Comparison and evaluation of two diagnostic methods for detection of npt II and GUS genes in Nicotiana tabacum

Silver nanoparticles for biolistic transformation in Nicotiana tabacum L

The present study reports the use of silver nanoparticles as a gene carrier, substituting gold microcarrier for biolistic gene delivery in Nicotiana tabacum L. Efficiency of biolistic transformation using silver nanoparticles (100 nm) was compared with that of gold microcarriers (0.6 micron) under varying helium pressure (450 psi, 650 psi, 900 psi and 1100 psi) and target distance (6 cm and 9 cm). Among the different concentrations (0.01-100 mgL^-1) of silver nanoparticles tried, 10 mgL^-1 produced the highest number of transient GUS expression (30) with statistical significance. Helium pressure of 650 and target distance of 9 cm, and 900 psi pressure and 6 cm distance resulted in the highest GUS expression with gold microcarriers and silver nanoparticles, respectively. Transformation efficiency was significantly higher with silver nanoparticles than gold microparticles as carriers resulting in a reduction up to 37.5-fold on the cost of consumables. Regeneration efficiencies of tissues bombarded with gold microcarriers and silver nanoparticles were 62.5% and 70.83%, respectively.

A simple, robust and equipment-free DNA amplification readout in less than 30 seconds

Molecular based diagnostic methods rely on the amplification of pathogen DNA but naked eye visualization of results is still challenging. We present here a simple and highly reliable DNA amplification readout system for naked eye detection of isothermally or PCR amplified DNA in less than 30 seconds. This system utilizes spermine to precipitate DNA amplicons and initiate bridging flocculation of a mix of charcoal and diatomaceous earth particles in suspension. In the absence of amplification, the charcoal particles remain suspended resulting in a black, non-transparent colloid solution while positive samples in which DNA amplification has occurred can be identified within seconds as the particles flocculate and settle leaving a transparent liquid phase. We have coupled this method with our rapid dipstick DNA purification method and isothermal DNA amplification to create a simple four-step diagnostic system that can be preassembled to reduce unnecessary manipulation in the field. The method's simplicity, low cost, minimal equipment and clear presence/absence readout makes it ideal for rapid diagnostic testing in the laboratory and in situations where users have limited technical training or resources including high school science classes and field-based research.

A simple and highly reliable DNA amplification readout system for naked eye detection of amplified DNA in under 30 seconds.

Development and evaluation of a reverse transcription loop-mediated isothermal amplification assay for detection of beet necrotic yellow vein virus

Sugar beet can be infected by many different viruses that can reduce yield; beet necrotic yellow vein virus (BNYVV) is one of the most economically important viruses of this crop plant. This report describes a new reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay for identification of BNYVV. In addition, a novel immunocapture (IC) RT-LAMP assay for rapid and easy detection (without RNA extraction) of BNYVV was developed here and compared with DAS-ELISA and RT-LAMP assays. Our results show that the IC-RT-LAMP assay is a highly reliable alternative assay for identification of BNYVV.

Assessing zygosity in progeny of transgenic plants: current methods and perspectives

Homozygosity is highly desirable in transgenic plants research to ensure the stable integration and inheritance of transgene(s). Simple, reliable and high-throughput techniques to detect the zygosity of transgenic events in plants are invaluable tools for biotechnology and plant breeding companies. Currently, a number of basic techniques are being used to determine the zygosity of transgenic plants in T1 generation. For successful application of any technique, precision and simplicity of approach combined with the power of resolution are important parameters. On the basis of simplicity, resolution and cost involved, the available techniques have been classified into three major classes which are conventional methods, current methods and next generation methods. Conventional methods include antibiotic marker-based selection and the highly labor intensive Southern blot analysis. In contrast, methods such as real time PCR, TAIL PCR and competitive PCR are not only cost effective but rapid as well. Moreover, methods such as NGS, digital PCR and loop-mediated isothermal amplification also provide a cost effective, fast and not so labor intensive substitute of current methods. In this review, we have attempted to compare and contrast all the available efficient methods to distinguish homozygous plants in progeny of transgenics. This review also provides information of various techniques available for determining zygosity in plants so as to permit researchers to make informed choices of techniques that best suit their analyses. More importantly, detection and subsequent selection of homozygous individuals is central for facilitating the movement of transgenic plants from the laboratory to the field.