Biochemical responses to the combined stress by drought and fungal infection in peanut

GUZZO MC; POSADA G; PAREDES JA; SUAREZ P; COSTAMAGNA CA; RAGO AM; MONTEOLIVA MI

Congreso; XXXIII Congreso de la Sociedad Argentina de Fisiologia Vegetal; 2021

SAFV

In Argentina, peanut (Arachis hypogaea L.)production is mostly affected by seasonal droughts (up to 30% of yieldreductions) and peanut smut, caused by the fungal pathogen Thecaphora frezii.Both factors may occur simultaneously in the same season. Our group has beenstudying biochemical responses to drought for several years. Drought stress inpeanut induces changes in chlorophylls (related to the photosynthetic capacityof the plant and yield), proline (as part of the osmotic response), and redoxstatus (total non-enzymatic capacity -FRAP- and oxidative membrane damage-MDA-). Recently we found that dry years increase the severity of the disease,but biochemical and physiological responses to the combination of drought andthe pathogen have not been addressed yet. We aimed to evaluate if the presenceof the pathogen under drought accentuates or reduces the known responses to waterdeficit. We grew peanut plants in the greenhouse until all the pots wereflowered (~30 days). Then water was reduced until the soil humidity reached 30%of field capacity. The soil was maintained at 30% for 30 days, when leaves sampleswere collected. Proline, chlorophylls, FRAP, and MDA were measured in pools ofat least 3 leaves from different pots for each treatment. Relativewater content was measured to check the efficiency of the treatment. We found notablechanges in proline and chlorophylls, which weredifferentially induced by the presence of the pathogen, suggesting the fungus mightbe favored by the typical responses associated with drought tolerance in groundnut.