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Pious Thomas

Pious Thomas
Designation: 
Principal Scientist (Horticulture)
Division/Section: 
Division of Biotechnology
Specialisation: 
Biotechnology (Endophytic & Molecular Microbiology)
Qualification: 
Ph.D; Post-Doctorate
Experience (No. of Years): 
25 yrs
Research Accomplishments: 

MAJOR RESEARCH ACCOMPLISHMENT:  Demonstration of abundant bacterial colonization in the peri-space between cell wall and plasma membrane in banana, and revelation of cytoplasmic peri-space as a niche for endophytic bacteria;  Description of ''Cytobacts' and 'Peribacts, the intracellular colonizing endophytic bacteria TECHNOLOGIES DEVELOPED:  Micropropagation technology for (i) papaya, (ii) triploid seedless watermelon, (iii) grapes and (iv) chrysanthemum;  Sachet technique for the small-scale acclimatization of micropropagated plants of different crops;  Diagnostics for the detection of covert and endophytic bacteria in tissue cultures; METHODOLOGIES:  Spotting-and-tilt-spreading (SATS) as a simple and efficient method for bacterial cfu estimation over spread plating;  Use of cotton with high hydrophilicity for Bacillus spore surveillance over foam, nylon, or polyester swabs and high spore recovery efficiency;  Optimization of seedling root-injury-inoculation technique for the screening of tomato against Ralstonia solanacearum at seedling stage;  Development of single-plate-serial-dilution-spotting (SP-SDS) as an assured tool for bacterial cfu estimation; CONCEPTS:  Role of leaf in promotion of adventitious rooting; Identification and cloning of genes involved in regulation of rooting in stem cuttings  Identification of covert and unsuspecting association of diverse bacteria as the cause for the decline in the performance or degeneration of micropropagated cultures  Cleansing the established in vitro cultures from covert microbial contaminants through a combination of surface disinfection, antibiotic challenge followed by recurrent tissue indexing  Identification of normally unsuspected routes of microbial entry in plant tissue cultures including deep seated endophytes, alcohol resistant bacteria and autoclaving defying spore-formers, and identification of 90% ethanol as a universally adoptable better bacteri/sporicidal level of alcohol  Establishing the ubiquitous and integral association of endophytes with plant tissue in no-cultivable form through molecular and microscopic techniques  Isolation and characterization of a series of bacterial endophytes from different plant hosts including field grown plants and in vitro stocks;  Elucidation of the chances of bacterial cell injury due to the inoculum spreader during spread plating and development of a simple spotting-and-tilt-spreading (SATS) to maximize CFU and to avoid CFU inconsistencies during bacterial sampling.

Important Publications: 

