Abstract
The plant growth-promoting rhizobacteria (PGPR) on the host plant surface play a key role in biological control and pathogenic response in plant functions and growth. However, it is difficult to elucidate the PGPR effect on plants. Such information is important in biomass production and conversion. Brachypodium distachyon (Brachypodium), a genomics model for bioenergy and native grasses, was selected as a C3 plant model; and the Gram-negative Pseudomonas fluorescens SBW25 (P.) and Gram-positive Arthrobacter chlorophenolicus A6 (A.) were chosen as representative PGPR strains. The PGPRs were introduced to the Brachypodium seed's awn prior to germination, and their possible effects on the seeding and growth were studied using different modes of time-of-flight secondary ion mass spectrometry (ToF-SIMS) measurements, including a high mass-resolution spectral collection and delayed image extraction. We observed key plant metabolic products and biomarkers, such as flavonoids, phenolic compounds, fatty acids, and auxin indole-3-acetic acid in the Brachypodium awns. Furthermore, principal component analysis and two-dimensional imaging analysis reveal that the Brachypodium awns are sensitive to the PGPR, leading to chemical composition and morphology changes on the awn surface. Our results show that ToF-SIMS can be an effective tool to probe cell-to-cell interactions at the biointerface. This work provides a new approach to studying the PGPR effects on awn and shows its potential for the research of plant growth in the future.
| Original language | English |
|---|---|
| Article number | 031006 |
| Journal | Biointerphases |
| Volume | 17 |
| Issue number | 3 |
| DOIs | |
| State | Published - May 1 2022 |
Funding
X.-Y. Yu acknowledges the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory (ORNL) for partial support of this work. R. Komorek and X.-Y. Yu acknowledge the Environmental and Biological Science Directorate (EBSD) Mission seed Laboratory Directed Research and Development for the initial support of culture and experimental effort. Part of the experiment was covered by the Pacific Northwest National Laboratory (PNNL), W. R. Wiley Environmental Molecular Sciences Laboratory (EMSL) Strategic Science Area of Intercellular Thrust. The authors thank Jiyoung Son and Wen Liu for technical assistance in the sample analysis. A portion of the research was performed using EMSL (grid.436923.9), a DOE Office of Science User Facility sponsored by the Office of Biological and Environmental Research under the general EMSL user Proposal Nos. 50093 and 50170. ORNL is managed by UT-Battelle, LLC, for the U. S. Department of Energy (DOE) under Contract No. DE-AC05-00OR22725. PNNL is operated by Battelle for the DOE under Contract No. DE-AC05-76RL01830. Y. Zhang acknowledges the Chinese Science Council and the PNNL Alternative Sponsored Fellowship (ASF) for the graduate student fellowship. This manuscript has been authored in part by UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy (DOE). The publisher acknowledges the U.S. government license to provide public access under the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan).