亚洲棉主要农艺性状的遗传多样性分析

[目的]旨在通过对150份亚洲棉种质资源的7个农艺性状和5个纤维品质性状进行遗传多样性、相关性、主成分和聚类分析,以期为棉花遗传改良和种质利用提供一定的理论参考依据。[方法]选取150份亚洲棉种质资源,采用随机区组设计种植于试验田,在整个生育期内调查株高、第一果枝长度、果枝数、结铃数、第一果枝节位、单铃重、衣分、上半部平均长度、整齐度指数、断裂比强度、马克隆值、伸长率12个性状,进行变异分析、相关性分析、主成分分析和聚类分析。[结果]该批棉花种质资源具有丰富的遗传多样性,12个农艺性状的变异系数从大到小依次为衣分(29.2%)、结铃数(23.0%)、第一果枝长度(22.6%)、单铃重(19.8%)、第一果枝节位(15.6%)、株高(15.5%)、果枝数(10.0%)、马克隆值(7.6%)、上半部平均长度(6.4%)、伸长率(5.7%)、断裂比强度(4.4%)和整齐度指数(2.3%);相关性分析表明,株高与第一果枝长度、果枝数、结铃数、第一果枝节位及单铃重呈显著正相关,第一果枝长度与结铃数、单铃重及衣分呈显著正相关,果枝数与结铃数呈显著正相关,单铃重与衣分呈显著正相关,衣分与伸长率呈显著正相关,上半部平均长度与断裂比强度呈显著负相关;主成分分析表明前5个主成分累计贡献率达到64.536%,第Ⅰ主成分主要和纤维品质有关,第Ⅱ主成分主要与结铃数有关,第Ⅲ和第Ⅳ主成分主要与果枝数有关,第Ⅴ主成分主要与第一果枝节位有关;通过聚类分析将150份亚洲棉种质资源在遗传距离为41.3时划分为4类,第Ⅰ类群和第Ⅳ类群的棉花材料可作为改良棉花衣分的材料加以利用,最具有代表性的材料分别为江苏常熟鸡脚棉和乐业逻西中棉1-3;第Ⅱ类群和第Ⅲ类群的棉花材料可作为株型改良的材料加以利用,最具有代表性的材料分别为河南商丘灰籽和山东惠民德平县一窝猴。[结论]该研究结合多个指标综合评价棉花种质资源,可为棉花育种工作中优良品种的选育提供理论依据。

FgGyp8 as a putative FgRab1 GAP is required for growth and pathogenesis by regulating FgSnc1-mediated secretory vesicles fusion in Fusarium graminearum

Fusarium graminearum is an important plant pathogenic fungus that causes disease and yield reduction in many cereal crops, such as wheat and barley. Gyp8 stimulates GTP hydrolysis on Ypt1 in yeast. However, the functions of Gyp8 in plant pathogenic fungi are still unknown. In this study, we investigated the roles of Fg Gyp8 in F. graminearum by genetic and pathological analyses. Through gene knockout and phenotypic analyses, we found that Fg Gyp8 is required for vegetative growth in F. graminearum. The conidiation, conidial size and number of septa per conidium of ΔFggyp8 mutant are significantly reduced when compared to the wild type PH-1. Furthermore, Fg Gyp8 is crucial for pathogenicity on wheat coleoptiles and wheat heads. Fg Gyp8 contains a conserved TBC domain. Domain deletion analysis showed that the TBC domain, C-and N-terminal regions of Fg Gyp8 are all important for its biological functions in F. graminearum. Moreover, we showed that Fg Gyp8 catalyzes the hydrolysis of the GTP on Fg Rab1 to GDP in vitro, indicating that Fg Gyp8 is a GTPase-activating protein(GAP) for Fg Rab1. In addition, we demonstrated that Fg Gyp8 is required for Fg Snc1-mediated fusion of secretory vesicles with the plasma membrane in F. graminearum. Finally, we showed that Fg Gyp8 has functional redundancy with another Fg Rab1 GAP, Fg Gyp1, in F. graminearum. Taken together, we conclude that Fg Gyp8 is required for vegetative growth, conidiogenesis, pathogenicity and acts as a GAP for Fg Rab1 in F. graminearum.

玉屏风多糖对肠道菌群失调小鼠免疫功能的影响

为探究玉屏风多糖对肠道菌群失调小鼠免疫功能的影响,选取健康雄性小鼠30只,设对照组、肠菌群失调模型组、自然恢复组、高、中、低剂量组。对照组灌服生理盐水,其他组均灌胃浓度8 g/kg体重氨苄西林。灌服5 d后,处死模型组,观察建模情况。高、中、低剂量组分别灌服不同浓度的玉屏风多糖,其余两组灌服相同体积的生理盐水。治疗10 d后处死采样,测定生长性能、脾脏体指数以及血清、小肠中免疫因子含量。结果显示:低、中、高剂量组小鼠的脾脏、胸腺指数均高于自然恢复组;而血清中TNF-α的含量低于自然恢复组;其中M、H组体重增长和小肠s Ig A的含量均明显高于自然恢复组(P<0.05)。

鳜鱼致病性迟缓爱德华氏菌的分离鉴定及药敏试验

【目的】明确鳜鱼发病死亡的原因,并进行病原菌分离鉴定及药敏特性分析,为生产养殖中有效防治迟缓爱德华菌病提供参考依据。【方法】从患病鳜鱼肝脏中分离优势菌株,采用回归感染试验确定其致病性,通过细菌生理生化及16S rDNA序列分析对菌株进行鉴定,并以K-B纸片扩散法进行药物敏感性检测。【结果】分离出的菌株FS170808具有一定致病力,可使健康鳜鱼发病死亡,其半致死剂量为9.5×10~5CFU/mL;菌株FS170808经生理生化和16S rDNA序列分析鉴定均为迟缓爱德华氏菌(Edwardsiella tarda),其对氨苄西林、头孢曲松、头孢呋辛、庆大霉素、卡那霉素、氧氟沙星、四环素和多西环素等17种药物高度敏感,对头孢氨苄、头孢拉定、头孢他啶、新霉素和多粘菌素B中度敏感,对苯唑西林、复方新诺明、麦迪霉素和万古霉素已产生耐药性。【结论】迟缓爱德华氏菌可引起鳜鱼发病死亡,生产养殖中可选用氨苄西林、头孢曲松、头孢呋辛和庆大霉素等高度敏感性药物进行防治。