CONTRASTING THE BIOCHEMICAL AND PHYSIOLOGICAL RESPONSE OF LOTUS ECOTYPES SUBJECTED TO COLD STRESS

CALZADILA P.I.; SIGNORELLI S.; MAIALE S.J.; MONZA J.; RUIZ O.A.

MAR DEL PLATA

Congreso; CONGRESO 2015 SAIB; 2015

Sociedad Argentina de Bioquímica y Biología Molecular

Lotus is an important genus of Leguminosae,used as forage due to their high nutritional value and adaptability to marginalconditions for agriculture. However, its dry matter production is drasticallyreduced in coolest season. To evaluate this situation, the acclimation responseof two L. japonicus ecotypes (MG-1 and MG-20) was studied under coldstress.  Plants of 3-weeks-old wereanalyzed at different times (first, fourth and seventh day) of stress (5-9 ± 1°C) and control (21-25 ± 1 °C), showing that photoinhibition occursdifferentially between ecotypes, being MG-1 more affected than MG-20. On theother hand, the Reactive Oxygen Species (ROS) and Reactive Nitrogen Species(RNS) production were analyzed under stress, finding no differences between treatmentsor ecotypes. Nevertheless, NADPH levels were reduced in plants subjected tostress, and being more dramatically in MG-1. Moreover, antioxidant enzymesactivities were measured. Only SOD isozymes showed a contrasting responsebetween accessions and treatments, increasing in MG-20. Immunoblot of D1 and D2proteins were done to analyze the effect in photosynthesis showing that whileD1 protein contents remained constant, D2 turnover was evident. Our study providesa deeper insight into the response to cold stress in legumes.