Environment influences the genetic structure and genetic differentiation of Sassafras tzumu (Lauraceae)

Abstract

Abstract Background Sassafras tzumu , an elegant deciduous arboreal species, belongs to the esteemed genus Sassafras within the distinguished family Lauraceae. With its immense commercial value, escalating market demands and unforeseen human activities within its natural habitat have emerged as new threats to S. tzumu in recent decades, so it is necessary to study its genetic diversity and influencing factors, to propose correlative conservation strategies. Results In this investigation, we employed genotyping-by-sequencing technology to scrutinize the genetic diversity and structure of 106 individuals of S. tzumu, carefully gathered from 13 naturally occurring habitats in China. The primary results could be summarized as follows: the genetic diversity of S. tzumu was inferior to those of most other woody plants. Moreover, S. tzumu exhibited a moderate level of genetic differentiation (FST=0.103), with the preponderance of genetic variation residing within populations (71%). Our findings unveiled that the 13 populations could be categorically classified into four distinct genetic clusters (K = 4). Notably, the populations from Mount Hengshan (HS) and Mount Shaoshan (SS) coalesced into a single genetic cluster, while the populations from Mount Lushan (LS) and Mount Meiling (ML) formed another genetic cluster, with the remaining two populations occupying unique genetic clusters. Utilizing the multiple matrix regression with randomization (MMRR) analysis method, we unveiled that genetic distance was concurrently influenced by both geographical distance and environmental distance (r = 0.57, p < .01). However, it was noteworthy that the regression coefficient of environmental distance was nearly threefold greater than that of geographical distance, thus underscoring the prominence of environmental distance in shaping genetic distance (βE = 0.46, p < .01; βD = 0.16, p < .01). Conclusions S. tzumu had a moderate level of genetic differentiation and low genetic diversity in our study. The environmental distance of S. tzumu had a greater impact on its genetic diversity than geographical distance. It is of utmost significance to formulate and implement meticulous management and conservation strategies to safeguard the invaluable genetic resources of S. tzumu.