Raka Mitra

Education & Professional History

Massachusetts Institute of Technology, SB; Stanford University, PhD

Dr. Mitra is a molecular and cellular biologist interested in the interactions between plants and microbes. Her lab studies bacterial pathogens of plant roots with the goal of understanding disease development and plant defense.

The bacterial wilt pathogen, Ralstonia solanacearum, causes one of the most devastating bacterial diseases of plants worldwide, affecting hundreds of plant species including many major crops such as tomato and potato.  It is estimated that this economically important disease results in over one billion US dollars lost annually for the potato industry alone.  Because this pathogen is typically restricted to warm climates, the losses resulting from bacterial wilt are particularly acute for subsistence farmers living in equatorial zones.

While the resistance mechanisms that protect plants against bacterial pathogens of leaves are well-studied, little is known about resistance to Ralstonia, which typically infects plants via the root systems and ultimately colonizes the plant vasculature resulting in wilting and death. During infection, bacteria inject proteins directly into the cytoplasm of the plant cell.  These proteins are called “effector proteins”.   The Mitra lab studies the role of these effector proteins in plant disease with the hope of better understanding how plants may defend themselves against this pathogen.

Biology 126: Energy Flow in Biological Systems
Follows the pathways through which energy and matter are acquired, stored, and utilized within cells, organisms, and ecosystems. The focus moves among the different levels of organization from protein function to nutrient movement through ecosystems.
Co-requisite: Lab (BIOL126L)
Textbook: Freeman, Biological Science

Biology 280: Cell Biology An examination of the structures and processes that underlie the life of cells, both prokaryotic and eukaryotic. Topics to be covered include energy capture, storage, and utilization; cellular reproduction; organelles, membranes, and other cellular components; and cell-cell communication.
Prerequisites: Introductory Biology (Biology 125 and 126).
Corequisite: Lab (BIOL281)
Textbook: Alberts, Molecular Biology of the Cell. 

Biology 234: Microbiology with Lab
A study of the metabolism, genetics, structure, and function of microorganisms. While presented in the framework of the concepts of cellular and molecular biology, the emphasis will be on the uniqueness and diversity of the microbial world. The course integrates lecture and laboratory, and will fulfill requirements of a microbiology course with lab for veterinary or pharmacy schools.
Co-requisite: Lab (BIOL235)
Textbook: Swanson, Microbe

Biology 385: Microbial Pathology
Microbes are the most abundant organisms on earth, and microbial pathogens have caused human and plant disease epidemics worldwide. This course will focus upon the pathogenic strategy of a variety of well-studied microbes in order to illustrate our understanding of the molecular and cellular nature of microbial disease. We will analyze current and seminal papers in the primary literature focusing on mechanisms employed by microbes to attack hosts.
Prerequisites: Introductory Biology (Biology 125 and 126), and either Genetics (Biology 240) or Cell Biology (Biology 280).
Readings: Scientific Papers. 

Plant pathogens and symbionts target the plant nucleus. N. Tehrani and RM Mitra. Current Opinion in Microbiology (2023).

Tomato deploys defence and growth simultaneously to resist bacterial wilt disease. V Meline, CG Hendrich, AN Truchon, D Caldwell, R Hiles, R Leuschen-Kohl, T Tran, RM Mitra, C Allen, AS Iyer-Pascuzzi. Plant, Cell & Environment (2022).

Ralstonia solanacearum effectors localize to diverse organelles in Solanum hosts. NL Denne, RR Hiles, O Kyrysyuk, AS Iyer-Pascuzzi, RM Mitra. Phytopathology (2021).

What are the Top 10 Unanswered Questions in Molecular Plant-Microbe Interactions? JM Harris, P Balint-Kurti, JC Bede, B Day, S Gold, EM Goss, LJ Grenville-Briggs, KM Jones, A Wang, Y Wang, RM Mitra, KH Sohn, ME Alvarez. Molecular Plant-Microbe Interactions (2020) 33 (12), 1354-1365.

EffectorK, a comprehensive resource to mine for Ralstonia, Xanthomonas, and other published effector interactors in the Arabidopsis proteome. M González‐Fuente, S Carrère, D Monachello, BG Marsella, AC Cazalé, C Zischek, RM Mitra, N Rezé, L Cottret, MS Mukhtar, C Lurin, LD Noël, N Peeters. Molecular plant pathology (2020) 21 (10), 1257-1270.

