Research Summary

Major research highlights of the lab

Initial studies were focused on identifying candidate defense related genes from the wild resistant Piper species Piper colubrinum, and optimization of suitable molecular platforms for gene functional studies in this non-model plant. Highlights of the study are as follows:

• Identification of candidate defense genes from P.capsici resistant wild pepper-Piper colubrinum by Suppression Subractive Hybridization (SSH) approach (Dicto and Manjula, 2005.
• Defense gene functional validation by protein level expression and downstream functional assays (Mani and Manjula 2010;Mani and Manjula 2011.
• Optimization of gene silencing platforms in Piper colubrinum by hairpin RNAi and VIGS strategy (Mani et al, 2012; Anu et al 2015a, Anu et al 2015b).

Current focus of the lab

Our ongoing work in the important spice crop Piper nigrum (black pepper) broadly aims at identification of specific molecular components that prime the plant innate immunity during its interaction with the pathogen (Phytophthora capsici). Some highlights of the study are:

• In the absence of necessary molecular information in black pepper, we have used a simple and integrative ‘omics’ approach to derive and understand the molecular changes associated with P.nigrum X P.capsici interaction. (Mahadevan et al, 2016.
• Our study is the first to identify, characterize and quantitate novel proteomics information in black pepper in response to P.capsici infection, which was further validated in the light of our transcript level expression data.
• Putative priming targets have been identified, and these are being functionally evaluated by transcript level by qRT-PCR analysis and Virus-Induced Gene Silencing (VIGS)/ overexpression  approaches in planta.

Significant achievements

• Generation of annotated transcriptome and proteome databases at different time points of pathogen infection in the major spice crop Piper nigrum (Transcriptome data submitted in NCBI SRA; Proteome data available via ProteomeXchange with identifier PXD003887).
• Some potential ‘priming’ targets have been identified (and there are in the pipeline), in Piper nigrum, which are useful resources for developing ‘priming’ as a crop protection strategy in black pepper.
• Optimized molecular platforms including gene silencing by VIGS and over expression strategies in Piper sp and model plants (Nicotiana sp and Arabidopsis thaliana) respectively, for defense gene functional studies.

Title of projects (last 5 years)

• RNAi methods for functional validation of defense related genes from Piper colubrinum
• Optimization of Human recombinant Granulocyte Colony Stimulating Factor production in tobacco.
• Molecular analysis of mutualistic interaction of Centella asiatica and Piriformospora indica and its effects on secondary metabolite production.
• Molecular analysis of Pathogen Associated Molecular Patterns (PAMP) triggered immunity in Piper nigrum – Phytophthora capsici phytopathosystem.