This critical review comprehensively analyses nano-sized metal oxide fertilizers (NMOFs) and their transformative potential in sustainable agriculture.

Transmission is a crucial part of a viral life cycle and transmission mode can have an important impact on virus biology. It was demonstrated that transmission mode can influence the virulence and evolution of a virus; however, few empirical data are available to describe the direct underlying changes in virus population structure dynamics within the host. Potato virus Y (PVY) is an RNA virus and one of the most damaging pathogens of potato. It comprises several genetically variable strains that are transmitted between plants via different transmission modes. To investigate how transmission modes affect the within-plant viral population structure, we have used a deep sequencing approach to examine the changes in the genetic structure of populations (in leaves and tubers) of three PVY strains after successive passages by horizontal (aphid and mechanical) and vertical (via tubers) transmission modes. Nucleotide diversities of viral populations were significantly influenced by transmission modes; lineages transmitted by aphids were the least diverse, whereas lineages transmitted by tubers were the most diverse. Differences in nucleotide diversities of viral populations between leaves and tubers were transmission mode-dependent, with higher diversities in tubers than in leaves for aphid and mechanically transmitted lineages. Furthermore, aphid and tuber transmissions were shown to impose stronger genetic bottlenecks than mechanical transmission. To better understand the structure of virus populations within the host, transmission mode, movement of the virus within the host, and the number of replication cycles after transmission event need to be considered. Collectively, our results suggest a significant impact of virus transmission modes on the within-plant diversity of virus populations and provide quantitative fundamental data for understanding how transmission can shape virus diversity in the natural ecosystems, where different transmission modes are expected to affect virus population structure and consequently its evolution. Viruses can be transmitted between hosts via different modes, that can differently shape the population of transmitted viruses and thus have important implications for their biology and evolution. Potato virus Y, a damaging potato pathogen, can be transmitted between potato plants by aphid feeding, by wounding, or via tubers (mother to daughter plants). In this study, we have investigated how these three transmission modes directly affect the structure of the virus populations within the potato plants. We discovered that the mode of virus transmission significantly affected the population of the virus transmitted to the new plant. For example, virus populations transmitted by aphids were the least diverse while the ones transmitted vertically through tubers were the most diverse. To fully understand the effect of transmission modes on virus populations we needed to consider the events following the transmission, such as viral movement within a plant. Understanding the role that transmission modes play on the diversity and evolution of virus populations helps us to elucidate the mechanisms shaping the diversity of the virus in the field, and provides valuable information for future plant virus epidemiological studies that could promote the development of novel management strategies.

Potato tuber necrotic ringspot disease (PTNRD) is a tuber deformity associated with infection by the tuber necrotic strain of Potato virus Y (PVY^NTN). PTNRD negatively impacts tuber quality and marketability and poses a serious threat to seed and commercial potato production worldwide. PVY^NTN symptoms differ in the cultivars Waneta and Pike: Waneta expresses severe PTNRD and foliar mosaic with vein and leaf necrosis, whereas Pike does not express PTNRD and mosaic is the only foliar symptom. To map loci that influence tuber and foliar symptoms, 236 F₁ progeny of a cross between Waneta and Pike were inoculated with PVY^NTN isolate NY090029 and genotyped using 12,808 Potato SNPs. Foliar symptom type and severity were monitored for 10 weeks, while tubers were evaluated for PTNRD expression at harvest and again after 60 days in storage. Pairwise correlation analyses indicate a strong association between PTNRD and vein necrosis (τ = 0.4195). QTL analyses revealed major-effect QTLs on chromosomes 4 and 5 for mosaic, 4 for PTNRD, and 5 for foliar-necrosis symptoms. Locating QTLs associated with PVY-related symptoms provides a foundation for breeders to develop markers that can be used to screen out potato clones with undesirable phenotypes, e.g., those likely to develop PTNRD or to be symptomless carriers of PVY.

Fig mosaic disease (FMD) is a complex viral disease with which 12 viruses, including a confirmed causal agent, fig mosaic emaravirus (FMV), and three viroids are associated worldwide. FMD was first described in California in the early 1930s. Symptoms include foliar chlorosis, deformation, and mosaic patterns. FMD is disseminated by vegetative propagation, seed transmission, and vectors, including a mite, Aceria ficus. Management of the disease in fig orchards relies on scouting and elimination of infected trees. In this review, we focus on the distribution of the FMD-associated viruses and viroids by summarizing worldwide surveys and their genome structure. We also determined the full-length sequence of FMV and fig badnavirus 1 (FBV-1) isolates from Connecticut and compared the virus and viroid sequences from fig isolates. We suggest important areas of research including determining the potential synergistic effect of multiple viruses, elucidating the full-length genome sequence of each associated virus, and relating virus titer to phenotypic changes in Ficus carica.