XXXV Reunião Anual da SBBqResumoID:8147


Strategies to large-scale extraction of dsRNA from papaya latex infected with Papaya meleira virus (PMeV)


Rodrigues, S.P.1; Piccin, J.G.Z1; Ventura, J.A.1,2; Fernandes, P.M.B1.



1 Núcleo de Biotecnologia, CCS, UFES, Vitória, ES; 2 INCAPER-ES; biotecnologia.ufes.gmail.com


Papaya meleira virus (PMeV) is the causal agent of papaya (Carica papaya L.) sticky disease which causes an exudation of a fluid and watery latex from the fruits and leaves together with other disease symptoms that compromise the fruits commercially. It possesses a 12 kbp dsRNA molecule whose extraction from latex has been mainly used to viral molecular diagnoses. Our recent electron microscopy and molecular data indicate that the PMeV particles are strongly linked to polymers present in the latex. Strategies able to release the virus from such polymers could improve the dsRNA extraction method, allowing the replacement of costly reagents. Besides its use to PMeV diagnosis, such molecules are promising RNA silencing inducers to be used against PMeV in papaya. Thus, pellets of latex containing PMeV particles were submitted to: HCl/KCl chloride buffer pH 2,5, 10% SDS solution, 0,01% β-mercaptoethanol solution and 0-8 M urea solution for 15 min; high hydrostatic pressure (50-250 MPa) and heat (60-90 oC) for 10 min; shaking using a ultra-sonic or vortex type shaker for 45 min. The latex was centrifuged and the supernatant was submitted to gel electrophoresis. No treated latex was used as negative control. A light band was observed after shaking and pressures of 200 and 250 MPa. Better results were observed after urea treatment from 6-8 M, in which almost all dsRNA molecules were released. No band was seen after the other treatments, indicating that the strong linkage between PMeV and latex polymers was not broken. Therefore, HHP and urea treatment allow easily dsRNA to be extracted in large concentration.