【作者】 柴一秋；

【导师】 陈利锋；

【作者基本信息】 南京农业大学 ， 植物病理学， 2003， 硕士

【摘要】 甘薯栽培品种胜利百号感染根腐病菌后出现开花的病理现象。从开花的甘薯胜利百号根部分离到93株病原菌菌株，经鉴定引起甘薯根腐和病理性开花的病原菌为茄病镰孢甘薯专化型（Fusarium solani（Mart）Sacc．f．sp．bmams McClure，简称FSB）。用FSB的V100-93-06菌株室内接种胜利百号呈现根腐病典型症状和开花现象。V100-93-6还可抑制胜利百号芽的生长和促进其根的生长。 FSB及其代谢产物能够诱导甘薯产生病理症状。FSB的V100-93-6菌株分生孢子接种胜利百号（感病品种）和徐18（抗病品种）薯苗，分生孢子浓度（1×10³、5×10³、1×10⁴、5×10⁴和1×10⁵孢子/ml）越高，胜利百号（接种后40天）出现的症状越严重；采用1×10⁵孢子/ml分生孢子浓度接种胜利百号后时间越长（10～40天），症状越明显。V100-93-6菌株F2培养基培养滤液（或稀释液）能够诱导胜利百号薯苗呈现的症状与分生孢子接种所致症状相似。薯苗在10⁰、10^-1、10^-2、10^-3和10^-4～10^-10稀释浓度处理后9天的病情指数分别为0.9～3.0、0～2.5、0～2.1、0～1和0，呈现随处理浓度下降植株症状减轻的趋势。能诱导胜利百号薯苗产生甘薯根腐病症状的FSB代谢产物对热稳定，分子量大于1000道尔顿。FSB代谢产物处理徐18薯苗没有明显症状。 FSB侵染甘薯后，引起甘薯叶片、茎尖和根部组织内源脱落酸（ABA）含量大幅升高。根部最早出现ABA升高现象，但茎尖ABA积累浓度最高，最高值为1003.1nmol/g.Fw。而与对照相比，受病菌侵染后甘薯叶片、茎尖和根部组织内源赤霉素(GA_1/3)含量一直处于较低水平，最大值仅为4.1nmol/gfw，并随着接种后时间的延长而呈下降趋势。另外，FSB菌丝体內含有微量ABA（153.66pmol/g.Fw），但培养滤液中含有较高浓度（26.75mg/l）ABA。甘薯组培苗经FSB代谢产物外源处理9小时后，ABA含量显著上升，处理15小时后，ABA含量呈下降趋势。然而，GA_1/3含量在处理15小时时出现显著上升。这可能是由于ABA和GA_1/3具有拮抗作用引起的。甘薯受FSB侵染后表现不蔓生而直立生长，近地表节间产生气生须根，入秋后大量现蕾开花，这些病理现象的产生可能与病植株内源ABA升高、GA_1/3降低有关。更多还原

【Abstract】 Root rot is one of the fungal diseases of sweet potato (Ipomoea batatas Lam.) in China. While most cultivars cannot flower in nature in Jiangsu, China, Shenglibaihao, a susceptible cultivar, flowers when infected by the root rot pathogen. In this study, ninety-three strains are isoalted from the rotted roots of flowering Shenglibaihao and are identified as Fusarium solani (Mart) Sacc. f.sp. batatas McClure (FSB). The FSB strain V100-93-06 induces Shenglibaihao to produce typical symptoms of root rot including flowering, resulting in shorten buds and lengthen roots, In the inoculation experiment, the disease index (0-2.8) increases as the inoculum concentrations increase from 1 103 to 1 105 spores/ml and as the time after inoculation increase from 10 to 40 days. The cultural filtrates of FSB on F-2 media (NH4NO3 10.0g, KH2PO45.0g, MgSO47H2O 2.5g, L-xylose 30g, H2O 1000ml) can induce similar symptoms. The seedlings show symptoms with disease index from 0.9-3.0 to 0 at 9th day after treatment with filtrates at different dilutions from 1:1 to 1:1010, respectively. Boiling for 10 min has no effect on the symptom induction of the cultural filtrate. The bioactive components) in the filtrate seems larger than 1000 dalton in molecular weight. The endogenous ABA concentration of leaf, shoot and root increase significantly in FSB infected sweet potato plants. The accumulation of ABA occurs firstly in root, and the highest concentration (1.0 pmol/gfw) occurs in shoot. The endogenous GA1/3 concentration of leaf, shoot and root of infected sweet potato keeps at a low level during the experiment period, and the GAi/3 concentration tends to decrease with the highest concentration at 4.1 nmol/gfw. hi addition, while ABA concentration in FSB mycelia is low (153.66 pmol/gfw), ABB concentration in the cultural filtrate of FSB is high (26.75 mg/1). Sweet potato tissue cultured seedlings increase significantly in ABA concentration 9hrs after treatment with FSB filtrate, while the ABA concentrations decrease and the GA1/3 concentration increases sharply at 15hrs. The disease symptoms may be induced by the changes of the concentration of ABA and GA1/3 in the tissue. The root rot sweet potato grows up right with being no tail, having air root in knots near ground and flowering widely at autumn.更多还原