Shengchang Yang

Species in Semisulcospiridae are important in freshwater ecology and have great research value, yet their genomic resources remain very limited. Here, we present de novo assembled transcriptomes from six species of Hua in Semisulcospiridae, including Hua textrix (Heude, 1888), H. yangi L.-N. Du, J.-X. Yang & Chen, 2023, H. wujiangensis L.-N. Du, J.-X. Yang & Chen, 2023, and three undescribed species. Assembly was performed using Trinity, resulting in average contig lengths ranging from 716.6 to 883.3 bp and transcript numbers ranging from 147,147 to 268,741. Benchmarking Universal Single-Copy Ortholog (BUSCO) analysis was used to assess the transcriptome completeness. The functional annotation of transcripts for each species had over 18,000 BLAST hits, 17,000 GO terms, 15,000 KEGG pathways, 8,000 Pfam accessions, and 140 COG functional categories. This study provides valuable transcriptomic resources for the six Hua species, which can be used for various research of Semisulcospiridae, including biodiversity, phylogeny, and comparative genomics.

Tamarix chinensis Lour. is a halophytic shrub native to coastal China, commonly used in afforestation and ecological restoration due to its high tolerance to salinity and drought. To understand how this species maintains genetic variation and adapts to extreme environments, we examined the genetic diversity, mating system, and spatial genetic structure of a natural T. chinensis population on the geographically isolated and environmentally harsh Wudi Seashell Island. Using both SSR and ISSR markers, we observed high levels of genetic diversity despite the small population size and spatial fragmentation. SSR markers revealed an average of 11.75 alleles per locus, with an expected heterozygosity (He) of 0.754 and an observed heterozygosity (Ho) of 0.702. ISSR markers showed a polymorphic locus rate of 97.87%, with a mean He of 0.402. Parentage analysis revealed relatively long seed and pollen dispersal distances, with most dispersal occurring within 150 m and seeds and pollens occasionally reaching 948 m and 447 m, respectively. The species exhibited a mixed mating system, with a multilocus outcrossing rate of 0.554, contributing to gene flow and reducing inbreeding. A fine-scale spatial genetic structure was detected within 75 m, consistent across both SSR and ISSR markers, suggesting limited local gene dispersal. These findings provide new insights into the adaptive strategies of T. chinensis in marginal habitats and offer valuable guidance for conservation and restoration efforts in vulnerable coastal ecosystems.