Development and characterisation of EST-SSR-based markers in curry leaf (Murraya koenigii)

Abstract

Crop improvement strategies depend on a better understanding of their genetic architecture. Murraya koenigii L. an important medicinal and aromatic value vegetable/spice tree crop, needs genetic improvement in yield and other agronomic traits. In the present study, EST-SSRs have been developed using the transcriptome sequence of curry leaf. A total of 12861 EST-SSRs were identified among the tested transcripts. The mononucleotide motif (58.8%) was more abundant than those with tri (20%), di (14.6%) and other higher order motifs (6.61%). About 24 EST-SSR primers were validated and all of them were polymorphic. The estimates of unbiased gene diversity ranged from 0.70 (for the marker MK1 locus) to 0.98 (at the MK8 locus), with an average of 0.88. The estimate of PIC values varied from 0.66 (at the MK1 locus) to 0.97 (at the MK8 locus) with a mean of 0.85, irrespective of the repeat motif-based markers. The 50 Murraya accessions could be classified into four clusters based on EST-SSR marker allelic data. Significant differences among the genotypes classified into different clusters for all three quantitative traits, namely, leaf yield, aroma intensity and essential oil content, suggested that EST-SSR marker alleles are efficient in discriminating the genotypes at loci controlling horticulturally important quantitative traits as well. To the best of our knowledge and belief, the present study is the first report on the development, validation and use of EST-SSR for assessing the genetic diversity of Murraya koenigii.