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21.
During 1997–2000 the virulence variation and distribution of virulence phenotypes of Bremia lactucae (lettuce downy mildew) in natural populations of Lactuca serriola (prickly lettuce) were studied. Altogether 139 isolates of B. lactucae originating from the Czech Republic, France and Germany were examined for the presence of 27 virulence factors (v-factors) and their combinations. In the Czech population, 37 different v-phenotypes (P1–P37) of B. lactucae were found to occur on L. serriola . Most v-phenotypes were characterized by v-factors that match resistance ( Dm genes/R-factors) carried by L. serriola . A wide diversity of v-phenotypes was recorded every year, but most were rare and did not reappear in other populations of B. lactucae . The three v-phenotypes P21, P28 and P29 were most frequent and widely distributed. There was variation both between spatially isolated populations and within populations of the pathogen. Geographic differences in virulence were found for the southern parts of Moravia, where the phenotypic composition of pathogen populations was completely different from the remaining part of the area investigated. However, some populations had v-phenotypes similar to those of spatially distant populations in Moravia. 相似文献
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AtSOS基因在紫花苜蓿中的表达及其耐盐性研究 总被引:1,自引:0,他引:1
本研究采用基因工程技术改良紫花苜蓿耐盐性,通过种植转基因耐盐紫花苜蓿达到改良土壤的目的。以紫花苜蓿子叶节为外植体,通过农杆菌介导法将来源于拟南芥的AtSOS1-AtSOS2-AtSOS3多基因表达载体导入阿尔冈金紫花苜蓿中,经PCR检测、抗除草剂筛选和RT-PCR鉴定,获得了能稳定表达的转基因株系。以转基因的紫花苜蓿和野生型紫花苜蓿为材料进行盐处理,每个处理重复3次,测定其生理生化指标、株高、Na+和K+含量、细胞膜透性、叶绿素含量。结果显示,在不同盐浓度处理下,所有植株的株高均有所增长,但在100和200 mmol·L-1的NaCl处理下,转基因植株的长势显著高于野生型植株;随着处理时间的增加,所有植株的叶绿素含量均呈先上升后下降的趋势,且野生型植株叶绿素含量均低于转基因植株;在100和200 mmol·L-1的NaCl处理下,转基因植株的细胞膜透性、超氧化物歧化酶活性和脯氨酸含量的增加量均小于野生型植株,而过氧化物酶、过氧化氢酶活性和可溶性糖含量的增加量均大于野生型;各植株中丙二醛含量均下降,且野生型植株下降的更为明显;盐处理后,转基因植株根系中Na+的积累比野生型植株少,而K+的吸收多于野生型植株。转AtSOS基因的紫花苜蓿通过发挥AtSOS途径的作用,促进了植物体将细胞内的Na+外排,从而减轻盐胁迫对植物体的伤害,提高了转基因植株的耐盐性。 相似文献
26.
ZHU Zhen LI Bing ZHOU Xu-zheng WEI Xiao-juan CHENG Fu-sheng ZHANG Ji-yu 《中国畜牧兽医》2016,43(12):3368-3374
Antibiotic resistance genes have become a recognized environmental pollutant, threatening the ecological safety and human health. The application of antibiotics in the clinical and animals breeding, making the environmental microorganisms living with the impact of the residue of antibiotics and elements of resistance genetic and leading to antibiotic resistant bacteria to gain a competitive advantage and destroyed the stability of ecosystem. In this paper, we expounded the concept of resistance gene transmission by the view of macro environment. Through analyzing the mechanism of resistance development,environmental pollution caused by drug resistance and the impact of environmental microorganism for drug resistance, we clarified the key role of the environment in the development of the characteristics of bacterial resistance and analysis environmental resistance.Such as the ecological diversity of flora, the types and the spread of resistant bacteria, the residues of antibiotics and the transmission of the resistance genes. 相似文献
27.
为探明引起贵州省某鸭场雏鸭发病的病原及其致病性和耐药情况,本研究对该鸭场送的疑似细菌感染病鸭进行剖检,取鼻黏膜、心脏和肝脏等组织器官接种于培养基中进行细菌分离鉴定,通过对分离菌进行药敏试验、动物回归试验和毒力基因检测研究其耐药情况和致病性。结果显示,分离菌在血琼脂培养基上生长16 h后呈现为边缘整齐、有光泽的乳白色菌落,伴有β-溶血现象,经革兰氏染色后在生物显微镜下呈两端钝圆、弧状、排列无规则的革兰氏阴性短小杆菌,与霍乱弧菌相符;16S rDNA基因序列同源性及系统进化树显示,该分离菌与霍乱弧菌同源性高达99.6%~99.7%聚为一支;药敏试验结果显示,分离菌对大部分药物都表现为耐药,其中对氨苄西林、克林霉素、复方新诺明、苯唑西林和克林霉素等抗菌药耐药性较强,对头孢哌酮和头孢曲松敏感;动物回归试验显示,分离菌可导致试验组雏鸭5 d内全部发病死亡,表明该分离菌对雏鸭具有较强的致病性;毒力基因PCR检测结果显示,检测的霍乱弧菌相关毒力基因hlyA、ompW和chxA为阳性,而检测的O1群rfb、O139群rfb、tcpA及ctxA基因为阴性,表明本次分离的霍乱弧菌携带有致病基因,但不属于O1和O139血清群。结果表明,该鸭场雏鸭发病的疫情病原为非O1/O139血清群霍乱弧菌,该菌致病性强且对多种抗菌药物耐药。本试验结果为贵州省鸭霍乱弧菌病的防控提供了参考依据。 相似文献
28.
