Modifying Plant Characteristics
 Using RNA Interference

Objective & Introduction

Objective

The objective of this project is to demonstrate how RNAi modifies the expression of genes which affect pathogen growth during plant infection. One example is to determine the effect of the knock-out of EDS1 on B. napus response to Albugo candida, a pathogen of the Brassica species and the cause of white rust of crucifer, by infecting the B. napus EDS1 RNAi lines with A. candida.  A second example is to prevent petal formation by  inhibiting the PI gene expression in Arabidopsis using the RNAi technique.

Introduction

•Ribonucleic acid interference (RNAi) is a technique that is used to “knock-out” the expression of a chosen gene (Small, et al., 2007; Mansoor, et al., 2006). Enhanced Disease Susceptibility 1 (EDS1) is a gene that has been shown to be involved in plant defence against several pathogens (Falk, et. al, 1999). Transgenic plant lines with an RNAi construct (shown in Figure 1 at the bottom of this page) to knock-out the EDS1 gene were developed.

•Arabidopsis lines transformed with an RNAi construct to suppress the Pistilata gene (PI) that is associated with flower development were generated. Modifying Brassica plants by inhibiting petal formation using RNAi technique could increase resistance to Sclerotinia sclerotiorum, (Hegedus, et. al, 2005) a major pathogen of Brassica. Petals are a source of nutrients and help the pathogen, which utilizes senescing petals, to establish infection.

 

MAP OF THE RNAi PLASMID CONE USED IN THIS STUDY

Figure 1. Map of the RNAi plasmid clone used in this study.

The gene of interest (red) is cloned in reverse orientations which leads to the generation of dsRNA, resulting in gene silencing. “35S” is the promoter.  “BAR is a gene used to associate the RNAi construct with.