Induction of hairy roots a promising and useful biotechnological tool in tobacco (Nicotiana tabacum L.) and bitter apple (Citrullus colocynthis L.) plants using Rhizobium rhizogenes

Abstract

The article discusses the use of hairy roots culture obtained through inoculation with Rhizobium rhizogenes in medicinal plants. Specifically, it focuses on optimizing hairy root induction in tobacco (Nicotiana tabacum L.) and Abu Jahl's melon (Citrullus colocynthis L.) explants using different strains of R. rhizogenes (15834, R1000, MSU440, and 1724). The study examines the effect of bacterial density and the type of explant on hairy root induction in tobacco and Abu Jahl's melon plants. Transgenic nature of the explants were confirmed using a specific primer for the rolB gene and PCR analysis. Results indicated that all four strains induced hairy roots in tobacco, while just MSU440 and 1724 strains effectively induced hairy roots in Abu Jahl's melon after using acetosyringone supplement. The type of explant significantly influenced hairy root induction, with leaf explants showing the highest transgenicity. Bacterial concentrations did not have a significant effect on hairy root induction across different plant species/strains. This research presents a protocol for inducing hairy roots in tobacco and bitter apple plants. Hairy roots are well known for their simplified cultivation requirements, fast growth rate, growth in hormone-free environments, and ease of genetic manipulation, making them a reliable source for producing plant materials and compounds with medicinal and commercial value. Overall, the successful induction of hairy roots in tobacco and Abu Jahl's melon plant highlights the potential for further exploitations and various utilizations of these hairy roots as a valuable biotechnological tool. The resulting data can also be applied to protect wild and endangered medicinal plants. Although the necessity of using acetosyringone; typically produced by dicots, to initiate hairy root in Abu Jahl's melon may be a limitation factor, it applies to using acetosyringone even in monocots. Now, with the combined use of super-virulent Agrobacterium strains and phenolic compounds such as acetosyringone, Ri-mediated transformation has become a major method of choice for transformation even in monocots.