梨火疫病病原菌的分离鉴定及室内抑菌药剂筛选

为明确新疆库尔勒地区梨火疫病致病菌,并筛选有效防治药剂。采用平板划线法获得分离物,结合致病性测定、形态学特征与分子生物学技术综合鉴定致病菌,采用“药液-菌液共培养法”与“抑菌圈法”测定16种杀菌剂对其室内毒力。鉴定分离物为Erwinia amylovora。16种杀菌剂对梨火疫病菌均有抑制作用。其中,0.3%四霉素AS抑菌效果最好,EC₅₀为2.968μg/mL。研究结果对梨火疫病田间药剂防治提供科学依据。     

贵州多花黄精根腐病病原菌鉴定及生防菌筛选

【目的】明确贵州多花黄精根腐病病原菌,并筛选出对该病原菌有生防活性的生防菌,为多花黄精根腐病的诊断及绿色防控提供依据。【方法】对贵州省台江县的感病多花黄精块茎进行分离纯化、致病性验证,并结合形态学特征和分子生物学技术进行病原菌鉴定。利用平板对峙试验筛选出抑菌活性高的生防菌株,综合培养形状、形态学特征和系统发育树分析,明确其分类学地位,并测定其发酵液对病原菌菌丝生长的抑制作用。【结果】从感病多花黄精样品中分离出 28 株真菌,其中 12 株可导致明显的根腐病症状,2GF1 导致的根腐病病状最为明显。形态学特征和系统发育树分析结果显示,鉴定出的 12 株病原菌为尖孢镰刀菌（Fusarium oxysporum）。平板对峙试验结果表明,真菌中生防效果较好的为菌株 WHD01、抑制率 95.21%;细菌中生防效果较好的为菌株 WHD04、抑制率 78.99%。结合形态学和分子生物学将 WHD01、WHD02、WHD03、WHD04分 别 鉴 定 为 绿 木 霉（Trichoderma virens）、 大 伏 革 菌（Phlebiopsis gigantea）、 解 淀 粉 芽 孢 杆 菌（Bacillus amyloliquefaciens）、贝莱斯芽孢杆菌（Bacillus velezensis）。发酵液浓度为 200 mL/L 时,WHD01、WHD02、WHD03、WHD04 对病原菌菌丝生长的抑制效果分别为 32.70%、26.72%、33.05% 和 33.52%。【结论】明确了贵州省台江县多花黄精根腐病的病原菌为尖孢镰刀菌,并筛选到具有生防作用的 4 株生防菌株,可为多花黄精根腐病的绿色防治提供理论依据。     

扶桑绵粉蚧虫生真菌 FE-1 菌株的鉴定及其毒力测定

【目的】评价从扶桑绵粉蚧（Phenacoccus solenoposis）僵虫中分离的虫生真菌在害虫生物防治中 的应用潜力,为开发其作为生物防治制剂提供基础。【方法】采用组织分离法,从扶桑绵粉蚧僵虫中分离纯化 虫生真菌菌株,综合培养性状、形态学特性和系统发育树分析,明确其分类学地位;利用扫描电镜技术,探究 菌株对扶桑绵粉蚧的侵染方式,明确其对扶桑绵粉蚧的侵染力;采用浸虫法,室内测定分离菌株对扶桑绵粉蚧 雌成虫的致病力。【结果】从扶桑绵粉蚧僵虫中分离纯化获得一株真菌菌株 FE-1,形态学结果发现菌株 FE-1 在 PDA 培养基培养 5 d 后菌落直径为 50~60 mm,菌落正面为橙白色,分生孢子形态呈两种类型,小型孢子为 长柱形,大型孢子为镰刀型;综合培养性状、形态学特征和系统发育树分析结果鉴定菌株 FE-1 为木贼镰刀菌 （Fusarium equiseti）;扫描电镜结果表明菌株 FE-1 侵染扶桑绵粉蚧的方式主要为分生孢子在表皮处萌发形成芽 管,然后水平生长,并在特定接触表皮处形成膨大的附着孢进入昆虫体腔,明确了菌株 FE-1 对扶桑绵粉蚧侵染 力;室内毒力测定结果表明,菌株 FE-1 对扶桑绵粉蚧雌成虫的致病力随着分生孢子浓度的增大逐渐增强;孢子 浓度为 1×108 CFU/mL 时,LT50 为 3.32 d,接种 7 d 后,扶桑绵粉蚧雌成虫的校正死亡率为 87.50（±1.79）%, LC50 为 1.8×105 CFU/mL。【结论】从扶桑绵粉蚧僵虫中分离纯化获得的木贼镰刀菌菌株 FE-1,其在扶桑绵粉 蚧体壁能形成膨大的附着孢进行侵染,对扶桑绵粉蚧具有一定的侵染力。同时,该菌株在室内对扶桑绵粉蚧雌 成虫有较好的致死效果,极具生防潜力,可为扶桑绵粉蚧的生物防治研究提供优质的原材料。     

