【作者】 缪凯；

【导师】 李焕秀；

【作者基本信息】 四川农业大学 ， 蔬菜学， 2008， 硕士

【摘要】 番茄青枯病是由Ralstonia solanacearum引起的一种毁灭性病害,在世界各地均有发生,热带、亚热带地区更为严重,该病为土传病害,寄主范围广。目前,番茄青枯病发生日益频繁,造成了番茄的大面积减产甚至绝收,已成为番茄生产上的重要障碍。然而对番茄青枯病生理生化抗性机制的研究却很少,并且,番茄抗青枯病材料很难收集,这就对番茄抗病育种造成了很大的困难。传统的鉴定方法多为苗圃和田间调查,费时,工作量大。80年代后,酶法和分子标记辅助育种普遍运用,大大缩短了抗病育种的进程。本文通过研究番茄抗感品种(材料)接种青枯菌前后几种酶活性及同工酶的变化,以预测番茄对青枯病的抗性水平,以便有选择地进行繁殖和育种工作,减少了盲目性,提高工作效率,同时推动与抗青枯病有关的其它生理生化指标的研究和番茄抗青枯病机制的研究。本文研究了S13、S24、L33、L55和强丰5个番茄品种(材料)对青枯病的苗期和成株期抗病性,5种防御性酶(PAL、PPO、POD、SOD和CAT)活性的变化和两种同工酶(PPO和POD)的变化,结果如下:经过常规接种测定,在四川农业大学园艺系试验田番茄病株提取的供试青枯菌菌株具有致病性。番茄苗期采用伤根灌注法接种,接种最佳浓度为3×10~8 CFU/ml。分别于接种后7d、14d、21d周进行发病株率调查。结果表明,S13、S24、L33、L55四个材料发病率在三次调查中均明显低于强丰。综合上述三个时期调查结果,可以将五个番茄材料的抗性水平初步分成三类:S13、S24、L33为中抗;L55为耐病;强丰为感病。番茄成株期采用伤根灌注法接种,接种浓度为6×10~8个菌/ml。结果表明,S13,S24,L33,L55四个番茄材料的抗性指数分别为8.6,8.3,9.5,6.8,均在5-9.9范围内,属中抗品种。而强丰的抗性指数只有2.8,属感病品种。番茄苗期未接种青枯菌处理各品种(系)叶片5种防御酶活性处在动态平衡中。接种青枯菌后,各品种(系)叶片PAL、PPO、POD、SOD 4种酶活性均升高,S13、S24、L33、L55酶活性始终高于接种前,且上升速度、最大增幅、峰值均高于强丰,而强丰接种后酶活性初期高于接种前,后期酶活性则低于接种前。接种青枯菌后,5个番茄材料叶片CAT活性变化紊乱,没有规律。除强丰外其余的四个番茄材料PAL、PPO、POD和SOD活性峰值的高低与苗期感病性呈显著负相关,而与成株期抗病性呈显著正相关,所以,接种青枯菌后番茄叶片PAL,PPO,POD,SOD4种酶可以作为早期筛选抗病育种材料的辅助指标,CAT酶还有待于进一步研究。番茄苗期接种青枯菌后,S13、S24、L33、L55叶片POD和PPO同工酶谱带数与接种前相比较没有变化,但各酶带的活性均明显增强,而感病品种强丰苗期叶片POD和POD同工酶酶带与接种前酶带强度差异不大,无明显变化。更多还原

【Abstract】 Tomato bacterial wilt caused by Ralstonia solanacearum is a devastating disease.It has occurred in various parts of the world,especially in tropical and subtropical regions.It is a kind of soil-borne disease and has a wide range of hosts. At present,the tomato bacterial wilt happens in an increasing frequence,which results in a decreasing production and total destruction in a large area of tomatoes. Tomato bacterial wilt has become a major obstacle in tomato cultivation.However, researches on the physiological and biochemical mechanisms of resistance to tomato bacterial wilt are very few,and it is very difficult to collect anti-bacterial wilt tomato materials.These problems cause many difficulties in breeding anti-bacterial wilt tomatoes.Most of traditional identification methods are nursery and field surveys. They are very time-consuming and have heavy workload.After the 1980s, enzymatic methods and molecular marker-assisted breeding are widely used and could reduce the resistance breeding process greatly.In this paper,the changes of enzyme activity and isoenzyme were studied after inoculating with Ralstonia solanacearum,so that the levels of resistance to bacterial wilt could be forecasted.As a result,breeding work could be carried out selectively and work efficiency could also be improved.At the same time,this research could promote the study on other physiological and biochemical indicators about the resistance to tomato bacterial wilt.In this paper,the seedling and adult resistance identifications of five tomato cultivars to bacterial wilt were studied.Meantime,the activity changes of five enzymes and changes of two isoenzymes were studied.The results were as followings:Through the routine inoculation assay,the strain of Ralstonia solanacearum extracted from the diseased tomato plant in the experimental field of horticulture department in sichuan agricultural university had pathogenicity.The tomato seedlings were inoculated by cutting the roots and pouring.The best concentration of the bacteria used to inculate the tamato was 3×10~8 CFU/ml.The disease rates were investigated at the seven day,the fourteen day,and the twenty-first day after the inoculation.The results showed that the disease rates of S13、S24、L33、L55 were significantly lower than that of Qiangfeng.From the results of the three investi-gations above-mentioned,the five kinds of tomato could be divided into three types:S13、S24、L33 were moderate resistance varieties;L55 was a disease tolerant variety;Qiangfeng was a disease susceptible variety.The tomato adults were inoculated by cutting the roots and pouring.The concentration of the bacteria used to inculate the tamato was 6×10~8 CFU/ml.The results showed that the resistance indexes of the four tomatoes were 8.6,8.3,9.5, 6.8.All of the resistance indexes were bewteen the range of 5-9.9,so they were moderate resistance varieties.However,the resistance indexe of Qiangfeng was only 2.8,so it was a disease susceptible variety.The activities of five defense enzymes in the tomato leaves without inoculating with Ralstonia solanacearum were in dynamic equilibrium.After inoculation,the four enzymes’(PAL,PPO,POD,SOD) activities of all varieties were increasing.The enzyme activities of S13,S24,L33,L55 were always higher than those of the enzyme activities before the inoculation,and the ascending speed,the largest increasing rate, the peak values of the four cultivars were higher than those of Qiangfeng.The enzyme activities of Qiangfeng in early days after inoculation was higher than that of the enzyme activitie before inoculation,while was lower than those of that of the enzyme activitie before inoculation in late days after inoculation.The changes of enzyme activities of CAT in leaves of all cultivars were turbulent and were absence of orderliness after inoculation.The enzyme activity peak values of the PAL,PPO, POD,SOD in the four tomato materials except Qiangfeng were negatively correlated with seedling infection,and were positively correlated with adult resistance.So,the four enzymes(POD,PPO,PAL,SOD) of tomato leaves could be used as assistant guidelines of selecting the resistance cultivars in early phase after inoculation with R.solanacearum,while CAT needed more studies.There were no apparent changes at isozyme spectra numbers of POD and PPO in leaves of S13,S24,L33,L55 after inoculation with Ralstonia solanacearum,but the intensities of the isozyme spectra were significantly enhanced.However,the intensity of the isozyme spectra of Qiangfeng had no apparent change.更多还原