Biology subjects

Dozois, J. A.

Publications and source records attributed to Dozois, J. A..

4 recordsLinked to original sources

bioRxiv2026

Seed microbiota legacy mitigates the effect of drought in wheat

Seeds carry epiphytes and endophytes microbial partners that can shape plant fitness. However, whether these microbial communities serve as transgenerational memory systems of parental stress remains largely unstudied. Here, we combined multi-year field rainfall manipulation experiments in eastern Canada with a greenhouse experiment in western Canada to test whether seed-associated microbiota transmit drought legacies across plant generations. In the field experiment, reduced rainfall initially decreased yield in the drought-sensitive wheat cultivar (AC Nass), but selected for distinct seed bacterial endophyte communities. In subsequent generations, plants whose seed microbiota retained compositional similarity to these drought-adapted communities showed enhanced yield stability under upcoming water stress. A transgenerational field test confirmed that daughter plants derived from drought-exposed parent plants maintained performance under water limitation, whereas those from wetter origins did not. In an independent greenhouse assay using seeds from Saskatchewan fields differing in long- and short-term irrigation history, AC Nass plants from water-stress legacy sites exhibited higher photosynthetic efficiency, water-use efficiency, and root bacterial diversity under drought. Together, these findings demonstrate that seed-associated microbiota act as ecological archives of stress history, transmitting drought legacies across generations in a cultivar and year-dependent manner.

microbiology↗

bioRxiv2025

Plant miRNAs and amino acids interact to shape soil bacterial communities.

Plants and microbes use many strategies to acquire soil amino acids. Recent findings suggest that genes related to amino acid metabolism and transport are influenced by plant miRNAs. This was the first report of a plant-derived molecule with the potential to modify microbial amino acid uptake. Here, we first show that Arabidopsis modifies its root miRNA content when fertilized with a mixture of 17 amino acids. The miRNAs that responded to amino acid fertilization and other rhizosphere-abundant miRNAs were applied to a simplified soil community, grown with diverse amino acid sources, to test if they interfered with microbial community growth, community composition and amino acid consumption. Plant miRNAs affected the communitys growth in over 70 % of the amino acid sources. The effectiveness of plant miRNAs also depended on the N source supplied to the microbial community, with the strongest effect observed with L-lysine. Specifically, ath-miR159a reduced the microbial consumption of L-lysine, further supporting that plant miRNAs can influence microbial amino acid uptake. Plant miRNAs also affected the relative abundance of specific bacterial taxa, which we subsequently isolated. All isolates were affected in terms of growth when exposed to miRNAs. Two out of three isolates were also impacted in their amino acid consumption. Surprisingly, while plant miRNAs inhibited amino acid consumption at both the community and isolate levels, they had mostly positive effects. Our results suggest that rhizospheric plant miRNAs might have a role in modulating the amino acid consumption of soil bacteria, but not necessarily in a competitive framework.

microbiology↗

bioRxiv2022

Early season soil microbiome best predicts wheat grain quality

Previous studies have shown that it is possible to accurately predict wheat grain quality and yields using microbial indicators. However, it is uncertain what the best timing for sampling is. For optimal usefulness of this modeling approach, microbial indicators from samples taken early in the season should have the best predictive power. Here, we sampled a field every two weeks across a single growing season and measured a wide array of microbial parameters (amplicon sequencing, abundance of N-cycle related functional genes, and microbial carbon usage) to find the moment when the microbial predictive power for wheat grain baking quality is highest. We found that the highest predictive power for wheat grain quality was for microbial data derived from samples taken early in the season (May-June) which coincides roughly with the seedling and tillering growth stages, that are important for wheat N nutrition. Our models based on LASSO regression also highlighted a set of microbial parameters highly coherent with our previous surveys, including alpha- and beta-diversity indices and N-cycle genes. Taken together, our results suggest that measuring microbial parameters early in the wheat growing season could help farmers better predict wheat grain quality.

microbiology↗

bioRxiv2021

Animal soil food web complexity triggers shifts in microbial communities, including PAH degraders, but without clear effects on phenanthrene phytoremediation

The aim of this study was to determine whether the complexity of the animal soil food web (SFWC) is a significant factor influencing the soil microbial communities, the productivity of the willow, and the degradation rates of 100 mg kg-1 phenanthrene contamination. The SFWC treatment had eight levels: just the microbial community (BF), or the BF with nematodes (N), springtails (C), earthworms (E), CE, CN, EN, CEN. After eight weeks of growth, the height and biomass of willows were significantly affected by the SFWC, whereas the amount of phenanthrene degraded was not affected, reaching over 95% in all pots. SFWC affected the structure and the composition of the bacterial, archaeal and fungal communities, with significant effects of SFWC on the relative abundance of fungal genera such as Sphaerosporella, a known willow symbiont during phytoremediation, and bacterial phyla such as Actinobacteriota, containing many PAH degraders. These SFWC effects on microbial communities were not clearly reflected in the community structure and abundance of PAH degraders, even though some degraders related to the Actinobacteriota and the diversity of Gram-negative degraders were affected by the SFWC treatments. Overall, our results suggest that, under our experimental conditions, SFWC does not affect significantly willow phytoremediation outcomes. ImportancePolycyclic aromatic hydrocarbons (PAH) pose a threat to soil ecosystems. Phytoremediation is a green technology that can help restore ecosystems health affected by PAH contamination. Past research on phytoremediation of PAH has focused on the roles of plant and microbes in contaminant fates. However, soil environments usually harbor large faunal communities that interact with both the plant and the microbial communities, potentially altering the phytoremediation process. We hypothesized that soil food web complexity (SFWC), represented by increasing levels of soil fauna, influences PAH degradation through interactions with the plant and the microbes. In this study, we demonstrated that SFWC increases the plant biomass and changes the composition of the microbial community, especially the fungal structure. In our pot experiment, more complex levels of SFWC did not contribute to higher degradation rates, but the increased plant biomass and the higher relative abundance of fungal genera associated with lower plant stress could indirectly contribute to better phytoremediation outcomes. Our results highlight the importance of considering the contributions of soil fauna to the success of phytoremediation.

microbiology↗