Biology subjects

Hawkes, C. V.

Publications and source records attributed to Hawkes, C. V..

2 recordsLinked to original sources

bioRxiv2024

Stability of the Wheat Seed Mycobiome Across North Carolina's Longitudinal Gradient

Improving wheat yield and performance involves selecting varieties that are well adapted for a regional area. Although host genotype and environment are major factors that impact crop performance and resilience, less is known about the relative contribution and occurrence of wheat seed endophytic fungal communities across spatial and temporal scales. An increased understanding of composition and assembly of beneficial endophytic fungal communities across regional scales provides valuable insight into the stability of the endophytic seed mycobiome. Our aim in this study was to examine the relative contribution and impact of latitude and longitude gradients within North Carolina (NC) on wheat seed fungal community structure of two regionally adapted soft red winter wheat cultivars, Hilliard and USG 3640. We examined the endophytic wheat seed microbiome of the two winter wheat cultivars planted in official variety trials at five geographic locations across NC in 2021 and two geographic locations in 2022. ITS1 sequence-based analysis of surface disinfested wheat seeds was conducted to determine alpha and beta diversity. Species richness is influenced by geographical location, however wheat seed mycobiome community structure is stable across cultivars and years. Latitude and longitude contributed to the observed variation in wheat seed mycobiome structure, in addition to yield, seed moisture, and leaf nutrients. When surveying taxa present within all cultivars, geographical sites and years, Alternaria and Epicoccum spp. exhibited high relative abundance in the wheat seed mycobiome. Our results provide a comprehensive catalog of core fungal taxa well-adapted to diverse environments and conserved across wheat cultivars.

microbiology↗

bioRxiv2023

Effective seed sterilization methods require optimization across maize genotypes

Studies of plant-microbe interactions using synthetic microbial communities (SynComs) often require the removal of seed-associated microbes by seed sterilization prior to inoculation to provide gnotobiotic growth conditions. A diversity of seed sterilization protocols have been developed in the past and have been used on different plant species with various amounts of validation. From these studies it has become clear that each plant species requires its own optimized sterilization protocol. It has, however, so far not been tested if the same protocol works equally well for different varieties and seed sources of one plant species. We evaluated six seed sterilization protocols on two different varieties (Sugar Bun & B73) of maize. All unsterilized maize seeds showed fungal growth upon germination on filter paper, highlighting the need for a sterilization protocol. A short sterilization protocol with hypochlorite and ethanol was sufficient to prevent fungal growth on Sugar Bun germinants, however a longer protocol with heat treatment and germination in fungicide was needed to obtain clean B73 germinants. This difference may have arisen from the effect of either genotype or seed source. We then tested the protocol that performed best for B73 on three additional maize genotypes from four sources. Seed germination rates and fungal contamination levels varied widely by genotype and geographic source of seeds. Our study shows that consideration of both variety and seed source is important when optimizing sterilization protocols and highlights the importance of including seed source information in plant-microbe interaction studies that use sterilized seeds.

microbiology↗