Elegba Wilfred, McCallum Emily, Gruissem Wilhelm, Vanderschuren Hervé
Plant Biotechnology, Institute of Molecular Plant Biology, Department of Biology, ETH Zurich, Zurich, Switzerland.
Biotechnology and Nuclear Agriculture Research Institute, GAEC, Legon, Ghana.
Front Plant Sci. 2021 May 25;12:668042. doi: 10.3389/fpls.2021.668042. eCollection 2021.
Cassava is an important staple crop that provides food and income for about 700 million Africans. Cassava productivity in Africa is limited by viral diseases, mainly cassava mosaic disease (CMD) and cassava brown streak disease (CBSD). Genetic barriers such as high heterozygosity, allopolyploidy, poor seed set, and irregular flowering constrain the development of virus-resistant cassava varieties conventional breeding. Genetic transformation represents a valuable tool to circumvent several challenges associated with the development of virus resistance and other valuable agronomic traits in cassava. The implementation of genetic transformation in many local African cultivars is limited either by the difficulty to produce friable embryogenic callus (FEC), low transformation, and/or regeneration efficiencies. Here, we report the successful induction of organized embryogenic structures (OES) in 11 farmer-preferred cultivars locally grown in Ghana. The production of high quality FEC from one local cultivar, ADI 001, facilitated its genetic transformation with high shoot regeneration and selection efficiency, comparable to the model cassava cultivar 60444. We show that using flow cytometry for analysis of nuclear ploidy in FEC tissues prior to genetic transformation ensures the selection of genetically uniform FEC tissue for transformation. The high percentage of single insertion events in transgenic lines indicates the suitability of the ADI 001 cultivar for the introduction of virus resistance and other useful agronomic traits into the farmer-preferred cassava germplasm in Ghana and Africa.
木薯是一种重要的主粮作物，为约7亿非洲人提供食物和收入。非洲的木薯生产力受到病毒病的限制，主要是木薯花叶病（CMD）和木薯褐色条纹病（CBSD）。诸如高杂合性、异源多倍体、结实率低和开花不规则等遗传障碍限制了通过传统育种培育抗病毒木薯品种的发展。基因转化是克服与木薯抗病毒性及其他重要农艺性状开发相关的若干挑战的一项宝贵工具。在许多非洲当地品种中，基因转化的实施受到难以产生易碎胚性愈伤组织（FEC）、转化效率低和/或再生效率低的限制。在此，我们报告了在加纳当地种植的11个农民喜爱的品种中成功诱导出有组织的胚性结构（OES）。从一个当地品种ADI 001中生产出高质量的FEC，促进了其基因转化，具有高芽再生和选择效率，与模式木薯品种60444相当。我们表明，在基因转化之前使用流式细胞术分析FEC组织中的核倍性可确保选择遗传上一致的FEC组织进行转化。转基因系中高比例的单插入事件表明ADI 001品种适合将抗病毒性和其他有用的农艺性状引入加纳和非洲农民喜爱的木薯种质中。
