Diversification of mulberry (Morus indica var. S36), a vegetatively propagated tree species

Abstract

Genetic diversity among plants sprouted from seven year old clones of mulberry (Morus indica var. S36) was studied using molecular markers such as ISSR and RAPD. The clones showed significant variability in sex expression and the sprouting behavior. These changes were appeared after seven years of rigorous pruning and training (pruned once in every 3-4months). Genetic diversity analysis revealed significant DNA polymorphism differences among these clones. Through multiple regression analysis, four DNA markers associated with specific traits were identified. Cloning, sequencing and bioinformatics analyses suggested probable involvement of transposable elements along with enzymes and transcriptional regulating factors. The results of this preliminary report call for detailed analyses at biochemical, physiological and molecular levels coupled with inheritance pattern of these markers and their corresponding phenotypic traits. The markers identified for sprouting and sex expression are of much use in early identification of hybrids with the respective traits. REFERENCES Bennetzen, J.L. (2000) Transposable element contribution to plant gene and genome evolution. Plant Mol. Biol. 42, 251-259. Breto, M.P., Ruiz, C., Pina, J.A. and Asins, M.J. (2001) The diversification of Citrus clementina Hort. Ex Tan., a vegetatively propagated crop species. Mol. Phylogenet. 21, 285-293. Chatterjee, S.N., Nagaraja, G.M., Srivastava, P.P. and Naik, G. (2004) Morphological and molecular variation of Morus laevigata in India. Genetica. 39, 1612—1624. Dandin, S.B., Susheelamma, B.N., Jolly, M.S., Mallikarjunappa, R.S. and Giridhar, K. (1983) Karyomorphological studies in a few varieties of mulberry (Morus spp.). National seminar on Silk Research and Development, Bangalore, March 10-13, 1983, p. 3. Das, B.K. and Mukherjee, S.K. (1992) Modification of sex expression in mulberry by colchicines-B, a potent antigibberllin. Indian J. Sericulture. 31, 173–175. Felsenstein, J. (1993) PHYLIP (Phylogeny inference package) version 3.5c. Department of Genetics, University of Washington, Seattle. Genus, J. (1982) Plant steroid hormones-what are they and what they do. Trans Biochem. Sci. 7, 7-9. Grandbastien, M.A. (1998) Activation of plant transposons under stress conditions. Trends Plant Sci. 3, 181-187. Kasiviswanathan, K., Krishnaswami, S. and Choudhury, P.C. (1979) Long term studies on the cultivar, spacing and nitrogen fertilization for the improvement of yield potential of mulberry. Indian J. Sericulture. 28, 23-29. Kreher, S.A., Fore, S.A. and Collins, B.S. (2000) Genetic variation within and among patches of the clonal species, Vacciniun syaminieum L. Mol. Ecol. 9, 1247-1252. Lal, M. and Jaiwasl, V.S. (1988) Modification of flower sex and acid phosphatase activity by phthalimides in female plant of Morus nigra L. Plant Growth Regulation. 7, 29-37. Nei, M. (1987) Molecular Evolutionary Genetics. Columbia University Press, New York.NY. Osborne, R. (1985) Sex change in cycads - hope for woodii, Encephalartos. 2, 20-22. Persson, H.A. and Gustavsson, B.A. (2001) The extent of clonality and genetic diversity in lingonberry (Vaccinium vitisidaea L.) revealed by RAPDs and leafshape analysis. Mol Ecol. 10, 1385-1397. Sastry, C.R. (1984) Mulberry varieties, exploitation and pathology. Sericologia. 24, 333-359. Sneath, P.H.A. and Sokal, R.R. (1973) Numerical taxonomy. W. H. Freeman, San Francisco. Suyama, Y., Obayashi, K. and Hayashi, I. (2000) Clonal structure in a dwarf bamboo (Sasa senanensis) population inferred from amplified fragment length polymorphism (AFLP) fingerprints. Mol. Ecol. 9, 901-906. Tikader, A., Vijayan, K., Raghunath, M.K., Chakraborti, S.P., Roy, B.N. and Pavankumar, T. (1995) Studies on sexual varieties in mulberry (Morus spp ). Euphytica. 84, 115-120. Vijayan. K. and Chatterjee S.N. (2003) ISSR profiling of Indian cultivars of mulberry (Morus spp.) and its relevance to breeding programs, Euphytica. 131, 53-63. Wessler, S.R. (1996) Plant retrotransposons: Turned on by stress. Curr. Biol. 6, 959- 961. Wu, J., Krutovskii, K.V. and Strauss, S.H. (1999) Nuclear DNA diversity, population differentiation, and phylogenetic relationnships in the California closed-cone pines based on RAPD and allozyme markers. Genome. 42, 893-908. Wright, S. (1978) Evolution and Genetics of populations. Vol.4. Variability within and among natural populations. University of Chicago Press, Chicago. Yang, L., Yang, S.T., Weid, X.H. and Gui, J.F. (2001) Genetic diversity among different clones of the gynogenetic silver crucian curp, Carassius auratusgibetio, revealed by transferrin and isozyme markers. Biochem. Genet. 39, 213-225.