First de novo genome specific development, characterization and validation of simple sequence repeat (SSR) markers in Genus Salvadora.

Salvadoraceae constitutes ecologically imperative desert families of 3 genera-Azima, Dobera and Salvadora. Under genus Salvadora of this family, S. oleoides is a keystone species of socio-economic and medicinal value. This species naturally grows in the arid zones but currently experiencing severe fragmentation due to land use change and reduced regeneration, which may have resulted in the depletion of genetic diversity. Hence, it is up-most important to develop genomic resources for studying the population genetics in S. oleoides. This study aims to develop robust microsatellites markers, which were not yet reported in genus Salvodora due to lack of genome sequence information. We developed novel microsatellites markers in S. oleoides using Illumina paired-end sequencing technology. In total, 14,552 simple sequence repeat (SSR) markers were successfully designed from 21,055 microsatellite repeats detected in the 13 Gb raw sequence data. Afterwards, a subset of 101 SSRs were randomly selected and validated, 94 primers were successfully amplified and 34 showed polymorphisms. These SSRs were used to estimate the measures of genetic diversity in three natural populations of state Rajasthan and Gujarat. Importantly, average number of alleles (Na), observed heterozygosity (Ho), expected heterozygosity (He), and polymorphism information content (PIC) were recorded as 2.4, 0.529, 0.357, and 0.326, respectively. Furthermore, 15 primers were evaluated in S. persica for cross-transferability, and all were successfully amplified but only eight showed polymorphisms. This study has been conducted first time for S. oleoides and pioneer among the native species of arid-zone in India.

Anti-biofilm activity of Salvadora persica on cariogenic isolates of Streptococcus mutans: in vitro and molecular docking studies.

Salvadora persica sticks are used for chewing and oral-hygiene measures worldwide. The growth inhibition and anti-biofilm effects of various extracts on cariogenic Streptococcus mutans isolates were evaluated. Biofilm inhibition, gas chromatography-mass spectrometry (GC-MS) analyses for phytochemicals and their possible mode of interaction with biofilm response regulators were revealed using LigandFit docking protocols. All S. persica extracts showed considerable inhibitory activity and the cariogenic S. mutans showed varied susceptibility when compared with controls. The percentage reduction in biofilm inhibition obtained for methanol, ethanol, chloroform, acetone, and aqueous extracts were 87.92%, 85.75%, 72.44%, 61.66% and 58.68%, respectively. GC-MS analyses revealed >28 compounds, of which benzyl (6Z,9Z,12Z)-6,9,12-octadecatrienoate, 3-benzyloxy-1-nitro-butan-2-ol and 1,3-cyclohexane dicarbohydrazide interacted efficiently with the bacterial communication quorum-sensing (QS) regulators Streptococcus OmpP and Staphylococcus Lux proteins. The bioactive, dual-function, anti-biofilm agents in S. persica not only inhibit growth, but also control the colonization and accumulation of caries-causing S. mutans.