(1). Thomas, P., Sadashiva, A.T., Upreti, R. and Mujawar, M. M. 2015. Direct delivery of inoculum to shoot tissue interferes with genotypic resistance to Ralstonia Solanacearum in tomato seedlings. Journal of Phytopathology 163: 320-323; (2). Thomas, P. and Upreti, R. 2015. Evaluation of tomato seedling root-associated bacterial endophytes towards organic seedling production. Organic Agriculture. doi: 10.1007/s13165-015-0111-9; (3). Upreti, R., and Thomas, P. 2015. Root-associated bacterial endophytes from Ralstonia solanacearum resistant and susceptible tomato cultivars and their pathogen antagonistic effects. Frontiers in Microbiology 6: 255; (4). Thomas, P, Sekhar, A.C., Upreti, R., Mujawar, M.M., Pasha, S.S. 2015. Optimization of single plate-serial dilution spotting (SP-SDS) with sample anchoring as an assured method for bacterial and yeast cfu enumeration and single colony isolation from diverse samples. Biotechnology Reports 8: 45-55; (5) Sekhar, A.C., and Thomas, P. 2015. Isolation and identification of shoot-tip associated endophytic bacteria from banana cv. Grand Naine and testing for antagonistic activity against Fusarium oxysporum f. sp. cubense. American Journal of Plant Sciences 6: 943-954; (6) Thomas, P., Mujawar, M. M., Sekhar, A. C. and Upreti, R. (2014). Physical impaction injury effects on bacterial cells during spread-plating influenced by cell characteristics of the organisms. Journal of Applied Microbiology 116, 911-922; (7) Thomas, P., Sekhar, A. C., Mujawar, M. M. (2014) Vulnerability of Bacillus spores and of related genera to physical impaction injury with particular reference to spread-plating. Journal of Applied Microbiology 117: 1358-1372; (8) Thomas, P., and Sekhar, A.C. (2014). Live cell imaging reveals extensive intracellular cytoplasmic colonization of banana genotypes by normally non-cultivable endophytic bacteria. AoB PLANTS 6:plu002; (9) Thomas, P., and Reddy, M.K. (2013). Microscopic elucidation of abundant endophytic bacteria colonizing the cell wall – plasma membrane peri-space in the shoot-tip tissue of banana. AoB PLANTS 5:plt0111; (10) Thomas, P., Mujawar, M. M., Upreti, R., Sekhar, A. C. 2013. Improved recovery of Bacillus spores from nonporous surfaces with cotton swabs over foam, nylon, or polyester, and the role of hydrophilicity of cotton in governing the recovery efficiency. Applied and Environmental Microbiology. 79: 381-384. (11) Thomas, P., Sekhar, AC., Mujawar, MM. 2012. Non-recovery of varying proportions of viable bacteria during spread-plating governed by the extent of spreader usage and proposal for an alternate spotting-spreading approach to maximize the CFU. Journal of Applied Microbiology 113: 339-350 (12) Thomas, P. 2012. Long-term survival of Bacillus spores in alcohol and identification of 90% ethanol as relatively more spori/bactericidal. Current Microbiology 64: 130-139; (13). Thomas, P. 2011. Intense association of non-culturable endophytic bacteria with antibiotic-cleansed in vitro watermelon and their activation in degenerating cultures. Plant Cell Reports 30: 2313-2325; (14) Thomas, P. and Kumari, S. 2010 Inconspicuous endophytic bacteria mimicking latex exudates in shoot-tip cultures of papaya. Scientia Horticulturae. 124: 469-474; (15) Thomas, P., Soly, T. A. 2009. Endophytic bacteria associated with growing shoot tips of banana (Musa sp.) cv. Grand Naine and the affinity of endophytes to the host. Microbial Ecology 58: 952-964; (16) Thomas P., Swarna GK, Patil P and Rawal R. D. 2008. Ubiquitous presence of normally non-culturable endophytic bacteria in field shoot-tips of banana and their gradual activation to quiescent cultivable form in tissue cultures. Plant Cell Tissue Organ Culture 93:39-54; (17) Thomas, P., Kumari, S., Swarna, G.K. and Gowda, T.K.S. 2007. Papaya shoot tip associated endophytic bacteria isolated from in vitro cultures and host-endophyte interaction in vitro and in vivo. Canadian Journal of Microbiology 53: 380-390; (18) Thomas, P. 2006. Isolation of an ethanol-tolerant endospore-forming Gram-negative Brevibacillus sp as a covert contaminant in grape tissue cultures. Journal of Applied Microbiology 101: 764-774; (19). Thomas, P. 2004. In vitro decline in plant cultures: Detection of a legion of covert bacteria as the cause for degeneration of long-term micropropagated triploid watermelon cultures. Plant Cell Tissue and Organ Culture 77: 173-179

(20) Thomas, P. and Upreti, R. 2014. Testing of bacterial endophytes from non-host sources as potential antagonistic agents against tomato wilt pathogen Ralstonia solanacearum. Advances in Microbiology 4: 656-666

Awards & Recognitions, Patents, Inventions, etc: 

 Fellow, National Academy of Agricultural Sciences, New Delhi (from 1st Jan. 2011);  Fellow, National Academy of Biological Sciences (NABS), Chennai (from June 2012);  Shri. Hari Krishna Shasri Memorial Award (2011) from IARI, New Delhi in Feb. 2012 for research contributions in the area of Molecular Profiling and Endophytic Microbiology;  Shri. Giridhari Lal Chadha Memorial Gold Medal (2010), from Horticultural Society of India New Delhi;  DBT Overseas Associateship (Short-term) Award (2006-07); 6 months (March-Sept. 2007). Availed at the Flinders University, Adelaide, Australia;  Sukumar Basu Memorial Award (1999-2000) conferred by IARI, New Delhi in Feb. 2002 for research contributions in the area of Horticultural Biotechnology;  DBT, Overseas Long term Associateship (Long-term) Award (1999-2000) availed at the University of Michigan, Ann Arbor, USA (1½ yrs);  Commonwealth Post-Doctoral Fellowship awarded during 1989-90 for advanced research at the University of Sheffield, Sheffield, U. K. (1+ year) 1989-1990);  Young Scientist Award at Kerala Science Congress 1990  Best Poster Award from Horticultural Society of India, New Delhi;  Fellow: Horticultural Society of India, New Delhi (From Nov. 2010)  Member/Fellow, Plant Tissue Culture Association of India (PTCA-I), New Delhi (From Feb 2004)

Contact Details
Email Address: 
pioust@iihr.res.in
Telephone #: 
28466420 ext 410
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