Tomato chlorosis virus, an emergent plant virus still expanding its geographical and host ranges

Abstract

Summary Tomato chlorosis virus (ToCV) causes an important disease that primarily affects tomato, although it has been found infecting other economically important vegetable crops and a wide range of wild plants. First described in Florida (USA) and associated with a ‘yellow leaf disorder’ in the mid‐1990s, ToCV has been found in 35 countries and territories to date, constituting a paradigmatic example of an emergent plant pathogen. ToCV is transmitted semipersistently by whiteflies (Hemiptera: Aleyrodidae) belonging to the genera Bemisia and Trialeurodes . Whitefly transmission is highly efficient and cases of 100% infection are frequently observed in the field. To date, no resistant or tolerant tomato plants are commercially available and the control of the disease relies primarily on the control of the insect vector. Taxonomy Tomato chlorosis virus is one of the 14 accepted species in the genus Crinivirus , one of the four genera in the family Closteroviridae of plant viruses. Virion and genome properties The genome of ToCV is composed of two molecules of single‐stranded positive‐sense RNA, named RNA1 and RNA2, separately encapsidated in long, flexuous, rod‐like virions. As has been shown for other closterovirids, ToCV virions are believed to have a bipolar structure. RNA1 contains four open reading frames (ORFs) encoding proteins associated with virus replication and suppression of gene silencing, whereas RNA2 contains nine ORFs encoding proteins putatively involved in encapsidation, cell‐to‐cell movement, gene silencing suppression and whitefly transmission. Host range In addition to tomato, ToCV has been found to infect 84 dicot plant species belonging to 25 botanical families, including economically important crops. Transmission Like all species within the genus Crinivirus , ToCV is semipersistently transmitted by whiteflies, being one of only two criniviruses transmitted by members of the genera Bemisia and Trialeurodes . Disease symptoms Tomato ‘yellow leaf disorder’ syndrome includes interveinal yellowing and thickening of leaves. Symptoms first develop on lower leaves and then advance towards the upper part of the plant. Bronzing and necrosis of the older leaves are accompanied by a decline in vigour and reduction in fruit yield. In other hosts the most common symptoms include interveinal chlorosis and mild yellowing on older leaves. Control Control of the disease caused by ToCV is based on the use of healthy seedlings for transplanting, limiting accessibility of alternate host plants that can serve as virus reservoirs and the spraying of insecticides for vector control. Although several wild tomato species have been sh...

An Acylsucrose-Producing Tomato Line Derived from the Wild Species Solanum pimpinellifolium Decreases Fitness of the Whitefly Trialeurodes vaporariorum

“…In tomato plants (Solanum lycopersicum L.), T. vaporariorum is vector of plant viruses of the genera Crinivirus and Torradovirus (families Closteroviridae and Secoviridae, respectively) [4][5][6][7][8]. Among them, the crinivirus tomato chlorosis virus (ToCV) is a major emerging virus worldwide [4,9]. The direct and indirect damages caused by T. vaporariorum can then result in significant tomato yield losses [10,11].…”

Mechanisms of plant virus transmission by the whitefly <italic>Bemisia tabaci</italic>

“…然而, 也有研究认为TYLCV不能 够在烟粉虱体内复制. Becker等人 [70] 和Sánchez-Cam- 种 [73] . 该属病毒对甜菜、葫芦、莴苣、甘薯以及番茄 等重要经济作物的生产造成巨大影响, 并且常常会与 其他病毒复合侵染危害作物 [74] .…”

Host Plant Resistance to Bemisia tabaci to Control Damage Caused in Tomato Plants by the Emerging Crinivirus Tomato Chlorosis Virus

“…Control of whitefly-transmitted viruses in tomato crops relies frequently on intensive chemical applications against the insect vector to reduce virus spread (Lapidot et al, 2014;Rojas et al, 2018;Fiallo-Olivé and Navas-Castillo, 2019). In fact, control of ToCV is mainly based in insecticide applications against whiteflies but has proven largely ineffective (Fiallo-Olivé and Navas-Castillo, 2019). Virus-resistant tomatoes are widely used commercially to effectively reduce the damage caused by TYLCV (Lapidot and Friedmann, 2002;Vidavski et al, 2008).…”

“…Among them, emerging whitefly (Hemiptera: Aleyrodidae)-transmitted viruses such as the crinivirus (genus Crinivirus , family Closteroviridae ) tomato chlorosis virus (ToCV) or begomoviruses (genus Begomovirus , family Geminiviridae ) causing the tomato yellow leaf curl disease (tomato yellow leaf curl virus, TYLCV, the most widespread type), severely damage tomato crops worldwide ( Hanssen et al, 2010 ; Rybicki, 2015 ; Rojas et al, 2018 ; Fiallo-Olivé and Navas-Castillo, 2019 ). Emergence of ToCV and TYLCV has been associated with the global spread of the whitefly Bemisia tabaci (Gennadius) in tropical and warm regions worldwide ( Tzanetakis et al, 2013 ; Fereres, 2015 ; Gilbertson et al, 2015 ; Rojas et al, 2018 ; Fiallo-Olivé and Navas-Castillo, 2019 ). ToCV is transmitted in a semipersistent manner (short acquisition and inoculation periods) and TYLCV in a persistent manner (long acquisition and inoculation periods), respectively ( Cohen and Antignus, 1994 ; Wintermantel, 2016 ; Fiallo-Olivé and Navas-Castillo, 2019 ).…”

“…Emergence of ToCV and TYLCV has been associated with the global spread of the whitefly Bemisia tabaci (Gennadius) in tropical and warm regions worldwide ( Tzanetakis et al, 2013 ; Fereres, 2015 ; Gilbertson et al, 2015 ; Rojas et al, 2018 ; Fiallo-Olivé and Navas-Castillo, 2019 ). ToCV is transmitted in a semipersistent manner (short acquisition and inoculation periods) and TYLCV in a persistent manner (long acquisition and inoculation periods), respectively ( Cohen and Antignus, 1994 ; Wintermantel, 2016 ; Fiallo-Olivé and Navas-Castillo, 2019 ).…”