Metabolic changes in leaves of Prunus persica inoculated with Taphrina deformans

NOVELLO, MARIA ANGELINA; DRINCOVICH, MARÍA FABIANA; LARA, MARÍA VALERIA

Congreso; LVII SAIB Meeting - XVI SAMIGE Meeting ? SAIB-SAMIGE Joint Meeting 2021 on line.; 2021

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Leaf peach curl is a disease affecting Prunus persica trees around the world. The causal of the disease is the dimorphic fungus Taphrina deformans. In addition to leaf hypertrophy and reddish coloration, the disease is characterized by a decrease in photosynthesis. In order to identify early defense responses of Prunus persica against Taphrina deformans infection, in a previous work we analyzed differentially expressed genes (DEGs) by RNA-seq in leaves from a susceptible (DS) and a resistant (DR) genotype after 12 and 96 hours of fungal inoculation. Fold change was calculated as the relation between normalized gene counts at 12 or 96 hpi with respect to 0 hpi for each genotype. Functional classification of DEGs revealed that photosynthesis was among the ten most enriched categories in both genotypes. In this way, to get insight into the effects of the pathogen in plant photosynthesis and carbohydrate metabolism in asymptomatic leaves, we explored the levels of chlorophylls (Chls), some sugars such as sucrose, glucose, starch, among others, and some proteins such as Rubisco and sorbitol dehydrogenase in leaves challenged with the fungus. Two genotypes with contrasting sensitivity (DS and DS) were analyzed after 12 and 96 hours post inoculation with T. deformans, and compared to the control at 0 hpi. Chla and -b decreased at 12 and 96 hpi with respect to 0 hpi in DS, while slightly decrease in Chlb were observed at 96 hpi in DR. In both genotypes, Rubisco content decreased at 96 hpi with respect to 0 hpi. Starch content decreased in both genotypes at 12 and 96 hpi with respect to 0 hpi; however, the reduction was greater in DS than in DR. Moreover, starch content tended to be restored at 96 hpi in DR. Sucrose levels also decreased in both genotypes at after inoculation. With respect to glucose, while it decreased in DR over time after inoculation, glucose content increased in DS, with maximum levels at 12 hpi.These findings, together with transcriptomic data suggests a decrease in photosynthesis and the synthesis of starch in infected leaves of DS, with the use of sucrose, sorbitol and starch at early stages of infection. Therefore a change to a type of metabolism similar to that of sink tissues takes place in asymptomatic leaves. In the resistant genotype a similar trend was observed. In conclusion, photosynthetic changes that are usually observed in infected leaves where symptoms are observed start to occur very early after inoculation.