玉米叶斑病在世界范围内发生并影响玉米生产。玉米可以被几种引起叶斑病的病原体感染,比如双极星,双极星,弯孢菌种类,链格孢属物种,等。在目前的研究中,根据形态特征鉴定了30种从有症状的玉米叶片中回收的Epicoccum分离株,致病性,和nuLSU的多位点序列分析,ITS,tub2和rpb2。这些玉米分离株分为五个Epicoccum物种,包括E.nigrum,E.layuense,E.sorghinum,E.latusicollum,和肺炎E.致病性试验表明,所有5种Epicoccum都可以在玉米叶片上产生小的椭圆形和纺锤形斑点。病变中心为灰黄色至深灰色,周围有褪绿区域。此外,Epicoccum分离株对黑龙江省20个主要玉米品种具有较高的致病性,但对常用杀菌剂多菌灵和戊唑醇的敏感性不同。此外,这些Epicoccum分离株显示出不同的果胶酶生产能力,纤维素酶,蛋白酶,淀粉酶,漆酶,还有明胶酶,但都显示出较高的脂肪酶活性。这是E.layuense在全球范围内的第一份报告,E.latusicollum,和肺炎大肠杆菌作为玉米叶斑病的病原体。肺炎大肠杆菌首先被报道为植物病原体。
Maize leaf spot occurs worldwide and affects maize production. Maize can be infected by several pathogens causing leaf spot, such as Bipolaris zeicola, Bipolaris maydis, Curvularia species, Alternaria species, etc. In the current study, 30 Epicoccum isolates recovered from symptomatic maize leaves were identified based on morphological characteristics, pathogenicity, and multilocus sequence analyses of nuLSU, ITS, tub2, and rpb2. These maize isolates were grouped into five Epicoccum species, including E. nigrum, E. layuense, E. sorghinum, E. latusicollum, and E. pneumoniae. Pathogenicity tests showed that all five Epicoccum species could produce small ellipse- and spindle-shaped spots on maize leaves. The lesion center was grayish yellow to dark gray and surrounded by a chlorotic area. Furthermore, the Epicoccum isolates exhibited high pathogenicity to 20 main maize varieties of Heilongjiang Province but showed different sensitivities to the commonly used fungicides carbendazim and tebuconazole. In addition, these Epicoccum isolates showed different production capacity of pectinase, cellulase, protease, amylase, laccase, and gelatinase, but all showed high lipase activity. This is the first report globally of E. layuense, E. latusicollum, and E. pneumoniae as causal agents of maize leaf spot. E. pneumoniae was first reported as a plant pathogen.