Belowground microbes mitigate plant-plant competition

TitleBelowground microbes mitigate plant-plant competition
Publication TypeJournal Article
Year of Publication2017
AuthorsFonseca MB, Dias T, Carolino MM, Franca MGC, Cruz C
JournalPlant Science
Date PublishedSep
Type of ArticleArticle
ISBN Number0168-9452
Accession NumberWOS:000407407100019
KeywordsARBUSCULAR MYCORRHIZAL FUNGI, Biochemistry & Molecular Biology, Bradyrhizobium sp., competition, Dimorphandra wilsonii, dimorphandra-wilsonii, evolution, growth, mycorrhizal colonization, nitrogen, Plan-plant, Plant Sciences, responses, Rhizodeposition, ROOTS, soil, Urochloa decumbens, water-use efficiency

Dimorphandra wilsonii, a Cerrado endemic Fabaceae tree, is threatened by land-use changes. The few remaining individuals occur in areas dominated by alien grasses like Urochloa decumbens. We tested the impact of nitrogen (N) availability and symbionts' presence on mitigating the effects of competition from U. decumbens. Dimorphandra wilsonii seedlings were 50-week pot-cultivated under limiting (3 mM) or non-limiting (10 mM) N, with or without U. decumbens, and inoculated or not with a N-fixer (Bradyrhizobium sp.) and an arbuscular mycorrhizal fungus (AMF - Glomus etunicatum), both forming symbioses in the field. Since D. wilsonii seedlings grew more and 'lost' fewer nutrients under the symbionts' presence, symbionts mitigated plant-plant competition. Under limiting N, inoculated D. wilsonii seedlings grew more (despite no nodulation), but N fixation was only suggested when inoculated D. wilsonii seedlings competed with U. decumbens. D. wilsonii C-13, and substrate's carbon and respiration suggest that only the microbes performing key functions received plant carbon. Under non-limiting N, inoculated D. wilsonii seedlings became enriched in C-13, substrate accumulated carbon and microbial respiration increased, suggesting a more generalist microbial community. Data suggest inoculating D. wilsonii seeds/seedlings with AMF and N-fixers as a conservation measure. However, long-term field-studies need to confirm these conclusions.

Alternate JournalPlant Sci.