Browsing by Author "Klimaszewska, K."
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- Mycorrhiza-like structures in rooted microshoots of Pinus pinea L.Publication . Castro, M. R.; Ragonezi, C.; Klimaszewska, K.; Lima, M.; de Oliveira, P.; Zavattieri, M. A.Pinus pinea L. (stone pine) is one of the major plantation species in Iberian Peninsula, being Portugal the largest edible seed producer in the world. The induction and improvement of in vitro rhizogenesis of microshoots of Pinus pinea was developed in our laboratory using a co-culture system with ECM fungi. In the acclimation phase in mixed substrates, or in rhizotrons, anatomical and morphological studies were done to observe the evolution of the root system in microshoots from the co-culture system vs. control plants. Extensive dichotomous and coralloid branching of lateral roots occurred spontaneously in inoculated and control plants as well. Moreover, similar branching occurred in liquid culture of excised seedling roots without the presence of ECM fungi. The striking similarity of these organs with pine ectomycorrhizas prompted their anatomical analysis; however the presence of Hartig net was not confirmed. These results suggested that the development of ECM-like structures might have occurred spontaneously.
- O-coumaric acid ester, a potential early signaling molecule in Pinus pinea and Pisolithus arhizus symbiosis established in vitroPublication . Ragonezi, C.; Teixeira, D.; Caldeira, A. T.; Martins, M .R.; Santos-Silva, C.; Ganhão, E.; Klimaszewska, K.; Zavattieri, M. A.During ectomycorrhizal (ECM) establishment, biochemical signals lead to the development of complex structures in both the plant and the fungus that ultimately result in the formation of an ectomycorrhiza. The cross-talk between partners begins before physical contact. Our objective was to investigate the chemical nature of the signals during the first stages of in vitro mycorrhization of Pinus pinea with Pisolithus arhizus. For this purpose a double-phase solid liquid medium was expressly developed for the co-culture in order to simplify the extraction and further molecules analysis. O-coumaric acid ester was identified using HPLC UV and LC DAD MS on the second day of co-culture and its presence was detected for up to 10 days. These results contribute to the characterization of biochemical signals during pre-colonization involving conifer species and an ECM fungus, and demonstrate the suitability of the double-phase medium developed for the growth of both organisms and for the analysis of released chemical mediators.