Genetic diversity of the threatened Chinese endemic plant, Sinowilsonia henryi Hemsi. (Hamamelidaceae), revealed by inter-simple sequence repeat (ISSR) markers

Identification and Characterization of Gonatobotryum apiculatum Causing Leaf Spot and Blight on Sinowilsonia henryi

Sinowilsonia henryi is a rare and endangered plant, as well as an endemic species in China. In July 2018, leaf spot and blight disease was observed on S. henryi in Yichang, Hubei, China. A fungus isolated from disease tissues was identified as Gonatobotryum apiculatum based on morphology and sequence analyses of ITS and LSU regions. Phylogenetic analyses indicated that the species belongs to Dothioraceae (Dothideales). Morphologically, the species produced two distinct types of conidia from authentic media, both conidia were described here. Pathogenicity tests showed that the fungus is a pathogen causing leaf spots on S. henryi. This is the first report of leaf spot and blight disease on S. henryi caused by G. apiculatum in China.

Characterization and development of EST-derived SSR markers in Sinowilsonia henryi (Hamamelidaceae)

PREMISE OF THE STUDY

Polymorphic microsatellite markers were developed to reveal the genetic diversity of extant populations and the mating system of Sinowilsonia henryi (Hamamelidaceae).

METHODS AND RESULTS

In this study, nuclear simple sequence repeat (SSR) markers were developed using the Illumina high-throughput sequencing technique (RNA-Seq). The de novo-assembled transcriptome generated a total of 64,694 unique sequences with an average length of 601 bp. A total of 2941 microsatellite loci were detected. Of the 121 tested loci, 13 loci were polymorphic and eight were monomorphic among 72 individuals representing three natural populations of the species. The number of alleles per locus ranged from one to four, and the observed and expected heterozygosity at population level were 0.00-1.00 and 0.10-0.66, respectively.

CONCLUSIONS

The developed expressed sequence tag (EST)-SSRs will be useful for studying genetic diversity of S. henryi as well as assessing the mating system among Sinowilsonia species.