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Influence of Plant Developmental Phase and Irrigation Level on Cultivable Microbiome of Maize Root
by
, , , and
Carina Sá
1, 
Clarisse Brígido
2,3,
Cátia Fidalgo
1,
Adília Pires
1,
Artur Alves
1
,
Etelvina Figueira
1
and
Paulo Cardoso
1,*
1
CESAM, Centre for Environmental and Marine Studies and Department of Biology, University of Aveiro, 3810-193 Aveiro, Portugal
2
MED Mediterranean Institute for Agriculture, Environment and Development & CHANGE Global Change and Sustainability Institute, Universidade de Évora, Largo dos Colegiais 2, 7004-516 Évora, Portugal
3
Santarém Polytechnic University, School of Agriculture, Quinta do Galinheiro, S. Pedro, 2001-904 Santarém, Portugal
*
Author to whom correspondence should be addressed.
Biology 2025, 14(12), 1694; https://doi.org/10.3390/biology14121694 (registering DOI)
Submission received: 23 October 2025
/
Revised: 21 November 2025
/
Accepted: 25 November 2025
/
Published: 28 November 2025
Simple Summary
Water deficit affects crop productivity and the composition of root-associated microbial communities. Thus, it is important to understand the dynamics of bacterial communities during maize development and their response to water stress, shedding light on community adaptations. The analysis of the shifts on the ability of the bacterial community in improving plant development during water deficit is useful in the selection of biofertilizers. In this study, we observed shifts in the principal bacterial genera and in the community ability to improve plant growth during maize development in the presence of water stress. Our results give us insights into the best timing and conditions to select bacterial strains able to improve crop tolerance to stress.
Abstract
Plant growth-promoting bacteria can help plants survive in stressful environments. Here, we describe the isolation of root-surface and endophytic bacteria from maize roots at two different phases of the plant life cycle (vegetative and reproductive), grown under three different water regimes (100%, 50%, and 0%). Isolates were typed using BOX-PCR to identify unique genetic fingerprints, resulting in a total of 400 strains. These strains were screened for osmotic stress tolerance using 15% polyethylene glycol 6000. Isolates were also tested for bacterial plant growth-promoting traits, including the ability to produce siderophores, indole-3-acetic acid synthesis, and phosphate solubilization, both in the presence and absence of osmotic stress. The results showed that in the reproductive phase, a higher percentage of endophytic and rhizoplane bacteria were tolerant to osmotic stress. Additionally, the highest values of alginate and siderophore production by rhizoplane bacteria were also observed in the reproductive phase. These findings suggest that isolation of maize bacteria should consider the plant’s developmental phase and hydric stress conditions to effectively select bacterial strains that enhance crop resilience in drought-affected areas.
