Sustainable Agriculture by Increasing Nitrogen Fertilizer Efficiency Using Low-Resolution Camera Mounted on Unmanned Aerial Vehicles.

Nitrogen use efficiency in modern agriculture is very low. It means that a lot of synthetic chemicals are wasted rather than utilized by crops. This can cause more problems where the soil surface is thin and rocky like Jeju Island in the Republic of Korea. This is because overly used nitrogen fertilizer can be washed into the underground water and pollute it. Thus, it would be important to monitor the nitrogen deficiency of crops in the field to provide the right amount of nitrogen in a timely manner so that nitrogen waste can be limited. To achieve this, the normalized difference vegetation index (NDVI) was used to monitor chlorophyll content, which is tightly associated with nitrogen content in the buckwheat field. The NDVI was calculated with the data obtained by a low-resolution camera mounted on an unmanned aerial vehicle. The results showed that the NDVI can estimate the chlorophyll content of buckwheat. These simple but clear results imply that precision agriculture could be achieved even with a low-resolution camera in a cost-effective manner to reduce the pollution of underground water.

Isolation and characterization of metabolites from Bacillus licheniformis MH48 with antifungal activity against plant pathogens.

In this study, we isolated Bacillus licheniformis MH48 from rhizosphere soil and demonstrated that this strain shows significant antifungal activity against Rhizoctonia solani, Colletotrichum gloeosporioides, and Phytophthora capsici. Our results showed that a 50% concentration of bacterial cell-free culture filtrate of B. licheniformis MH48 shows strong activity against fungal pathogens. Benzoic acid produced by B. licheniformis MH48 was purified by various chromatographic techniques and identified by nuclear magnetic resonance and gas chromatography-mass spectrometry analysis. Benzoic acid displayed antifungal activity against R. solani and C. gloeosporides with minimum inhibitory concentration of 128 µg/mL against mycelial growth. Microscopic examination revealed that benzoic acid (50 µg/mL and 100 µg/mL) transformed C. gloeosporioides conidial morphology and inhibited conidial germination. In addition, benzoic acid (100 µg/mL and 200 µg/mL) degraded R. solani mycelia. Therefore, our results demonstrate that B. licheniformis MH48 strain shows potential for utility as a biological agent for the control of various fungal pathogens of plants.

Effect of long-term different fertilization on bacterial community structures and diversity in citrus orchard soil of volcanic ash.

This study was conducted to assess bacterial species richness, diversity and community distribution according to different fertilization regimes for 16 years in citrus orchard soil of volcanic ash. Soil samples were collected and analyzed from Compost (cattle manure, 2,000 kg/10a), 1/2 NPK+compost (14-20-14+2,000 kg/10a), NPK+compost (28-40-28+2,000 kg/10a), NPK (28-40-28 kg/10a), 3 NPK (84-120-84 kg/10a), and Control (no fertilization) plot which have been managed in the same manners with compost and different amount of chemical fertilization. The range of pyrosequencing reads and OTUs were 4,687-7,330 and 1,790-3,695, respectively. Species richness estimates such as Ace, Chao1, and Shannon index were higher in 1/2 NPK+compost than other treatments, which were 15,202, 9,112, 7.7, respectively. Dominant bacterial groups at level of phylum were Proteobacteria, Acidobacteria, and Actinobacteria. Those were occupied at 70.9% in 1/2 NPK+compost. Dominant bacterial groups at level of genus were Pseudolabrys, Bradyrhizobium, and Acidobacteria. Those were distributed at 14.4% of a total of bacteria in Compost. Soil pH displayed significantly closely related to bacterial species richness estimates such as Ace, Chao1 (p<0.05) and Shannon index (p<0.01). However, it showed the negative correlation with exchangeable aluminum contents (p<0.05). In conclusion, diversity of bacterial community in citrus orchard soil was affected by fertilization management, soil pH changes and characteristics of volcanic ash.

Computational identification and phylogenetic analysis of the oil-body structural proteins, oleosin and caleosin, in castor bean and flax.

Oil bodies (OBs) are the intracellular particles derived from oilseeds. These OBs store lipids as a carbon resource, and have been exploited for a variety of industrial applications including biofuels. Oleosin and caleosin are the common OB structural proteins which are enabling biotechnological enhancement of oil content and OB-based pharmaceutical formations via stabilizing OBs. Although the draft whole genome sequence information for Ricinus communis L. (castor bean) and Linum usitatissimum L. (flax), important oil seed plants, is available in public database, OB-structural proteins in these plants are poorly indentified. Therefore, in this study, we performed a comprehensive bioinformatic analysis including analysis of the genome sequence, conserved domains and phylogenetic relationships to identify OB structural proteins in castor bean and flax genomes. Using comprehensive analysis, we have identified 6 and 15 OB-structural proteins from castor bean and flax, respectively. A complete overview of this gene family in castor bean and flax is presented, including the gene structures, phylogeny and conserved motifs, resulting in the presence of central hydrophobic regions with proline knot motif, providing an evolutionary proof that this central hydrophobic region had evolved from duplications in the primitive eukaryotes. In addition, expression analysis of L-oleosin and caleosin genes using quantitative real-time PCR demonstrated that seed contained their maximum expression, except that RcCLO-1 expressed maximum in cotyledon. Thus, our comparative genomics analysis of oleosin and caleosin genes and their putatively encoded proteins in two non-model plant species provides insights into the prospective usage of gene resources for improving OB-stability.

Biocontrol of Late Blight (Phytophthora capsici) Disease and Growth Promotion of Pepper by Burkholderia cepacia MPC-7.

A chitinolytic bacterial strain having strong antifungal activity was isolated and identified as Burkholderia cepacia MPC-7 based on 16S rRNA gene analysis. MPC-7 solubilized insoluble phosphorous in hydroxyapatite agar media. It produced gluconic acid and 2-ketogluconic acid related to the decrease in pH of broth culture. The antagonist produced benzoic acid (BA) and phenylacetic acid (PA). The authentic compounds, BA and PA, showed a broad spectrum of antimicrobial activity against yeast, several bacterial and fungal pathogens in vitro. To demonstrate the biocontrol efficiency of MPC-7 on late blight disease caused by Phytophthora capsici, pepper plants in pot trials were treated with modified medium only (M), M plus zoospore inoculation (MP), MPC-7 cultured broth (B) and B plus zoospore inoculation (BP). With the sudden increase in root mortality, plants in MP wilted as early as five days after pathogen inoculation. However, plant in BP did not show any symptom of wilting until five days. Root mortality in BP was markedly reduced for as much as 50%. Plants in B had higher dry weight, P concentration in root, and larger leaf area compared to those in M and MP. These results suggested that B. cepacia MPC-7 should be considered as a candidate for the biological fertilizer as well as antimicrobial agent for pepper plants.