Gallionellaceae in rice root plaque: metabolic roles in iron oxidation, nutrient cycling, and plant interactions.
| Title: | Gallionellaceae in rice root plaque: metabolic roles in iron oxidation, nutrient cycling, and plant interactions. |
|---|---|
| Authors: | Chan, Clara S.1,2,3,4 cschan@udel.edu, Dykes, Gretchen E.3,4,5,6, Hoover, Rene L.1,3,4, Limmer, Matt A.5, Seyfferth, Angelia L.1,5 angelias@udel.edu |
| Source: | Applied & Environmental Microbiology. Dec2023, Vol. 89 Issue 12, p1-23. 23p. |
| Subject Terms: | *IRON oxidation, *NUTRIENT cycles, *RICE, *PLANT life cycles, *LIFE cycles (Biology), *IRON |
| Abstract: | On the roots of wetland plants such as rice, Fe(II) oxidation forms Fe(III) oxyhydroxide-rich plaques that modulate plant nutrient and metal uptake. The microbial roles in catalyzing this oxidation have been debated and it is unclear if these iron-oxidizers mediate other important biogeochemical and plant interactions. To investigate this, we studied the microbial communities, metagenomes, and geochemistry of iron plaque on field-grown rice, plus the surrounding rhizosphere and bulk soil. Plaque iron content (per mass root) increased over the growing season, showing continuous deposition. Analysis of 16S rRNA genes showed abundant Fe(II)-oxidizing and Fe(III)-reducing bacteria (FeOB and FeRB) in plaque, rhizosphere, and bulk soil. FeOB were enriched in relative abundance in plaque, suggesting FeOB affinity for the root surface. Gallionellaceae FeOB Sideroxydans were enriched during vegetative and early reproductive rice growth stages, while a Gallionella was enriched during reproduction through grain maturity, suggesting distinct FeOB niches over the rice life cycle. FeRB Anaeromyxobacter and Geobacter increased in plaque later, during reproduction and grain ripening, corresponding to increased plaque iron. Metagenome-assembled genomes revealed that Gallionellaceae may grow mixotrophically using both Fe(II) and organics. The Sideroxydans are facultative, able to use non-Fe substrates, which may allow colonization of rice roots early in the season. FeOB genomes suggest adaptations for interacting with plants, including colonization, plant immunity defense, utilization of plant organics, and nitrogen fixation. Taken together, our results strongly suggest that rhizoplane and rhizosphere FeOB can specifically associate with rice roots, catalyzing iron plaque formation, with the potential to contribute to plant growth. [ABSTRACT FROM AUTHOR] |
| Copyright of Applied & Environmental Microbiology is the property of American Society for Microbiology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Academic Search Complete |
Be the first to leave a comment!