Project description:Sorghum bicolor is one of the most important cereal crops in the world, predominantly grown in sub‑Saharan Africa by smallholder farmers. Despite its outstanding resilience to abiotic stresses, approximately 20% of sorghum yield is annually lost on the African continent due to infestation with the parasitic weed Striga hermonthica. Existing Striga management strategies to decrease Striga infestation often show low efficiency and are not easily integrated into current agricultural practices. Microbial-based solutions may prove an effective, low-cost mode for reducing Striga parasitism in sub-Saharan Africa. Here, we demonstrate that the microbiome component of a field soil suppresses Striga infection of sorghum. Potential mechanisms underlying the soil microbiome’s influence on the host plant include root endodermal suberization and aerenchyma formation. Moreover, we observed a depletion of haustorium inducing factors, compounds essential for Striga to establish the host-parasite association, in root exudates collected from sorghum grown in the presence of the soil microbiome as compared to sterile conditions. We further identified individual microbial taxa associated with reduced Striga infection via changes in root cellular anatomy and differentiation as well as in exudate composition. Our study identifies a suite of traits that can be harnessed by individual microbial isolates or their consortia to induce Striga resistance. Combining microbes that elicit Striga resistance directly (affecting the parasite) via repression of haustorium formation with those that act indirectly (affecting the host), by reducing of Striga penetration through root tissue, can broaden the effectiveness of microbe-induced protection from Striga.
Project description:Soil microorganisms carry out decomposition of complex organic carbon molecules, such as chitin. High diversity of the soil microbiome and complexity of the soil habitat has posed a challenge to elucidate specific interactions between soil microorganisms. Here, we overcame this challenge by studying a model soil consortium (MSC-2) that is composed of 8 species. The MSC-2 isolates were originally obtained from the same soil that was enriched with chitin as a substrate. Our aim was to elucidate specific roles of the 8 member species during chitin metabolism in soil. The 8 species were added to sterile soil with chitin and incubated for 3 months. Multi-omics was used to understand how the community composition, transcript and protein expression and chitin-related metabolites shifted during the incubation period. The data clearly and consistently revealed a temporal shift during chitin decomposition and defined contributions by individual species. A Streptomyces species was a key player in early steps of chitin decomposition, followed by other members of MSC-2. These results illustrate how multi-omics applied to a defined consortium untangles complex interactions between soil microorganisms.
Project description:Sweet potato virus disease (SPVD) is one of the most devastating diseases affecting sweetpotato (Ipomoea batatas), an important food crop in developing countries. SPVD develops when sweetpotato plants are dually infected with sweet potato feathery mottle virus (SPFMV) and sweet potato chlorotic stunt virus (SPCSV). In the current study, global gene expression between SPVD affected plants and virus-tested control plants (VT) were compared in the susceptible ‘Beauregard’ and resistant ‘NASPOT 1’ (Nas) sweetpotato cultivars at 5, 9, 13 and 17 days post inoculation (DPI).
Project description:Considering the crucial role of root exudates, we hypothesized that continuous wheat cultivation would lead to lower glucose release, resulting in lower microbial growth, activity, and biomass. For the first time in situ glucose imaging was optimized for studying the interactions in the first (W1) and third (W3) wheat after break crop plots in the field. Glucose imaging method combined with soil microbial respiration, enzyme kinetics and the quantification SWEET genes expression levels in wheat plants. W3 had the lowest proportion of hotspots for glucose release with 1.35 % of the total soil surface area, indicating a 17.7 % decline compared to W1. Also, the expressions of functional orthologous genes of SWEET1a in wheat roots were significantly upregulated in W3 compared to W1. The growing microbial biomass in the rhizosphere soil of W1 was about five times higher than W3. Differences in SWEET gene expression and shift in glucose release is linked to altered root physiology and exudation processes, potentially reflecting the plant's strategy to create a less favourable environment for opportunistic pathogens. Hence, this study provides novel insights into the complex interactions between continuous wheat cultivation, root exudation, microbial dynamics, gene expression, and enzymatic activities.