Metabolomics of tomato xylem sap during bacterial wilt reveals Ralstonia solanacearum produces abundant putrescine, a metabolite that accelerates wilt disease. TM Lowe‐Power, CG Hendrich, E von Roepenack‐Lahaye, B Li, D Wu, R Mitra, BL Dalsing, P Ricca, J Naidoo, D Cook, A Jancewicz, P Masson, B Thomma, T Lahaye, AJ Michael, C Allen. Environmental microbiology (2018) 20 (4), 1330-1349.

Enhancing Interactions between Research Lab Students & Their Communities. EK Peterson, RM Mitra. The American Biology Teacher (2016) 78 (6), 509-511.

Ralstonia solanacearum requires PopS, an ancient AvrE-family effector, for virulence and to overcome salicylic acid-mediated defenses during tomato pathogenesis. JM Jacobs, A Milling, RM Mitra, CS Hogan, F Ailloud, P Prior, C Allen. MBio (2013) 4 (6).

The Genetic Network Controlling the Arabidopsis Transcriptional Response to Pseudomonas syringae pv. maculicola: Roles of Major Regulators and the Phytotoxin Coronatine. L Wang, RM Mitra, KD Hasselmann, M Sato, L Lenarz-Wyatt, JD Cohen, F Katagiri, J. Glazebook. Molecular plant-microbe interactions (2008) 21 (11), 1408-1420.

An ERF transcription factor in Medicago truncatula that is essential for Nod factor signal transduction. PH Middleton, J Jakab, RV Penmetsa, CG Starker, J Doll, P Kaló, R Prabhu, JF Marsh, RM Mitra, A Kereszt, B Dudas, K VandenBosch, SR Long, DR Cook, GB Kiss, GED Oldroyd. The Plant Cell (2007) 19 (4), 1221-1234.

Medicago truncatula NIN is essential for rhizobial-independent nodule organogenesis induced by autoactive calcium/calmodulin-dependent protein kinase. JF Marsh, A Rakocevic, RM Mitra, L Brocard, J Sun, A Eschstruth, SR Long, M Schultze, P Ratet, GED Oldroyd Plant physiology (2007) 144 (1), 324-335.

A high‐performance, small‐scale microarray for expression profiling of many samples in Arabidopsis–pathogen studies. M Sato, RM Mitra, J Coller, D Wang, NW Spivey, J Dewdney, C Denoux, J Glazebrook, F Katagiri. The Plant Journal (2007) 49 (3), 565-577.

Nitrogen fixation mutants of Medicago truncatula fail to support plant and bacterial symbiotic gene expression. CG Starker, AL Parra-Colmenares, L Smith, RM Mitra, SR Long. Plant physiology (2006) 140 (2), 671-680.

Nodulation signaling in legumes requires NSP2, a member of the GRAS family of transcriptional regulators. P Kaló, C Gleason, A Edwards, J Marsh, RM Mitra, S Hirsch, J Jakab, S Sims, SR Long, J Rogers, GB Kiss, JA Downie, GED Oldroyd. Science (2005) 308 (5729), 1786-1789.

Six nonnodulating plant mutants defective for Nod factor-induced transcriptional changes associated with the legume-rhizobia symbiosis. RM Mitra, SL Shaw, SR Long. Proceedings of the National Academy of Sciences (2004) 101 (27), 10217-10222.

A Ca2+/calmodulin-dependent protein kinase required for symbiotic nodule development: gene identification by transcript-based cloning. RM Mitra, CA Gleason, A Edwards, J Hadfield, JA Downie, GED Oldroyd, SR Long. Proceedings of the National Academy of Sciences (2004) 101 (13), 4701-4705
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Plant and bacterial symbiotic mutants define three transcriptionally distinct stages in the development of the Medicago truncatula/Sinorhizobium meliloti symbiosis. RM Mitra, SR Long. Plant physiology (2004) 134 (2), 595-604.

Pharmacological Analysis of Nod Factor-Induced Calcium Spiking in Medicago truncatula. Evidence for the Requirement of Type IIA Calcium Pumps and Phosphoinositide Signaling.EM Engstrom, DW Ehrhardt, RM Mitra, SR Long. Plant physiology (2002) 128 (4), 1390-1401.

Evidence for structurally specific negative feedback in the Nod factor signal transduction pathway. GED Oldroyd, RM Mitra, RJ Wais, SR Long. The Plant Journal (2001) 28 (2), 191-199.

Genetic evidence that butternut canker was recently introduced into North America. GR Furnier, AM Stoltz, RM Mustaphi, ME Ostry. Can. J. Bot. (1999) June; 77(6):783-785.

Isozyme variation in Minnesota populations of Eurasian watermilfoil. GR Furnier GR, MM Mustaphi. Aquatic Bot. (1992) Oct; 43(3):305-309.