Jawahar Singh, Ph.D.

Engineering how plants make their own fertilizer.

I am a plant molecular biologist using multi-omics, functional genomics and synthetic biology to study how nutrient signalling gates root nodule symbiosis. My future lab aims to combine this mechanistic work with CRISPR crop engineering to develop legumes that need less fertilizer.

Postdoctoral Research Associate

Sainsbury Laboratory, University of Cambridge

Enabling Nutrient Symbioses (ENSA) Root nodule symbiosis CRISPR engineering
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Dr. Jawahar Singh

Legumes I have worked on

Chickpea (Cicer arietinum) flower Chickpea Cicer arietinum
Common bean (Phaseolus vulgaris) seedling Common bean Phaseolus vulgaris
Soybean (Glycine max) pods Soybean Glycine max
Cowpea (Vigna unguiculata) plants in the growth room Cowpea Vigna unguiculata

Research highlights

How nutrient status decides whether a legume forms nitrogen-fixing nodules

Phosphate and nodulation

Plant and Cell Physiology, 2025

Singh et al. 2025

We showed for the first time that a phosphate-starvation transcription factor, PHR-L7, binds and regulates the master nodulation gene NIN, so phosphate availability helps decide whether a legume commits to forming nitrogen-fixing nodules.

Adequate Pi: SPX sequesters PHR-L7 and NIN is expressed, enabling symbiosis. Low Pi: PHR-L7 is active, NIN is repressed, no symbiosis.
Under adequate phosphate, SPX sequesters PHR-L7 (inactive) and NIN is expressed, enabling symbiosis. Under low Pi, PHR-L7 becomes active, represses NIN, and nodulation is blocked.

Evidence: PvPHR-L7 RNAi increases nodulation and over-expression reduces it; recombinant PvPHR-L7 binds P1BS motifs in the PvNIN and PvTML promoters (EMSA); and it activates both promoters in N. benthamiana leaves. Full data in the paper.

Phosphate is a gatekeeper that determines whether legumes commit to nitrogen-fixing symbiosis.

PHR-L7, NIN promoter, 2025 Read the paper

Engineering nitrogen fixation in crop legumes

Ongoing at Cambridge

Which genes hold nitrogen fixation back in crop legumes, and can removing or retuning them make nodules work better?

In Prof. Sebastian Schornack's group at the Sainsbury Laboratory, as part of the international ENSA programme (Enabling Nutrient Symbioses in Agriculture), I study conserved negative regulators of nitrogen fixation in cowpea and soybean.

  • Find candidate regulators that are conserved across nodulating legumes.
  • Edit them in cowpea and soybean with CRISPR-Cas9 knockouts and promoter fine-tuning.
  • Test nodule formation and nitrogen fixation with molecular, genetic and cell-biology approaches.

Work in progress: results will appear here once published.

Cowpea, soybean, CRISPR-Cas9 ENSA profile

Selected publications

2026

Beyond Nitrogen: Phosphate Controls Root Nodule Symbiosis Commitment

Singh, J., Valdés-López, O., & Schornack, S. Trends in Plant Science

Perspective on how phosphate status controls the decision to nodulate

doi.org/10.1016/j.tplants.2026.01.001

2025

Phosphate deficiency reduces nodule formation through a phosphate starvation response-like protein in Phaseolus vulgaris

Singh, J., Mendoza-Soto, A. B., Tiwari, M., et al. Plant and Cell Physiology

PvPHR-L7 binds the NIN promoter and limits nodulation under low phosphate

doi.org/10.1093/pcp/pcaf069

2023

Harnessing the potential of symbiotic associations of plants in phosphate-deficient soil for sustainable agriculture

Singh, J., Isidra-Arellano, M.C., & Valdés-López, O. Plant and Cell Physiology

Review on symbiotic strategies for phosphate-poor soils

doi.org/10.1093/pcp/pcad059

2023

Role of Nod factor receptors and its allies involved in nitrogen fixation

Singh, J. & Verma, P. K. Planta

Review on Nod factor receptor signalling

doi.org/10.1007/s00425-023-04090-7

2023

Discovering the genetic modules controlling root nodule symbiosis under abiotic stresses: salinity as a case study

Singh, J. & Valdés-López, O. New Phytologist

Salinity as a case study of nodulation under abiotic stress

doi.org/10.1111/nph.18627

2022

Genome-wide identification, expression, and characterization of CaLysM-RLKs in chickpea root nodule symbiosis

Singh, J. & Verma, P. K. Environmental and Experimental Botany

Identified 17 LysM-RLKs governing Nod factor perception in chickpea

doi.org/10.1016/j.envexpbot.2022.104999

Also 8 MPMI editorials, 8 book chapters and other co-authored papers.

