The Effect of Sub-MIC of Salvadora persica on Growth and Virulence Gene Expressions in Streptococcus mutans.

Dental caries is a multifactorial infectious chronic disease caused by particular bacteria and their virulence products that causes demineralization and progressive deterioration of the dental enamel. Many studies have proven miswak to have a critical antibacterial impact, particularly on cariogenic bacteria and periodontal pathogens, in the oral cavity. This study aimed to investigate the effect of different concentrations of Salvadora persica plant extract on growth and virulence gene expressions at mRNA levels in S. mutans. A total of 191 clinical samples from tooth swabs were collected, and sub-cultured on specific medium agar identified using biochemical and molecular approaches. MIC for the extract was determined and a bacterial growth curve was made to determine the growth phases and the optimum time for adding the extract at different concentrations. RT-qPCR technique was performed, and the REST-2009 software program was used for data analysis. Out of 191 swabs from the tooth 31 isolates were identified using several biochemical and molecular tests. Several S. mutans biofilm-related virulence genes and their Ct values were produced from RT-PCR under the effect of low and high doses of Meswak concentrations. Ct values and reaction efficiency were produced in RT-qPCR by Rotorgen3000, data then were analysed by REST-2009 software. Five isolates were selected to examine the effect of the extract on the mRNA levels using qPCR after growing them with both doses of the extract for about 30hrs. Levels of virulence gene mRNA were regulated differentially in cultures with added both extract doses. The isolates produced significantly lower virulence gene mRNA levels in cultures grown with both plant extract doses. The results produced in this study here provide new insights regarding several virulence gene expressions in S. mutans at the molecular levels when grown under different concentrations of Salvadora persica plant extract.

Evaluation of the genetic diversity of wild Salvadora persica 'Arak' from Saudi Arabia.

Assessment of genetic diversity is crucial for efficient selection genotypes in plant breeding and improvement programs. Studies of genetic diversity of S. persica are rare relative to the large species diversity in Saudi Arabia, despite its valuable importance as one of the most popular medicinal plants. We investigate the genetic variability and genetic differentiation among and within wild Salvadora persica populations distributed in four regions of Saudi Arabia. Twelve sequence-related amplified polymorphism (SRAP) primers combination generated 326 alleles, with an average of 27.2 alleles per primer. All primers showed 100 polymorphism percentage, and higher PIC values exceeded 0.90. Jaccard similarity values varied between 0.04 to 0.43, with an average of 0.31, which showed a weak relationship among the accessions and their origin. Based on UGPMA and principal coordinate analysis, accessions collected from the same region showed less aggregation. Genetic diversity parameters showed that both Aflaj and Joodah populations recorded the highest mean values for the effective number of alleles (1.26 and 1.24). Shannon index and genetic heterozygosity (0.23 and 0.15 for both populations), and percent of polymorphism 45.45% for Aflaj and 43.87 for Joodah population. Most of the genetic variation was because of differences within populations (77%) and 23% among populations. SRAP markers explored the genetic diversity among and within S. persica populations. In this work, genetic diversity within populations was high, and the population structure was weak. We detected no specific geographic structure, which may reveal an active movement of plants among populations.

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.