Meet our PhD’s: Rafael Narancio, PhD La Trobe University


Current Role: Research Scientist, National Institute of Agriculture Research (INIA), Uruguay

PhD Research: Transgenic white clover plants with a molecular stack of traits for delayed leaf senescence, aluminium tolerance and alfalfa mosaic virus resistance. Generation and molecular and functional characterisation


White clover is an important pasture plant in temperate parts of the world and the major legume species found in temperate dairy pastures in Australia. Its productivity and persistence in pastures is limited by susceptibility to viruses, sensitivity to acidic soils with high levels of free aluminium ions and limited phosphorus availability, and by summer heat and low soil moisture.  Nichols et al. (2012) identify as a primary objective for white clover breeding in Australia to improve the reliability of the species where there is currently predominant (annual rainfall of 850-1000 mm), and enhance its adaptability to pasture areas where annual rainfall is around 650-850 mm, considered to be marginal for the species. In order to reach these goals, long-term persistence and reliable forage yields throughout the year are the central aims for improving white clover pastures (Smith and Fennessy, 2011; Jahufer et al., 2012).

Previous studies showed that resistance to or tolerance of the above limitations to productivity could be introduced independently into white clover plants by Agrobacterium-mediated transformation with three separate transgenes (Panter et al. 2011; Lin et al., 2010; Rossello et al., 2010). My thesis project started from the idea that transgene stacking in elite white clover lines can potentially improve the value of new cultivars by adding multiple agriculturally-relevant traits for which significant variation is not present in the species. Therefore, transgenic white clover plants expressing three transgenes for delayed leaf senescence, aluminium tolerance, and virus resistance concomitantly were generated in this project.

Science outcomes

Thirty transgenic lines were generated expressing three transgenes concomitantly. These lines were evaluated in the laboratory and under glasshouse conditions to identify the events expressing the desired characteristics. Lines exhibiting the optimal molecular attributes, and potential for a higher performance under water limiting conditions and/or aluminium toxic conditions were identified and selected.

Next step towards the development of plants expressing the desired characteristics will involve selection of the best performing lines in the subsequent breeding generations in field conditions.

Industry impact

It is expected that production of white clover plants with the desired characteristics may contribute to overcome the abovementioned biotic and abiotic stresses. It is expected that this will lead to a higher persistence of the species, and a more stable forage yield during the productive years under challenging conditions. Overall, an increase in white clover persistence could represent a major contribution to the Australian dairy industry.

Education program

As a Dairy Futures CRC and DairyBio student, I was able to visit dairy farms, and interact with farmers and industry leaders. This provided me with the possibility of learning how the Australian dairy industry works and understand its major demands. Furthermore, I was also able to expand my professional network as a consequence of these connections.

The DairyBio program also allowed me to have a more fluent interaction with other PhD students and scientists, which was highly relevant in order to exchange research ideas and experiences during the course of the project.