ABSTRACT
Water scarcity and salinity are major challenges facing agriculture today, which can be addressed by engineering plants to grow in the boundless seawater. Understanding the mangrove plants at the molecular level will be necessary for developing such highly salt-tolerant agricultural crops. With this objective, we sequenced the genome of a salt-secreting and extraordinarily salt-tolerant mangrove species, Avicennia marina, that grows optimally in 75% seawater and tolerates >250% seawater. Our reference-grade ~457 Mb genome contains 31 scaffolds corresponding to its chromosomes. We identified 31,477 protein-coding genes and a salinome consisting of 3246 salinity-responsive genes and homologs of 614 experimentally validated salinity tolerance genes. The salinome provides a strong foundation to understand the molecular mechanisms of salinity tolerance in plants and breeding crops suitable for seawater farming.
Subject(s)
Avicennia/genetics , Genome, Plant/genetics , Salt Tolerance/genetics , Salts/metabolism , Agriculture/methods , Avicennia/metabolism , DNA, Plant/chemistry , DNA, Plant/genetics , Gene Expression Profiling/methods , Gene Expression Regulation, Plant , Genome Size/genetics , Genomics/methods , RNA-Seq/methods , Salinity , Seawater , Sequence Analysis, DNA/methodsABSTRACT
BACKGROUND & OBJECTIVES: New Delhi metallo-ß-lactamase 1 (NDM-1) cleaves the beta-lactam ring, and confers bacterial resistance against most of the beta-lactam antibiotics, except tigecycline and colistin. Among these two antibiotics, colistin is considered toxic, and therefore, its clinical use and dosage need cautious approach. In the present study, six organic acids were screened individually and in combination of two acids for their effectiveness against NDM-1 Escherichia coli and a combination of colistin and oxalic or succinic acid was tested to find out the potential of combination therapy for reducing the dose of toxic colistin. METHODS: Antibacterial activity of the organic acid and their combinations was tested by disc diffusion method against NDM-1 E. coli, and minimum inhibitory concentration (MIC) was determined by broth dilution method. Synergistic effect between organic acids and colistin was tested by checkerboard method. RESULTS: Oxalic acid showed the highest zone of inhibition (15±1 mm) followed by succinic acid, tartaric acid, fumaric acid, citric acid and malic acid. The combination of two acids did not increase the zone of inhibition significantly. MIC was found to be the lowest with oxalic acid and succinic acid (320 µg/ml). In the presence of 160 µg/ml oxalic acid or succinic acid, MIC of colistin was reduced from 8 to 4 µg/ml, indicating synergistic effect. INTERPRETATION & CONCLUSIONS: Our findings showed that combination therapy using colistin and oxalic acid or succinic acid might find safe clinical application of this antibiotic in controlling infections due to NDM-1 bacteria.
