【作者】 王羽；

【导师】 肖崇刚；

【作者基本信息】 西南农业大学 ， 植物病理学， 2004， 硕士

【摘要】 番茄青枯病[Ralstonia solanacearum(smith)Yabuuchi et al]是一类危害严重的世界性病害。由于病原菌可经土壤传播并进入寄主维管束进行危害，所以防治起来十分困难。本实验通过几种方法获得了260株无致病力青枯菌，对这些菌株进行拮抗筛选，并进一步测定了拮抗菌诱导番茄植株的生理生化变化情况。 1．从发生青枯病的番茄茎中直接分离出198株无致病力青枯菌，编号依次为1~#-198~#：通过紫外光诱变法获得的无致病力菌株有45株，编号依次为UV1~#～UV45~#：通过转代获得的无致病力菌株有17株，编号依次为ZD1~#~ZD17~#。 2．采用平板喷雾法做平板拮抗筛选，筛选出39个有抑菌圈的菌株。这39株中有38株为直接筛选所得的菌株，有一株为紫外光诱变所得，转代菌株没有抑菌圈现象。其中60~#、125~#、134~#、133~#和131~#菌株在对Bs01～05的平板拮抗试验中，抑菌带宽依次为2.1cm、2.0cm、1.9cm、1.6cm和1.5cm。 3．采用番茄“合作903”品种对这39株平板拮抗菌进行温室盆栽试验，最终筛选出两株无致病力青枯菌菌株100~#、134~#对番茄青枯病具有较好的防效。两个菌株的重复盆栽试验结果表明8d后的相对防效分别可达到86.4％和81.7％，20d后相对防效仍分别可达到37.7％和44.4％。 4．通过不同施用方式的盆栽控病试验比较表明，采用大苗浸根法的防治效果要优于浸种的方法。如同一菌株134~#，仅采用浸种的方法，7d后的相对防效为31％左右，20d后的相对防效为19％左右，而浸根的方法7d后的相对防效可达90％左右，20d后的相对防效可达到44％左右。 5．通过134~#菌株接种番茄，测定寄主体内与抗病反应有关的酶如过氧化物酶(POD)、苯丙氨酸解氨酶(PAL)和多酚氧化酶(PPO)活性变化的结果表明，番茄在受到无致病力菌株处理后，三种酶活性均有显著增强，尤其以PAL活性变化最为敏感，酶活性高峰出现较早；POD活性也迅速上升，说明番茄受无毒菌株处理后能激活植物本身清除体内活性氧的活性和抗病代谢过程，具有清除番茄体内活性氧、诱导番茄产生抗病性的作用；PPO活性也有显著增加，说明番茄在经过无毒菌株处理后能激活植物本身免疫系统，增加醌类物质的合成量。更多还原

【Abstract】 Bacterial wilt of tomato (Ralstonia solanacearum) is an important disease on the crop worldwide. The disease is difficult to control because the pathogen is soil-borne and vascular parasite. In the present study, three different techniques were applied to obtain avirulent isolates of R. solanacearum and these avirulent isolates were further screened for antagonistic bacteria against the pathogen.1.A number of 198 avirulent isolates of R. solanacearum were isolated directly from diseased tomato stem tissues, 45 were obtained through ultraviolet radiation treatment, and 17 were induced via continuous culturing in vitro.2.Of the avirulent isolates, 39 were found antagonistic against R. solanacearum by antagonism test on PDA plates. These antagonistic bacteria were mostly from the isolates directly isolated (38), only one was from the UV-induced isolates and none from the continuous culturing induced avirulent isolates.3.Tests on tomato plants (cultivar: Hezuo 903) showed that two avirulent isolates (numbered 100# and 134#) had strong antagonistic activity against R. solanacearum; the disease control efficiency was 86.4% and 81.7% at 8 days, and 37.7% and 44.4% at 20 days following treatment, respectively.4. Different methods of application of 134# bacteria were compared on tomato plants. Results showed that root-soaking is more effective than seed coating. The disease suppression efficiency was 90% and 44% at 7 and 20 days respectively after root soaking, but only 31% and 19% at 7 and 20 days after seed treatment.5. Tests showed that the activity of POD, PAL PPO enzymes increased apparently in tomato plant tissues treated with 134# bacteria. The change of PAL activity was most sensitive and exhibited first in the defence system of the plants. A quick increase of POD activity was detected after 134# bacteria application, indicating that the antagonistic bacteria could activate the processes of removing active oxygen and disease resistant metabolisms in the plant tissues. The increase of PPO activity was also significant and this may indicates that the antagonistic bacteria can increase the synthesis of quinones and thus activate the immuosystem of the plants.更多还原