, multiplied in vitro, and tested for resistance to common scab caused by S. turgidiscabies and S. scabies in a glasshouse and in three different fields. Evaluation of ca. 6500 tubers showed that the 18 potato genotypes differed in scab indices and disease severity (P < 0·0001). The relative shoot height in vitro (thaxtomin A used at 0·5 μg mL^?1) and the scab index in the field showed significant correlation (r_s = ?0·463, P = 0·0528, n = 18), also consistent with the results obtained under controlled conditions in the glasshouse. Hence, the in vitro bioassay may be used to discard scab‐susceptible genotypes and elevate the overall levels of common scab resistance in the potato breeding populations.     

西藏小麦品种(系)的抗条锈性鉴定与评价

为了解西藏小麦品种的抗条锈性表现和筛选抗病品种,于2012—2014年对西藏本地48份小麦生产品种、保存品种及区域试验材料分别进行田间自然诱发抗条锈病性调查和抗性基因分子标记检测。抗病性调查结果表明:2年均表现为抗病的材料有19份,均表现为感病的有24份,分别占全部材料的39.6%和50.0%;有5份材料抗性表现不稳定(抗-感),占全部材料的10.4%。分子检测结果显示:48份供试材料中,未检测到Yr10阳性标记,8份检测到Yr15阳性标记,15份检测到Yr26阳性标记。田间抗病性鉴定结合抗性基因分子检测表明:3份材料可能携带Yr15,2份可能携带Yr26,Yr15和Yr26的出现频率为10.42%。结论:西藏小麦品种(系)的抗条锈性较弱,生产上抗性较强的抗病基因相对较少,今后应进一步加强抗病良种的引进、选育和推广工作。     

柔嫩艾美耳球虫MAGL基因的克隆及表达

酰基甘油酯酶(MAGL)是将酰基甘油分解为甘油和游离脂肪酸的丝氨酸水解酶家族成员之一,在酯代谢中起着关键酶的作用,是研制抗鸡球虫药物的重要靶标。本研究利用生物信息学技术预测拼接了柔嫩艾美耳球虫MAGL基因序列,以第二代裂殖子总RNA为模板,通过RTPCR技术获得Etmagl基因。将Etmagl与pCold-43a载体连接,构建pCold-43a-Etmagl重组载体,并在大肠杆菌BL21中获得可溶性蛋白,经亲和层析获得纯化的重组蛋白。结果显示,扩增的Etmagl序列ORF长1 752 bp,编码584个氨基酸,与预测序列相似度为99%,与弓形虫MAGL相似度好(55%);IPTG诱导后融合蛋白高效表达,大小约为114 ku,经免疫印迹鉴定为目的蛋白。本研究成功利用大肠埃希菌原核表达体系重组表达并纯化了柔嫩艾美耳球虫酰基甘油脂肪酶,为建立以MAGL为靶标的抗球虫药物筛选模型奠定了基础。     

Potential hazard characteristics of Tilia, Betula, and Acer trees removed in the Helsinki City Area during 2001–2003

In order to study decay, and to improve the management and protection of old urban trees, a total of 256 felled urban trees were examined during 2001–2003: 95 Tilia spp., 74 Betula spp., and 87 Acer spp. Most of the trees (73%) were located in the main parks and along the main streets in the downtown area of Helsinki City, Finland. The mean age of the trees was over 60 years, and the majority (64%) were old park trees. Poor condition and increasing risk of failure were the main reasons for felling in 82% of the cases. Thirty three percent of these trees were degenerated or dead, but the amenity value of 14% of the risk trees was still high. The latter were old, big trees which posed a potential hazard, but had a vital and balanced crown.Some characteristic profiles for potential failure were identified for each of the tree species studied: Ganoderma lipsiense in the butts and hollows in the stems of Tilia spp., weak fork formations together with Rigidoporus populinus on Acer spp., and degeneration together with decay in the stem on Betula spp.Decay fungi most commonly identified were R. populinus, G. lipsiense, Inonotus obliquus and Piptoporus betulinus. In addition, Kretzschmaria deusta was very common in three of the parks, and on every one of the tree species investigated.     

不同播期对紫花苜蓿生长性状及草产量的影响

2009年在内蒙古鄂尔多斯赛乌素嘎查,采用随机区组法进行了不同播期对紫花苜蓿生长性状及草产量影响的田间试验研究。连续2年对出苗时间、出苗率、越冬率、株高、物候期、草产量、鲜干比、茎叶比的测定结果表明,在春播与秋播区间内,出苗时间与播种日期存在显著的正相关关系,生育时期随播期的提前而相应提前;秋播越早,根颈越粗,入土越深,当年越冬性越强,翌年草产量也越高;不同播期对鲜干比、茎叶比影响甚微。综合评价认为,该地种植紫花苜蓿,宜选择秋季播种,阈值为9月中旬。     

Estimating annual GPP,NPP and stem growth in Finland using summary models

In this study we introduce and test a new simple approach for estimating annual stand-level gross primary production (GPP), net primary production (NPP) and stem biomass growth based on carbon acquisition and allocation, by combining existing summary models. The focus is on the variation of GPP and NPP across different parts of Finland caused by climate.     

马铃薯早疫病的杀菌剂田间药效试验

马铃薯早疫病近年来在各马铃薯主产区发生比较严重,为此我们进行了马铃薯早疫病杀菌剂药效筛选试验。结果表明:防治效果较好的是25%阿米西达1 000倍、60%氟吗啉.代森锰锌600倍、52.5%抑快净2 000倍,防效分别为87.71%、84.13%、81.26%。由于防治效果比较明显,所以建议在生产上使用。