Mulenga Rabson M, Legg James P, Ndunguru Joseph, Miano Douglas W, Mutitu Eunice W, Chikoti Patrick C, Alabi O J
Zambia Agriculture Research Institute, Mount Makulu Central Research Station, Chilanga, Lusaka, Zambia.
International Institute of Tropical Agriculture, Dar es Salaam, Tanzania.
Plant Dis. 2016 Jul;100(7):1379-1387. doi: 10.1094/PDIS-10-15-1170-RE. Epub 2016 Apr 8.
A survey was conducted from April to May 2014 in 214 farmers' fields located across six major cassava-producing provinces (Western, Northwestern, Northern, Luapula, Lusaka, and Eastern) of Zambia to determine the status of cassava mosaic disease (CMD) and the species diversity of associated cassava mosaic geminiviruses (CMG). Mean CMD incidence varied across all six provinces but was greatest in Lusaka Province (81%) and least in Northern Province (44%). Mean CMD severity varied slightly between provinces, ranging from 2.78 in Eastern Province to 3.00 in Northwestern Province. Polymerase chain reaction discrimination of 226 survey samples, coupled with complete DNA-A genome sequence analysis, revealed the presence of African cassava mosaic virus (ACMV), East African cassava mosaic virus (EACMV), and East African cassava mosaic Malawi virus (EACMMV) as single or mixed infections of different proportions. Single-virus infections were predominant, occurring in 62.8% (ACMV), 5.8% (EACMMV), and 2.2% (EACMV) of samples relative to mixed-virus infections, which occurred in 19.5% (ACMV + EACMMV), 0.4% (ACMV + EACMV), and 0.9% (ACMV + EACMV + EACMMV) of samples. Phylogenetic analysis revealed the segregation of virus isolates from Zambia into clades specific to ACMV, EACMV, and EACMMV, further confirming the presence of all three viruses in Zambia. The results point to a greater diversity of CMG across major cassava-growing provinces of Zambia and implicate contaminated cassava cuttings in disease spread.
2014年4月至5月，在赞比亚六个主要木薯生产省份（西部、西北部、北部、卢阿普拉、卢萨卡和东部）的214块农田进行了一项调查，以确定木薯花叶病（CMD）的状况以及相关木薯花叶双生病毒（CMG）的物种多样性。所有六个省份的CMD平均发病率各不相同，其中卢萨卡省最高（81%），北部省最低（44%）。各省之间的CMD平均严重程度略有差异，从东部省的2.78到西北部省的3.00不等。对226个调查样本进行聚合酶链反应鉴别，并结合完整的DNA-A基因组序列分析，结果显示存在非洲木薯花叶病毒（ACMV）、东非木薯花叶病毒（EACMV）和东非木薯花叶马拉维病毒（EACMMV），它们以不同比例单独或混合感染。单病毒感染占主导，相对于混合病毒感染，样本中ACMV单病毒感染占62.8%，EACMMV占5.8%，EACMV占2.2%；混合病毒感染中，ACMV + EACMMV占19.5%，ACMV + EACMV占0.4%，ACMV + EACMV + EACMMV占0.9%。系统发育分析表明，赞比亚的病毒分离株分为ACMV、EACMV和EACMMV特定的进化枝，进一步证实了赞比亚存在所有这三种病毒。结果表明，赞比亚主要木薯种植省份的CMG多样性更大，并表明受污染的木薯插条与疾病传播有关。
