甘蔗褐条病病原菌分离鉴定及其室内毒力的测定

Isolation, Identification and Laboratory Toxicity Determination of the Pathogen of Sugarcane Brown Stripe

针对海南省不同植蔗区甘蔗褐条病的典型病斑进行分离培养、单孢纯化、形态学观察、致病性检测以及结合r DNA-ITS序列分析鉴定病原菌。分离到的5株病原菌,经回接实验表明,病原菌HT-4致病性最强,能引起与田间病害一致的症状,将菌株HT-4的r DNA-ITS序列在NCBI上进行BLAST比对。结果表明:菌株HT-4与离蠕孢属(Bipolaris)相似性达到99%,结合形态学分析确定该菌是甘蔗褐条病的病原菌。室内毒力实验表明:在7种供试药剂中,50%咪鲜胺锰盐和10%苯醚甲环唑对病原菌抑制效果最好,EC50值分别为4.400 6 mg/L和9.421 1 mg/L。结果为甘蔗褐条病的防控提供科学参考。

In the study, the typical symptomatic tissues of sugarcanes brown stripe disease were collected from various sugarcane producing areas of Hainan. The pathogen of sugarcanes brown stripe disease was isolated and cultured. Moreover, single spore isolates, morphological observation, pathogenicity test, and combined with molecular biology methods were used to identify the pathogen. The inoculation experiment showed that the strain HT-4 was the most virulent and all of the 5 strains caused symptoms consistent with those observed in the fields, rDNA-ITS sequences of the strain HT-4 were submitted to NCBI to conduct the BLAST analysis. The strain HT-4 showed 99% of identity with Bipolaris, indicating that, the strain HT-4 was the pathogen causing sugarcane brown stripe. Laboratory toxicity tests indicated that the 50% proehloraz-manganese chloride complex and 10% difenoconazole had strong suppressing activites against the pathogen, with an EC50 of 4.400 6 mg/L and 9.421 1 mg/L, respectively. The study could provide valuable reference for the prevention and control of suzarcane brown stride disease.