Kidulile Christina Edward, Miinda Ateka Elijah, Alakonya Amos Emitati, Ndunguru Joseph Canisius
Department of Biotechnology Mikocheni Agricultural Research Institute Dar es Salaam Tanzania.
Institute for Biotechnology Research Jomo Kenyatta University of Agriculture and Technology Nairobi Kenya.
J Phytopathol (1986). 2018 Oct;166(10):739-745. doi: 10.1111/jph.12725. Epub 2018 Aug 12.
Cassava mosaic disease is caused by cassava mosaic begomoviruses (CMBs) and can result in crop losses up to 100% in cassava () in Tanzania. We investigated the efficacy of chemotherapy and thermotherapy for elimination of (EACMV) of Tanzanian cassava. In vitro plantlets from EACMV-infected plants obtained from coastal Tanzania were established in the greenhouse. Leaves were sampled from the plants and tested to confirm the presence of EACMV. Plantlets of plants positive for EACMV were initiated in Murashige and Skoog (MS) medium. On the second subculture, they were subjected into chemical treatment in the medium containing salicylic acid (0, 10, 20, 30 and 40 mg/L) and ribavirin (0, 5, 10, 15 and 20 mg/L). In the second experiment, EACMV-infected plantlets were subjected to temperatures between 35 and 40°C with 28°C as the control. After 42 days of growth, DNA was extracted from plant leaves and PCR amplification was performed using EACMV specific primers. It was found that plant survival decreased with increasing levels of both salicylic acid and ribavirin concentrations. In general, plants treated with salicylic acid exhibited a lower plant survival % than those treated with ribavirin. However, the percentage of virus-free plants increased with an increase in the concentration of both ribavirin and salicylic acid. The most effective concentrations were 20 mg/L of ribavirin and 30 mg/L of salicylic acid; these resulted in 85.0% and 88.9% virus-free plantlets, respectively. With regard to thermotherapy, 35°C resulted in 79.5% virus-free plantlets compared to 69.5% at 40°C. Based on virus elimination, ribavirin at 20 mg/L, salicylic acid 30 mg/L and thermotherapy at 35°C are recommended for production of EACMV free cassava plantlets from infected cassava landraces.
木薯花叶病由木薯花叶双生病毒（CMBs）引起，在坦桑尼亚可导致木薯作物损失高达100%。我们研究了化学疗法和热疗法对消除坦桑尼亚木薯上的东非木薯花叶病毒（EACMV）的效果。从坦桑尼亚沿海地区采集的感染EACMV的植株上获取离体苗，在温室中进行培育。从这些植株上采集叶片进行检测，以确认EACMV的存在。将检测出EACMV呈阳性的植株的离体苗接种到Murashige和Skoog（MS）培养基上。在第二次继代培养时，将它们置于含有水杨酸（0、10、20、30和40毫克/升）和利巴韦林（0、5、10、15和20毫克/升）的培养基中进行化学处理。在第二个实验中，将感染EACMV的离体苗置于35至40°C的温度下，以28°C作为对照。生长42天后，从植株叶片中提取DNA，并使用EACMV特异性引物进行PCR扩增。结果发现，随着水杨酸和利巴韦林浓度的增加，植株存活率下降。总体而言，用水杨酸处理的植株存活率低于用利巴韦林处理的植株。然而，无病毒植株的百分比随着利巴韦林和水杨酸浓度的增加而增加。最有效的浓度分别是20毫克/升的利巴韦林和30毫克/升的水杨酸；这两种浓度分别产生了85.0%和88.9%的无病毒离体苗。关于热疗法，35°C处理产生了79.5%的无病毒离体苗，而40°C处理产生的无病毒离体苗为69.5%。基于病毒消除效果，推荐使用20毫克/升的利巴韦林、30毫克/升的水杨酸以及35°C的热疗法，从受感染的木薯地方品种中培育出无EACMV的木薯离体苗。
