The complete chloroplast genome sequence of Intsia bijuga (Colebr.) Kuntze (Fabaceae: Detaroideae: Afzelieae)

Intsia bijuga (Colebr.) Kuntze. (1891) is a threatened mangrove species, belonging to the Fabaceae family and is native to the western Pacific coast and Southeast Asia. Here, we applied short-read Illumina technology to sequence and assemble its chloroplast genome. The complete chloroplast genome is 158,363 bp in length, composed of one large single-copy (LSC) region of 87,489 bp, one small single-copy (SSC) region of 19,438 bp, and a pair of inverted repeats (IRs) of 25,719 bp. A total of 129 unique genes were annotated, comprising 84 protein-coding genes, eight rRNA genes, and 37 tRNA genes. Our phylogenetic analysis showed the placement of I. bijuga (OL699920.1) with Afzelia species within Fabaceae family

A multi-proxy reconstruction of the late Holocene vegetation dynamics in Krabi mangroves, Thailand Andaman Sea

Pollen, charcoal, loss on ignition, geochemistry, and geophysical analyses were used to reveal the palaeoenvironment, vegetation, and sedimentary dynamics of the Krabi mangroves and the Andaman coast during the late Holocene. Two sediment cores, radiocarbon dated to ∼4400 cal BP, were collected from the Nai Nang mangroves in Krabi Province, the Thailand Andaman coast. This analysis documented how the area evolved from a tidal channel to a tidal area dominated by mangrove ecosystems. During the tidal channel phase (∼4400–2700 cal yr BP), the study site was characterized by a high-energy depositional environment, where sediment accumulated along tidal channels. Mangrove development began around 4400 cal yr BP and was influenced by varying contributions from tidal and freshwater inputs. Sea level during this period showed a slight rise until ∼4200 cal yr BP, followed by a subsequent fall. From ∼2700 to 1050 cal yr BP, the tidal channel was filled with finer sediments, forming intertidal flats that supported mangroves, back mangroves, and freshwater forest taxa, indicating a transition to mixed coastal vegetation. Sea levels remained relatively low during this period. From around 1050 cal yr BP to the present, mangroves replaced the previous mixed coastal vegetation, most likely driven by rising sea levels, particularly during the last 200 years. The observed sedimentation rates indicate that mangroves in Krabi will need to undergo continued future landward migration to adapt to changing coastal conditions, given the current and projected global sea-level rise

Complete chloroplast genome sequences of five Bruguiera species (Rhizophoraceae): comparative analysis and phylogenetic relationships

Bruguiera is a genus of true mangroves that are mostly distributed in the Indo-West Pacific region. However, the number of published whole chloroplast genome sequences of Bruguiera species are limited. Here, the complete chloroplast sequences of five Bruguiera species were sequenced and assembled using Illumina data. The chloroplast genomes of B. gymnorhiza, B. hainesii, B. cylindrica, B. parviflora and B. sexangula were assembled into 161,195, 164,295, 164,297, 163,228 and 164,170 bp, respectively. All chloroplast genomes contain 37 tRNA and eight rRNA genes, with either 84 or 85 protein-coding genes. A comparative analysis of these genomes revealed high similarity in gene structure, gene order and boundary position of the LSC, SSC and two IR regions. Interestingly, B. gymnorhiza lost a rpl32 gene in the SSC region. In addition, a ndhF gene in B. parviflora straddles both the SSC and IRB boundary regions. These genes reveal differences in chloroplast evolution among Bruguiera species. Repeats and SSRs in the chloroplast genome sequences were found to be highly conserved between B. cylindrica and B. hainesii as well as B. gymnorhiza and B. sexangula indicating close genetic relationships based on maternal inheritance. Notably, B. hainesii, which is considered a hybrid between B. gymnorhiza and B. cylindrica, appears to have inherited the chloroplast from B. cylindrica. Investigating the effects of selection events on shared protein-coding genes showed a positive selection in rps7 and rpl36 genes in all species compared to land-plant species. A phylogenetic analysis, based on 59 conserved chloroplast protein-coding genes, showed strong support that all Bruguiera species are in the clade Rhizophoraceae. This study provides valuable genetic information for the study of evolutionary relationships and population genetics in Bruguiera and other mangrove species