Cost-benefit analysis of nanofertilizers and nanopesticides emphasizes the need to improve the efficiency of nanoformulations for widescale adoption.

Nanotechnology-based approaches have demonstrated encouraging results for sustainable agriculture production, particularly in the field of fertilizers and pesticide innovation. It is essential to evaluate the economic and environmental benefits of these nanoformulations. Here we estimate the potential revenue gain/loss associated with nanofertilizer and/or nanopesticide use, calculate the greenhouse gas emissions change from the use of nanofertilizer and identify feasible applications and critical issues. The cost-benefit analysis demonstrates that, while current nanoformulations show promise in increasing the net revenue from crops and lowering the environmental impact, further improving the efficiency of nanoformulations is necessary for their widescale adoption. Innovating nanoformulation for targeted delivery, lowering the greenhouse gas emissions associated with nanomaterials and minimizing the content of nanomaterials in the derived nanofertilizers or pesticides can substantially improve both economic and environmental benefits.

Illumina sequencing of 16S rRNA tag shows disparity in rhizobial and non-rhizobial diversity associated with root nodules of mung bean (Vigna radiata L.) growing in different habitats in Pakistan.

In Rhizobium-legume symbiosis, the nodule is the most frequently studied compartment, where the endophytic/symbiotic microbiota demands critical investigation for development of specific inocula. We identified the bacterial diversity within root nodules of mung bean from different growing areas of Pakistan using Illumina sequencing of 16S rRNA gene. We observed specific OTUs related to specific site where Bradyrhizobium was found to be the dominant genus comprising of 82-94% of total rhizobia in nodules with very minor fraction of sequences from other rhizobia at three sites. In contrast, Ensifer (Sinorhizobium) was single dominant genus comprising 99.9% of total rhizobial sequences at site four. Among non-rhizobial sequences, the genus Acinetobacter was abundant (7-18% of total sequences), particularly in Bradyrhizobium-dominated nodule samples. Rhizobia and non-rhizobial PGPR isolated from nodule samples include Ensifer, Bradyrhizobium, Acinetobacter, Microbacterium and Pseudomonas strains. Co-inoculation of multi-trait PGPR Acinetobacter sp. VrB1 with either of the two rhizobia in field exhibited more positive effect on nodulation and plant growth than single-strain inoculation which favors the use of Acinetobacter as an essential component for development of mung bean inoculum. Furthermore, site-specific dominance of rhizobia and non-rhizobia revealed in this study may contribute towards decision making for development and application of specific inocula in different habitats.

New Arsenate Reductase Gene (arrA) PCR Primers for Diversity Assessment and Quantification in Environmental Samples.

The extent of arsenic contamination in drinking water and its potential threat to human health have resulted in considerable research interest in the microbial species responsible for arsenic reduction. The arsenate reductase gene (arrA), an important component of the microbial arsenate reduction system, has been widely used as a biomarker to study arsenate-reducing microorganisms. A new primer pair was designed and evaluated for quantitative PCR (qPCR) and high-throughput sequencing of the arrA gene, because currently available PCR primers are not suitable for these applications. The primers were evaluated in silico and empirically tested for amplification of arrA genes in clones and for amplification and high-throughput sequencing of arrA genes from soil and groundwater samples. In silico, this primer pair matched (≥90% DNA identity) 86% of arrA gene sequences from GenBank. Empirical evaluation showed successful amplification of arrA gene clones of diverse phylogenetic groups, as well as amplification and high-throughput sequencing of independent soil and groundwater samples without preenrichment, suggesting that these primers are highly specific and can amplify a broad diversity of arrA genes. The arrA gene diversity from soil and groundwater samples from the Cache Valley Basin (CVB) in Utah was greater than anticipated. We observed a significant correlation between arrA gene abundance, quantified through qPCR, and reduced arsenic (AsIII) concentrations in the groundwater samples. Furthermore, we demonstrated that these primers can be useful for studying the diversity of arsenate-reducing microbial communities and the ways in which their relative abundance in groundwater may be associated with different groundwater quality parameters. IMPORTANCE: Arsenic is a major drinking water contaminant that threatens the health of millions of people worldwide. The extent of arsenic contamination and its potential threat to human health have resulted in considerable interest in the study of microbial species responsible for the reduction of arsenic, i.e., the conversion of AsV to AsIII In this study, we developed a new primer pair to evaluate the diversity and abundance of arsenate-reducing microorganisms in soil and groundwater samples from the CVB in Utah. We observed significant arrA gene diversity in the CVB soil and groundwater samples, and arrA gene abundance was significantly correlated with the reduced arsenic (AsIII) concentrations in the groundwater samples. We think that these primers are useful for studying the ecology of arsenate-reducing microorganisms in different environments.