Correction: Anwer et al. Molecular and Morphological Characterization of Exserohilum turcicum (Passerini) Leonard and Suggs Causing Northern Corn Leaf Blight of Maize in Bihar. Bioengineering 2022, 9, 403.

In the original publication [...].

The curious case of genome packaging and assembly in RNA viruses infecting plants.

Genome packaging is the crucial step for maturation of plant viruses containing an RNA genome. Viruses exhibit a remarkable degree of packaging specificity, despite the probability of co-packaging cellular RNAs. Three different types of viral genome packaging systems are reported so far. The recently upgraded type I genome packaging system involves nucleation and encapsidation of RNA genomes in an energy-dependent manner, which have been observed in most of the plant RNA viruses with a smaller genome size, while type II and III packaging systems, majorly discovered in bacteriophages and large eukaryotic DNA viruses, involve genome translocation and packaging inside the prohead in an energy-dependent manner, i.e., utilizing ATP. Although ATP is essential for all three packaging systems, each machinery system employs a unique mode of ATP hydrolysis and genome packaging mechanism. Plant RNA viruses are serious threats to agricultural and horticultural crops and account for huge economic losses. Developing control strategies against plant RNA viruses requires a deep understanding of their genome assembly and packaging mechanism. On the basis of our previous studies and meticulously planned experiments, we have revealed their molecular mechanisms and proposed a hypothetical model for the type I packaging system with an emphasis on smaller plant RNA viruses. Here, in this review, we apprise researchers the technical breakthroughs that have facilitated the dissection of genome packaging and virion assembly processes in plant RNA viruses.

Molecular and Morphological Characterization of Exserohilum turcicum (Passerini) Leonard and Suggs Causing Northern Corn Leaf Blight of Maize in Bihar.

Maize is considered the third most important cereal crop in Asia after rice and wheat. Many diseases affect this crop due to the cultivation of various hybrids. This research aimed to characterize the causative agent of northern corn leaf blight disease in Bihar, India, caused by Exserohilum turcicum (Passerini) Leonard and Suggs. Leaf samples were collected from infected fields in five maize growing districts of Bihar in 2020-2022. A total of 45 fungal isolates from 135 samples were examined for cultural, morphological, and molecular characteristics and were identified as E. turcicum. The isolates were grouped into four groups based on colony color, i.e., olivaceous brown, blackish brown, whitish black, and grayish, and into two groups based on regular and irregular margins. The conidial shapes were observed to be elongated and spindle-shaped with protruding hilum, with conidial septa ranging from 2-12. Similarly, conidial length varied from 52.94 µm to 144.12 µm. ß-tubulin gene sequences analysis made it possible to verify the identities of fungal strains and the phylogenetic relationships of all isolates, which were clustered in the same clade. The ß-tubulin gene sequences of all the isolates showed a high level of similarity (100%) with reference isolates from GenBank accession numbers KU670342.1, KU670344.1, KU670343.1, KU670341.1, and KU670340.1. The findings of this study will serve as a baseline for future studies and will help to minimize yield losses.

Inhibition of potato leafroll virus multiplication and systemic translocation by siRNA constructs against putative ATPase fold of movement protein.

Viruses cause many severe plant diseases, resulting in immense losses of crop yield worldwide. Therefore, developing novel approaches to control plant viruses is crucial to meet the demands of a growing world population. Recently, RNA interference (RNAi) has been widely used to develop virus-resistant plants. Once genome replication and assembly of virion particles is completed inside the host plant, mature virions or sometimes naked viral genomes spread cell-to-cell through plasmodesmata by interacting with the virus-encoded movement protein (MP). We used the RNAi approach to suppress MP gene expression, which in turn prevented potato leafroll virus (PLRV) systemic infection in Solanum tuberosum cv. Khufri Ashoka. Potato plants agroinfiltrated with MP siRNA constructs exhibited no rolling symptoms upon PLRV infection, indicating that the silencing of MP gene expression is an efficient method for generating PLRV-resistant potato plants. Further, we identified novel ATPase motifs in MP that may be involved in DNA binding and translocation through plasmodesmata. We also showed that the ATPase activity of MP was stimulated in the presence of DNA/RNA. Overall, our findings provide a robust technology to generate PLRV-resistant potato plants, which can be extended to other species. Moreover, this approach also contributes to the study of genome translocation mechanisms of plant viruses.

First report on molecular basis of potato leaf roll virus (PLRV) aggravation by combined effect of tuber and prevailing aphid.

OBJECTIVE: The Potato Leaf Roll Virus (PLRV) is one of the most devastating virus causing severe yield losses worldwide in potato. The comprehensive observations were made to study the PLRV infestation in major potato growing areas of Bihar (India) and further detailed molecular basis of PLRV aggravation was established. RESULTS: Although aphids population were found comparatively lower with maximum symptomatic plants, our molecular data further confirms the presence of PLRV in all possible symptomatic tissues such as tubers, shoots and leaves. For the first time, we have proposed molecular basis of aggravation of PLRV, where tuber acts as a reservoir during off-season and further transmitted by aphids.