Agrobacterium-Mediated Transient Gene Expression in Developing Ricinus communis Seeds: A First Step in Making the Castor Oil Plant a Chemical Biofactory

Abstract

The castor oil plant represents a promising platform to produce oils with industrial applications. However, its use in biotechnology is limited by the absence of a well-established procedure to transform it, and a poor understanding of gene regulation and promoter use in this species. As such, a method has been developed to express proteins or hairpin-RNA in this plant, a method based on the direct injection of Agrobacterium into the developing endosperm of castor oil fruit, enabling different constructs and promoters to be tested. This method produces a high rate of transformation and a good proportion of viable seeds that express reporter genes for up to 20 days after infiltration (DAI). Gene expression under the control of different promoters was tested by quantitative real-time polymerase chain reaction and by directly assaying the activity of the galactouronidase reporter gene, which proved to be strongest when driven by the glycinin promoter. Constructs expressing a fatty acid elongase from Lesquerella fendleri were tested, the expression of which provoked an important increase in the lesquerolic acid in the castor oil endosperm at 5 and 10 DAI, although this fatty acid did not accumulate significantly in the final mature seeds. The nature of this response could reflect the poor availability of substrates for this enzyme. In the light of this data, the potential of this technique to test promoters and different constructs in castor oil plants and other oilseeds is discussed.

Opportunities and Challenges of Castor Bean (Ricinus communis L.) Genetic Improvement

“…The method is based on the direct injection of Agrobacterium into the developing endosperm of castor oil fruits. The rate of transformation reached was 80% and a good proportion of viable seeds was also reported [114]. Several attempts to eliminate toxic and allergenic substances have been made by traditional breeding techniques.…”

Identification and Functional Characterization of the RcFAH12 Promoter from Castor Bean in Arabidopsis thaliana

“…The direct genetic transformation of castor bean is the main bottleneck for revealing the genes and their promoter functions although a meristem-based protocol has been established with low transformation efficiency (0.04%) [18]. In addition, the genetic transformation of the castor bean is restricted by its long-life cycle, poor repeatability, and high chimeras, which seriously hinders the molecular elucidation of the castor gene function.…”

Agroinfiltration Mediated Scalable Transient Gene Expression in Genome Edited Crop Plants

“…The temporary integration of the exogenous DNA in the plant progeny is the basis of transient transformation of plant tissues [ 102 ]. Agrobacterium -mediated genetic transformation involves transfection of millions of plant cells by T-DNA in a short period.…”