Comparative results of RAPD and ISSR markers for genetic diversity assessment in Melocanna baccifera Roxb. growing in Mizoram State of India

The genetic similarity among 12 accessions of Melocanna baccifera from Mizoram in India was tested using RAPD and ISSR markers. RAPD and ISSR DNA profile shows high polymorphism of DNA fragments. Genetic similarity among accessions was calculated according to Dice similarity coefficient;the mean level of genetic similarity with populations of M. baccifera by using RAPD and ISSR markers were 0.600 and 0.650, respectively. The similarity coefficients were then used to construct a dendrogram using the UPGMA cluster analysis. Cluster analysis base on Dice coefficient shows twomajor groups. Mantel test revealed the different distribution pattern of the polymorphism between RAPD and ISSR markers and the correlation coefficient (r) was found as r = 0.1902

Optimization of DNA isolation and PCR protocol for RAPD analysis of selected medicinal and aromatic plants of conservation concern from Peninsular India

Genetic analysis of plants relies on high yields of pure DNA samples. Here we present the optimization of DNA isolation and PCR conditions for RAPD analysis of selected medicinal and aromatic plants of conservation concern from Peninsular India containing high levels of polysaccharides, polyphenols and secondary metabolites. The method involves a modified CTAB extraction employing polyvinyl pyrrolidone while grinding, successive long-term Chloroform : lsoamyalcohol extractions, an overnight RNase treatment with all steps carried out at room temperature. The yield of DNA ranged from 1-2 μg/μl per gram of the leaf tissue and the purity (ratio) was between 1.6-1.7 indicating minimal levels of contaminating metabolites. The technique is ideal for isolation of DNA from different plant species and the DNA isolated was used for randomly amplified polymorphic DNA (RAPD) analysis. RAPD protocol was optimized based on the use of higher concentration of MgCl2 (3 mM), lower concentrations of primer (0.5 μM) and Taq polymerase (0.2 units), 50 ng of template DNA and an annealing temperature of 37°C, resulted optimal amplification. Reproducible amplifiable products were observed in all PCR reactions. Thus the results indicate that the optimized protocol for DNA isolation and PCR was amenable to plant species belonging to different genera which is suitable for further work on diversity analysis.Keywords: Vitex pubescens, Nervilia aragoana, Gymnema sylvestre, Withania somnifera, Origanum majorana, Boswellia serrata, Saraca asoca, Gloriosa superba, polysaccharides, PCR amplificatio

Is callose a barrier for lead ions entering Lemna minor L. root cells?

Plants have developed a range of strategies for resisting environmental stresses. One of the most common is the synthesis and deposition of callose, which functions as a barrier against stress factor penetration. The aim of our study was to examine whether callose forms an efficient barrier against Pb penetration in the roots of Lemna minor L. exposed to this metal. The obtained results showed that Pb induced callose synthesis in L. minor roots, but it was not deposited regularly in all tissues and cells. Callose occurred mainly in the protoderm and in the centre of the root tip (procambial central cylinder). Moreover, continuous callose bands, which could form an efficient barrier for Pb penetration, were formed only in the newly formed and anticlinal cell walls (CWs); while in other CWs, callose formed only small clusters or incomplete bands. Such an arrangement of callose within root CWs inefficiently protected the protoplast from Pb penetration. As a result, Pb was commonly present inside the root cells. In the light of the results, the barrier role of callose against metal ion penetration appears to be less obvious than previously believed. It was indicated that induction of callose synthesis is not enough for a successful blockade of the stress factor penetration. Furthermore, it would appear that the pattern of callose distribution has an important role in this defence strategy

Genetic diversity in Oroxylum indicum (L.) Vent. (Bignoniaceae), a vulnerable medicinal plant by random amplified polymorphic DNA marker

Random amplified polymorphic DNA (RAPD) markers were used to assess genetic diversity in Oroxylum indicum (L.) Vent (Bignoniaceae) a vulnerable medicinal plant collected from eight locationsin Andhra Pradesh, India. High level of genetic similarity was observed in the collected accessions. Forty random primers, each with 10 bases generated a total of 188 polymorphic bands out of the 387total bands, that is, polymorphism of 49.61% was observed. Overall genetic similarity based on 40 random primers was 87%. Cluster analysis based on Dice coefficient showed two major groups. Theresults show that the genetic diversity of this species is low, possibly depicting a difficulty in adapting to environmental variations. This distributive pattern of genetic variation of O. indicum accessionsprovides important baseline data for conservation and collection strategies for this species. The collected accessions were introduced to University of Hyderabad field gene bank along with other redlisted plants of Deccan ecoregion