Apio Hellen B, Elegba Wilfred, Nunekpeku Wonder, Otu Solomon Ayeboafo, Baguma Julius Karubanga, Alicai Titus, Danso Kenneth Ellis, Bimpong Isaac Kofi, Ogwok Emmanuel
Tissue culture and Transformation Laboratory, National Crops Resources Research Institute (NaCRRI), Kampala, Uganda.
Biotechnology and Nuclear Agriculture Research Institute (BNARI), Ghana Atomic Energy Commission (GAEC), Accra, Ghana.
Front Plant Sci. 2024 Sep 16;15:1414128. doi: 10.3389/fpls.2024.1414128. eCollection 2024.
Cassava () production and productivity in Africa is affected by two viral diseases; cassava mosaic disease (CMD) and cassava brown streak disease (CBSD). Induced mutagenesis of totipotent/embryogenic tissues or plant material can lead to the generation of CMD and/or CBSD tolerant mutants. To massively produce non-chimeric plants timely and with less labor, totipotent cells or tissues are a pre-requisite. This study aimed to determine the effect of gamma radiation on the proliferation and growth of friable embryogenic callus (FEC) and nodal cuttings respectively. To obtain FEC, 2-6 mm sized leaf lobes of nine cassava genotypes were plated on Murashige and Skoog (MS) basal media supplemented with varying levels (37, 50, 70, 100) μM of picloram for production of organized embryogenic structures (OES). The OES of five cassava genotypes (Alado, CV-60444, NASE 3, NASE 13 and TME 204) were crushed and plated in Gresshoff and Doy (GD) basal media in combination with the amino acid tyrosine in varying concentrations for FEC production. FEC from five cassava genotypes and nodal cuttings of nine genotypes were irradiated using five different gamma doses (0, 5, 10, 15, 20 and 25 Gy) at a dose rate of 81Gy/hr. The lethal dose (LD)50 was determined using the number of roots produced and flow cytometry was done to determine the ploidy status of plants. The highest production of OES was noted in Alado across varying picloram concentrations, while TME 204 obtained the highest amount of FEC. The irradiated FEC gradually died and by 28 days post irradiation, FEC from all five cassava genotypes were lost. Conversely, the irradiated in vitro nodal cuttings survived and some produced roots, while others produced callus. The LD50 based on number of roots varied from genotype to genotype, but plants remained diploid post-irradiation. Accordingly, the effect of gamma irradiation on Ugandan cassava genotypes (UCGs) was genotype-dependent. This information is foundational for the use of tissues as target material for cassava mutation breeding.
木薯（）在非洲的产量和生产力受到两种病毒性疾病的影响，即木薯花叶病（CMD）和木薯褐色条纹病（CBSD）。对全能/胚性组织或植物材料进行诱变可导致产生耐CMD和/或CBSD的突变体。为了及时且省力地大量生产非嵌合体植物，全能细胞或组织是先决条件。本研究旨在分别确定γ辐射对易碎胚性愈伤组织（FEC）增殖和生长以及茎节插条的影响。为了获得FEC，将9种木薯基因型的2 - 6毫米大小的叶裂片接种在添加不同浓度（37、50、70、100）μM毒莠定的Murashige和Skoog（MS）基础培养基上，以产生有组织的胚性结构（OES）。将5种木薯基因型（Alado、CV - 60444、NASE 3、NASE 13和TME 204）的OES压碎，并接种在Gresshoff和Doy（GD）基础培养基中，同时添加不同浓度的氨基酸酪氨酸以生产FEC。对5种木薯基因型的FEC和9种基因型的茎节插条使用5种不同的γ剂量（0、5、10、15、20和25 Gy），剂量率为81Gy/小时进行辐照。使用产生的根的数量确定致死剂量（LD）50，并进行流式细胞术以确定植物的倍性状态。在不同毒莠定浓度下，Alado的OES产量最高，而TME 204获得的FEC数量最多。辐照后的FEC逐渐死亡，辐照后28天，所有5种木薯基因型的FEC均消失。相反，辐照后的离体茎节插条存活，一些产生根而另一些产生愈伤组织。基于根数量的LD50因基因型而异，但辐照后植物仍为二倍体。因此，γ辐射对乌干达木薯基因型（UCGs）的影响取决于基因型。该信息是将组织用作木薯突变育种目标材料的基础。
