The impact of soil erosion on soil fertility and vine vigor

Fig: Soil Organic Carbon and weight of prune residue (Novara et al. 2018)

Soil is the most important natural resources for food production. Unfortunately, due to human induced cause like land degradation, it is causing soil erosion. Erosion impacts crop yields and threatens soil system (Mol and Keesstra, 2012). Erosion also leads to loss of nutrients, decrease thickness of soil level and lower soil water holding capacity (García-Díaz et al. 2017; Li et al., 2016). In Europe wheat yield losses ranged from 0.04% year and 0.67% year in Australia (Cerdà et al., 2017, Den Biggelaar et al. 2003). Researcher Agata Novara and her colleagues conducted a research to analyze the interactions among vines vigor, sediment delivery and soil organic carbon (SOC) in a sloping vineyard. Their results confirmed that soil erosion, sediment redistribution and SOC across the slope strongly affected by topographic features and curvature. To avoid the negative effects of soil fertility reduction on plant vigor, farmers can increase the use of external input which lead to a decrease of yield sustainability. In order to maintain the yield sustainability, we should control soil erosion and can help increase yield sustainability.

Original article:
Novara, A., Pisciotta, A., Minacapilli, M., Maltese, A., Capodici, F., Cerdà, A., & Gristina, L. (2018). The impact of soil erosion on soil fertility and vine vigor. A multidisciplinary approach based on field, laboratory and remote sensing approaches. Science of The Total Environment, 622-623, 474–480. doi:10.1016/j.scitotenv.2017.11.272 

Are we making our life endangered by drinking water?

Figure: Drinking water system (Su, H.-C et al. 2018)

Antibiotics not only play as a therapeutic drug for human beings but also for aquaculture, livestock and farming. With the excessive use of antibiotics, it has made the environment contaminated by antibiotic resistant bacteria, antibiotic residues, antibiotic resistance genes (ARG). Since the rise of environmental contaminants, the antibiotic resistance genes (ARG) were detected in various places in our environment such as hospital wastewater, wastewater treatment plants, chicken, beef, pork, dairy. These ARGs can transfer to humans by drinking water sources and endangering human life. Su, H.-C and his colleagues conducted a research to investigate and occurrence and diversity of ARGs in source water, water treatment plants and tap water. Their research showed that 27 different ARGs were present in those water sources. The total abundance of the detected ARGs in tap water was much lower than that in source water. Sand filtration and sedimentation in drinking water treatment plants could effectively remove ARGs. It was found that Pseudomonas may be involved in the proliferation and dissemination of ARGs in the studied drinking water treatment system. It could be noted that sedimentation and sand filtration could be effective methods for removing ARGs in aquatic systems.



Original article:
Su, H.-C., Liu, Y.-S., Pan, C.-G., Chen, J., He, L.-Y., & Ying, G.-G. (2018). Persistence of antibiotic resistance genes and bacterial community changes in drinking water treatment system: From drinking water source to tap water. Science of The Total Environment, 616-617, 453–461. doi:10.1016/j.scitotenv.2017.10.318 

Is Our Use of Antibiotics Creating More Resistant, Virulent Bacterial Strains?

By: Alexandra Ortiz 

Human Gut and Environmental Metagenomic Comparison. Schematic overview of the comparative study of the human gut and environmental metagenomes. Researchers mined in the genes of the human gut and environmental bacterial communities to understand the relationship between antibiotic resistance genes and virulence factors (VFs). Their efforts were able to show that there is a link between the dissemination of VFs and antibiotic resistance. 

