Abstract - Heterotrimeric G proteins (G-proteins), composed of α, β and γ subunits, are essential signaling molecules in most living organism. In humans, G-proteins control vision, smell, taste, and dysfunctions in their signaling causes diseases such as cholera and cancer. In animals and fungi, G-protein-coupled receptors activate signaling by binding GTP to the Gα subunit and signaling stops when the GTPase activity in Gα hydrolyzes GTP to GDP. This mode of action has been universally accepted since Alfred Gilman and Martin Rodbell were awarded the Nobel Prize in 1994. Our work on plant G-proteins has produced numerous surprises and proven that plant G-proteins evolved much faster than their animal counterparts , developing new and atypical subunits [2, 3], and adopting novel functions controlling important agricultural traits . Our new results have added the greatest surprise so far: Plant G-proteins do not necessarily use GTP (or any other nucleotide) to exert their functions in plants . We will present evidence showing that plant G-proteins can mediate signaling in a nucleotide independent manner. Point mutations in the Arabidopsis thaliana Gα subunit were produced in order to abolish nucleotide binding without affecting their 3D structure. These mutations were used to complement Gα-deficient mutants with full restoration of many, but not all, mutant phenotypes. In addition, our CRISPR generated G-protein mutations in tomato have shown that G-proteins have a much more important role in plant defense than previously thought.
Biography - Dr. Jimmy Botella is a Professor of Plant Biotechnology at the University of Queensland, Australia. He started his studies at the University of Malaga and obtained a degree in Quantum Chemistry from the University of Madrid (Spain) and a PhD in Biochemistry from the University of Malaga (Spain). In 1995 he joined the University of Queensland where he established the Plant Genetic Engineering Laboratory (PGEL) specialising in the fields of tropical and subtropical agricultural biotechnology. Dr Botella has eleven international patents in the field of Plant Biotechnology, has founded two biotechnology companies and is a member of the Expert Scientific Panel for the Agricultural Biotechnology Council of Australia. He has been awarded the Chinese Academy of Sciences Visiting Professorship for Senior International Scientists and holds an adjunct position as Professor of Innovation at Henan University (PRC). His research interests include plant defence signalling, point-of-care diagnostics and biotechnological approaches for crop improvement.