RT Journal Article T1 Stem endophytes increase root development, photosynthesis, and survival of elm plantlets (Ulmus minor Mill.) A1 Martínez-Arias, Clara A1 Sobrino Plata, Juan A1 Medel, David A1 Gil, Luis A1 Martín, Juan Antonio A1 Rodríguez-Calcerrada, Jesús AB Long-lived trees benefit from fungal symbiotic interactions in the adaptation to constantly changing environments. Previous studies revealed a core fungal endobiome in Ulmus minor which has been suggested to play a critical role in plant functioning. Here, we hypothesized that these core endophytes are involved in abiotic stress tolerance. To test this hypothesis, two core endophytes (Cystobasidiales and Chaetothyriales) were inoculated into in vitro U. minor plantlets, which were further subjected to drought. Given that elm genotypes resistant to Dutch elm disease (DED) tend to show higher abiotic stress tolerance than susceptible ones, we tested the endophyte effect on two DED-resistant and two DED-susceptible genotypes. Drought stress was moderate; endophyte presence attenuated stomata closure in response to drought in one genotype but this stress did not affect plant survival. In comparison, long-term in-vitro culture proved stressful to mock-inoculated plants, especially in DED-susceptible genotypes. Interestingly, no endophyte-inoculated plant died during the experiment, as compared to high mortality in mock-inoculated plants. In surviving plants, endophyte presence stimulated root and shoot growth, photosynthetic rates, antioxidant activity and molecular changes involving auxin-signaling. These changes and the observed endophyte stability in elm tissues throughout the experiment suggest endophytes are potential tools to improve survival and stress tolerance of DED-resistant elms in elm restoration programs. PB Elsevier SN 0176-1617 YR 2021 FD 2021 LK https://hdl.handle.net/20.500.14352/99610 UL https://hdl.handle.net/20.500.14352/99610 LA eng NO Clara Martínez-Arias, Juan Sobrino-Plata, David Medel, Luis Gil, Juan Antonio Martín, Jesús Rodríguez-Calcerrada. Stem endophytes increase root development, photosynthesis, and survival of elm plantlets (Ulmus minor Mill.). Journal of Plant Physiology. Volume 261, 2021, 153420, ISSN 0176-1617, https://doi.org/10.1016/j.jplph.2021.153420 NO Ministerio de Economía y Competitividad (España) DS Docta Complutense RD 7 abr 2025