Detection of Sri Lankan cassava mosaic virus by loop-mediated isothermal amplification using dried reagents

Single-tube colorimetric loop-mediated isothermal amplification (LAMP) assay for high-sensitivity detection of SLCMV in cassava from southern India

Sri Lankan cassava mosaic virus (SLCMV) is a major cause for mosaic infections in cassava leaves, resulting in significant economic losses in southern India. SLCMV leads to growth retardation, leaf curl, and chlorosis in the host, with rapid transmission through whitefly insect vectors. Detecting SLCMV promptly is crucial, and the study introduces a novel and efficient colorimetric Loop-mediated isothermal amplification (LAMP) assay for successful detection in 60 min. Three primer sets were designed to target the conserved region of the SLCMV genome, specifically the coat protein gene, making the assay highly specific. The LAMP assay offers rapid and sensitive detection, completing within 60 min in a temperature-controlled water bath or thermal cycler. Compared to PCR techniques, it demonstrates 100 times superior sensitivity. The visual inspection of LAMP tube results using a nucleic acid dye and observing ladder-like pattern bands in a 2 % agarose gel confirms the presence of SLCMV. The assay is specific to SLCMV, showing no false positives or contaminations when tested against other virus. The standardized SLCMV LAMP assay proves technically efficient, providing a rapid, specific, simple, and low-cost solution, streamlining the detection and management of SLCMV.

Novel plant disease detection techniques-a brief review

Plant pathogens cause severe losses to agricultural yield worldwide. Tracking plant health and early disease detection is important to reduce the disease spread and thus economic loss. Though visual scouting has been practiced from former times, detection of asymptomatic disease conditions is difficult. So, DNA-based and serological methods gained importance in plant disease detection. The progress in advanced technologies challenges the development of rapid, non-invasive, and on-field detection techniques such as spectroscopy. This review highlights various direct and indirect ways of detecting plant diseases like Enzyme-linked immunosorbent assay, Lateral flow assays, Polymerase chain reaction, spectroscopic techniques and biosensors. Although these techniques are sensitive and pathogen-specific, they are more laborious and time-intensive. As a consequence, a lot of interest is gained in in-field adaptable point-of-care devices with artificial intelligence-assisted pathogen detection at an early stage. More recently computer-aided techniques like neural networks are gaining significance in plant disease detection by image processing. In addition, a concise report on the latest progress achieved in plant disease detection techniques is provided.

Point-of-Care DNA Amplification for Disease Diagnosis and Management

Early detection of pests and pathogens is of paramount importance in reducing agricultural losses. One approach to early detection is point-of-care (POC) diagnostics, which can provide early warning and therefore allow fast deployment of preventive measures to slow down the establishment of crop diseases. Among the available diagnostic technologies, nucleic acid amplification-based diagnostics provide the highest sensitivity and specificity, and those technologies that forego the requirement for thermocycling show the most potential for use at POC. In this review, I discuss the progress, advantages, and disadvantages of the established and most promising POC amplification technologies. The success and usefulness of POC amplification are ultimately dependent on the availability of POC-friendly nucleic acid extraction methods and amplification readouts, which are also briefly discussed in the review.

First Report of Crown Gall of Kiwifruit (Actinidia deliciosa) Caused by Agrobacterium fabacearum in China and the Establishment of Loop-Mediated Isothermal Amplification Technique

Kiwifruit is moderately sweet and sour and quite popular among consumers; it has been widely planted in some areas of the world. In 2019, the crown gall disease of kiwifruit was discovered in the main kiwifruit-producing area of Guizhou Province, China. This disease can weaken and eventually cause the death of the tree. The phylogeny, morphological and biological characteristics of the bacteria were described, and were related to diseases. The pathogenicity of this species follows the Koch hypothesis, confirming that A. fabacearum is the pathogen of crown gall disease of kiwifruit in China. In this study, Loop-mediated isothermal amplification (LAMP) analysis for genome-specific gene sequences was developed for the specific detection of A. fabacearum. The detection limit of the LAMP method is 5 × 10^-7 ng/μL, which has high sensitivity. At the same time, the amplified product is stained with SYBR Green I after the reaction is completed, so that the amplification can be detected with the naked eye. LAMP analysis detected the presence of A. fabacearum in the roots and soil samples of the infected kiwifruit plant. The proposed LAMP detection technology in this study offers the advantages of ease of operation, visibility of results, rapidity, accuracy and high sensitivity, making it suitable for the early diagnosis of crown gall disease of kiwifruit.