Location: Coastal Plain Soil, Water and Plant Conservation Research
Project Number: 6082-13000-011-005-R
Project Type: Reimbursable Cooperative Agreement
Start Date: Mar 1, 2025
End Date: Dec 31, 2025
Objective:
Determine the influence of cotton genetic diversity on soil microbial rhizospheric communities, and identify unique microbial species that may play a significant role in cotton plant development
Approach:
This work would represent a new line of study focused on assessing the influence of cotton variety on root-associated microbial communities. The experiment would be conducted on plots located at the Coastal Plains Soil, Water, and Plant Research Center. The initial year of the study, in collaboration with Dr. Todd Campbell (ARS-USDA, Florence SC) will focus on five genetically diverse varieties of cotton: four upland varieties (Gossypium hirsutum); and one variety of Pima cotton (Gossypium barbadense) as a control. All varieties will be planted under conventional tillage and irrigated throughout the study as needed to avoid drought stress. Further years of analysis will expand the research to look at G × E × M interactions, as the field site also has conservation and cover crop managements available for use, and with managements duplicated in a fashion where irrigated vs non-irrigated differences can also be introduced. Plants will be destructively sampled at each of the four stages along cotton plant development: three weeks post-emergence; pre-bloom; early-bloom; and late-bloom. At each stage, four plants of each variety will be harvested, and rhizosphere soils will be collected. Cotton roots, and rhizosphere soils not used in microbiological or molecular biological analyses will be archived at -80 °C for future analyses. DNA will be extracted from the rhizospheric soil from four representative plants from each variety at each development stage, and bacterial 16S libraries will be assembled and sequenced using the Ion S5 next-generation sequencing platform (ThermoFisher). Additional soil chemical analyses will be performed at each sampling site. Soil N, P, pH, and EC data will be collected to help separate plant variety influences on microbial communities from environmental influences. Additionally, cotton yields will be determined for each subplot by hand harvest, and samples will be processed on laboratory gins to determine lint yield and analyzed for fiber quality. Relationships between microbial communities and plant varieties, as well as soil chemical characteristics, cotton yields, as well as lint yield and fiber quality will be determined using non-metric multidimensional scaling and cluster analysis methods. Rhizospheric soil from all plants from each variety, and at each stage, will be used to identify patterns in microbial function by looking at C cycling (ß-glucosidase), N cycling (N-acetyl-ß-glucosaminidase), P cycling (acid phosphatase), and overall microbial activity (fluorescein diacetate (FDA) hydrolysis patterns.