Over the years, our excessive use of antibiotics in both medicine and agriculture has selected for antibiotic-resistant bacterial strains in human and environmental communities. Although pathogenic bacteria are the targets of antibiotics, nonpathogenic bacteria are affected in antibiotic contaminated environments. Pathogenic bacteria use virulence factors for parasitizing hosts that include proteins for adhesion and invasion of tissues, secretion of toxins and iron acquisition systems. Interestingly, environmental bacteria use these virulence factors (VFs) to adhere and colonize different surfaces, compete with other bacteria, and access resources such as iron. Escudiero et al. (2019) conducted a comparative study between environmental and human gut microbial communities from different human populations across the world to identify differences between and among the sampled communities. They were able to find a higher diversity of antibiotic resistance (AR) and VFs in environmental samples when compared to human gut samples. However, human fecal microbiomes had a higher accumulation of AR than environmental communities. This research was also able to catch a glimpse of what the pre-antibiotic era of the human resistome looks like in uncontacted Ameridian gut microbiome samples. Lastly, the correlation found between AR and VF diversity in both human and environmental samples suggests that as our use of antibiotics continues, we may be selecting for more virulent, resistant bacteria. 

Beneficial Bacteria Give it Away for Drought Resistant Chili Pepper Plants

By: Alexandra Ortiz

The Use of Plant-Growth Promoting Bacteria for Drought-Resistant Crops.  Overview of how plant-growth-promoting bacteria (PGPB) play a role in defending the chili pepper plant from drought stress. PGPBs can serve as biostimulants by reducing the levels of stress hormones produced and biofertilizers by making limiting nutrients such as phosphate and iron more available for plants. Root colonization is important in PGPBs for critical plant-bacterial interactions such as the production of specialized compounds that prevent desiccation. Image source: Alexandra Ortiz.

Drought is one of the largest causes of crop yield losses across the world. With increasing demands for water, there is a need to expand biotechnological approaches for the development of drought-resistant plants or the use of drought-resistant plant growth-promoting microorganisms. Horticultural crops such as chili peppers are extremely sensitive to moisture stress, specifically in the root zone, therefore, water is crucial for the cultivation of these high-value crops (Walters and Jha, 2016). Vigani and colleagues proposed the use of two known plant growth-promoting pepper associated bacteria to defend the plant from dry conditions in a hydroponic and terrestrial system. They suggested that the bacteria’s plant growth-promoting characteristics that allow for enhanced nutrient availability, reduced stress hormone production, and root colonization abilities coupled with resistance to drought conditions would enhance the pepper plant’s survival under low moisture conditions. They were able to find that pepper plants grown in drought-stressed hydroponic systems that were subjected to the bacteria had no visible symptoms of drought stress. In soil, drought-stressed plants showed no significant differences in biomass when compared to the irrigated, uninoculated plants. Therefore, Vigani et al., (2019) were able to utilize these bacteria to protect the pepper plants from drought in soil and hydroponic systems.

References

Walters, S.A., and A.K. Jha. (2016). Sustaining Chili Pepper Production in Afghanistan through Better Irrigation Practices and Management. Agriculture 6(4), 62.

Bacteria to the Rescue

Bacteria to the Rescue

By: Laura Murillo

Over the course of time, society has become more and more dependent on oil as the main source of energy. With increasing demand, most of the oil has to be brought from overseas. The ocean is very unpredictable, and despite taking all the precautions possible, oil spills are bound to happen. Together, scientists and engineers have developed different techniques to attempt removing oil from the surface of the oceans. One of these approaches consists of encircling oil batches so that they become thick enough to allow a skimmer or vacuum to collect. Most of the methods like the one mentioned require a lot of man-power, money and time. That is one of the reasons Cheng and his team focused on oil-degrading bacteria, Brevibacillus parabrev. By coating the bacteria in a shell of magnetic Fe₃O₄ nanoparticles (M-bacteria), they were able to encapsulate and isolate oil from water. The oil can then be removed by an external magnetic field, or it can be degraded by the same M-bacteria. One of the advantages of this approach is being able to recycle the magnetic nanoparticles, and the low cost of the bacterial cell fabrication. The possibilities are endless for this eco-friendly clean-up crew.

Figure 1. Graphical representation of M-bacteria encapsulating oil in water, then being separated by an outside magnetic field. Because of the bacteria's properties, the separated oil can be further broken down.

Original article:

Cheng, H., Li, Z., Li, Y., Shi, Z., Bao, M., Han, C., & Wang, Z. (2019). Multi-functional magnetic bacteria as efficient and economical Pickering emulsifiers for encapsulation and removal of oil from water. Journal of Colloid and Interface Science.