The Role of Plant Genotype, Culture Medium andAgrobacteriumon Soybean Plantlets Regeneration during Genetic Transformation

Abstract

An efficient and reproducible plant regeneration protocol is essential for genetic manipulation of important crops in vitro through Agrobacterium-mediated genetic transformation. However, the establishment of such a procedure for recalcitrant legumes like soybean is still a major challenge. Genotype specificity, culture conditions and inefficient recovery of transgenic microshoots are some of the most important factors which requires optimisation before an efficient system of regeneration can be developed. The purpose of this chapter was to provide a review, and report on the varied responses obtained during the assessment of factors that cause recalcitrance during genetic transformation of soybean. Agrobacterium infected double cotyledonary-node explants were tested on MS basal culture medium containing combinations of cytokinins-auxins, as well the different concentrations of antibiotics for callus and shoot proliferation. The study showed that, the efficiency of microshoots and callus induction varied widely between cultures and among the genotypes. About 1.0-20.0 and 5.0-20.0% of callus and shoot induction frequency were obtained on cotyledonary explants transformed with Agrobacterium compared to more than 60% efficiency obtained in the controls, respectively. This study revealed that, there are some neglected factors playing a crucial role in genetic manipulation, which require optimisation before genetic transformation and in vitro regeneration of transgenic plants could be achieved.

Agbiogeneric soybean with glyphosate tolerance: Genetic transformation of new Colombian varieties

“…Despite an abundance of protocols, approaches and attempts at improving genetic transformation of soybean, it is still considered a recalcitrant species (Xu et al 2022). Successful transformation of soybean with A. tumefaciens depends on factors such as culture medium, plant genotype, type of explant, bacterial strain and density, and their interaction (Mangena 2019). Rojas et al (2018) reported the transformation of two Colombian soybean varieties with a codon-optimized version of the A. tumefaciens cp4epsps gene using only elements in the public domain and showed the importance of the plant genotype and strain specificity.…”

“…Soybean is considered a recalcitrant species for genetic transformation mediated by A. tumefaciens due to constraining factors that need to be optimized such as the specific interaction between plant genotype and bacterial strain, plant variety dependent regeneration, toxicity of antibiotics, A. tumefaciens overgrowth, in vitro selection and explant type, among others (Mangena 2019).…”

Climate change and vulnerabilities of children in rural Zimbabwe: The case of ward 14 of Bikita District, Zimbabwe

“…The vulnerabilities of children of ward 14 of Bikita District due to climate change are in sharp contrasts of the social justice value of Ubuntu or Hunhu philosophy. Social justice is based on the principle of fairness, love, compassion, equality, genuineness among others (Mangena 2012). Such principles are part of the Ubuntu or Hunhu philosophy (Mangena 2012).…”

“…Social justice is based on the principle of fairness, love, compassion, equality, genuineness among others (Mangena 2012). Such principles are part of the Ubuntu or Hunhu philosophy (Mangena 2012). There is social injustice when children drop out of school, engage in substance abuse, being victims or survivors of child marriages or child labour among others.…”

CRISPR/Cas9 in plant biotechnology: applications and challenges

“…Various studies have reported that the A. rhizogenes -mediated transformation system could have been the cause of low transformation efficiency observed in soybean (Li et al, 2019 ; Bai et al, 2020 ; Zhang et al, 2020a ), rice (Butt et al, 2017 ; Usman et al, 2021 ), and tomato (Ron et al, 2014 ) genome editing. Varying culture conditions can also influence the infection and regeneration rates of the Agrobacterium- infected explants, which affects the reproducibility of the results obtained (Hamada et al, 2018 ) as observed in soybean (Li et al, 2017; Hada, 2018 ; Mangena, 2018 ), clover ( Trifolium subterraneum L.) (Rojo, 2021 ), and cassava (Nyaboga et al, 2015 ). This further showed inconsistencies observed in transformation efficiency through Agrobacterium mediated delivery.…”