Citrus Variegated Chlorosis: an Overview of 30 Years of Research and Disease Management

Abstract

The emergence of citrus variegated chlorosis (CVC) disease had dramatic consequences to the citrus industry in Brazil. First reported in São Paulo State in 1987, this disease affected approximately 100 million sweet orange trees in the region 20 years later. However, current estimates indicate that the number of diseased trees has been reduced 25-fold since 2009. In this review we summarize research on CVC since its emergence, focusing on work that has contributed to the observed success in managing this disease in the field. Knowledge that CVC is caused by a bacterium (Xylella fastidiosa-now classified as X. fastidiosa subsp. pauca) that is transmited by infected plant material (grafting and nursery plant) and insect vectors, the citrus nursery production system switched in 2003 to a certification program in which plants are grown in insect proof screen-houses and routinely monitored for X. fastidiosa infection. Research triggered by the genome sequencing of a CVC isolate in 2000, the first plant pathogenic bacterium to have its complete genome sequenced, integrated molecular tools and approaches into research aimed at understanding the biology of this pathogen. Ultimately, the challenges imposed by CVC led to significant improvements in the scientific and technical knowledge linked to sweet orange production, and to the development of a more sustainable and resilient citrus industry in Brazil.

Global orange juice market: a 16-year summary and opportunities for creating value

“…Indulgence-"my gift" Many consumers place some special food as a reward as they accomplish their tasks. Belk (1975); Boniface (2016) 10. Flavors and sensory aspects (textures, smell, colors), knowledge about food ingredients characteristics…”

“…In 2017, Florida had to deal with hurricane Irma, which caused a 40% reduction in orange juice production due to flooding of orchards and early fruit dropping (Gochez et al 2020). In Brazil, citrus canker and also citrus variegated chlorosis (CVC) contribute to impact citrus production due to yield losses and increase in productions costs (Coletta Filho et al 2020). Finally, greening or HLB (huanglongbing) is currently the main threat to citrus production in the main citrus producing areas around the world including Brazil, USA, and China (Bassanezi et al 2020;Zhou 2020;Graham et al 2020).…”

Severity assessment in the Nicotiana tabacum-Xylella fastidiosa subsp. pauca pathosystem: design and interlaboratory validation of a standard area diagram set

“…The plant pathogenic bacterium Xylella fastidiosa is an emergent global threat to several perennial crops including citrus, grape, coffee, almond, oak, plum, and olive (Saponari et al 2013;Mansfield et al 2012;Almeida et al 2019). There is a vast amount of information generated by novel sequencing technologies, but functional genomics studies are a bottleneck due the difficult to studies involving a slow-growing bacteria and perennial hosts (Coletta-Filho et al 2020).…”

Xylella fastidiosa subsp. pauca Strains Fb7 and 9a5c from Citrus Display Differential Behavior, Secretome, and Plant Virulence

“…In the case of CVC, pauca strains are widespread in all major citrus-producing regions in South America and disease incidence reached over 40% of producing trees in peak years in the early 2000s and since has dramatically been reduced due to a combination of labor and cost-intensive pest control management practices for citrus greening disease [14]. As more pauca strains become studied, their common and peculiar genetic characteristics are being described in increasing detail [14][15][16][17]. This information enables a better understanding of intra and inter-subspecies evolution, as well as their relationship with host range and geographic distribution [14].…”

“…As more pauca strains become studied, their common and peculiar genetic characteristics are being described in increasing detail [14][15][16][17]. This information enables a better understanding of intra and inter-subspecies evolution, as well as their relationship with host range and geographic distribution [14]. In light of the rapid dissemination and impact of this phytopathogen, there is great interest in understating the molecular aspects of plant-microbe interactions in these pathosystems.…”