Genetic diversity of Horsfieldia tetratepala (Myristicaceae), an endangered plant species with extremely small populations to China: implications for its conservation

Genetic variation determines the evolutionary potential of a species and
is vital for fully understanding the evolution of a species, as well as
for developing optimal conservation strategies. Horsfieldia tetratepala is
an economically important rainforest tree which has declined steadily,
mainly though habitat destruction, and an endangered, narrow endemic in
China where it is also classified as a Plant Species with Extremely Small
Populations (PSESP). Effective conservation strategies for H. tetratepala
are required urgently, but limited information about its genome is
available. Accordingly, restriction site-associated DNA sequencing
(RAD_seq) was used to sequence sixty-three H. tetratepala trees covering
ten isolated populations to assess genome-level diversity and population
structure, generating 8,103 high-quality SNPs. Low genetic diversity and
moderate genetic differentiation was observed among populations, but
Bayesian clustering divided the sampled H. tetratepala populations into
two genetic clusters, though with some populations from Guangxi and Yunnan
intermixed. Because of increasing of habitat fragmentation and human
disturbance, conservation priority should be placed on populations with
higher genetic variation (e.g., BB, TKH, DWS, and GLQ). Overall, our study
provides valuable genomic resources for H. tetratepala that will
significantly advance the formulation of effective conservation
strategies.