La vida secreta de las plantas: relaciones sorprendentes con los microorganismos del suelo

Las plantas y los microorganismos interaccionan aportándose beneficio mutuo, lo cual puede ser aplicado para la conservación del medioambiente.Peer Reviewe

Nuclear DNA Endoreduplication and Expression of the Mitotic Inhibitor Ccs52 Associated to Determinate and Lupinoid Nodule Organogenesis

Lotus japonicus determinate nodules differ greatly from indeterminate nodules in their organogenesis and morphological characteristics, whereas Lupinus albus lupinoid nodules share features of determinate and indeterminate nodules. The mitotic inhibitor Ccs52A is essential for endoreduplication and ploidy-dependent cell enlargement during symbiotic cell differentiation in Medicago truncatula indeterminate nodules. ccs52A homolog genes were isolated from lupin and lotus nodules; the deduced Ccs52A proteins showed high sequence similarity with other Cdh-1-type activators of the anaphase-promoting complex and were grouped with A-type Ccs52 proteins from different plants. In lupin, ccs52A expression was restricted to the earlier stages of nodule development, whereas ccs52A transcripts accumulated in lotus nodule primordia and, to a lesser extent, in mature nodules. Nodule development in Lupinus albus involved a progressive increase in nuclear and cellular size and ploidy level; similarly, Lotus japonicus nodules contained polyploid nuclei and enlarged cells in the infected zone. Nevertheless, in situ hybridization experiments showed the highest ccs52A expression in the inner cortex cells of the lupin nodule primordium, probably associated to the increased size of these cells in mature nodules. In view of our results, Ccs52A-mediated endoreduplication appears to be a universal mechanism required for nodule cell differentiation during the establishment of nitrogen-fixing symbioses. Additional keyword: polyploidy

Biological nitrogen fixation improves production of ATP and nitrogen status in Lotus japonicus

1 página - Poster presentado en Iberian Plant Biology 2023. XVIII Portuguese-Spanish Congress on Plant Biology and the XXV Meeting of the Spanish Society of Plant Biology. 9-12 Julio 2023, Braga, Portugal.There is a lack of studies unravelling the effect of legume‐rhizobia interactions on plant respiratory energy efficiency. In plants, the existence of the alternative oxidase pathway (AOP) in the mETC confers metabolic flexibility by regulating the dissipation of reducing equivalents from TCA cycle, helping to maintain redox status and nutrient balance but decreasing yield of respiration. It is thought that carbon requirements of the symbiont and nitrogen transfer to the plant from nodules may affect the activities of both cytochrome oxidase pathway (COP) and AOP in plant organs for the benefit of plant yield in N poor soils. The main objective of this research was to create different plant N status by growing plants of WT Lotus japonicus at 5 mM and 10 mM KNO3, and in symbiosis with Mesorhizobium meliloti (0 mM KNO3). Besides, plants displaying spontaneous nodule formation (snf) mutations were grown at 1 mM KNO3. By isotope‐ratio mass spectrometry, we evaluated discrimination against 18O during respiration, and δ13C and δ14N in plant organs to determine ATP synthesis, changes in plant C economy, and N transfer from nodules. By high‐performance liquid chromatography (HPLC) and inductively coupled plasma (ICP) spectrometry, we also determined the content of NADH and nutrients as proxies of changes in TCA cycle activity and in plant nutrient economy. Our results indicated that nitrogen is vital in the modulation of respiratory metabolism, and that symbiosis improves production of ATP via COP, probably due to an incremented photosynthetic demand of symbiont for inorganic carbon and improved N status. Overall, our results shed some light into the complexity of legume‐rhizobia interactions involving plant respiration and essential plant nutrients

Effect of nitrogen supply and Rhizobia symbiosis in the isotopic composition of essential plant elements, nutrient content, TCA cycle activity and respiratory energy balance of Lotus japonicus

Resumen de la comunicación oral presentada en: I Spanish-Portuguese Congress on Beneficial Plant-Microbe Interactions (BeMiPlant) and XVIII National Meeting of the Spanish Society of Nitrogen Fixation (XVIII SEFIN). Oeiras, Portugal, 17-19 octubre (2022)This work was supported by FONDECYT No. 1191118 from National Agency for Research and Development (ANID) and the Chilean Scholarship Program/Becas de doctorado nacional/2017–21180329

Suppression of reactive oxygen species accumulation in chloroplasts prevents leaf damage but not growth arrest in salt-stressed tobacco plants

Crop yield reduction due to salinity is a growing agronomical concern in many regions. Increased production of reactive oxygen species (ROS) in plant cells accompanies many abiotic stresses including salinity, acting as toxic and signaling molecules during plant stress responses. While ROS are generated in various cellular compartments, chloroplasts represent a main source in the light, and plastid ROS synthesis and/or elimination have been manipulated to improve stress tolerance. Transgenic tobacco plants expressing a plastid-targeted cyanobacterial flavodoxin, a flavoprotein that prevents ROS accumulation specifically in chloroplasts, displayed increased tolerance to many environmental stresses, including drought, excess irradiation, extreme temperatures and iron starvation. Surprisingly, flavodoxin expression failed to protect transgenic plants against NaCl toxicity. However, when high salt was directly applied to leaf discs, flavodoxin did increase tolerance, as reflected by preservation of chlorophylls, carotenoids and photosynthetic activities. Flavodoxin decreased salt-dependent ROS accumulation in leaf tissue from discs and whole plants, but this decline did not improve tolerance at the whole plant level. NaCl accumulation in roots, as well as increased osmotic pressure and salt-induced root damage, were not prevented by flavodoxin expression. The results indicate that ROS formed in chloroplasts have a marginal effect on plant responses during salt stress, and that sensitive targets are present in roots which are not protected by flavodoxin.Para citar este articulo: Lodeyro AF, Giró M, Poli HO, Bettucci G, Cortadi A, Ferri AM, et al. (2016) Suppression of Reactive Oxygen Species Accumulation in Chloroplasts Prevents Leaf Damage but Not Growth Arrest in Salt-Stressed Tobacco Plants. PLoS ONE 11(7): e0159588. doi:10.1371/journal.pone.0159588Fil: Lodeyro, Anabella F. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario (IBR -CONICET); Argentina.Fil: Giró, Mariana. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario (IBR -CONICET); Argentina.Fil: Poli, Hugo O. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario (IBR -CONICET); Argentina.Fil: Bettucci, Gabriel. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Departamento de Ciencias Biológicas; Argentina.Fil: Cortadi, Adriana. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Departamento de Ciencias Biológicas; Argentina.Fil: Ferri, Alejandro M. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Departamento de Química Analítica; Argentina.Fil: Carrillo, Néstor. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario (IBR -CONICET); Argentina