The Sugar Sensor, Trehalose-6-Phosphate Synthase (Tps1), Regulates Primary and Secondary Metabolism during Infection by the Rice Blast Fungus: Will Magnaporthe oryzaeâ•Žs â•œSweet Toothâ•š become Its â•œAchillesâ•Ž Heelâ•š?

The Sugar Sensor, Trehalose-6-Phosphate Synthase (Tps1), Regulates Primary and Secondary Metabolism during Infection by the Rice Blast Fungus: Will Magnaporthe oryzae's " Sweet Tooth " become Its " Achilles' Heel " ?" (2011). Fungal Molecular Plant-Microbe Interactions. Paper 6. disparate cellular activities? To address this question, this review discusses our current understanding of tre-halose metabolism with an emphasis on its role inreg-ulating a subset of primary and secondary metabolic-pathways in M. oryzae during rice plant infection. Trehalose Metabolism in Plants and Yeast The most common biosynthetic route to synthesize trehalose starts with trehalose-6-phosphate synthase (OtsA in bacteria or TPS in eukaryotes). TPS catalyzes the production of the intermediate trehalose-6-phosphate (T6P) fromglucose-6-phosphate (G6P) and UDP-glucose (Foster et al. 2003; Vandesteene et al. 2010). T6P is subsequently dephosphorylated by trehalose phosphate phosphatase (TPP) to form trehalose (Figure 1). In Saccharomyces cerevisiae, trehalose biosynthe-sis also requires two regulatory subunits, TPS3 and TSL (Bell et al. 1998; Paul et al. 2008; Reinders et al. 1997), while M. oryzae carries only a single TPS3 homo-logue (Wilson et al. 2007). During trehalose catabolism, trehalases hydrolyse trehalose into two glucose units. Introduction The non-reducing disaccharide, trehalose (α-D-gluco-pyranosyl-α-D-glucopyranoside) is found in a wide range of organisms, including bacteria, plants, inverte-While commonly occurring as a storage compound, the treha-lose molecule can also play a purely mechanical role in the protection of cells against numerous environmental stresses such as prolonged periods of desiccation (Crowe et al. 1998; Singer and Lindquist 1998). In addition , the metabolism of trehalose has been implicated in the regulation of diverse cellular processes in plants and fungi, such as growth and development in Arabidopsis thaliana and maize (Eastmond et al. 2002; Satoh-Naga-sawa et al. 2006), the control of glycolysis in yeast (Ho-hmann et al. 1993; Thevelein and Hohmann 1995) and the establishment of disease by the devastating fungal pathogen of rice, Magnaporthe oryzae (Foster et al. 2003; Wilson et al. 2007). Focusing on this intriguing regulatory role, how might trehalose metabolism affect such