烟草赤星病生防菌的分离与鉴定

从连作障碍较严重的烟草根际土壤中分离出49株细菌活体纯培养物,依次编号为HHHB1～HHHB49,并筛选出对烟草赤星病病原菌（Alternaria alternate）具有拮抗活性的菌株HHHB7和HHHB19,二者抑菌圈直径分别为5、23 mm。二者初步定性为具有生防活性。多相鉴定结果表明,活性最强的菌株HHHB19隶属于假单胞菌属（Pseudomonas）,暂定名Pseudomonas sp. HHHB19。盆栽试验证实,HHHB19菌株悬液叶面喷雾混合处理对烟草赤星病不同发病阶段均表现出一定的防治效果,其中喷施14 d后防治效果达61.83%。菌株HHHB19可作为良好的生防菌备用资源。     

萱草叶枯病病原鉴定及药剂筛选

【目的】分离纯化上海应用技术大学萱草种质资源圃中疑似萱草叶枯病的病原菌,并对其进行鉴定;筛选对分离病原菌生长具有明显抑制作用的杀菌剂,为萱草叶枯病的田间防治提供科学依据。【方法】采集上海应用技术大学萱草种质资源圃中疑似萱草叶枯病病叶,采用组织分离法分离、纯化病原菌,并进行回接试验验证。对分离病原菌进行菌落形态和显微形态观察,并进行rDNA-ITS序列分析,采用MEGA 7.0软件中Neighbor-joining法构建其系统进化树,鉴定其分类地位。利用带毒平板法测定50%腐霉利可湿性粉剂、75%百菌清可湿性粉剂、77%硫酸铜钙可湿性粉剂对病原菌的室内毒力。【结果】从疑似萱草叶枯病病叶中分离得到病原菌YK1,其菌落呈雪白色放射状,分子孢子为卵圆形或近椭圆形,呈麦穗状,孢子壁为黑色,内容物透明,孢子大小为(3.63～7.27) μm×（3.63～7.27） μm,孢子壁约为1.82 μm。PCR扩增获得YK1内转录间隔区（ITS）序列,系统进化分析显示,在Limonomyces属菌种大类中YK1与秆褐霉菌（Limonomyces culmigenus）聚在同一分支上。3种低毒杀菌剂对YK1均有一定抑制作用,其中75%百菌清可湿性粉剂对YK1的抑制作用最强,其有效中浓度（EC₅₀）为0.114 7 mg/L。【结论】本次萱草叶枯病病原菌为秆褐霉菌（Limonomyces culmigenus）,75%百菌清可湿性粉剂对其有较好的抑制作用。     

农田生态环境损害鉴定评估技术需求

农田生态环境损害是生态环境损害赔偿案件的重要类型,主要涉及非法占地、非法采矿、污染排放等类型。现有农田生态环境损害鉴定评估标准规范从总体要求、不同环节、不同要素维度提出了鉴定要求,但在与现有损害鉴定评估标准的兼容性、技术标准规定的简便性以及损害调查指标和方法的系统性、因果关系判定的严密性、评价标准的全面性、费用和价值测算方法的一致性等方面还存在不足,需要充分整合现有标准,形成与现有国家标准相衔接且简单实用的农田损害鉴定评估标准,并推动重点领域技术方法突破,逐步完善以农田生态环境恢复和农产品价值评估为核心的农田损害价值量化技术体系,保障农田生态环境损害鉴定评估过程的规范性和结果的可靠性。     

