Optimisation of a Somatic Embryogenesis and Transformation Protocol for Farmer-Preferred Cassava Cultivars in Kenya
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Date
2016
Authors
Marigi, E.N.
Masanga, J.O.
Munga, T.L.
Karanja, L.S.
Ngugi, M.P.
Thagana, W.M.
Kirubi, D.
Mwangi, M.
Muiru, W.M.
Miano, D.W.
Journal Title
Journal ISSN
Volume Title
Publisher
African Crop Science Society
Abstract
Cassava (Manihot esculenta Crantz) is a major food crop in developing countries, and holds potential for
industrial use. It is, however, affected by various biotic and abiotic stresses that greatly affect its production. The
existing regeneration and transformation protocols are not compatible with all cassava cultivars, thus efficient and
robust transformation and regeneration protocols for farmer-preferred cultivars need to be optimised for ease of
transfer of novel genes. The objective of this study was to develop an efficient transformation and regeneration
protocol for a farmer-preferred Kenyan cassava cultivar. We cultured immature leaf lobe and stem explants on
Murashige and Skoog (MS) medium, supplemented with varying concentrations of 2,4-dichlorophenoxyacetic
acid (2,4-D), Picloram and รก-naphthalene acetic acid (NAA). Plants were recovered on media with 6-
Benzylaminopurine (BAP) and GA3 under a 16 hour light/8 hour darkness photoperiod regime. Results showed
high regeneration and transformation frequencies for both cultivars. High frequencies of callus induction (>98%)
for both cultivars, were obtained when 2,4-D and Picloram were used. Similarly, both auxins initiated somatic
embryogenesis, with Picloram producing the highest frequency of somatic embryos (>92%) in TMS 60444,
using stem explants. Gus assays revealed high frequencies of transformation of >77% (TMS 60444) and 60%
(Kibanda meno mkubwa). This protocol offers promising perspectives for rapid improvement of these cultivars
and, therefore, provides a platform for cleaning planting materials, as well as cassava genetic improvement
programmes such as control of viral diseases
Description
DOI: http://dx.doi.org/10.4314/acsj.v24i1.4S
Keywords
Cytokinin, Manihot esculenta, Regeneration protocol