San Francisco, April 2017 In 1992, Ronald joined
UC Davis as a faculty member. From 2003 to 2007 Ronald chaired the UC Davis Distinguished Women in Science seminar series, an event designed to support women's professional advancement in the sciences. She served as Faculty Assistant to the Provost from 2004 to 2007. Ronald is a vocal advocate for science and for sustainable agriculture. Her laboratory has been instrumental in the development of rice that is disease-resistant and flood-tolerant.
Xa21: Pattern recognition receptor-mediated immunity The Ronald laboratory studies the innate immune response, using the host organism
rice and the agriculturally important pathogen
Xanthomonas oryzae pv. oryzae (Xoo). In the 1990s, through conversations with rice geneticist
Gurdev Khush, Ronald became interested in the rice XA21 genetic locus, which conferred broad-spectrum resistance to
Xoo. She hypothesized that
Xa21 encoded a single protein that recognized a conserved microbial determinant. In 1995, the Ronald laboratory isolated and characterized the rice XA21
pattern recognition receptor. Subsequent discoveries in
flies, humans, mice, and
Arabidopsis revealed that animals and other plant species also carry membrane-anchored receptors with striking structural similarities to XA21 and that these receptors also play key roles in the immune response. For their discoveries of the fly and mice receptors,
Jules Hoffman and
Bruce Beutler received the
2011 Nobel Prize in Physiology or Medicine (jointly with
Ralph Steinman), indicating the importance of such research. This work resulted in part from the identification of a blight-resistant rice strain from
Mali,
Oryza longistaminata, in the late 1970s. The strain was studied and bred at the
International Rice Research Institute (IRRI) in
Los Baños,
Philippines. Ronald's group subsequently mapped, sequenced, and cloned the Xa21 gene from this rice strain. When US patent 5859339 was granted to the University of California for the XA21 gene, Ronald and law professor John Barton established a benefit-sharing model for the source countries of genetically important plant varieties called the Genetic Resources Recognition Fund. Ronald also launched a project with CGIAR to allow noncommercial use of the gene for nonprofit purposes and released the gene to IRRI for the development of rice strains to be grown in developing nations.
Paper retraction In 2009 Ronald's laboratory reported on the discovery of a bacterial protein that they believed was the activator of Xa21-mediated immunity. These reports were described by
ScienceWatch as "hot" and "highly cited". In 2013, Ronald retracted both scientific papers, notifying the scientific community that two bacterial strains had been mixed up. The error was discovered when new laboratory members Rory Pruitt and Benjamin Schwessinger The retractions were also reported on by
The Scientist. Retraction watch, a website that shines light on problems with papers and educates and celebrates research ethics and good practices stated, "that this was a case of scientists doing the right thing".
RaxX, the activator of Xa21-mediated immunity For two more years Ronald's laboratory repeated critical experiments and carried out new ones. In redoing their work, they introduced new procedures and controls to ensure that they were getting it right. Ronald reports that she was amazed not only by the perseverance and loyalty of her team, but also by the community support that she received during this difficult time. In 2015, Ronald published the discovery of the predicted ligand of XA21, a sulfated peptide called RaxX, correcting their mistake and bringing the research team full circle.
Genetic Resources Recognition Fund Ronald has sought ways to recognize source nations and institutions that have contributed to important scientific advances, such as the West African country of Mali, the source of the Xa21 rice gene. Working with law professor John Barton, Ronald tried to establish a benefit-sharing model for the source countries of genetically important plant varieties. In 1996, Ronald founded the Genetic Resources Recognition Fund (GRRF) at UC Davis. The intention of the fund was to collect payments from the licensing of academic discoveries that utilized plant materials from developing countries, and to redistribute those monies to source countries through fellowships, land conservation efforts, or other projects of benefit to nation partners.
Sub1: Tolerance to abiotic stress In 1996, Ronald began a project with rice breeder David Mackill who had recently demonstrated that tolerance to complete submergence mapped to the Submergence tolerance 1 (Sub1)
Quantitative trait locus (QTL). In 1997, the
USDA awarded Ronald and Mackill a grant to isolate the Sub1 locus. Ronald's laboratory led the positional cloning of the Sub1 QTL, revealed that it carried three ethylene response transcription factors (ERF) and demonstrated that one of the ERFs, which she designated Sub1A, was upregulated rapidly in response to submergence and conferred robust tolerance to submergence in transgenic plants . This work revealed an important mechanism with which plants control tolerance to abiotic stress and set the stage for in-depth molecular-genetic analyses of Sub1A-mediated processes with her collaborator
Julia Bailey-Serres, who joined the project in 2003. Mackill's team at the International Rice Research Institute
(IRRI) generated and released several Sub1A varieties (developed through
marker-assisted breeding) in seven countries including India, Indonesia and Bangladesh, where submergence destroys four million tons of rice each year, enough to feed 30 million people. With support from the
Bill and Melinda Gates Foundation, Sub1 rice has reached over six million farmers as of 2017. ==Public engagement==