Nowadays the cGMP and cAMP have been reported to be involved in several plant physiological processes, but the mechanisms trough they act and the signal
transduction events that follow, are still poorly characterized. The main aim of this project will be devoted to the study the roles played by these two cyclic nucleotides
in the signaling events that follow the avirulent pathogen attacks (Pseudomonas syringae) in Arabidopsis thaliana plants.
The main project resource will be the production of transgenic Arabidopsis plants with altered levels of cyclic nucleotides, both cGMP and cAMP. To this purpose
Arabidopsis plants that overexpress a mammalian guanylate cyclase or a phosphodiesterase will be generated to obtain altered levels of cGMP. Moreover,
Arabidopsis plants will be transformed with a chimeric protein, namely “cAMP-sponge” (cSA) in order to reduce the level of cAMP. The Arabidopsis transgenic
plants obtained will be subjected to the avirulent pathogen attack and analyses at phenotypic, biochemical and molecular levels will be pursued. In particular, we will
also analyze the cytoplasm dynamics of other second messengers, such as Ca2+ and H2O2 upon the pathogen attack in wild type plants or in the transgenic lines with
altered levels of cyclic nucleotides. To do so the produced transgenic lines with altered cNMP levels will be crossed with Arabidopsis lines expressing genetically
encoded probes for Ca2+ (Cameleon) and H2O2 (HyPer). This series of experiments will allow us to understand how cAMP and cGMP can affect the dynamics of
other second messengers deciphering their interrelationships in signaling events.
A transcriptomic, proteomic and phosphoproteomic characterization will also be pursued in order to discover genes and proteins involved in the signaling events
upon avirulent pathogen attack and in particular those regulated by cNMP.
The understading of the specific biological responses regulated by cAMP and cGMP and the downstream signaling events represents a big challenge in the plant field
and to do so a multidisciplinary approach is absolutely required.
The proponent groups are well qualified to pursue the described research with complementary expertise that will guarantee the success of the project.