Avaliação morfológica e enzimática de plantas de Psidium spp. infectadas com Meloidogyne enterolobii

Abstract

The guava tree is widely cultivated due to its edible fruits, and it is considered an important Brazilian tropical fruits. However, the guava production has been affected in many cultivation areas by Meloidogyne enterolobii infection. For this reason, this work aimed to analyze the morphological and enzymatic changes promoted by the M. enterolobii. In order to understand this, Psidium spp plants when infested by the nematode M. enterolobii and after 26 days (DAI) were analyzed. For these assays, it was worked with Psidium guajava cv ‘Paluma’ (susceptible to the nematode) and Psidium friedrichstalianium (Costa Rican guava trees -resistant to the nematode). These plants were grown in green house and after forty days, these plants were infested with the M. enterolobii nematode, and after 26 days leaves and roots were collected for morphological analysis (determination of the leaf area), for anatomical and histological analyses of the root (analyses of cross-sectional and longitudinal anatomical sections), and for enzymatic analyses (analyses of catalase, ascorbate peroxidase, and guaiacol peroxidase activities). Furthermore, it was also used an in silico approach using microarray data related to biotic stress using Arabidopsis thaliana data. The morphological and histological analyses confirmed the damages promoted by the M. enterolobii in guava and Costa Rica guava trees. It was also observed that the leaf area (LA) reduce with the infection of M. enterolobii in P. friedrichstalianium, and, in P. guajava, there was an increase in the LA. The histological structures alterations were observed by the presence of galls on the roots, disordered cells presence, hyperplasia and cellular hypertrophy, xylem damage, and feeding sites formation. The enzymatic analyses showed an increase in ROS. It was observed in P. friedrichstalianium an increase from APX activity when compared to Psidium guajava. The results obtained in the in silico analysis allowed us to build an interactome formed by 78 proteins that were presented in groups. This data suggest a potential response pathways involved in biotic stress, oxidative stress, proteins direct and indirectly associated with the two pathways, as well as the locations of these proteins in a cellular level. The results showed here may be a guideline for future studies and it helped to understand better the effects of Meloidogyne enterolobii nematode in Psidium spp species.