Biochemical characterization of diverse endophytic bacteria isolated from the seed endosperm of wild relatives and cultivated varieties of papaya

C Shanmugaraj; S Dubey; M N Pooja; Basavaprabhu L Patil

doi:10.24154/jhs.v21i1.5073

Authors

C Shanmugaraj ICAR-Indian Institute of Horticultural Research, Bengaluru Author
S Dubey Author
M N Pooja Indian Institute of Horticultural Research Author
Basavaprabhu L Patil Indian Institute of Horticultural Research Author

DOI:

https://doi.org/10.24154/jhs.v21i1.5073

Keywords:

Biochemical characterization, endophytic bacteria, papaya varieties, plant growth-promoting traits, Vasconcellea spp

Abstract

Endophytic bacteria associated with papaya seeds play an important role in nutrient mobilization and plant growth promotion. In the present study, endophytic bacteria isolated from seeds of wild papaya relatives (Vasconcellea cundinamarcensis, V. cauliflora, and V. goudotiana) and cultivated papaya varieties (Arka Prabhath and Arka Surya) were characterized for their morphological, biochemical, and plant growthpromoting traits. Molecular identification based on 16S rRNA gene sequencing revealed diverse taxonomic affiliations among the isolates. Functional characterization demonstrated considerable variability in nutrient solubilization, enzymatic activities, and indole-3-acetic acid (IAA) production. Isolates EAP14 and EVCa21 exhibited strong phosphate, potassium, and zinc solubilization abilities, while EVCu15 uniquely showed both cellulase and protease activities. High IAA production was observed in EVG8 and EVCu15, whereas several other isolates displayed moderate to high auxin-producing potential. Antibiotic sensitivity assays revealed diverse resistance patterns among the isolates. Overall, EAP14, EVCa21, and EVCu15 emerged as promising endophytes with multiple plant growth-promoting traits, indicating their potential application in sustainable agriculture and biofertilizer development. These findings highlight the functional diversity of papaya-associated seed endophytes and their possible role in improving nutrient availability and crop productivity.

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Author Biographies

C Shanmugaraj, ICAR-Indian Institute of Horticultural Research, Bengaluru

ICAR-IIHR
S Dubey

ICAR-IIHR
M N Pooja, Indian Institute of Horticultural Research

ICAR-IIHR
Basavaprabhu L Patil, Indian Institute of Horticultural Research

ICAR-IIHR

Dr. B. L. Patil did MSc (1998-2000) in Agriculture (Genetics) from UAS-Dharwad and PhD from Department of Plant Molecular Biology, University of Delhi (South Campus), during 2001-2005. During his PhD, he worked in a European Union funded program on geminiviruses, in collaboration with John Innes Centre, Norwich, UK. Part of his PhD research work was carried out in University of Stuttgart, Germany, for which he received the prestigious DAAD scholarship.

He did his Post-Doctoral research in Donald Danforth Plant Science Center, St. Louis, USA (2006-2010) and contributed for the characterization of cassava viruses from Africa and development of Virus Resistant transgenic Cassava, which had successful field trials in East Africa. Briefly he returned to India to join as Scientist-D, in the DBT institute National Agri-Food Biotechnology Institute (NABI), located in Mohali (Punjab). However to continue his research career in Plant Virology, he moved to University of Basel, Switzerland (2011-12), to work on characterization of cassava viruses from India in an Indo-Swiss program.

In 2012, he joined ICAR-National Research Centre on Plant Biotechnology (ICAR-NRCPB, now ICAR-NIPB), New Delhi, India, as a Senior Scientist. He was the first molecular virologist to join NRCPB (NIPB) and he initiated research on Pigeonpea sterility mosaic emaravirus, an emerging Emaravirus. He also received funding from ICAR-NPTC and DBT-BIRAC for transgenic control of papaya and cotton viruses. He has published extensively in reputed international journals, and has several book chapters to his credit and also edited few books. He is a recognized Editor & Reviewer for several International Journals, and reviewer for Grant Applications for International & National funding agencies, in his area of expertise. He has trained several research scholars from Africa, Americas and India in the area of Molecular Plant Virology and RNA-interference technology.

He has received several fellowships and grants during his research career and was honored with the IVS Fellow Award by the Indian Virological Society in 2014 in recognition for his contribution in the area of Plant Virology. During 2016-17 he received scholarship from the European Union funded Erasmus Mundus program to carry short term research in a European university under the BRAVE project. He also received Fulbright-Nehru Academic & Professional Excellence Fellowship for 2022-23. He has been nominated by CSIR & ICAR as an external expert to assess their scientists for their promotion.

In July 2018, he relocated to Indian Institute of Horticultural Research (IIHR), another ICAR institute in Bengaluru and he continues to work as a Principal Scientist on Molecular Plant Pathology, with multiple projects funded by DBT, DBT-BCIL and ICAR-AMAAS. His major emphasis is on management of plant pests & pathogens using Genome Editing and RNAi-based technologies. In 2024 he has taken over as the Head of the Division of Basic Sciences, ICAR-IIHR, Bengaluru.

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