Research and adoption of biotechnology strategies could improve California fruit and nut crops

California's fruit and nut tree crops represent one-third of the state's cash farm receipts and 70% of U.S. fruit and nut production. Advances in crop biotechnology and genetic engineering could help protect these valuable crops from pests and diseases and improve productivity. However, due to the difficulty of genetically engineering woody tree crops, as well as intellectual property concerns, regulatory hurdles and public perceptions about genetic engineering, biotechnology has not gained a foothold in this area of agriculture. Our survey of published genetic engineering research and issued field trial permits between 2000 and 2011 revealed that citrus and grape are the focus of most current work, and that walnut — not the more widely planted almond — is the focus among nut crops. Matching publicly funded genetic engineering research projects to a survey of the industry's top needs, we found that far less than half of the funded research has focused on the top-identified pest and disease threats. The most promising genetic engineering technology for fruit and nut tree crops may be transgrafting, which could address consumer concerns and benefit growers

Regulatory status of transgrafted plants is unclear

The regulatory implications of using transgrafted plants are currently unknown. A plant's vascular system can selectively transport across graft junctions endogenous elements such as full-length RNAs, sRNAs, proteins, hormones, metabolites and vitamins, and even elicit epigenetic effects, heritably changing the way genes are expressed without changing the actual DNA sequence. However, not all of these elements are transported freely, and they either require specific molecular signals or cellular transporters to aid in their movement through a plant's vascular system

Research and adoption of biotechnology strategies could improve California fruit and nut crops

California's fruit and nut tree crops represent one-third of the state's cash farm receipts and 70% of U.S. fruit and nut production. Advances in crop biotechnology and genetic engineering could help protect these valuable crops from pests and diseases and improve productivity. However, due to the difficulty of genetically engineering woody tree crops, as well as intellectual property concerns, regulatory hurdles and public perceptions about genetic engineering, biotechnology has not gained a foothold in this area of agriculture. Our survey of published genetic engineering research and issued field trial permits between 2000 and 2011 revealed that citrus and grape are the focus of most current work, and that walnut — not the more widely planted almond — is the focus among nut crops. Matching publicly funded genetic engineering research projects to a survey of the industry's top needs, we found that far less than half of the funded research has focused on the top-identified pest and disease threats. The most promising genetic engineering technology for fruit and nut tree crops may be transgrafting, which could address consumer concerns and benefit growers

Regulatory status of transgrafted plants is unclear

The regulatory implications of using transgrafted plants are currently unknown. A plant's vascular system can selectively transport across graft junctions endogenous elements such as full-length RNAs, sRNAs, proteins, hormones, metabolites and vitamins, and even elicit epigenetic effects, heritably changing the way genes are expressed without changing the actual DNA sequence. However, not all of these elements are transported freely, and they either require specific molecular signals or cellular transporters to aid in their movement through a plant's vascular system

Research and adoption of biotechnology strategies could improve California fruit and nut crops

California's fruit and nut tree crops represent one-third of the state's cash farm receipts and 70% of U.S. fruit and nut production. Advances in crop biotechnology and genetic engineering could help protect these valuable crops from pests and diseases and improve productivity. However, due to the difficulty of genetically engineering woody tree crops, as well as intellectual property concerns, regulatory hurdles and public perceptions about genetic engineering, biotechnology has not gained a foothold in this area of agriculture. Our survey of published genetic engineering research and issued field trial permits between 2000 and 2011 revealed that citrus and grape are the focus of most current work, and that walnut — not the more widely planted almond — is the focus among nut crops. Matching publicly funded genetic engineering research projects to a survey of the industry's top needs, we found that far less than half of the funded research has focused on the top-identified pest and disease threats. The most promising genetic engineering technology for fruit and nut tree crops may be transgrafting, which could address consumer concerns and benefit growers

Mobility of Transgenic Nucleic Acids and Proteins within Grafted Rootstocks for Agricultural Improvement.

Grafting has been used in agriculture for over 2000 years. Disease resistance and environmental tolerance are highly beneficial traits that can be provided through use of grafting, although the mechanisms, in particular for resistance, have frequently been unknown. As information emerges that describes plant disease resistance mechanisms, the proteins, and nucleic acids that play a critical role in disease management can be expressed in genetically engineered (GE) plant lines. Utilizing transgrafting, the combination of a GE rootstock with a wild-type (WT) scion, or the reverse, has the potential to provide pest and pathogen resistance, impart biotic and abiotic stress tolerance, or increase plant vigor and productivity. Of central importance to these potential benefits is the question of to what extent nucleic acids and proteins are transmitted across a graft junction and whether the movement of these molecules will affect the efficacy of the transgrafting approach. Using a variety of specific examples, this review will report on the movement of organellar DNA, RNAs, and proteins across graft unions. Attention will be specifically drawn to the use of small RNAs and gene silencing within transgrafted plants, with a particular focus on pathogen resistance. The use of GE rootstocks or scions has the potential to extend the horticultural utility of grafting by combining this ancient technique with the molecular strategies of the modern era