Development of Microsatellite Markers in Tung Tree (Vernicia fordii) Using Cassava Genomic Sequences

Tung tree, Vernicia fordii, is a native oil-bearing woody plant of China. Oil extracted from the fruit is an important industrial and biodiesel feedstock. Microsatellite (simple-sequence repeat (SSR)) markers are effective in germplasm evaluation and marker-assisted breeding of plants. The objective of this study was to develop SSR markers in tung tree using cassava genomic sequences and test the effectiveness of the interspecific transferable SSR markers. According to the principle of comparative genomics, SSR markers were designed based on cassava genomic sequences and tested in tung tree and other Euphorbiaceae plant species. Among 255 cassava SSR markers, 104 (41 %) could effectively amplify DNA of tung tree, and a large portion of these transferable SSR markers could work well in other Euphorbiaceae species, Vernicia montana (98 %), castor bean (92 %), and Jatropha curcas (88 %). Genotyping a set of 16 tung tree accessions using the 104 transferable SSRs, a total of 437 alleles were obtained, 162 of which were polymorphic, and the Shannon information index varied from 0.000 to 0.560 with a mean of 0.139. A phylogenetic tree unambiguously distinguished the 32 accessions of the abovementioned five Euphorbiaceae species. Using cassava genomics resources is an effective approach to develop SSR markers for tung tree when its genome sequence is not available. The developed SSR markers should facilitate germplasm evaluation and other molecular-level investigations in tung tree.