Development Of EST-SSR Markers In Musella Lasiocarpa And Analysis Of Genetic Diversity Based On SSR Markers

Musella lasiocarpa (Franch.) C. Y. Wu ex H. W. Li, represents the monotypic genusMusella in the family Musaceae, native to southwestern China. It’s showy and lotus likeflowers made it widely used in gardening. It is now difficult to find wild populations as itsappropriate habitats have been fragmented due to widespread cultivation. We documented ninewild populations to date. Molecular markers would detect the differences of individuals atDNA level, and be helpful in genetic structure researching. To better understand M. lasiocarpawild populations and further chase its population genetic structure and conversation strategies,we developed49SSR markers by data mining from publicly available Musa EST sequences,and tested the genetic diversity among9wild M. lasiocarpa populations using22EST-SSRand8Genomic-SSR markers.1. In all,238unigenes flanking SSRs were randomly selected for PCR primers design,and then tested for amplification in Musella lasiocarpa, of which49displayed polymorphism.The total locus produced were147in24individuals from4wild M. lasiocarpa populations.The average allele number per locus was3.0, ranging from2to7. The observedheterozygosities per marker ranged from0.042to0.875(mean0.426) and expectedheterozygosities were0.232to0.823(mean0.537).2. A set of22polymorphic EST-SSR and8Genomic-SSR markers were analyzed using9wild M. Lasiocarpa populations. Genomic-SSR produced a higher PIC, number of alleles,effected number of alleles, heterozygosities and Shannon’s I (the mean value ofGenomic-SSR/EST-SSR were PIC=0.729/0.527， N_A＝11.5/5.5， N_E＝5.6/2.7， H_E＝0.584/0.743，I＝1.811/1.107). We detected the N_E, H_E, Shannon’ Iand found genetic diversityof M. lasiocarpa wild population were high. The population HH from Heqing county, Daliperformed the highest genetic diversity (N_E＝2.662，H_E＝0.554，I＝1.029) while WY fromWuding county, Chuxiong showed the lowest (N_E＝1.802，H_E＝0.372，I＝0.623). Geneticdiversity among9populations were HH> LJ> WL> YQ> HW> YR> YL> BB> WY, according to N_E, H_Eand Shannon’ I that were detected. Genetic diversity of populations generallydecreased along ancient Honghe River.3. The value of fixation indices FSTranged from0.112to0.371, mean0.244，indicatingthe lower genetic differentiation among populations than that was within populations. Total ofthe gene flow was0.793. And was at the low level due to Govindaraju’s Nm classification.AMOVA analysis showed that the24.13%variation was among populations and75.87%waswithin populations. The significant level was P<0.01. Genetic distance among populationswere between0.157－0.681. The9populations were clustered to3groups at the geneticdistance GD=0.33using UPGMA method, together with principal coordinates analysis (PCA).Group I: population WL, HW and YQ distributed along Northern ancient Yalong River. GroupII: population WY and YL distributed along ancient Yangzi River. The rest four populations,HH, LJ, YR and BB were clustered to group III. The Mantel test showed a significantcorrelations between geographic distance and genetic distance（R~2=0.344, P<0.01）. PopulationHH, LJ and HW should be protected urgently according to the genetic diversity level and thenumber of private alleles.