Genome sequence of an obligate hydrocarbonoclastic bacterium Alcanivorax marinus NMRL4 isolated from oil polluted seawater of the Arabian Sea.

Alcanivorax belongs to the hydrocarbonoclastic group of bacteria that are known for their preferential growth on alkanes and other related compounds. Here we report the genomic features of Alcanivorax marinus strain NMRL4 (=MCC 4632) isolated from oil polluted seawater of the Arabian Sea. Its 4,062,055 bp genome with 66.1% GC content encodes for 3935 coding sequences. The genome annotations of strain NMRL4 revealed the presence of multiple hydrocarbon degradation genes suggestive of its wider hydrocarbon substrate range. The strain encodes for three alkane monooxygenases, two cytochrome P450 and two flavin binding monooxygenases for degradation of short and long-chain alkanes. The genome shows capabilities for scavenging of nutrients, biofilm formation at oil-water interfaces, chemotaxis, motility and habitat specific adaptation. The genomic insights showed that the strain NMRL4 is an ideal candidate for bioremediation of pollutant petroleum hydrocarbons from the marine environment.

Plant-pathogen interactions: what microarray tells about it?

Plant defense responses are mediated by elementary regulatory proteins that affect expression of thousands of genes. Over the last decade, microarray technology has played a key role in deciphering the underlying networks of gene regulation in plants that lead to a wide variety of defence responses. Microarray is an important tool to quantify and profile the expression of thousands of genes simultaneously, with two main aims: (1) gene discovery and (2) global expression profiling. Several microarray technologies are currently in use; most include a glass slide platform with spotted cDNA or oligonucleotides. Till date, microarray technology has been used in the identification of regulatory genes, end-point defence genes, to understand the signal transduction processes underlying disease resistance and its intimate links to other physiological pathways. Microarray technology can be used for in-depth, simultaneous profiling of host/pathogen genes as the disease progresses from infection to resistance/susceptibility at different developmental stages of the host, which can be done in different environments, for clearer understanding of the processes involved. A thorough knowledge of plant disease resistance using successful combination of microarray and other high throughput techniques, as well as biochemical, genetic, and cell biological experiments is needed for practical application to secure and stabilize yield of many crop plants. This review starts with a brief introduction to microarray technology, followed by the basics of plant-pathogen interaction, the use of DNA microarrays over the last decade to unravel the mysteries of plant-pathogen interaction, and ends with the future prospects of this technology.