A method for generating virus-free cassava plants to combat viral disease epidemics in Africa

M N Maruthi; E Charles Whitfield; Gerald Otti; Silver Tumwegamire; Edward Kanju; James P Legg; Geoffrey Mkamilo; Robert Kawuki; Ibrahim Benesi; Anabela Zacarias; Therezia Munga; Francis Mwatuni; Edward Mbugua

doi:10.1016/j.pmpp.2018.09.002

A method for generating virus-free cassava plants to combat viral disease epidemics in Africa

Physiol Mol Plant Pathol. 2019 Jan:105:77-87. doi: 10.1016/j.pmpp.2018.09.002.

Authors

Affiliations

¹ Natural Resources Institute (NRI), University of Greenwich, Chatham Maritime, Kent, United Kingdom.
² International Institute of Agriculture (IITA), P.O Box 34441, Dar es Salaam, Tanzania.
³ Department of Agricultural Research and Development (DRD), P.O Box 2066, Dar es Salaam, Tanzania.
⁴ National Agricultural Research Organization (NARO), P.O Box 295, Entebbe, Uganda.
⁵ Department for Agricultural Research Services (DARS), Chitedze Research Station, P. O. Box 158, Lilongwe, Malawi.
⁶ National Institute of Agricultural Research (IIAM), P.O Box 3658, Maputo, Mozambique.
⁷ Kenya Agricultural and Livestock Research Organization (KALRO), Kenya.
⁸ Kenya Plant Inspectorate Services (KEPHIS), Plant Quarantine and Biosecurity Station, Muguga, P.O. Box 49592 00100, Nairobi, Kenya.
⁹ Genetic Technologies International Limited (GTIL), P.O. Box 47430-00100, Nairobi, Kenya.

Abstract

Here, we report a method to clean cassava plants from viral infections that cause cassava mosaic and brown streak diseases in Africa. Infected plants of resistant or tolerant varieties from Malawi, Mozambique, Kenya, Tanzania and Uganda were cleaned in the UK using a combination of tissue culture, chemotherapy and thermotherapy. In the first cycle of our virus-indexing procedure, we successfully cleaned 27 of the 31 varieties (87%), and after an additional three cleaning cycles, all plants were virus-free. Virus-free tissue-cultured plants were shipped back to Africa for distribution to farmers. This first cross-boundary effort provides important lessons for mitigating the two-major cassava viral diseases.

Keywords: ACMV, African cassava mosaic virus; CBSD, Cassava brown streak disease; CBSV, Cassava brown streak virus; CMD, Cassava mosaic disease; CTAB, Cetyl trimethylammonium bromide; Cassava brown streak disease; Cassava mosaic disease; EACMV, East African cassava mosaic virus; EACMV-Ug, East African cassava mosaic virus-Uganda; LFC, Laminar flow cabinet; MS, Murashige and Skoog; Manihot esculenta; PPM, Plant Preservation Mixture; RH, Relative humidity; SDW, Sterilised deionised water; UCBSV, Ugandan cassava brown streak virus; UIC, Unique identifying code; Virus diagnosis; Virus indexing.