The complete genome sequence of B. subtilis sub-strain QB928 has 4,146,839 DNA base pairs and 4,292 genes. The QB928 strain is widely used in genetic studies due to the presence of various markers [aroI(aroK)906 purE1 dal(alrA)1 trpC2]. Several noncoding RNAs have been characterized in the B. subtilis genome in 2009, including Bsr RNAs. Microarray-based comparative genomic analyses have revealed that B. subtilis members show considerable genomic diversity. FsrA is a small RNA found in Bacillus subtilis. It is an effector of the iron sparing response, and acts to down-regulate iron-containing proteins in times of poor iron bioavailability. A promising fish probiotic, Bacillus subtilis strain WS1A, that possesses antimicrobial activity against Aeromonas veronii and suppressed motile Aeromonas septicemia in Labeo rohita. The de novo assembly resulted in an estimated chromosome size of 4,148,460 bp, with 4,288 open reading frames. B. subtilis strain WS1A genome contains many potential genes, such as those encoding proteins involved in the biosynthesis of riboflavin, vitamin B6, and amino acids (ilvD) and in carbon utilization (pta). Transformation Natural bacterial transformation involves the transfer of DNA from one bacterium to another through the surrounding medium. In B. subtilis the length of transferred DNA is greater than 1271kb (more than 1 million bases). The transferred DNA is likely double-stranded DNA and is often more than a third of the total chromosome length of 4215 kb. It appears that about 7–9% of the recipient cells take up an entire chromosome. In order for a recipient bacterium to bind, take up exogenous DNA from another bacterium of the same species and recombine it into its chromosome, it must enter a special physiological state called competence. Competence in B. subtilis is induced toward the end of logarithmic growth, especially under conditions of amino-acid limitation. Under these stressful conditions of semistarvation, cells typically have just one copy of their chromosome and likely have increased DNA damage. To test whether transformation is an adaptive function for B. subtilis to repair its DNA damage, experiments were conducted using UV light as the damaging agent. These experiments led to the conclusion that competence, with uptake of DNA, is specifically induced by DNA-damaging conditions, and that transformation functions as a process for recombinational repair of DNA damage. While the natural competent state is common within laboratory B. subtilis and field isolates, some industrially relevant strains, e.g. B. subtilis (natto), are reluctant to DNA uptake due to the