A role for 3′-O-β-D-ribofuranosyladenosine in altering plant immunity

Our understanding of how, and the extent to which, phytopathogens reconfigure host metabolic pathways to enhance virulence is remarkably limited. Here we investigate the dynamics of the natural disaccharide nucleoside, 3′-O-β-D-ribofuranosyladenosine, in leaves of Arabidopsis thaliana infected with virulent Pseudomonas syringae pv. tomato strain DC3000. 3′-O-β-D-ribofuranosyladenosine is a plant derived molecule that rapidly accumulates following delivery of P. syringae type III effectors to represent a major component of the infected leaf metabolome. We report the first synthesis of 3′-O-β-D-ribofuranosyladenosine using a method involving the condensation of a small excess of 1-O-acetyl-2,3,5-three-O-benzoyl-β-ribofuranose activated with tin tetrachloride with 2′,5′-di-O-tert-butyldimethylsilyladenosine in 1,2-dichloroethane with further removal of silyl and benzoyl protecting groups. Interestingly, application of synthetic 3′-O-β-D-ribofuranosyladenosine did not affect either bacterial multiplication or infection dynamics suggesting a major reconfiguration of metabolism during pathogenesis and a heavy metabolic burden on the infected plant

ОПТИМИЗАЦИЯ СИНТЕЗА 2'- О-α- D-РИБОФУРАНОЗИЛАДЕНОЗИНА ПО МЕТОДУ СИМПЛЕКСНОГО ПЛАНИРОВАНИЯ

Disaccharide nucleosides belong to an important group of natural compounds found in t-RNA and poly(ADPribose). They are also key elements in the structure of antibiotics and other physiologically active compounds. Poly(ADP-ribosylation) is a posttranslational modification of proteins in eukariotic cells catalyzed by poly(ADPribose)-polymerazes. The importance of poly(ADP-ribose) has been established in many cellular processes such as DNA replication, recombination and repair and cellular differentiation. The development of the synthesis of poly(ADP-ribose) and it’s components is still a challenging problem. The synthesis of 2'-O-α-D-ribofuranosyladenosine, a monomeric unit of poly(ADP-ribose) reported earlier has been improved. An important step on this way is the formation of a 2'-O-glycosidic bond between the adenosine and carbohydrate moieties. A new strategy involving glycosylation of 3',5'-O-(1,1,3,3-tetraisopropyldisiloxane-1,3-diyl)adenosine has been suggested. Varying of the catalyst (SnCl4), nucleoside and carbohydrate relations by the simplex method allowed improving the yields in the glycosylation step from 35 to 64%. As a result, it made possible to reach a higher overall yield of 2'-O-α-D-ribofuranosyladenosine in comparison with the literature data.С помощью метода симплексного планирования оптимизирован синтез 2'-O-α-D-рибофура-нозиладенозина - мономерного звена поли(АDP-рибозы). Подбор оптимальных соотношений катализатора (SnCl4), нуклеозида и углеводной компоненты позволил повысить выходы на стадии гликозилирования с 35 до 64%