Abstract
Background and aims The interactions established between plants and endophytic fungi span a continuum from beneficial to pathogenic associations. The aim of this work was to explore the mechanisms underlying the potentially beneficial effects provoked by a fungal strain in legume species of the genus Lotus.
Methods The ability to solubilise phosphorous was evaluated in nine fungal strains isolated from roots of L. tenuis. A selected strain was further assessed for its ability to colonize plant roots in different Lotus species. The effects of the two interactions were assessed by analysis of the photosynthesis, sugar amount, and macronutrient status of leaves and roots.
Results A fungal isolate identified as Fusarium solani shows the highest phosphate-solubilisation activity and grows endophytically in roots of L. japonicus and L. tenuis. Fungal invasion enhances plant growth in L. japonicus but provokes a contrasting effect in L. tenuis. Photosynthesis, sugars and K content showed a differential effect in both plant species.
Conclusions Our results indicate neither of the plant species evaluated in this work were significantly stressed by F. solani. Thus, the differential responses observed are due to distinct mechanisms involving photosynthesis, potassium homeostasis, and carbohydrate metabolism that are employed by plants to maintain fitness during the endophytic interaction.
- Abbreviations
- ITS
- : Internal Transcribed Spacer gene
- TEF
- : alpha Transcription Elongation Factor gene
- PN
- : Net photosynthesis
- GS
- : stomatal conductance
- Ci
- : CO2 in the sub-stomatal cavity
- PSII
- : Photosystem II
- OJIP
- : O:Initial fluorescence, at 50 μs or less, J-I: intermediate levels at 2 ms and 30 ms, P: maximal fluorescence
- Fv/Fm (ΦPo,)
- : Maximum quantum yield of primary photochemistry
- PIabs
- : Performance Index on the Absorption Basis
- ABS
- : Absorption flux
- Sm
- : normalized total complementary area above the OJIP transient
- TRo
- : Trapped energy flux
- ETo
- : Electron transport flux
- DIo
- : Dissipation flux
- RC
- : Reaction centre
- CSo
- : Cross section
- ΨEo
- : Electron transport from quinone a to plastoquinone efficiency
- ΦEo
- : maximum yield of electron transport from Qa to plastoquinone primary photochemistry
- GC-EI/TOF-MS
- : gas chromatography coupled to electron impact ionization/time-of-flight mass spectrometry
- N
- : Total Nitrogen
- P
- : Total Phosphorus
- K
- : Total Potassium
- DSE
- : Dark septate endophytes.