Detection of Viral and Viroid Plant Pathogens in the Environment

Abstract

Plant viruses and viroids with obligate parasitism as the mode of existence, have to be in association with living cells of plant hosts always. However, some highly stable viruses have been detected in a free state in soil, water or air. Other viruses depend on the vectors such as insects, mites, nematodes or fungi present in the environment for their spread from infected plants to healthy plants which may be available in the same field or far away. The role of alternative/additional host plant species functioning as sources of virus infection has been demonstrated by applying various diagnostic techniques. The presence of viruses has been detected by employing biological, immunological and nucleic acid-based techniques. The effectiveness and reliability of detection varies significantly. However, molecular techniques have been shown to be more sensitive, specific and fast in providing the results, although they are unable to indicate the level of pathogenic potential of the viruses detected in the environmental samples. Viroids lacking natural vectors and stability outside living cells have been detected in several additional/alternative plant species which may function as reservoir of viroid infection.

CRISPR/Cas-Based Diagnostics in Agricultural Applications

“…According to globally estimated data, the average global yield loss of five major crops (wheat, rice, maize, potato, and soybean) in food security hotspots is due to 137 disease-causing pathogens, and the loss is greater in highly populated food shortage regions and areas prone to pests and diseases . The severity of the loss is contingent upon the timing of disease identification and the management method. , Early disease detection mitigates the loss by reducing the disease’s spread and allowing for prompt efforts to eradicate the pathogens . Utilizing disease-resistant or -tolerant high-yielding plant varieties is another strategy for reducing crop loss.…”

“…2 The severity of the loss is contingent upon the timing of disease identification and the management method. 3,4 Early disease detection mitigates the loss by reducing the disease's spread and allowing for prompt efforts to eradicate the pathogens. 5 Utilizing disease-resistant or -tolerant high-yielding plant varieties is another strategy for reducing crop loss.…”

Multifrequency Force Microscopy of Helical Protein Assembly on a Virus

“…The limitations in the resolution in the case of TMV have been mainly attributed to the very small lateral scale, to tip convolution effects, thermal fluctuations or to water condensation phenomena that may introduce instabilities during scanning 17 . Even if it is customary to perform AFM experiments with viruses in aqueous solution 18 19 , ambient air is preferred for imaging TMV, due to its high chemical and mechanical stability 20 21 , which is a key factor for its survival and its infectivity. A recent AFM study of single TMV particles in air employed image analysis algorithms, inspired by the cryo-EM methodology, with the aim to denoise the AFM topography and disclose periodic features invisible by simple image inspection 22 .…”