Biotech/GM crops in horticulture: plum cv. HoneySweet resistant to Plum pox virus

Abstract

Polák J., Kumar J., Krška B., Ravelonandro M. (2012): Biotech/GM crops in horticulture: Plum cv. HoneySweet resistant to Plum pox virus. Plant Protect. Sci., 48 (Special Issue): S43-S48.Commercialisation of Biotech/GM (Biotech) crops started in 1995. Not only field crops, but also horticultural transgenic crops are under development and are beginning to be commercialised. Genetic engineering has the potential to revolutionise fruit tree breeding. The development of transgenic fruit cultivars is in progress. Over the past 20 years an international public sector research team has collaborated in the development of HoneySweet plum which is highly resistant to Plum pox virus (PPV) the most devastating disease of plums and other stone fruits. HoneySweet was deregulated in the USA in 2010. HoneySweet (aka C5) has been evaluated for eleven years (2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012) in a regulated field trial in the Czech Republic for the resistance to PPV, Prune dwarf virus (PDV), and Apple chlorotic leaf spot virus (ACLSV), all of them being serious diseases of plum. Even under the high and permanent infection pressure produced through grafting, PPV has only been detected in HoneySweet trees in several leaves and fruits situated close to the point of inoculum grafting. The lack of infection spread in HoneySweet demonstrates its high level of PPV resistance. Co-infections of PPV with PDV and/or ACLSV had practically no influence on the quantity and quality of HoneySweet fruit which are large, sweet, and of a high eating quality. In many respects, they are superior to the fruits of the well-known cultivar Stanley. Many fruit growers and fruit tree nurseries in the Czech Republic are supportive of the deregulation of HoneySweet plum to help improve the plum production and control the spread of PPV.

‘HoneySweet’ (C5), the First Genetically Engineered Plum pox virus–resistant Plum (Prunus domestica L.) Cultivar

“…When graft inoculated with PPV-infected budwood or when vegetative ''root suckers'' from susceptible rootstocks have become infected, 'HoneySweet' trees have shown scarce and mild symptoms in the basal leaves near the source of infection. Systemic infection has generally not been detected, but when detected, it has been limited with mild symptoms that have diminished over multiple growing seasons (Polak et al, 2012). 'HoneySweet' trees have been shown to be resistant to all major strains of PPV (Ravelonandro et al, 2014).…”

Effects of economically important virus diseases on the expression of some pomological traits and nutritional compounds in GM plum cultivar HoneySweet (Prunus domestica L.)

“…Polák et al (2012) reported that fruits of the genetically modified (GM) 'HoneySweet' , after joint infections of PPV with Plum dwarf virus (PDV) and/or Apple chlorotic leaf-spot virus (ACLSV), appeared to suffer no deterioration in either quality or quantity. Useniket al (2014) measured the levels of individual sugars and other compounds in the plum 'Brkinska češpa' (P. domestica L.), in fruits produced by trees suffering from short-term and long-term PPV infections, and determined that the fruits from long-term infected trees had the poorest pomological traits and also the most modified composition regarding nutritional and phenolic compounds Strick and Martin (2003) measured the effect of the Raspberry bushy dwarf virus on yield, fruit quality and growth of canes in the blackberry 'Marion' .…”

Grafting of Genetically Engineered Plants

“…Transgenic papaya with resistance to Papaya ringspot virus is the only commercialized GE fruit crop. Transgenic plum with resistance to Plum pox virus (PPV) was finally registered in 2011, but has not been commercialized in the United States because PPV is not spreading and the need for resistance is limited (Pol ak et al, 2012). Recently, 'Arctic R ' (nonbrowning) apple cultivars have been developed using RNAi-mediated intragenic technology (Okanagan Specialty Fruits, 2015), which subsequently provoked a new wave of the debate over GE fruits, and thus, commercialization has stalled.…”