Background: Understanding the genetic diversity in endangered species that occur inforest remnants is necessary to establish efficient strategies for the species conservation, restoration and management.Panax vietnamensisHa et Grushv. is medicinally important, endemic and endangered species of Vietnam. However, genetic diversity and structure of population are unknown due to lack of efficient molecular markers.Results: In this study, we employed Illumina HiSeq™ 4000 sequencing to analyze the transcriptomes ofP. vietnamensis(roots, leaves and stems). Raw reads total of 23,741,783 was obtained and then assembled, from which the generated unigenes were 89,271 (average length = 598.3191 nt). The 31,686 unigenes were annotated in different databases i.e. Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, Nucleotide Collection (NR/NT) and Swiss-Prot for functional annotation. Further, 11,343 EST-SSRs were detected. From 7774 primer pairs, 101 were selected for polymorphism validation, in which; 20 primer pairs were successfully amplified to DNA fragments and significant amounts of polymorphism was observed within population. The nine polymorphic microsatellite loci were used for population structure and diversity analyses. The obtained results revealed high levels of genetic diversity in populations, the average observed and expected heterozygosity were H_O = 0.422 and H_E = 0.479, respectively. During the Bottleneck analysis using TPM and SMM models (p < 0.01) shows that targeted population is significantly heterozygote deficient. This suggests sign of the bottleneck in all populations. Genetic differentiation between populations was moderate (F_ST = 0.133) and indicating slightly high level of gene flow (Nm = 1.63). Analysis of molecular variance (AMOVA) showed 63.17% of variation within individuals and 12.45% among populations. Our results shows two genetic clusters related to geographical distances.Conclusion: Our study will assist conservators in future conservation management, breeding, production and habitats restoration of the species.

Cinnamomum parthenoxylon is an endemic and endangered species with significant economic and ecological value in Vietnam. A better understanding of the genetic architecture of the species will be useful when planning management and conservation. We aimed to characterize the transcriptome of C. parthenoxylon, develop novel molecular markers, and assess the genetic variability of the species. First, transcriptome sequencing of five trees (C. parthenoxylon) based on root, leaf, and stem tissues was performed for functional annotation analysis and development of novel molecular markers. The transcriptomes of C. parthenoxylon were analyzed via an Illumina HiSeq^TM 4000 sequencing system. A total of 27,363,199 bases were generated for C. parthenoxylon. De novo assembly indicated that a total of 160,435 unigenes were generated (average length = 548.954 bp). The 51,691 unigenes were compared against different databases, i.e. COG, GO, KEGG, KOG, Pfam, Swiss-Prot, and NR for functional annotation. Furthermore, a total of 12,849 EST-SSRs were identified. Of the 134 primer pairs, 54 were randomly selected for testing, with 15 successfully amplified across nine populations of C. parthenoxylon. We uncovered medium levels of genetic diversity (PIC = 0.52, Na = 3.29, Ne = 2.18, P = 94.07%, Ho = 0.56 and He = 0.47) within the studied populations. The molecular variance was 10% among populations and low genetic differentiation (Fst = 0.06) indicated low gene flow (Nm = 2.16). A reduction in the population size of C. parthenoxylon was detected using BOTTLENECK (VP population). The structure analysis suggested two optimal genetic clusters related to gene flow among the populations. Analysis of molecular variance (AMOVA) revealed higher genetic variation within populations (90%) than among populations (10%). The UPGMA approach and DAPC divided the nine populations into three main clusters. Our findings revealed a significant fraction of the transcriptome sequences and these newlydeveloped novel EST-SSR markers are a very efficient tool for germplasm evaluation, genetic diversity and molecular marker-assisted selection in C. parthenoxylon. This study provides comprehensive genetic resources for the breeding and conservation of different varieties of C. parthenoxylon.

