Potyvirus associated to Momordica charantia in Puerto Rico

Background/Question/Methods

The transmission dynamics of viruses within cultivated crops is often well-known, but the possibility that viruses may be exchanged between cultivated and nearby wild plants exists. For the protection of natural environments it is necessary to understand the dynamics of exchange between cultivated and non-cultivated; as natural environments may be strongly  affected or function as reservoirs for new pathogens. For these reasons, the diversity of viruses in non-cultivated plants needs to be understood. Herein, we focus on Potyvirus in Momordica charantia (Cucurbitaceae), an alien invasive vine in Puerto Rico. This diverse genus of viruses is very common in crop plants, and infects a wide range of plant families. We sampled 347 M. charantia plants across Puerto Rico including adjacent islands of Culebra and Vieques. We used an enzyme-linked immunosorbent assay for detection of viruses and RT-PCR to amplify the CP region using MJ1 and MJ2. The virus BCMV (915) served as an outgroup. Maps of both symptomatic and asymptomatic plants were developed using the species distribution model algorithm MaxEnt and potential distributions were developed by screening 20 environmental variables for the most informative layers.

Results/Conclusions

We found that viruses PRSV and ZYMV were the most commonly encountered potyviruses and were closely related.  The presence of disease symptoms in M. charantia was closely associated with the presence of PRSV and ZYMV. The distribution of PRSV, ZYMV and symptoms (found in M. charantia) is clearly related to nearby crop sites. Phylogenetic relationships among PRSV found in 42 samples of M. charantia were complex and showed that PRSV-W and PRSV-P form a clade, yet no biogeographical signal was evident. To understand the exchange of virus from cultivated crop plants we need to develop improved molecular techniques, taking into account the motion vectors and life cycle. The impact of virus introduced into natural environments has been little studied. Our study will give a preliminary view of the distribution of a non-cultivated plant infection. The potyvirus infection of Momordica charantia is closely related to the presence of crops.