Title: Plant proteomic responses to signal compounds lipo-chito-oligosaccharide and thuricin

Sowmyalakshmi Subramanian

McGill University, Canada


Dr. Sowmya Subramanian did her BSc, MSc (Botany, Cytogenetics) from Bangalore University and Master of Technology (M. Tech) from Indian Institute of Technology, Kharagpur, India. She moved to Canada in 2006 and obtained MS (Agriculture) from Dalhousie University and PhD (Plant Science) from Department of Plant Science, Macdonald Campus/McGill University, Canada, where she continues to study Plant-microbe interaction as a Post-doctoral fellow in Prof. Donald Smith’s lab. Her primary research interests include Plant stress physiology and ‘Omics’ (Transcriptomics, Proteomics and Metabolomics) of both plants and microbes in Plant-Microbe interactions with emphasis on biostimulants from rhizosphere bacteria.


Lipo-chitooligosaccharides (LCO) and thuricin 17 (Th17) are bacterial signal compounds secreted by the rhizosphere bacteria of soybean, Bradyrhizobium japonicum 532C and Bacillus thuringiensis NEB17. At femtomolar concentrations these signal compounds promote plant growth and impart salt stress tolerance to Arabidopsis, soybean, corn and tomato. In all these studies, seeds and plants at the vegetative stage of growth were the most positively and visually affected. In each of these plants, the proteome responses vary depending on the abiotic stressors such as salt, drought and low temperature stress; the carbon, nitrogen and energy metabolic pathways were affected. Some of the key upregulated proteins in LCO and Th17 treated samples, in comparison with control, were ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit, ribulose-1,5-bisphosphate carboxylase small subunit, ATP synthase β-subunit and chlorophyll a/b binding protein type II, along with shifts in stress proteins specific to each of these stressors. In soybean plants, the protein shifts were circadian specific under optimal plant growth conditions. The specificity of these responses plays crucial roles in organ maturation and transition from one stage to another in the plants' life cycles. This understanding of the response of biostimulants is a crucial component in agriculture and to address global food production. This talk summarizes some of the key findings of the proteomics work done on these two signaling compounds.