Biology subjects

Bainard, L. D.

Publications and source records attributed to Bainard, L. D..

3 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↗

bioRxiv2022

Soil chemistry and soil history significantly structure oomycete communities in Brassicaceae crop rotations

Oomycetes are critically important soil microbial communities, especially for agriculture where they are responsible for major declines in yields. Unfortunately, oomycetes are vastly understudied compared to bacteria and fungi. As such, our understanding of how oomycete biodiversity and community structure varies through time in the soil remains poor. Soil history established by previous crops is one factor known to structure other soil microbes, but has not been investigated for its influence on oomycetes. In this study, we established three different soil histories in field trials; the following year these plots were planted with five different Brassicaceae crops. We hypothesized that the previously established soil histories would structure different oomycete communities, regardless of their current Brassicaceae crop host, in both the roots and rhizosphere. We used a nested-ITS amplicon strategy incorporated with MiSeq metabarcoding, where the sequencing data was used to infer amplicon sequence variants (ASVs) of the oomycetes present in each sample. This allowed us to determine the impact of different soil histories on the structure and biodiversity of the oomycete root and rhizosphere communities from the five different Brassicaceae crops. We found that each soil history structured distinct oomycete rhizosphere communities, regardless of different Brassicaceae crop hosts, while soil chemistry structured the oomycete communities more during a dry year. Interestingly, soil history appeared specific to oomycetes, but was less influential for bacterial communities previously identified from the same samples. These results advance our understanding of how different agricultural practices and inputs can alter edaphic factors to impact future oomycete communities. Examining how different soil histories endure and impact oomycete biodiversity will help clarify how these important communities may be assembled in agricultural soils. HighlightsO_LICrop rotations model how soil history impacts subsequent microbial communities C_LIO_LIBrassicaceae oilseed crops might mitigate pathogenic oomycetes C_LIO_LISoil history significantly structures oomycete communities C_LIO_LIOomycetes are significantly affected by soil chemistry C_LIO_LIBrassicaceae crop hosts weakly influence oomycete communities C_LI O_FIG O_LINKSMALLFIG WIDTH=115 HEIGHT=200 SRC="FIGDIR/small/499733v1_ufig1.gif" ALT="Figure 1"> View larger version (64K): org.highwire.dtl.DTLVardef@1f2160aorg.highwire.dtl.DTLVardef@84fbeforg.highwire.dtl.DTLVardef@b81689org.highwire.dtl.DTLVardef@1cfacf4_HPS_FORMAT_FIGEXP M_FIG C_FIG

microbiology↗

bioRxiv2021

Relative and quantitative rhizosphere microbiome profiling result in distinct abundance patterns

Next-generation sequencing is recognized as one of the most popular and cost-effective way of characterizing microbiome in multiple samples. However, most of the currently available amplicon sequencing approaches are inherently limited, as they are often presented based on the relative abundance of microbial taxa, which may not fully represent actual microbiome profiles. Here, we combined amplicon sequencing (16S rRNA gene for bacteria and ITS region for fungi) with real-time quantitative PCR (qPCR) to characterize the rhizosphere microbiome of wheat. We show that the increase in relative abundance of major microbial phyla does not necessarily result in an increase in abundance. One striking observation when comparing relative and quantitative abundances was a substantial increase in the abundance of almost all phyla associated with the rhizosphere of plants grown in soil with no history of water stress as compared with the rhizosphere of plants growing in soil with a history of water stress, which was in contradiction with the trends observed in the relative abundance data. Our results suggest that the estimated absolute abundance approach gives a different perspective than the relative abundance approach, providing complementary information that helps to better understand the rhizosphere microbiome.

ecology↗