The increase of photosynthetic carbon assimilation as a mechanism of adaptation to low temperature in Lotus japonicus.
Calzadilla, P. I., Vilas, J. M., Escaray, F. J., Unrein, F., Carrasco, P. and Ruiz, O. A.
Instituto de Investigaciones Biotecnologicas-Instituto Tecnologico de Chascomus (IIB-INTECH), UNSAM-CONICET, Buenos Aires, Argentina.
Institut de Biologie Integrative de la Cellule (I2BC), CNRS, CEA, Universite Paris-Sud, Universite Paris-Saclay, Gif sur Yvette, France.
Departamento de Bioquimica y Biologia Molecular-Universitat de Valencia, Valencia, Spain.
Departamento de Bioquimica y Biologia Molecular-Universitat de Valencia, Valencia, Spain. carrascp@uv.es.
Instituto de Fisiologia y Recursos Geneticos Vegetales (IFRGV) Ing "Victorio S Trippi", Instituto Nacional de Tecnologia Agropecuaria (INTA), Cordoba, Argentina.
Low temperature is one of the most important factors affecting plant growth, it causes an stress that directly alters the photosynthetic process and leads to photoinhibition when severe enough. In order to address the photosynthetic acclimation response of Lotus japonicus to cold stress, two ecotypes with contrasting tolerance (MG-1 and MG-20) were studied. Their chloroplast responses were addressed after 7 days under low temperature through different strategies. Proteomic analysis showed changes in photosynthetic and carbon metabolism proteins due to stress, but differentially between ecotypes. In the sensitive MG-1 ecotype acclimation seems to be related to energy dissipation in photosystems, while an increase in photosynthetic carbon assimilation as an electron sink, seems to be preponderant in the tolerant MG-20 ecotype. Chloroplast ROS generation was higher under low temperature conditions only in the MG-1 ecotype. These data are consistent with alterations in the thylakoid membranes in the sensitive ecotype. However, the accumulation of starch granules observed in the tolerant MG-20 ecotype indicates the maintenance of sugar metabolism under cold conditions. Altogether, our data suggest that different acclimation strategies and contrasting chloroplast redox imbalance could account for the differential cold stress response of both L. japonicus ecotypes.
Scientific Reports 9(1): 863 (2019)