MOLECULAR PHYLOGENY OF MANGROVES IX Molecular marker assisted intra-specific variation and species relationships in the Indian mangrove tribe Rhizophoreae

Molecular phylogeny and genetic diversity in all the nine species (Rhizophora mucronata, R. apiculata, R. stylosa, Bruguira cylindrical, B. parviflora, B. gymnorriza, Ceriops tagal and C. decandra) and a natural Rhizophora hybrid, of the mangrove Rhizophoraceae, occurring in the Indian sub-continent were analysed using random amplified polymorphic DNA (RAPD), restriction fragment length polymorphism (RFLP) and RFLP of polymerase chain reaction amplified chloroplast genes (PCR-RFLP) as markers. Intra-specific variability as revealed by RAPDs were low in all the analysed species. Inter-specific RFLP analysis revealed species-specific profiles in some probe-enzyme combinations. The rDNA repeat units, as flanked by the Hind III restriction sites was found to be very conserved within each genus and three different rDNA repeat units were observed among the four genera. Generic differences in PCR-RFLP were observed only in rbcL and trnS-psbC gene regions. Species differences were observed in Rhizophora in the PCR-RFLP of trnS-psbC and trnL-UAA with Hae III and Taq I, respectively. Rhizophora mucronata was found to be the chloroplast donor for the natural inter-specific hybrid. A dendrogram based on the data sets from all the three marker systems revealed that the four genera segregated into three species groups. © 2002 Elsevier Science B.V. All rights reserved.