养殖废弃物堆肥中抗生素和抗性基因的降解研究 总被引:2,自引:1,他引:1
抗生素的滥用及排放会造成细菌产生耐药性以及抗生素抗性基因(Antibiotic resistance genes, ARGs)的传播和扩散。畜禽粪便是导致环境中抗生素污染的主要来源之一。本文综述了四环素类、大环内酯类、喹诺酮类、β-内酰胺类、磺胺类和氨基糖苷类等在水土环境中广泛存在的抗生素及其环境残留水平和对动植物、微生物的影响,分析了当前利用堆肥技术降解畜禽粪便中抗生素和ARGs效果及机制的研究情况。总结得出,猪粪中抗生素残留量最高,其中四环素类残留量为1390~354 000 mg·kg^-1,磺胺类170.6~89 000 mg·kg^-1,氟喹诺酮类411.3~1 516.2 mg·kg^-1,硝基呋喃类85.1~158.1 mg·kg^-1,大环内酯类1.4~4.8 mg·kg^-1。堆肥对大部分抗生素具有好的降解效果,其中四环素类抗生素降解率为62.7%~99%,磺胺类为0~99.99%,对大环内酯类几乎可以完全降解,但是,堆肥无法降解喹诺酮类抗生素。养殖废弃物堆肥过程中,ARGs的降解情况同样因抗生素种类和堆肥方式而不同。已有的研究表明,除大环内酯类ARGs外,堆肥对其他ARGs均具有有效的降解效果,降解率为50.03%~100%。堆肥初期的优势菌门是厚壁菌门、放线菌门、变形菌门和拟杆菌门;堆肥结束后放线菌门成为最优势菌门。初始抗生素的浓度不影响堆肥结束时微生物的群落组成。温度和pH是影响抗生素降解的最主要因素,而ARGs的降解效果主要受温度影响。 相似文献
29.
Due to the growing interest in Central and Eastern Europe on cropping of wheat in optional late autumn terms, called facultative, genetic research and field evaluation were taken on four spring cultivars: Tybalt (NL), Monsun (DE), Ostka Smolicka (PL) and Bombona (PL), currently being recommended by breeders. The PPD gene analyze, expression level of dehydrine genes (WCS120 and WDHN13) in cooling test, and qPCR for RNA isolation and analyses of WCS120 and WDHN13 gene expression at the BBCH12 stage of wheat were estimated. Molecular analysis of PPD-D1 gene confirmed the presence of photoperiod sensitive allele ppd-D1b in all tested genotypes. The highest level of NRE WCS120 gene was detected in cultivars Tybalt and Bombona. Two-year field experimental study assessed the growth, development and productivity of facultative and spring crops of studied cultivars. Based on our results from field experiments and result of molecular analysis of alleles of PPD-D1 gene, the tested genotypes can be considered as potentially facultative genotypes. 相似文献
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Zhengong Yin Huidong Qi Qingshan Chen Zhanguo Zhang Hongwei Jiang Rongsheng Zhu Zhenbang Hu Xiaoxia Wu Candong Li Yong Zhang Chunyan Liu Guohua Hu Dawei Xin Zhaoming Qi 《Plant Breeding》2017,136(5):688-698
Plant height is closely related to seed yield of soybean. The goal of this study was to identify important loci affecting soybean plant height using meta‐analysis based on a reference physical map. Plant height related to QTLs was mapped across eight years with a RIL population by WinQTLCart v2.5. 182 QTLs related to plant height of soybean from database and our research were collected, and each QTL was projected onto the soybean physical map by software BioMercator v2.1. The confidence interval of meta‐QTL ranged from 0.09 to 5.07 Mb, and the mean phenotypic variance ranged from 4.9% to 73.0%. Furthermore, 4,259 candidate genes were located in these consensus QTLs, and 40 of them were involved in the plant growth and stem elongation and annotated as plant hormone signal transduction (pathway ID ko04075) in KEGG pathway. These results would lay a foundation for fine mapping of QTLs/genes related to plant height and marker‐assisted selection for breeding in soybean. 相似文献