Thermospermine catabolism increases Arabidopsis thaliana resistance to Pseudomonas viridiflava

MARÍA MARINA; FRANCISCO VERA SIRERA; JOSÉ L. RAMBLA; MIGUEL A. BLÁZQUEZ; JUAN CARBONELL; FERNANDO L. PIECKENSTAIN; OSCAR A RUIZ

JOURNAL OF EXPERIMENTAL BOTANY

OXFORD UNIV PRESS

Lugar: Oxford; Año: 2013 vol. 64 p. 1393 - 1402

0022-0957

The present work investigated the biological roles of the tetraamine thermospermine (TSpm) by analysing its contribution to Arabidopsis basal defence against the biotrophic bacterium Pseudomonas viridiflava. The participation of polyamine oxidases (PAOs) in TSpm homeostasis and TSpm mediated defence, was also investigated. Exogenous supply of TSpm increased Arabidopsis Col-0 resistance to P. viridiflava. Similarly, ectopic expression of the TSpm biosynthetic gene ACL5 also increased Arabidopsis resistance to the above-mentioned pathogen, while a null acl5 mutant exhibited a decrease in resistance, as compared to Col-0 plants. This increase in disease resistance was blocked by the PAO inhibitor SL-11061, thus demonstrating the participation of TSpm oxidation in the enhancement of resistance provided by TSpm accumulation and ectopic ACL5 expression. Analysis of PAO genes expression in transgenic 35S::ACL5 and Col-0 plants supplied by exogenous TSpm suggests that PAO 1, 3 and 5 are the main PAOs involved in TSpm catabolism. In summary, TSpm exhibited the potential to perform defensive functions previously reported for its structural isomer Spm, and the relevance of these findings is discussed on the basis of ACL5 expression and TSpm concentration in planta. Moreover, the present work demonstrates that manipulation of TSpm biosynthesis and catabolism can modify plant resistance to pathogens.