Priyanka Giri

in silico-prediction of downstream WRKY interacting partners of MAPK3 in Brassica.

Protein-Protein interactions (PPIs) are vital to most biological processes thus the identification of PPIs is of primary importance. Here, we endeavor to identify the downstream interacting partners of (BjMPK3P) in Brassica juncea using the docking approach. Out of 63 and 37 members of BrWRKY and BnWRKY transcription factors, 50 and 29 members are showing interactions with BjMPK3P respectively while the rest are showing non-interaction. Twenty two WRKY members are common to both the species. Using minimal sequence motif search as well as through docking approach several novel WRKY interacting proteins were also reported in the present study which need to be confirmed by in vitro kinase assay. Together, the results obtained essentially enhance our knowledge of the MAPK interacting protein network and provide a valuable research resource for developing a nearly important link between pathogen-activated MAPK signaling pathways and downstream transcriptional programming.

Effect of zeatin on the infection process and expression of MAPK-4 during pathogenesis of Alternaria brassicae in non-host and host Brassica plants

Recent studies have revealed an important role of hormones in plant immunity. Cytokinins are phytohormones that are involved in various regulatory processes including plant defense. Zeatin a cytokinin antagonizes the effect of Alternaria brassicae pathotoxin in cell culture of Brassica juncea . Phytohormones are also the inducers of MAP Kinase signaling pathways which are the important signaling modules in eukaryotic cells. In this paper, an attempt was made to study the exogenous application of zeatin on the disease score, infection behavior of A. brassicae , expression pattern of MAPK-4 in the non host Sinapsis alba , host B. juncea susceptible c.v Varuna, B. juncea moderately tolerant c.v. Divya and transgenic Brassica to confer its role in plant immunity. We observed that high concentration of zeatin led to increased defense responses by delaying the infection process as well as significantly reducing the disease score. Semi-quantitative RT-PCR reveals that zeatin also increases the expression of MAPK-4 at early hours of infection. Our result supports that zeatin up regulates plant immunity via an elevation of MAPK-4 and clearly reflects that it antagonizes the effect of A. brassicae . The crosstalk between zeatin and MAPK signaling pathway may help plants fine-tune defense responses against A. brassicae in the disease Alternaria blight. Keywords : Alternaria blight, Brassica , disease score, MAPK, pathogenesis, infection process African Journal of Biotechnology Vol. 12(17), pp. 2164-2174

In silico-prediction of downstream MYB interacting partners of MAPK3 in Arabidopsis.

Protein-Protein interactions (PPIs) are vital to most biological processes thus the identification of PPIs is of primary importance. Here, we endeavor to identify the downstream interacting partners of (AtMAPK3P) in Arabidopsis thaliana using the docking approach. Out of 131 members of MYB transcription factors 41 members are showing interactions with AtMAPK3P while the rest are showing non-interaction. Using minimal sequence motif search as well as through docking approach several novel MYB interacting proteins were also reported in the present study which need to be confirmed by in vitro kinase assay. Together, the results obtained essentially enhance our knowledge of the MAPK interacting protein network and provide a valuable research resource for developing a nearly important link between pathogen-activated MAPK signaling pathways and downstream transcriptional programming.

In-Silico Approaches for Studying the MAP Kinase Signaling Pathways Involved in Resistance Against Alternaria Blight in Brassica

The most devastating fungal disease of Brassica is Black spot or Alternaria blight caused by Alternaria brassicae. Alternaria brassicae causes the disease through the production of host specific toxin viz. chlorotic and necrotic toxins, which are responsible for the formation of chlorotic, necrotic and green islands like disease symptoms in susceptible Brassica leaves. Signal transduction is the means by which cells respond to extracellular information. Mitogen- activated protein kinase (MAPK) cascades are important signaling modules in eukaryotic cells. MAPK are important intermediates in signal transduction pathways that are initiated by many types of cell surface receptors. They function Downstream of sensors/receptors and regulate cellular responses to external and endogenous stimuli. Mitogen activated kinase, ensures their specificity of action by interacting with its different substrates through docking domains. Specific docking interactions between MAPKs and its substrate are crucial for efficient and accurate signal transmission.