Functionally relevant novel microsatellite markers for efficient genotyping in Stevia rebaudiana Bertoni

Abstract

Stevia rebaudiana Bertoni is a perennial herb that belongs to family Asteraceae. It produces rebaudioside which is one of the key components responsible for extraordinary sweetness of stevia. It produces steviol glycosides which are proved beneficial for diabetes type II patients and controlling blood pressure in hypertension patients (Hsieh et al. 2003; Gregersen et al. 2004). Moreover, stevia is a rich source of antioxidants, antimicrobial and antifungal compounds (Lemus-Mondaca et al. 2012), imparting great economic and commercial value to this crop. Stevia is indigenous to Central and South America (Brandle et al. 2002). However, it was introduced in the late 1990s in India. Selfincompatibility, poor-seed viability, low germination rates and entomophilous pollination are among the major challenges in management and genetic improvement of stevia through conventional breeding approaches (Mitra and Pal 2007). To date, population genetic analysis in S. rebaudiana has been performedusing arbitrary markers such as RAPD, AFLP and ISSRs (Yao et al. 1999; Heikal et al. 2008; Hassanen and Khalil 2013) which lead to underestimation of the recessive allele frequency in a population causing a bias in the estimates of genetic diversity and differentiation (Nybom 2004). Further, limitations such as low reproducibility rate, inability to detect heterozygous individual or/and locus nonspecificity, makes them less preferred markers (Kalia et al. 2011). In contrast, unigene derived microsatellite markers developed from public database, supersede other markers due to their codominant nature, hypervariability, genomewide occurrence, robustness and ability to establish