城市池塘水质时间变化特性--以扬州大学江阳路南校区池塘为例

城市中的池塘是城市水体的重要组成部分,为揭示城市化背景下池塘水体水质的时间变化特性,选取扬州大学江阳路南校区池塘为研究区,对该池塘2018年7月至2019年6月的水质参数蓝绿藻浓度(Phyco)、水温(WT)、溶解氧(DO)、pH与电导率(EC)进行观测,采用变异系数法、单因子水质标识指数法以及多元线性回归法对各参数的变化特性进行评价。结果显示:池塘WT呈季节性变化;观测期间pH变化范围为7.74~9.98,水体呈碱性;DO变化的随机性较强,未表现出明显变化规律;各水质参数变异性及权重从大到小依次为WT>DO>EC>pH;以DO为指标的单因子水质标识指数结果表明:池塘DO达到Ⅲ类水要求的时段占总观测时段的84%;多元线性回归分析结果表明:DO与WT、pH呈正相关,与Phyco呈负相关,Phyco及pH的变化对DO浓度的影响相对于WT大。     

Migration pathways,speed and mortality of Atlantic salmon (Salmo salar) smolts in a Scottish river and the near‐shore coastal marine environment

Long‐distance migration of Atlantic salmon (Salmo salar) is known to result in high levels of mortality. For a species experiencing global population decline, it is thus vital to better understand migration behaviour, both in the river and marine stages. Atlantic salmon smolts (n = 50) were tracked using acoustic telemetry in the River Deveron, Scotland, and adjacent coastal area. Higher rates of mortality were observed in the river (0.77% per km) than the early marine stage of migration (0.0% per km). Mortality likely resulted from predation. Higher swim speeds were recorded in the early marine stage compared with the river (marine = 7.37 ± 28.20 km/day; river = 5.03 ± 1.73 km/day [mean ± SD]), a potential predator avoidance behaviour. The majority of smolts leaving the river did so in darkness and on a flooding tide. Overall river and marine migration success were linked to nights of lower lunar brightness. Marine migration speed decreased with increasing environmental noise levels, a finding with implications for fisheries management. The migration pathway in the early marine environment did not follow obvious geographical features, such as the coastline. Thus, we suggest that early marine environment pathways are more influenced by complex water currents. These findings highlight factors that influence smolt migration survival and behaviour, areas on which future research should focus.     

Winter movement activity patterns of anadromous Arctic charr in two Labrador lakes

Anadromous Arctic charr, Salvelinus alpinus, feed in the marine environment for several months during the summer and migrate back to fresh water in late summer to spawn and/or overwinter. While overwintering, anadromous Arctic charr are generally believed to reduce or cease feeding, and they are poorly described in their winter movement activity. This study used telemetry data collected from two locations to describe overwintering movement activity, including interindividual variation. Movement activity declined markedly during the ice‐covered period, suggesting opportunistic maintenance feeding was used as an energy conservation strategy. Fall and spring movement was correlated with daylight hours, and ice break‐up had a significant effect on the timing of outmigration. Movement activity was negatively correlated with body length, with smaller individuals being more active than larger fish. Although general activity patterns were evident, there were significant differences among individuals, particularly during spring immediately prior to lake departure. Lake size and individual differences in metabolic rate may account for some of this variation.     

Improvement,identification, and target prediction for miRNAs in the porcine genome by using massive,public high-throughput sequencing data

Despite the broad variety of available microRNA (miRNA) research tools and methods, their application to the identification, annotation, and target prediction of miRNAs in nonmodel organisms is still limited. In this study, we collected nearly all public sRNA-seq data to improve the annotation for known miRNAs and identify novel miRNAs that have not been annotated in pigs (Sus scrofa). We newly annotated 210 mature sequences in known miRNAs and found that 43 of the known miRNA precursors were problematic due to redundant/missing annotations or incorrect sequences. We also predicted 811 novel miRNAs with high confidence, which was twice the current number of known miRNAs for pigs in miRBase. In addition, we proposed a correlation-based strategy to predict target genes for miRNAs by using a large amount of sRNA-seq and RNA-seq data. We found that the correlation-based strategy provided additional evidence of expression compared with traditional target prediction methods. The correlation-based strategy also identified the regulatory pairs that were controlled by nonbinding sites with a particular pattern, which provided abundant complementarity for studying the mechanism of miRNAs that regulate gene expression. In summary, our study improved the annotation of known miRNAs, identified a large number of novel miRNAs, and predicted target genes for all pig miRNAs by using massive public data. This large data-based strategy is also applicable for other nonmodel organisms with incomplete annotation information.