Taxonomic status and genetic variation of the genus Castanea (Fagaceae) in Iran based on psbA and trnH-psbA

Species in the genus Castanea Mill. are one of the worthwhile species in the Hyrcanianforest of west Guilan (N Iran) with low region such as Siahmazgi, Ghalerodkhan and Visrod. that do not have good condition by reason of human interfering and disease. They have varying economic importance as nut tree crops, therefore, DNA barcoding technique can be a straightforward method for taxonomic status appointment of the genus Castanea Mill. in the north of Iran. In this research, six individuals from three relict populations of Castanea in western regions of Hyrcanian forest (Guilan province) were selected and amplified for plastid trnHpsbA region. Results indicated that, the length of psbA region is about 66 bp without any nucleotide diversity, and the length of trnHpsbA intergenic spacer is 427-416 bp. The Hyrcanian samples of Castanea with a 11 bp deletion in trnH-psbA spacer have the minimum length (416 bp). From five singleton position, first and second singleton positions were related to C. dentata (position 366 and 495), third position was related to C. sativa (position 401), and the fourth and fifth positions were related to C. pumila (positions 406 and 437). Hyrcanian samples did not show genetic distance, and they had most similarity with C. sativa. Haplotype diversity was 0.58, and totally, four haplotypes were recognized. Based on the obtained phylogenetic tree, the Hyrcanian samples of Castanea form a distinct clade but with bootstrap lower than 50%.