Complex relationships between agricultural managements and lettuce above- and belowground interactions

URCELAY, CARLOS; VIDELA MARTIN; CACCIA, MILENA

Lyon

Congreso; 10th Congress of the International Symbiosis Society and 3rd edition of the International Conference on Holobionts; 2022

International Symbiosis Society

Conventional agriculture, based on the use of synthetic inputs, has negative impacts on the ecosystems. Agroecological managements have shown to temper these negative effects by enhancing ecological processes. Among soil biota, arbuscular mycorrhizal fungi (AMF) are plant root symbionts that improve access to nutrients. These fungi may also affect plant growth and biotic interactions. While it is well documented that distinct agricultural man- agements differentially affect AMF communities, it remains poorly studied how these changes feedback on aboveground plant interactions. We compared the effects of AMF from conventional and agroecological management on let- tuce (Lactuca sativa) mycorrhizal colonization, growth and nutrition and on the oviposition of the leaf miner Liriomyza huidobrensis (Diptera: Agromizydae). In greenhouse, we grew lettuce in pots with soils from farms with conventional (C) and agroecological (A) managements from central Argentina. Treatments included: a) Sterile soil (S), b) microbial filtrate without AMF (MO) c) soil with microbiota and AMF (AMF) (n=10). After 60 days plants were exposed for 48hs to L. huidobrensis mated females. We evaluated plant biomass, mycorrhizal colonization, leaf phosphorous content, and the num- ber of eggs that leafminers laid. Mycorrhizal colonization was four times higher with AMF from A than C treatments, al- though plants biomass was lower in AMF than S and MO, in both managements. Phospho- rous content was significantly higher in plants with MO and AMF in comparison to S, either in conventional and agroecological management. The number of eggs laid in AMF treatments from agroecological fields were significantly lower compared with the rest of treatments from both management types. The number of eggs augmented with aerial dry mass and phospho- rous content. Our results show the existence of complex relationships between agricultural managements and vegetable interactions. While AMF from agroecological management increased mycor- rhizal colonization and reduced plant growth, leaves were less preferred by leaf miners.