Assessment of morphological and genetic variability through genic microsatellite markers for essential oil in Sandalwood (Santalum album L.)

Abstract

Sandalwood (Santalum album L; family Santalaceae) is a highly significant aromatic oil yielding tree. It is valued for two important traits, heartwood and essential oil obtained from the heartwood. This study was proposed to assess the morphological and genetic variability of sandalwood accessions. For this, genotypes were randomly selected (n = 177) from the 14 populations from three states in southern India. The total heartwood oil content and quality was estimated by UV method and GC-MS. Total 14 oil-specific genic SSR markers were procured to evaluate the genetic diversity among the sandalwood accessions. Total core size, heartwood content, and oil of S. album ranged from 4.4 to 19.1 cm; 0.0 to 17.3 cm; and 0.0 to 5.96% with covariance 27.61, 85.25, and 73.12% followed by mean 9.74, 3.77, and 2.71, respectively. Genetic diversity estimates were highly polymorphic in terms of Na 7.28, Ne 5.89, He 8.0 PIC 0.891, with little Ho, and F-0.922. AMOVA revealed that minimal genetic variation among populations and highest variation was found among individuals with Nm (58.4). The UPGMA reveals the cluster favored the grouping pattern by the PCA analysis. Structure and PCA analysis clustered the entire populations into two major groups with F ST 0.046 in which population of Kerala and Karnataka were pure and Telangana accessions were found admixtures. No significant correlation (r 2 = 0.23, P = 0.00) was observed between heartwood oil and genetic structures. A high degree of transferability of genic markers would facilitate the assessment of novel genotypes for future tree improvement and conservation of Sandalwood populations.

Assessment of Genetic Diversity and Population Genetic Structure of Santalum album L. in India by Genic and Genomic SSR markers

“…Similar results were obtained in previous studies of Santalum and other tree species like O. lanceolata (Otieno et al, 2016), S. spicatum (Millar et al, 2012), S. lanceolatum (Jones et al, 2010), S. leptocladum (Jones et al, 2010), S. album (Fatima et al, 2019b) and Phyllostachys violascens , (Cai et al, 2019). In contrast to our study, low Na was observed in S. album by using genic SSR markers (Fatima et al, 2019a) and, Ambrosia artemisiifolia , (Meyer et al, 2017). The PIC value of 14 populations ranged from 0.83-0.96 (Table 2) in which 10 populations were highly polymorphic (PIC>0.8).…”

“…UPGMA cluster analysis showed IWC L1 KA and Nel L2 KA populations were clustered together in cluster II and confirmed the seedling source of S. album . Similar result was observed in another study of S. album by oil specific genic markers (Fatima et al, 2019a). On the other hand a previous study using random genomic markers indicated mixed clustering of S. album populations (Fatima et al, 2019b).…”

“…The structure result also confirmed AMOVA test and showed presence of genetic diversity within each presumed population groups. Similar results were reported in S. album and Corylus mandshurica (Fatima et al, 2019a; Fatima et al, 2019b; Zong et al, 2015;). The obtained results indicated the mix lineage of the nuclear genome and distributed randomly among the populations.…”

“…Genetic diversity analysis of S. album was performed by 39 (14 genic and 25 random genomic SSR markers). The DNA isolation, PCR and gel electrophoresis details were available (Fatima et al, 2019a & Fatima et al, 2019b).…”

“…Microsatellite SSR markers genic and genomic have proven to be efficient and accurate tool for the study of genetic variation in forest tree species compared with other markers (Kalia et al, 2011). However, very few genomic and genic microsatellite markers have been developed for S. album (Naseer et al, 2012; Patel et al 2016; Fatima et al, 2019a) to characterize genetic diversity and genetic differentiation of S. album . Therefore in this study, we aimed to evaluate the genetic diversity and reveal the population structure of the natural populations and plantations of S. album by using both genomic and genic microsatellite markers.…”