LAMP assay for GRBV
A LAMP assay can complement visual assessments for RBD, improving our ability to positively identify infected vines.
LAMP (loop mediated isothermal amplification) is a DNA- based assay that has been developed for the detection of GRBV (Romero Romero et al. 2019). The LAMP assay is 10,000 times more sensitive than polymerase chain reaction (PCR). Preliminary data indicate a strong consistency between LAMP and PCR results.
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The assay can be performed "in-house", and does not require special facilities, expensive equipment or highly trained laboratory personnel. It requires an initial investment of $4000 with subsequent costs at $3-$5 per sample.
LAMP testing would enable growers to test large numbers of samples, quickly generate results, and act accordingly to manage RBD.
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Applications of LAMP-GRBV
The LAMP-GRBV assay may be used to confirm infection status when a vine may have confusing symptoms caused by different biotic and abiotic factors. Listed below are a few situations where red blotch symptoms could be masked or present similarly to other disorders.
These vines tested positive for red blotch
White Cultivars where visual symptoms are absent
Vines that have subtle symptoms
Nutrient deficiency
These vines tested negative for red blotch but have similar symptoms
Spider mite damage
Unknown red leaf symptoms
LAMP-GRBV in Napa (2021-2022)
From 2021-2022 the UCCE Viticulture team tested 1,507 vines using the LAMP-GRBV assay. This included symptomatic and asymptomatic vines of white and red cultivars. Overall, there was very good agreement between visual symptom assessment and the LAMP assay result. Only two asymptomatic vines tested positive. When these vines were revisited one week later, they had RBD symptoms. Additionally, there was only one symptomatic vine that tested negative. We will continue to monitor this vine in subsequent years.
This matrix summarizes LAMP-GRBV assay results for symptomatic and asymptomatic red cultivar vines.
Resourcers: LAMP-GRBV
How to collect trunk samples for PCR or LAMP analysis.
How to set up & perform the LAMP-GRBV assay, and how to interpret the results. Includes step by step instructions to sample vines and conduct the assay.
Excel sheet with a list of the 6 primers used in the LAMP- GRBV assay
Approximate costs to conduct LAMP-GRBV, including which materials are needed & where to purchase them.
Step by step instructions for ordering primers to perform the LAMP-GRBV assay.
Introduces the LAMP-GRBV assay, how it was developed, and approximate time it may take to preform.
How to use LAMP-GRBV to complement visual symptom assessments.
How RBD symptoms vary by cultivar, site, block, & time of year.
How to effectively map RBD symptoms.