寧夏地區歐李根癌病病原菌鑒定及防治藥劑篩選1)

趙巖 白田田 顧欣 王新譜 馬文禮 王昊 楊波

(寧夏大學，銀川，750021) (寧夏農墾農林牧技術推廣服務中心)

The experiment was conducted to identify and screen microbicides against crown gall of Cerasus humilis in Ningxia. The pathogen was isolated using tissue isolation method. The pathogenicity of carrot and sunflower was determined according to robertkoch’s law using carrot and sunflower as indicator plants. The morphological, physiological and biochemical properties were analyzed, and 16S rDNA sequence analysis was used for classification and identification. The toxicity of nine low-toxic microbicides was tested by using the inhibition zone method of filter paper, and the microbicides with strong inhibitory effect on the pathogenic bacteria were screened out, and the control effect was verified with sunflower as the indicator plant. The results showed that ATJ1 strain isolated from the root cancer tissue of C. humilis could obviously proliferate on the inoculation site of carrot disk and sunflower, and was pathogenic. The ATJ1 strain was classified as Agrobacterium tumefaciens biotype I. In the indoor agent screening, tetramycin and ethephon had the best control effect, with 83.80% and 72.55% inhibition at 400×dilution, and EC50 of 5.13 and 985.75 mg/L, respectively. In pot experiments, both tetramycin and ethylicin had strong antibacterial effects on the pathogen ATJ1. No disease occurred at the inoculation site of sunflower, but high concentration of the drug would lead to phytotoxicity. Therefore, low concentrations (≥1 200×dilution) of tetramycin or ethylicin are suitable for the control of Agrobacterium tumefaciens in C. humilis.

歐李(Cerasushumilis(Bge.) Sok.)，薔薇科(Rosaceae)櫻桃屬(Ceraras)多年生落葉灌木，因果實富含活性鈣，又稱鈣果[1]，為我國特有的果樹資源。歐李的根蘗更新能力強，根系發達，具有抗寒耐旱、耐瘠薄、耐鹽堿等特性，果實色澤鮮艷，風味獨特，營養豐富，具有較高的開發利用和研究價值[2-4]。2011年，寧夏香山地區壓砂地試種歐李成功，全區多地進行引種栽培，種植面積擴大至約1 400 hm2。2015年，寧夏多地發現歐李根癌病。隨著種植年限增加和栽培面積擴大，該病害在寧夏呈蔓延趨勢，對當地歐李產業發展造成嚴重威脅。

果樹根癌病是由根癌土壤桿菌引起的土傳植物病害[5]。該菌寄主范圍廣，已知可侵染93科331屬643種植物[6]，涉及核果、漿果、堅果類果樹和其他觀賞類植物[7]。病原菌的侵染可誘導植株大量合成生長素和細胞分裂素，導致細胞異常增殖，在根頸、側根部位形成大小不一的冠癭[8-9]。植株患病早期，樹體的地上部無明顯癥狀。隨著冠癭數量和體積的增加，植株細根數量減少，生長遲緩，樹勢逐漸衰弱，直至全株枯死，造成林果業嚴重損失[10-11]。根據生理生化特征和致病性差異，根癌土壤桿菌被分為Ⅰ型、Ⅱ型、Ⅲ型3種生物型[12-13]。桃、蘋果和櫻桃的根癌病菌為生物Ⅰ型或Ⅱ型，葡萄根癌病菌為生物Ⅲ型[14-17]。歐李根癌病病原菌及其生物型有待確定。

果樹根癌病是典型的土傳病害，主要防治技術包括選育抗病品種、物理切除、化學防治和生物防治[18]。……