Articles
NATURAL AND INDUCED PATHOGEN RESISTANCE IN TEMPERATE FRUIT TREES AND GRAPEVINES
Article number
940_82
Pages
581 – 590
Language
English
Abstract
The control of fruit tree virus and phytoplasma diseases is currently based on avoidance practices and prophylactic measures.
Host resistance probably is the most attractive and sustainable approach to control virus diseases in long-lived horticultural crops such as fruit trees, where short-term measures do not give any benefit.
However, the development of new fruit tree cultivars is difficult and time consuming, since their breeding cycle usually requires more than ten years.
Because most cultivars are highly heterozygous, chances of combining virus resistance with other desired horticultural characteristics are low.
The most important pathogens of fruit trees (pome fruits, stone fruits, citrus) and grapevines in Southern Europe and the Mediterranean basin considered by the EPPO are shortly introduced.
Development of virus-resistant cultivars using classical breeding has been limited due to the scarcity of known resistance genes, genetic barriers and the complexity of the target crops.
Although many types of resistance have been described, that can be effective against viruses or their vectors; unfortunately so far not so many have been found in fruit trees.
Successful examples of classical cross protection to contain Citrus tristeza virus (CTV) and Prunus necrotic ringspot virus (PNRSV) are presented.
Finally, genetically engineered protection against the most devastating virus diseases, Plum pox virus (PPV) in Prunus, CTV in Citrus and Grapevine fanleaf virus (GFLV) in Vitis allowing, applying completely new avenues of protection, is discussed.
Increased knowledge of both the molecular genetics of plant viruses and, more recently, also of their hosts natural defence systems have resulted in the development of a number of novel ways to control virus diseases in plants.
An outlook is offered on strategies to meet new emerging threats, including avoidance and monitoring.
Defence strategies should be developed in due time, to prevent drastic losses to the European fruit and wine industry.
Host resistance probably is the most attractive and sustainable approach to control virus diseases in long-lived horticultural crops such as fruit trees, where short-term measures do not give any benefit.
However, the development of new fruit tree cultivars is difficult and time consuming, since their breeding cycle usually requires more than ten years.
Because most cultivars are highly heterozygous, chances of combining virus resistance with other desired horticultural characteristics are low.
The most important pathogens of fruit trees (pome fruits, stone fruits, citrus) and grapevines in Southern Europe and the Mediterranean basin considered by the EPPO are shortly introduced.
Development of virus-resistant cultivars using classical breeding has been limited due to the scarcity of known resistance genes, genetic barriers and the complexity of the target crops.
Although many types of resistance have been described, that can be effective against viruses or their vectors; unfortunately so far not so many have been found in fruit trees.
Successful examples of classical cross protection to contain Citrus tristeza virus (CTV) and Prunus necrotic ringspot virus (PNRSV) are presented.
Finally, genetically engineered protection against the most devastating virus diseases, Plum pox virus (PPV) in Prunus, CTV in Citrus and Grapevine fanleaf virus (GFLV) in Vitis allowing, applying completely new avenues of protection, is discussed.
Increased knowledge of both the molecular genetics of plant viruses and, more recently, also of their hosts natural defence systems have resulted in the development of a number of novel ways to control virus diseases in plants.
An outlook is offered on strategies to meet new emerging threats, including avoidance and monitoring.
Defence strategies should be developed in due time, to prevent drastic losses to the European fruit and wine industry.
Authors
M. Laimer
Keywords
Citrus tristeza virus (CTV), Grapevine fanleaf virus (GFLV), Papaya ringspot virus (PRSV), Plum pox virus (PPV), Prunus necrotic ringspot virus (PNRSV)
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