CHLOROPLAST PROTEOMICS REVEALS NEW INSIGHTS INTO THE LOW TEMPERATURE STRESS ACCLIMATION OF THE MODEL LEGUME LOTUS JAPONICUS

CALZADILA P.I.; VILAS J.M.; ESCARAY F.J.; CARRASCO SORLI, P.; RUIZ O.A.

BARCELONA

Congreso; CONGRESO DE LA SOCIEDAD DE FISIOLOGÍA VEGETAL ESPAÑOLA; 2017

SOCIEDAD ESPAÑOLA DE FISIOLOGIA VEGETAL

Low temperature is one of the most important factors affecting plant growth, directly altering the photosynthetic process and leading to photo-inhibition. With the aim to address the photosynthetic acclimation response of L. japonicus under cold stress, two ecotypes (MG-1 and MG-20) were studied. Previous data showed that photo-inhibition occurs in stress and differentially between ecotypes, being MG-1 more affected than MG-20. Furthermore, a chloroplastic redox imbalance was generated due to low temperature, but only in the sensitive ecotype. In this study, we used a proteomic approach to evaluate changes in the chloroplast proteome of both MG-1 and MG-20 ecotypes after 7 d of low temperature and control treatments. A total of 724 proteins were identified, of which 12 presented significative interaction between ecotypes and temperature treatments, 66 were differentially abundant between ecotypes and 64 between temperature treatments. Functional annotation and classification were performed using KEGG, Uniprot and LegumeIP databases, as well as the STRING software. A greater abundance of proteins related with photosynthesis ?light-reactions? (in particular, oxidative phosphorilation and antenna proteins) were identified in the MG-1 ecotype compared to the MG-20. By the contrary, in MG-20, proteins related with the carbon metabolism, the oxidative stress response and protein folding were more abundant. Changes in the photosynthetic and carbon metabolisms suggested two different acclimation strategies in the L. japonicus chloroplasts studied. While in the sensitive MG-1 ecotype those mechanisms seem to be implicated with energy dissipation in photosystems, regulation of the source/sink carbon ratio seems to be preponderant in the tolerant MG-20. Data showed that the differential response of both L. japonicus ecotypes to cold stress could be, at least partially, explained by these different acclimation strategies. As a conclusion, our results emphasized the relevance of the carbon metabolism in the low temperature acclimation of the model legume L. japonicus.