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Tomas Ruiz Argüeso (Villamol 1943 - Madrid 2020) was Full Professor of Microbiology and, until his death, Emeritus Professor at CBGP and Department of Biotechnology-Plant Biology at the Universidad Politécnica de Madrid.
Tomas Ruiz Argüeso (Villamol 1943 - Madrid 2020) was Full Professor of Microbiology and, until his death, Emeritus Professor at CBGP and Department of Biotechnology-Plant Biology at the Universidad Politécnica de Madrid. At the same University, he had previously graduated as an Agricultural Engineer and completed his Doctoral Thesis, focused on the study of the microbiology of honey. He then published with his supervisor (Alonso Rodríguez Navarro) pioneering articles on osmophilic microflora that are still regularly quoted today, 45 years after their publication. He later became interested in the symbiotic nitrogen fixation process, a central aspect in Plant Microbiology that he would pursue throughout his long research career. He initially worked on the isolation and characterization of endosymbionts from soybean, a crop that was being introduced in Spain at that time, and contributed to the development of the first inoculants in the country. He later joined the laboratory of Harold Evans at Oregon State University as a Fulbright postdoctoral to study hydrogen metabolism in the endosymbiotic legume bacteria, commonly known as rhizobia. This was complemented by a further stay, with help from the Juan March Foundation, in Donald Helinski's laboratory in La Jolla (UCSD) to incorporate Molecular Biology methodologies to his research. The center of his interest for most of his career was the hydrogen recycling system of rhizobia, a subject on which he published over 50 research papers that covered the discovery and sequencing of the genes involved to the biosynthesis mechanism of metalloenzyme, the provision of metals, the regulation of expression, and its role in improving nitrogen fixation by legumes, thus making the Rhizobium hydrogenase system the most studied and best known within the alpha-proteobacteria. In 2008 he joined the group of researchers who founded the CBGP, where in recent years he became interested in the characterization of new symbiotic systems. In this area, he actively collaborated with research groups in Latin America (Mexico, Peru, Chile, Brazil) and North Africa (Algeria, Tunisia), and demonstrated the existence of a very high diversity of soil bacteria capable of establishing diazotrophic symbiosis with legumes of the genus Lupinus. He described a new species of ultra-slow growing rhizobia associated with Lupinus mariae-josephae, a legume recently described in the Spanish Levante. He made a decisive contribution to the area of nitrogen fixation in Spain, having been a founding member of SEFIN, and later its president. Throughout his career he established a strong research group, known as the "rhizobials." He published more than 80 articles in international journals, led over 30 research projects, presented almost 300 contributions at national and international conferences, and directed 16 Doctoral Theses. A new Rhizobium species has been recently named (R. ruizarguesonis; doi: 10.1016/j.syapm.2020.126090) as a tribute to his many contributions. In parallel, he had a long teaching career in Microbiology, always remembered by his students for the enthusiasm and rigor of his classes. He also carried out a very notable task of service in different national and European research organizations and entities (CAICYT, CNEAI, OECD, EU, ...). And beyond his many achievements as a scientist and professor, Tomás always kept open the door of scientific curiosity and drawing pleasure from doing science, along with a friendly and close character, always ready to listen and help others. Those of us who have been fortunate and privileged to share these years with such an extraordinary researcher, teacher and friend will miss him. We are left with his many teachings and his memory. May he rest in peace.
