Papaya is the fruit of the plant Ca

Papaya is the fruit of the plant Carica papaya, in the genus Carica. It is native to the tropics of the Americas, and was cultivated in Mexico several centuries before the emergence of the Mesoameri-can classic cultures. Papaya (Carica papaya) is widely grown in the tropics and has been grown in Hawaii for over a century as well (Gonsalves 1998). It is a popular fruit. The juice has been seen to have an antiproliferative effect on liver cancer cells cultured in the laboratory, probably due to its component of lycopene (Rahmat et al. 2002).

A major production constraint for papaya world-wide is papaya ringspot virus (PRSV), a potyvirus that is rapidly transmitted by a number of aphid species in a nonpersistent manner (Gonsalves & Ishii 1980). Efforts to develop transgenic papaya to control PRSV began shortly after transgenic tobacco expressing the coat protein gene of to-bacco mosaic virus was developed and shown to be resistant to Tobacco mosaic virus. The papaya research team cloned the coat protein gene of PRSV, transformed embryogenic cultures of pa