Morphological changes, alteration of photosynthetic parameters and chlorophyll production induced by the infection of alfalfa dwarf virus in Medicago sativa plants

JAIME CAMILA; MUCHUT SEBASTIAN; REUTEMANN ANDREA; GIECO JORGE; DUNGER, GERMÁN

PLANT PATHOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2020

0032-0862

In Argentina, infections by alfalfa dwarf virus (ADV) affect the cultivation of alfalfa, which is globally one of the most important forage plants . The main objective of this study was to improve current understanding of the underlying mechanisms related with the dwarfism phenotype developed during the viral infection. We evaluated hydrogen peroxide production, callose deposition and PR5 gene expression levels to determine if ADV induces plant defence responses. At morphological level, we observed a higher epicuticular wax production and an increase in proliferation of cells from the fundamental parenchyma when plants were infected by this virus. We report here that plants infected by ADV have reduced net photosynthesis, stomatal conductance and transpiration/evaporation rate; but interestingly, infected plants have induced the production of chlorophyll. Finally, using transcriptional analysis we observed that ADV negatively affects the expression of genes related with synthesis of auxins, cytokinins and brassinosteroids. Our results suggest that the ADV infection induces a hormonal imbalance leading to an increase in chlorophyll pigment synthesis, stomatal closure and generating tissue deformation. Overall, we report novel results showing a morphological, physiological and photosynthetic characterization of dwarf plants affected by ADV.