Ca-bentonite (CB) alone and in a mixture with limestone (L), tobacco biochar (TB) and zeolite (Z) on the fixation, geochemical fractions and absorption of Cd and Zn by Chinese cabbage in smelter heavily polluted (S-HP) and smelter low polluted (S-LP) soils were investigated. The results showed that the CB + TB and CB + L + TB treatments significantly immobilized Cd up to 22.0% and 29.7%, respectively, and reduced uptake by Chinese cabbage shoot to 36.0% with CB + Z + L and 61.3% with CB + L in S-HP and S-LP soils compared with the control. The CB + Z + L + TB treatment mobilized Cd up to 4.4% and increased absorption in the shoot by 9.9% in S-HP soil. The greatest immobilization of Zn was 53.2% and 58.2% with the CB + Z + L + TB treatment, which reduced Zn uptake in the plant shoot by 10.0% with CB + L and 58.0% with CB + Z + L + TB in S-HP and S-LP soils. The CB + Z + TB and CB + TB treatments mobilized Zn up to 35.4% and 4.9%, respectively, in both soils. Furthermore, the uptake of Zn in plant shoot was observed by 59.0% and 7.9% with application of CB + Z and CB + TB treatments, respectively, in S-HP and S-LP soils. Overall, our results suggest that Ca-bentonite alone and in mixtures with different amendments can be used to reduce the phyto-extraction of Cd and Zn in Zn-smelter polluted soils.

Background: Bruguiera hainesiiC.G. Rogers 1919, a true mangrove tree is a critically endangered species (CR) in Vietnam. This species is restricted to the Con Dao National Park, Ba Ria-Vung Tau province, where it occurs in very tiny populations. However, the exploration of the chloroplast genome ofB. hainesiiin Vietnam has a serious lack of information. It is extremely challenging to promote the conservation ofB. hainesii. Therefore, urgently required to discover and comprehend the chloroplast genome ofB. hainesii.Methods: To detect evolutionary analysis between mangroves, we sequenced the complete chloroplast genome ofB. hainesiiusing next-generation sequencing technology (Illumina Hiseq X Ten).Results: We sequenced and assembled the complete chloroplast genome ofB. hainesii, which was deposited in GenBank as accession number OR086085. The DNA was circular with 164,305 bp length, comprising 37% GC. The genome contained a large single-copy region of 91,724 bp, inverted repeat regions of 26,360 bp, and a short single-copy region of 19,861 bp. Furthermore, it contained 130 genes, consisting of 83 protein-coding genes, 37tRNAs, and 8rRNAs. We detected 131 single-sequence repeats, including 119 mononucleotides, 11 dinucleotides, and one trinucleotide. Phylogenetic analysis showed strong support thatB. hainesiiwas sister toB. cylindrica.Conclusions: The findings in this study provide a foundation for species identification, evolutionary genetics, and the conservation of endangeredB. hainesiiin Vietnam.

Bruguiera hainesii is a rare mangrove species with limited populations worldwide, but there is lack of detailed knowledge about its population size and distribution in Vietnam. Its regeneration capacity is notably low, raising concerns about its long-term survival. This study aims to model the bioclimatic niche of B. hainesii to identify potential ecological regions in Vietnam suitable for its conservation and survival under current and future climate scenarios. Occurrence data were collected from the global GBIF database and recent field surveys in Vietnam conducted during 2023–2024. The Maxent model was used to predict bioclimatic suitability, with projections extended to future climate scenarios using ACCESS-CM2 under SSP2-4.5 (medium-emission scenario) for 2080–2100. The study identified Vietnam as a highly suitable region for B. hainesii despite its small population size. Projections indicate a potential expansion of ideal habitats under future climate conditions, highlighting the species' adaptability. The findings provide valuable insights into the conservation of B. hainesii, emphasising the importance of preserving existing populations and managing suitable habitats to ensure the species' long-term survival and regeneration. This research also underscores the role of bioclimatic niche modelling in guiding conservation strategies for endangered mangroves.