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Articles

Name

Sanjay Swami

Year of selection 2014
Cohort 1
e-mail

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Phone number

91-7976118024

Home Institute Jawaharlal Nehru University, India
Host Institute

Universidad Politecnica de Madrid

Lab, Institute, Country

Plant innate immunity group,  Centro de biotecnologia y genomica de plantas (CBGP), Madrid, SPAIN

Name of Researcher/Supervisor Dr. Lucia Jorda Miro, & Dr. Miguel Angel Torres
Duration of working period 40 months
Title and Brief report of the work (max 300 words)

ERECTA-YODA MAPK functional cascade and other phosphorylation events in innate immunity".   

YODA (YDA) is a MAPK Kinase Kinase that functions downstream the Receptor Like Kinase (RLK) ERECTA (ER). Besides controlling stomatal patterning and other plant developmental-associated processes, YDA-ER pathway regulates Arabidopsis immune responses. Constitutive activation of YDA in Arabidopsis (CA-YDA plants) confers broad-spectrum disease resistance. We performed a transcriptomic analysis that showed CA-YDA plants constitutively overexpress several cell wall-related and defence-associated genes. In addition, some putative SMALL SECRETED PEPTIDES (SSP1-8) and PUTATIVE RECEPTOR PROTEINS (PRP1-9) coding for RLKs, were upregulated in CA-YDA plants. We carried out disease resistance analysis on single mutants in these genes that revealed SSPs and PRPs are required to trigger Arabidopsis immune responses against the fungus Plectosphaerella cucumerina (PcBMM), the bacteria Pseudomonas syringae pv. tomato DC3000 or the oomycete Hyaloperonospora arabidopsidis Noco2. Moreover, mutants in SSP1 and PRP1 displayed enhanced susceptibility towards Cucumber Mosaic Virus, highlighting their putative role in immunity against a broad range of pathogens. We generated synthetic peptides corresponding to the C-terminal regions of SSP1 (PEP-A and PEP-E), SSP2 (PEP-O) and SSP7 (PEP-I) to determine their ability to trigger PAMP-triggered immune (PTI) responses. Preliminary data indicate that SSP7 and, to a lesser extent, SSP1 could act as activators of defence responses, as treatments with PEP-I and PEP-E are able to trigger some PTI events in WT plants (Col-0). Interestingly, neither these small signalling peptides nor PRP1 seem to be involved in regulating developmental parameters such as plant height and pedicel and silique length. Thus, the contribution of most of the selected SSPs and PRP1 remains unique to Arabidopsis defence responses. We therefore hypothesize that changes in the cell wall of CA-YDA plants may trigger novel immune responses in parallel to canonical disease resistance pathways regulated by phytohormones. This new defence surveillance system would rely on immunogenic peptides (SSPs)-RLK pairs that upon perception of pathogens or elicitors would act in a positive feedback loop maximizing the level of immunity.

Arabidopsis heterotrimeric G protein complex modulates PTI and regulates disease resistance to pathogens. To identify new immune response elements, a mutational screening was performed to identify suppressors of the enhanced susceptibility to PcBMM displayed by a mutation in the gene encoding the heterotrimeric G protein β subunit (AGB1). Four sgb (suppressor of G protein βeta1) mutants (sgb10, sgb11, sgb12 and sgb13) were identified based on their ability to fully rescue agb1-2 susceptibility. This study was mainly focused on the characterization of sgb10. We mapped this mutation on chromosome 3 and corresponded to a G to A transition in the coding sequence of MAP KINASE PHOSPHATASE 1 (MKP1; At3g55270).  Interestingly, mkp1/sgb10 mutant displayed elevated reactive oxygen species (ROS) levels that were compromised in the NADPH oxidase mutant rbohD, suggesting that the enhanced ROS production is generated by this oxidase. Moreover, we observed an epistatic, genetic interaction between mkp1/sgb10 and rbohD in Arabidopsis resistance response to PcBMM, suggesting that MKP1 and RBOHD are components of the same immune pathway and that this NADPH oxidase could be a downstream target of MKP1.

List of publications with impact factor, presentation of the research work in conferences/ seminars /workshops

• Alteration of cell wall xylan acetylation triggers defense responses that counterbalance the immune deficiencies of plants impaired in the β-subunit of the heterotrimeric G-protein. (the plant journal 5.901).                                                                              

YODA MAP3K kinase regulates plant immune responses conferring broad-spectrum disease resistance. (New Phytologist 7.33)                                                                                                      

Poster Presented as first author at XIII Reunion de Biologia Molecular de Plantas (RBMP), Universidad de Oviedo, SPAIN (June, 2016)

Poster presented as first author at New Frontiers at Plant Biology Workshop, CBGP, Madrid, SPAIN (June, 2016)

Oral Presentation in Junior Seminar Program, CBGP, Madrid, SPAIN (June 2016)

Present position

In search of Post Doctoral positions to build a scientific career


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