Plant-Microbiota-Soil

A Science of Synergistic Symbioses

Sit down before fact like a little child, and be prepared to give up every preconceived notion, follow humbly wherever and to whatever abyss Nature leads or you shall learn nothing.

Thomas Henry Huxley

Research


Interests & Aims

My long-term goal is to develop a microbiome-informed agronomy grounded in the evolutionary and ecological complexity of plant-microbiota interactions in agricultural soils.

My interests include:

  • The symbiosis continuum of the root microbiome: the shared molecular toolkit — secretion systems, effectors, signaling molecules — that pathogens, commensals, and mutualists draw from differently, and what determines where an organism falls on that continuum.
  • The context-dependence of microbial lifestyle: how the same organism can function as pathogen, commensal, or mutualist depending on the biotic environment it inhabits.
  • The mechanistic basis of biostimulant and biocontrol efficacy: what commercial biological claims actually require as evidence.
  • The microbial ecology of biogeochemical cycling, particularly nitrogen and carbon dynamics in agricultural systems.

Dissertation Research

Sundaresan Lab | UC Davis

Rice Root Synthetic Communities

My dissertation used synthetic bacterial communities (SynComs) of approximately 25 strains assembled from California rice field soils to address three fundamental questions about root microbiomes.

First, how faithfully do reduced-complexity communities recapitulate the structure of natural microbiomes, and at what taxonomic resolution does fidelity break down? Second, how reproducible is community assembly across independent experiments, and when variation occurs, is it structured or stochastic? Third, does community context modulate microbial lifestyle in predictable ways?

A central finding was that Herbaspirillum rubrisubalbicans, a rice endophyte, exhibits a pathogenic phenotype whose expression is contingent on microbial context. Its growth-inhibiting effect is suppressed both within the full synthetic community and through dual inoculation with specific partner strains — demonstrating that microbial lifestyle is not a fixed property of an organism but depends on the biotic context in which it finds itself. This has direct implications for how biological input products containing microbial consortia are evaluated and deployed.

Past Research

Hirsch Lab | UCLA

The Root Nodule Microbiome

Synergy between non-rhizobial microbes and the legume-rhizobia symbiosis.


Scientific Publications

First Author

Veliz, E., & Sundaresan, V. (2025). Root bacteria fine-tune tillering in rice through phytohormone interference and mimicry. Molecular Plant. [Commentary] DOI

Veliz, E.A., Martínez-Hidalgo, P., & Hirsch, A.M. (2017). Chitinase-producing bacteria and their role in biocontrol. AIMS Microbiology, 3(3), 689–705. [Review] DOI

Co-author

Khatibi, S.M.H., Dimaano, N.G., Veliz, E., Sundaresan, V., & Ali, J. (2024). Exploring and exploiting the rice phytobiome to tackle climate change challenges. Plant Communications. [Review] DOI

Martínez-Hidalgo, P., Humm, E.A., Still, D.W., Shi, B., Pellegrini, M., de la Roca, G., Veliz, E., et al. (2022). Medicago root nodule microbiomes: insights into a complex ecosystem with potential candidates for plant growth promotion. Plant and Soil, 471, 507–526. [Research] DOI

Youseif, S.H., Abd El-Megeed, F.H., Mohamed, A.H., Ageez, A., Veliz, E., & Martínez-Romero, E. (2021). Diverse Rhizobium strains isolated from root nodules of Trifolium alexandrinum in Egypt and symbiovars. Systematic and Applied Microbiology, 44, 126156. [Research] DOI

Edwards, J., Santos-Medellín, C., Nguyen, B., Kilmer, J., Liechty, Z., Veliz, E., et al. (2019). Soil domestication by rice cultivation results in plant-soil feedback through shifts in soil microbiota. Genome Biology, 20, 1–14. [Research] DOI