Genetic variation within the endangered mangrove species Sonneratia paracaseolaris (Sonneratiaceae) in China detected by inter-simple sequence repeats analysis

Sonneratia paracaseolaris, is a critically endangered mangrove species in China. Using inter-simple sequence repeats (ISSR) markers, we compared the genetic variation of introduced populations with that of natural populations to check whether the genetic diversity has been conserved. At the species level, genetic diversity was relatively high (P = 81.37%, He = 0.2241, and SI = 0.3501). Genetic variation in introduced populations (P = 75.78%, He = 0.2291, and SI = 0.3500) was more than that in natural populations (P = 70.81%, He = 0.1903, and SI = 0.2980). Based on Nei's G_ST value, more genetic differentiation among natural populations was detected (G_ST = 0.3591). Our data show that the genetic diversity of S. paracaseolaris was conserved in introduced populations to some extent, however, owing to the small natural populations and the threats they encountered, more plants should be planted to enlarge and restore the populations.