Mycorrhizae and their protective role against herbivores in a South American willow tree

COLL ARÁOZ, VICTORIA; OMACINI, MARINA; GALOTTA, MARIA PAULA; FERNÁNDEZ, PATRICIA C

Congreso; Asociación Latino Americana de Ecología Química 2021; 2021

Arbuscular mycorrhizal fungi (AMF) interact with most terrestrial plants, altering their gene expression and secondary metabolism. So far, the role of this common symbiosis on the interaction between Salix humboldtiana, a willow native to the southern hemisphere, and its natural enemies has been ignored. Our objective was to evaluate how the level of colonization by AMF and herbivory by insects affects the production of secondary metabolites associated with defenses of S. humboldtiana. We carried out a factorial experiment in pots with cuttings of S. humboldtiana growing for 6 months with soil from a gallery forest of the Rolling Pampa. We had 2 factors: Addition of inoculum with 3 AMF species (I+: 7g inoculum, I-: sterilized inoculum); and Herbivory by generalist 4th instar larvae of Spodoptera frugiperda (H+: damage for 10 days, H-: without damage). We measured plants growth rate, emission of volatile organic compounds and we estimated the colonization by AMF in roots. We did not detect differences in the growth rate of the plants according to the treatments, while inoculation increased colonization of AMF by 40% in roots. The results showed that inoculation affected the volatile profile of plants with and without herbivory by increasing the total amount of compounds present. Being this change more significant after damage by S. frugiperda for 10 days. Differential compounds were mainly mono and sesquiterpenes. These preliminary results suggest that soil microorganisms can play a role in the ability of S. humboldtiana to resist or tolerate its natural enemies.