Ectomycorrhizal fungus supports endogenous rhythmic growth and corresponding resource allocation in oak during various below- and aboveground biotic interactions

Abstract

Endogenous rhythmic growth (ERG) is displayed by many tropical and some major temperate tree species and characterized by alternating root and shoot flushes (RF and SF). These flushes occur parallel to changes in biomass partitioning and in allocation of recently assimilated carbon and nitrogen. To address how biotic interactions interplay with ERG, we cross-compared the RF/SF shifts in oak microcuttings in the presence of pathogens, consumers and a mycorrhiza helper bacterium, without and with an ectomycorrhizal fungus (EMF), and present a synthesis of the observations. The typical increase in carbon allocation to sink leaves during SF did not occur in the presence of root or leaf pathogens, and the increase in nitrogen allocation to lateral roots during RF did not occur with the pathogens. The RF/SF shifts in resource allocation were mostly restored upon additional interaction with the EMF. Its presence led to increased resource allocation to principal roots during RF, also when the oaks were inoculated additionally with other interactors. The interactors affected the alternating, rhythmic growth and resource allocation shifts between shoots and roots. The restoring role of the EMF on RF/SF changes in parallel to the corresponding enhanced carbon and nitrogen allocation to sink tissues suggests that the EMF is supporting plants in maintaining the ERG.

A Fine-Tuning of the Plant Hormones, Polyamines and Osmolytes by Ectomycorrhizal Fungi Enhances Drought Tolerance in Pedunculate Oak

“…and E. quercicola (S. Takam and U. Braun) [ 18 ]. Although it is well known that ECM fungi significantly increase the plants’ root absorptive area, which supports the oaks’ rhythmic growth [ 19 ] (especially during the summer’s drought [ 20 ]), the specific molecular mechanisms of how ectomycorrhizal fungi affect the plant’s growth regulators and the oak’s drought tolerance mechanisms remain unknown.…”

Plant Age and Soil Texture Rather Than the Presence of Root Hairs Cause Differences in Maize Resource Allocation and Root Gene Expression in the Field

“…Therefore, resource allocation studies can indirectly reveal how the plant integrates the information from abiotic and biotic environments. Among plant organs, the root represents a particularly influential sink that additionally regulates not only sink-source interactions in the shoot, but also between the roots and rhizosphere organisms [ 11 , 12 ].…”

Streptomycetaceae and Promicromonosporaceae: Two Actinomycetes Families from Moroccan Oat Soils Enhancing Solubilization of Natural Phosphate

“…Moreover, actinobacteria are known to be producers of a wide range of plant growth promoters and regulators, such as indole-3-acetic acid (IAA), cytokines, ACC deaminase, and various hydrolytic enzymes (cellulase, protease, keratinase, amylase, xylanase, lipase, and chitinase) [37]. All these value-added benefits in agriculture lead researchers to discover the great potential of these bacteria, notably in improving plant growth and as biocontrol agents [19,29,32,38]. However, the distribution of actinomycetes in Morocco and their use as biofertilizers for oat nutrition has not been yet explored.…”