Identification and analysis of genetic variation among rose cultivars using random amplified polymorphic DNA

Characterization of Indian bred rose cultivars using morphological and molecular markers for conservation and sustainable management

Rose (Rosa × hybrid L.) is one of the most important commercial ornamental crops cultivated worldwide for its beauty, fragrance and nutraceutical values. Characterization of rose germplasm provides precise information about the extent of diversity present among the cultivars. It also helps in cultivar identification, intellectual property right protection, variety improvement and genetic diversity conservation. In the present study, 109 Indian bred rose cultivars were characterized using 59 morphological and 48 SSR markers. Out of 48 SSRs used, 31 markers exhibited polymorphism and 96 alleles were identified with an average of 3.9 alleles per locus. Nei's expected heterozygosity value of each locus ranged from 0.08 (with SSR ABRII/RPU32) to 0.78 (SSR Rh58). The similarity coefficient values ranged from 0.42 to 0.90 which indicated presence of moderated diversity among Indian cultivars. The neighbor-joining tree based on morphological data grouped the cultivars into two major clusters and several minor clusters based on their morphological resemblance. However, UPGMA dendrogram constructed using matching coefficient values grouped the cultivars into eight different clusters. Interpopulation analysis revealed higher genetic similarities between Hybrid Tea and Floribunda cultivars. An analysis for presence of population sub-structure grouped the Indian cultivars into eight different genetic groups. Analysis of molecular variance revealed apportioning of 97.59% of the variation to within subgroup diversity and 3.07% to between the cultivar groups. We have demonstrated here successful utilization of robust SSR to distinguish cultivars and assess genetic diversity among Indian bred rose cultivars. The information provided here is useful for cultivar identification and protection, cultivar improvement and genetic diversity conservation.

Assessment of genetic variations among highly endangered medicinal plant Bacopa monnieri (L.) from Central India using RAPD and ISSR analysis

Genetic variations of 15 Brahmi (Bacopa monnieri L.) accessions were evaluated using random amplified polymorphic DNA (RAPD) and inter simple sequence repeats (ISSR) markers. During RAPD analysis, amplification of genomic DNA of the 15 accessions by 22 primers generated 197 fragments, of which 187 were polymorphic with an average of 8.95 bands per primer. The amplified products varied in size from 2,200 to 250 bp. Twenty-five selected ISSR primers produced 284 bands across 15 accessions, of which 270 were polymorphic with an average of 10.80 bands per primer. The PIC value ranges from 0.363 to 0.908 for RAPD primers, while 0.419 to 0.836 in case of ISSR. The size of amplified bands ranged from 2,800 to 240 bp. Similarity index values ranged from 0.16 to 0.95 (RAPD), 0.18 to 0.98 (ISSR) and 0.179 to 0.945 for pooled ISSR and RAPD markers data. Mantel test revealed the similar distribution pattern of the polymorphism between RAPD and ISSR markers and the correlation co-efficient (r) was 0.71384. The results indicated that both of the marker systems RAPD and ISSR, individually or combined can be effectively used in determination of genetic relationship among B. Monnieri accessions collected from different parts of Central India. It could be concluded that the information of genetic similarities and diversity among Brahmi accessions is necessary for their conservation and breeding programs.

Development of a species-specific sequence-characterized amplified region marker for roses

DNA fingerprints of four rose species, Rosa centifolia, R. Gruss-an-Teplitz, R. bourboniana, and R. damascena, were developed using RAPD-PCR. We identified a unique polymorphic band in R. centifolia. This 762-bp fragment was produced by the random primer GLI-2. The fragment was eluted and directly cloned in a TA cloning vector, pTZ57R/T. Digestion of the plasmid with EcoRI confirmed the cloning of GLI-2(762) in pTZ57R/T. A second enzyme, PstI, used in combination with EcoRI, gave complete digestion of the plasmid, and the 762-bp fragment was confirmed on the gel. Subsequently, the polymorphic amplicon was sequenced with an AB1 373 DNA sequencer system using the PRISM(TM) Ready Reaction DyeDeoxy(TM) Terminator Cycle Sequencing kit. After sequencing, specific primers (23 bp long) were designed based on the sequence of the flanking regions of the original RAPD fragment. These primers will effectively allow fingerprinting for the identification of R. centifolia species. In essence, we developed an SCAR marker to authenticate the identity of R. centifolia species and to distinguish it from its substitutes. Such techniques are required not only to complement conventional parameters in creating the passport data of commercial and medicinal products of rose, but also for routine quality control in commercial and government rosaries and rose nurseries.