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زیست شناسی مصنوعی برای تشخیص ویروس های گیاهی: کاربرد در بیماری نکروز کشنده ذرت
Synthetic Biology for Plant Viral Diagnostics: Application to Maize Lethal Necrosis Disease
Plant viruses are a risk to many economically important crops, including maize which serves as a staple food for people throughout the world. Indeed, a current epidemic of maize lethal necrosis (MLN) is affecting food security across eastern and central Africa. The disease results from synergistic interaction between two viruses; maize chlorotic mottle virus (MCMV) and sugarcane mosaic virus (SCMV; or other potyviruses). Rapid detection of disease causal agents is imperative for disease management. Advances in synthetic biology have led to new, reliable and affordable molecular diagnostic tools that overcome the limitations of current diagnostic tools used in agriculture. In 2016, Toehold switch technology was demonstrated for the detection of Zika virus in the developing world where resources are limited. This technology can potentially be used for detection of plant viruses. Using publicly available whole-genome sequences for 43 and 73 global isolates of MCMV and SCMV, respectively, an in silico filtering pipeline was used to identify five MCMV and six SCMV sequences that match the canonical structure of a toehold switch and form the basis for toehold switch construction. An in vitro screen was used to assess the functionality of the MCMV and SCMV toehold switches. In addition, three criteria: performance, sensitivity and stability were used to assess the merit for moving forward in the development of field-based sensors for MLN-viral detection.
اثرات متقابل هوابرد گیاه و گیاه بر عملکرد گیاهان همسایه با استفاده از گونه های وحشی و لاین های اصلاح شده ژنتیکی Arabidopsis thaliana
Effects of Plant-Plant Airborne Interactions on Performance of Neighboring Plants Using Wild Types and Genetically Modified Lines of Arabidopsis thaliana
Understanding plant-plant communication further elucidates how plants interact with their environment, and how this communication can be manipulated for agricultural and ecological purposes. Part of understanding plant-plant communication is discovering the mechanisms be-hind plant-plant recognition, and whether plants can distinguish between genetically like and unlike neighbors. It has been previously shown that plants can “communicate” with neighbor-ing plants through airborne volatile organic compounds (VOCs), which can act as signals related to different environmental stressors.
This study focused on the interaction among different genotypes of the annual plant Arabidopsis thaliana. Specifically, a growth chamber experiment was performed to compare how different genotypes of neighboring plants impacted a focal plant’s fitness-related phenotypes and developmental stages. The focal plant genotype was wild type Col-0, and the neighboring genotypes included the wild type Landsberg (Ler-0), and the genetically modified (GM) geno-types: Etr1-1 and Jar1-1. These GM lines have a single point-mutation that impacts their ability to produce a particular VOC. This allows for the evaluation of a particular role that a VOC may have on plant-plant airborne communication. Plants were grown in separate pots to eliminate potential belowground interactions through the roots, and distantly positioned to avoid aboveground physical contact between plants. In addition, to avoid potential VOC cross-contamination between different treatments (genotypes), each neighboring plant treatment occurred in separate, sealed growth chambers.
Results showed that when A. thaliana Col-0 plants were grown alongside neighbors of different genotypes, they exhibited some significant differences in fitness-related traits, such as increased rosette width, stem height, aboveground biomass, and total fruit number. However, these results differed with neighbor identity, and when the experiment was repeated. Arabidopsis thaliana also experienced developmental delays in bolting and flowering time, when exposed to neighbors having a mutation in their ethylene receptors (Etr1-1), but not from any other genotypes.
These results indicate that Arabidopsis thaliana is capable of differentiating neighbor identities through airborne VOCs. Since all mutations caused some significant changes to A. thaliana’s growth, it is likely that A. thaliana is sensitive to multiple changes in VOC signatures. However, there was high variability between replications, and some phenotypes did not experience expected changes based on previous studies. Therefore, more studies should be performed to discover the effects of different VOCs on plant-plant communication via airborne volatiles.