Goszczynska T, Botha W J, Venter S N, Coutinho T A
Agricultural Research Council, Plant Protection Research Institute, Private Bag X 134, Queenswood, Pretoria, South Africa.
Department of Microbiology and Plant Pathology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria 0002, Pretoria, South Africa.
Plant Dis. 2007 Jun;91(6):711-718. doi: 10.1094/PDIS-91-6-0711.
During 2004 to 2005, an unreported disease of maize (Zea mays) was observed on commercial fields in the Northwest and Mpumalanga Provinces of South Africa. Infected plants were stunted, with a vertical crack at the first internode. Inside the stem, a dark-brown, narrow lesion was present along the crack. Internal browning inside the stem extended upward, reaching the top internode in some plants. Seed cobs were underdeveloped. Diseased plants were scattered in the fields and 10 to 70% of the crop was affected. Gram-negative, facultatively anaerobic bacteria were consistently isolated from diseased tissues. Pathogenicity tests established that representative strains induced disease symptoms similar to those observed on maize plants in the field. Physiological and biochemical characterization using the API 20E and API 50CHE systems and 16S rRNA gene sequence analyses showed that the strains belonged to the genus Pantoea. The results of these tests also separated the strains into two groups. The first group, giving a positive reaction in the indole test, was similar to Pantoea ananatis. The second group of strains was indole negative and resembled P. agglomerans. The fluorescent amplified fragment length polymorphism (F-AFLP) genomic fingerprints generated by the indole-positive strains and P. ananatis reference strains were similar and clustered together in the dendrogram, confirming that the indole-positive bacteria causing brown stalk rot on maize were P. ananatis. The F-AFLP fingerprints produced by the indole-negative strains were distinctly different from those generated by P. ananatis, P. agglomerans, P. dispersa, P. citrea, P. stewartii subsp. stewartii, and P. stewartii subsp. indologenes. The results indicated that indole-negative bacteria causing brown stalk rot on maize might belong to a previously undescribed species of the genus Pantoea. This is the first report of a new disease on maize, brown stalk rot, caused by two bacterial species, P. ananatis and an undescribed Pantoea sp.
2004年至2005年期间，在南非西北省和姆普马兰加省的商业农田中观察到一种未报道过的玉米病害。受感染的植株发育不良，第一节间有垂直裂缝。在茎干内部，沿着裂缝有一条深褐色的狭窄病斑。茎干内部的褐化向上延伸，在一些植株中到达顶部节间。果穗发育不全。患病植株在田间呈散状分布，10%至70%的作物受到影响。从患病组织中一直分离出革兰氏阴性兼性厌氧菌。致病性试验证实，代表性菌株诱发的病害症状与田间玉米植株上观察到的症状相似。使用API 20E和API 50CHE系统进行的生理生化特性分析以及16S rRNA基因序列分析表明，这些菌株属于泛菌属。这些试验结果还将菌株分为两组。第一组在吲哚试验中呈阳性反应，与菠萝泛菌相似。第二组菌株吲哚试验呈阴性，与成团泛菌相似。吲哚阳性菌株和菠萝泛菌参考菌株产生的荧光扩增片段长度多态性（F-AFLP）基因组指纹图谱相似，并在聚类图中聚集在一起，证实导致玉米褐腐茎病的吲哚阳性细菌为菠萝泛菌。吲哚阴性菌株产生的F-AFLP指纹图谱与菠萝泛菌、成团泛菌、分散泛菌、柑橘泛菌、斯氏泛菌斯氏亚种和斯氏泛菌产吲哚亚种产生的指纹图谱明显不同。结果表明，导致玉米褐腐茎病的吲哚阴性细菌可能属于泛菌属中一个以前未描述过的物种。这是关于由菠萝泛菌和一个未描述的泛菌属物种引起的玉米新病害——褐腐茎病的首次报道。
