I am a DPhil student at the Department of Plant Sciences, University of Oxford. I did my undergraduate and masters studies in Environmental Biotechnology in Mexico, where I am originally from.
My project’s aim is to design a technique to assess the competitiveness and effectiveness of a wide range of rhizobial strains in different legumes. To enable the rapid identification of successful strains I use reporter genes such as:
Below are some examples of the interaction between rhizobia and pea plants using marker gene systems with single infection.
Figure 1. -Strain Rhizobium leguminosarum bv. viciae 3841 expressing the gusA marker gene in a pea plant.
Figure 2. Strain Rhizobium leguminosarum bv. viciae 3841 expressing the celB marker gene in a pea plant.
The photo below is an example of luminescence visualized using a NightOWL LB 983 in vivo Imaging System.
Figure 3. Rhizobium tropici CIAT 899 expressing the luxCDABE reporter plasmid in a common bean plant.
The use of marker genes help to evaluate competitiveness by a double infection in the same plant.
This photo shows double-stained pea roots inoculated with Rhizobium leguminosarum bv. viciae UPM791:gusA and Rlv3841:celB strains.
Figure 4. Nodules expressing gusA are pink/magenta and nodules expressing celB are blue.
The establishment of a rhizobial population inside a nodule usually results from a clonal infection but sometimes it is possible to find two being very friendly and sharing the same nodule.
Figure 5. Microscopic view of a pea root nodule showing a mixed infection.
In Oct 2017: DPhil Student, Year 4 of 4 years
Marcela’s DPhil project is supported by grants from CONACYT and Balliol College, Oxford