An Efficient Method for the Genetic Transformation of Acmella oleracea L. (Spilanthes acmella Linn.) with Agrobacterium tumefaciens

Abstract

Acmella oleracea L. is an important medicinal plant, commonly known as the toothache plant. It is a rich source of secondary metabolites used for the treatment of different human disorders. The demand for Acmella oleracea L. has increased due to its putative health benefits (in terms of both biomass quantity and bioactive compound purification). In vitro plant cultures have allowed the rapid increase of raw material availability through the use of suitable regeneration and multiplication systems. On the other hand, there is a general lack of methods for Acmella genetic transformation as a promising new technological approach for the improvement of secondary metabolites. In this work, an efficient transformation protocol has been established using the Agrobacterium tumefaciens LBA4404 strain bearing the binary vector pBI121 containing the NPTII gene for the resistance to kanamycin. Plant genetic transformation has been verified by direct polymerase chain reaction and GUS assay on regenerants. Transformation efficiency has been affected by the high level of the selection agent kanamycin. To our knowledge, this is the first report on the genetic transformation of A. oleracea, paving the way to further studies to improve in vitro plant growth and secondary metabolite production.

Establishment of a Novel and Efficient Agrobacterium-Mediated in Planta Transformation System for Passion Fruit (Passiflora edulis)

“…Using an in vitro somatic embryogenesis sonication-assisted transformation system, da Silva, Pinto [16] achieved a transformation efficiency of 28.3% in Passiflora cincinnata anthers. In vitro transformation and regeneration systems are applicable for various plant species, but they are time-consuming and labor-intense, require aseptic cultivation conditions, and achieve low regeneration rates [16,[20][21][22][23][24]. Furthermore, it is a high cost technology due to the requirement of sterile culture media, controlled sterile regeneration conditions, and long regeneration periods [44].…”

“…A.-mediated transformation results in the incorporation of one or more copies of the full-length T-DNA into the host genome, resulting in stable gene expression, which could be affected by different factors including additional virulence genes (Vir) [19]. Although in vitro plant regeneration is suitable to a wide range of agricultural relevant plant species [20][21][22][23], it is time consuming and requires aseptic conditions [24]. Furthermore, the long regeneration phase can lead to morphological abnormalities and somaclonal variations [25,26].…”

Development of biotechnological tools for the genetic improvement of Cannabis sativa L.

“…Shoot regeneration from a mixture of transformed and untransformed cells, transformed cells conforming only a sector in a shoot, cell cycle arrest of transformed cells, or transient expression of a transgene in some cells of a shoot are possible explanations for the generation of chimeras (Chen, 2011). On the other way, the combined use of uidA and nptII genes for verifying Agrobacterium-mediated plant transformation has been widely implemented in many other species such as Nicotiana rustica L. and Nicotiana tabacum L. (Hamill et al, 1991), Solanum lycopersicum L. (Dan et al, 2006), or more recently, Gossypium hirsutum L. and Acmella oleracea L. (Maggini et al, 2021). Regarding kanamycin resistance nptII gene, it should be noted that there are no previous works concerning its expression in C. sativa.…”