Detection ofCitrus tristeza virus(CTV) from Satsuma Owari mandarins(Citris unshiu)by direct tissue blot immunoassay (DTBIA), DAS‐ELISA, and biological indexing

Abstract

were indexed for biological properties. The results obtained from DTBIA tests showed that 20 of 119 (16.8%) tested trees were infected with CTV and 99 trees were virus free. All samples that tested positive in DTBIA were also positive in DAS-ELISA. After biological indexing, none of these 20 isolates showed any symptoms on sour orange, grapefruit, and sweet orange plants, but all isolates induced vein-clearing symptoms on Mexican lime (Citrus aurantifoli) in 9 months. Some isolates also caused leaf-cupping and chlorosis in Mexican lime. However, 15 months after initial grafting, all isolates induced mild to moderate stem-pitting on Mexican lime. In addition, young tissues, petioles, and leaf samples were collected periodically at monthly intervals for 1 year (2006) from a 25-year-old Satsuma Owari mandarin grafted on P. trifoliata in the Edremit Gulf. CTV was readily detected in tissue blots of young shoots and petioles from CTV-infected plants during the autumn, winter, and spring seasons. Similarly, the highest ELISA values were obtained in April; the lowest values were noted in September. This study showed that DTBIA is a rapid, sensitive, and reliable procedure for detecting CTV under field conditions.

Biological assays for plant viruses and other graft‐transmissible pathogens diagnoses: a review

“…Although many indexing hosts have been recommended, there is generally no validation data to support their use. Most have not been evaluated against a wide range of isolates, or through comparison with results from serological or molecular tests, even when differences in symptom expression between indicator plants have been pointed out (Garnsey, ; Damsteegt et al ., ; Jeffries, ; Kinard et al ., ; Kirby et al ., ; Singh & Ready, ; Vidalakis et al ., ; Korkmaz et al ., ; Constable et al ., , ; Thakur et al ., ; Razi et al ., ). Recently however, Wang et al .…”

“…Although many indexing hosts have been recommended, there is generally no validation data to support their use. Most have not been evaluated against a wide range of isolates, or through comparison with results from serological or molecular tests, even when differences in symptom expression between indicator plants have been pointed out (Garnsey, 1964;Damsteegt et al, 1998;Jeffries, 1998;Kinard et al, 2001;Kirby et al, 2001;Singh & Ready, 2003;Vidalakis et al, 2004;Korkmaz et al, 2008;Constable et al, 2010Constable et al, , 2013Thakur et al, 2011;Razi et al, 2012). Recently however, Wang et al (2013) have provided experimental and statistical data to support the view that Mexican lime (Citrus aurantifolia) should be considered as the standard indicator plant for broad-spectrum Citrus tristeza virus (CTV) detection, since it reacted with all symptomatic CTV isolates tested regardless of for example genotype or origin.…”

The serial and generation intervals from SARS-CoV-2 transmission dynamics and their potential application in the epidemiology of two citrus diseases

“…The disease, in endemic regions is present in more than 90% of citrus producing trees in an asymptomatic condition (Mora-Aguilera, 2008;Mora-Aguilera et al, 2005;Rivas-Valencia et al, 2017). In order to detect trees infected with CTV (asymptomatic or symptomatic), plant tissue is sampled and serological (ELISA) or molecular (RT-PCR) diagnostic techniques are applied (Hughes and Gottwald, 1998;Huang et al, 2004;Rosa et al, 2007;Ruiz-Ruiz et al, 2007;Korkmaz et al, 2008;Saponari et al, 2008). There are few studies on the incubation periods of CTV.…”

Biological Indexing and Molecular Approaches in Detecting a Mild Strain ‘CRS 4’ against Citrus tristeza Virus in Khasi Mandarin (Citrus reticulata)

“…Considering five times the average reading of ELISA OD 405 values for negative control (0.19) and the two blanks (0.072), the cut off value (0.56) was fixed and three groups were then formed as low range (0.56-1.0), medium range (1.1-1.8) and high range (>1.8) for covering samples from all the virus titre ranges. Among all the serological methods, enzymelinked immunosorbent assay (ELISA) is the most popular due to their dependability, rapidity and low relative cost have been widely used for CTV detection across the globe (Nikolaeva et al, 1998;Cambra et al, 2000;Korkmaz et al, 2008;Kishore et al, 2010;Tarafdar et al, 2012). Detection of CTV in Khasi mandarin by ELISA has been reported earlier from Assam and other North-Eastern states of India (Borah, 2011;Kashyap et al, 2013;Singh et al, 2017) with OD 405 values in the range of 0.689-2.270.…”