Full publication list Google Scholar

About

Background and research trajectory across India, Mexico, and the UK

I am a plant molecular biologist. My main question is how legumes decide when and where to form nitrogen-fixing root nodules. That decision draws on nutrient signals, developmental cues and signals exchanged with rhizobia, and understanding it could help reduce agriculture's dependence on synthetic fertilizers.

I started with salt-stressed millets in the Thar Desert (India), moved to Nod factor signalling in chickpea (New Delhi) and then to how phosphate controls nodulation commitment in common bean (Mexico). At Cambridge I now use CRISPR to engineer nitrogen fixation in cowpea and soybean.

I am an Assistant Features Editor at Molecular Plant-Microbe Interactions (MPMI), and I co-organized the satellite meeting on mentoring at the IS-MPMI Congress 2025 in Cologne.

2023–Present

Sainsbury Laboratory, University of Cambridge, UK

Postdoctoral Research Associate with Prof. Sebastian Schornack (ENSA). CRISPR engineering of cowpea and soybean to improve nitrogen fixation, and functional genomics of nodule development.

2022–2023

UNAM, Mexico City, Mexico

DGAPA Postdoctoral Fellow with Prof. Oswaldo Valdés-López. Showed that the phosphate-starvation factor PHR-L7 binds the NIN promoter. This links phosphate availability to the master switch of nodulation.

2016–2022

NIPGR, New Delhi, India

Ph.D. in Plant Biology with Prof. Praveen K. Verma. Discovered 17 LysM receptor-like kinases for Nod factor perception in chickpea. Identified MAP kinases that relay the Nod factor signal from the membrane to the nucleus.

2015–2016

JNVU, Jodhpur, India

Research Fellow with Prof. Shweta Jha. Stress proteomics in pearl millet. Identified salt-responsive proteins and physiological markers for stress tolerance breeding.

2012–2014

West Bengal State University, Kolkata, India

M.Sc. in Biochemistry. Training in protein biochemistry, enzymology and molecular biology. My interest in how nutrients and signalling molecules shape plant physiology started here.

Future Lab

When does a plant decide to invest in nitrogen fixation, and can we change that decision?

Building a nitrogen-fixing nodule is costly, so a legume weighs its nutrient status, development and environment before committing. My lab will ask how that decision is made at the level of individual cell types, and then rewire it. The guiding idea: more nodules do not necessarily mean more nitrogen fixation. What matters is whether a nodule forms correctly, fixes efficiently and stays productive.

01

Discover what limits nodule performance

Single-nucleus atlases and comparative genomics across nodulating and non-nodulating legumes to identify the genes, cell types and regulatory modules that set nodule formation, function and longevity.

Single-cell genomics Comparative genomics
02

Decode how nutrient signals gate symbiosis

Starting from the phosphate–NIN link from my work in common bean, define how phosphate and nitrogen status are read by the nodulation programme and where those signals converge on the master regulators.

Nutrient signalling Gene regulation
03

Engineer the decision in crop legumes

CRISPR and promoter engineering in cowpea and soybean to remove or tune the constraints identified in Aims 1 and 2, tested first in the lab and then in nutrient-poor soils where fertilizer is scarce.

CRISPR-Cas9 Promoter engineering

Working on legume biology, genome editing or sustainable agriculture? Get in touch to talk about collaborating.

Teaching and mentoring

Undergraduate supervision at Cambridge and hands-on mentoring in the lab

Teaching at Cambridge

Undergraduate supervisor for the Plant and Microbial Sciences (IBPMS) course, covering topics including Feeding the World, Pathological and Beneficial Plant-Microbe Interactions. Conducted revision sessions and guided students in essay writing, critical analysis, and interpretation of research data.

Research mentoring

Mentored multiple Master's research students and summer interns at Cambridge on root nodule development and molecular regulation of symbiosis. Provided hands-on training in molecular biology, confocal imaging, CRISPR techniques, and data analysis.

Community and service

Editing, organising and reviewing for the plant–microbe interactions community

Assistant Features Editor

Molecular Plant-Microbe Interactions (MPMI), 2024–present. I write plain-language summaries, author interviews and commentaries for the journal.

Conferences

Co-organizer and chair of the satellite meeting “Building Careers in MPMI through Effective Mentoring” at the IS-MPMI Congress 2025, Cologne. Poster judge for Best Poster Award. Mini-symposium co-organizer at Sainsbury Laboratory.

Peer review

Reviewer for The Plant Cell, New Phytologist, The Plant Journal, Journal of Experimental Botany, Frontiers in Plant Science, BMC Plant Biology, and Scientific Reports.

Awards and fellowships

DGAPA Postdoctoral Fellowship (UNAM, Mexico). CSIR-UGC Senior & Junior Research Fellowships (India). GATE qualified. Swachhta Saarthi Fellowship (Govt. of India).

Contact

Open to PI opportunities, collaborations, and seminar invitations worldwide

Address

Sainsbury Laboratory
University of Cambridge
47 Bateman Street
Cambridge CB2 1LR, UK