【摘要】 通过Ｔｎ５诱变、缺失分析和标记置换构建了一个缺失了ｒｐｆＣ基因上游约０．８ｋｂ序列的水稻黄单胞菌水稻变种突变株，该突变株被命名为ＳＬ３７５１，在剪叶接种植株试验中，ＳＬ３７５１对水稻广桂１１０具有极弱的毒性，而在浸种和喷雾接种试验中它不致病．在剪叶时，该突变株能在广桂１１０叶片中繁殖到每叶含１０７菌落，这比野生型低两个数量级，ＳＬ３７５１能侵染水稻种子并在随后长成的植株中定殖．用突变株浸种处理广桂１１０种子，在温室生长植株的分蘖和抽穗期分别剪叶接种野生型菌株，接种１４ｄ后，处理植株的病斑长度分别对比对照植株的病斑长３９．０％和１８．６％．在温室条件下，ＳＬ３７５１预处理广桂１１０种子能使水稻细菌性条斑病的病情指数降低５．３，预效５４．６％．１９９６年晚造，经ＳＬ３７５１浸种处理过的小苗移栽到大田中，在植株分蘖早期喷雾接种野生型菌株后２０ｄ，处理植株的病情指数为９．１５，比对照植株低３．６８．突变株浸种处理对白叶枯病的防效为２８．７％．这表明本研究将是一种新的具有发展潜力的生物防治水稻细菌性病害方法更多还原

【Abstract】 In this report,a Xanthomonas oryzae oryzae mutant with about 0 8 kb upstream sequence of rpf C gene deleted was constructed by Tn5 mutagenesis,deletion analysis and marker exchange process The mutant was named as SL3751 SL3751 was extremely weakly virulent on rice in leaf clipping inoculation test and nonpathogenic in seed soaking and leaf spraying inoculation tests This mutant could multiply in rice cultivar Guanggui 110 leaf to a level of about 10 7 cfu per leaf which was about two magnitudes lower than the wild type was when the bacteria was introduced to plant by leaf clipping SL3751 could also infect rice seeds and colonize in the subsequent grown up plants Treatment of rice cultivar Guanggui 110 seeds with the mutant resulted in 39 0% and 18 6% decreases in lesion length compared to those of the nonbacterized control plants 14 days after the plants were challenge inoculated by the wild type at tillering and heading stages respectively in the greenhouse Pretreatment of rice Guanggui 110 seeds with SL3751 caused decrease of DI of bacterial leaf streak at 5 3 giving control efficiency at 54 6% in the greenhouse When the plants grown from SL3751 treated Guanggui 110 seeds were planted in the field of the experimental farm of Guangxi University in the late crop of 1996, the DI of the treated plants was 9 15 which was 3 68 lower than that of the control plants 20 days after challenge inoculation with wild type by leaf spraying This work may suggest a new potential way to biocontrol rice bacterial diseases更多还原