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Objectives Development of sequencing technology has opened up vast opportunities for tree genomic research in the tropics. One of the aforesaid technologies named ONT (Oxford Nanopore Technology) has attracted researchers in undertaking testings and experiments due to its affordability and accessibility. To the best of our knowledge, there has been no published reports on the use of ONT for genomic analysis of Indonesian tree species. This progress is promising for further improvement in order to acquire more genomic data for research purposes. Therefore, the present study was carried out to determine the effectiveness of ONT in generating long-read DNA sequences using DNA isolated from leaves and wood cores of Macassar ebony (Diospyros celebica Bakh.). Data description Long-read sequences data of leaves and wood cores of Macassar ebony were generated by using the MinION device and MinKnow v3.6.5 (ONT). The obtained data, as the first long-read sequence dataset for Macassar ebony, is of great importance to conserve the genetic diversity, understanding the molecular mechanism, and sustainable use of plant genetic resources for downstream applications.

Objectives Efforts to restore tropical peat swamp forests in Indonesia face huge challenges of potential failures due to socio-economic factors and ecological dynamics attributed to lack of knowledge on the adaptive mechanisms of potential tree species such as Kapur (Dryobalanops aromatica C.F.Gaertn Syn. Dryobalanops sumatrensis J.F. Gmelin A.J.G.H Kostermans). This species is a multi-purpose tree that, commonly grows in mineral soils, but also in peat swamp as previously reported, which raised a fundamental question regarding the molecular mechanism of this adaptation. Therefore, a dataset was created aiming to detect candidates of adaptive genes in D. aromatica seedlings, cultivated in two contrasting potting media, namely mineral soil and peat media, based on RNA Sequencing Transcriptome Analysis. Data description The RNA transcriptome data of D. aromatica’s seedlings derived from young leaves of three one-year-old seedlings, raised in each dry mineral soil media and peat media, were generated by using Illumina HiSeq 4000 platform in NovogenAIT, Singapore. The acquired data, as the first transcriptome dataset for D. aromatica, is of a great importance in understanding molecular mechanism and responses of the involved genes of D. aromatica to the contrasting, growing potting media conditions that could also be useful to generate molecular markers.

Large-scale genetic structure revealed in tree populations in SE Asia, as well as in many temperate forests, has been shaped by climatic fluctuation in the late Pleistocene, most importantly by that in the last glacial period. In a comparative study of the phylogeographic patterns of two closely related dipterocarp species, Dryobalanops aromatica C.F.Gaertn. and D. beccarii Dyer, we investigated how changes in land area associated with changes in climate affected large-scale genetic structure. We examined the genetic variation of D. aromatica, collected from nine populations throughout the Sundaic region, and of D. beccarii, collected from 16 populations mainly in Borneo, using seven polymorphic microsatellite markers. The two species were clearly distinguishable in the STRUCTURE analysis, although hybridisation probably occurred in sympatric populations and also in several other populations. The D. aromatica populations were divided into two main groups by the STRUCTURE analysis: Malay–Sumatra and Borneo. Mixing of the Sumatra and Borneo clusters occurred on the Malay Peninsula, supporting the hypothesis that tropical rainforests expanded over a dried Sunda Shelf during the last glacial period. The two main genetic clusters might have been formed by repeated cycles of fluctuation in land area. The D. beccarii populations in Borneo were divided into four geographically distinct groups: western Sarawak, central inland Sarawak, central coastal Sarawak and Sabah. The population on the Malay Peninsula (Gunung Panti) was an admixture of the four Bornean clusters. This suggests that this population is a relic of the recent range expansion of D. beccarii during the last glacial period.

Genetic variation and structure of Ubame oak (Quercus phillyraeoides A. Gray), a shrub tree on the Pacific coast of Japan, were examined to elucidate historical population dynamics using five chloroplast DNA (cpDNA) marker regions and 11 nuclear microsatellite loci. Three cpDNA haplotypes (A, B and C) were identified in a screen of 41 populations across the entire distribution range in Japan. Haplotype A was the most prevalent and was found in the entire range. Haplotype B was locally restricted to the Kii Peninsula, while haplotype C was restricted to the southwestern part of Japan. These haplotypes corresponded with the nuclear genetic constitution revealed by microsatellite markers. Two genetically differentiated major groups were identified by STRUCTURE analysis applied to 536 individuals from 28 populations, and they mostly corresponded with the two major cpDNA haplotypes, A and C. These populations were further divided into three geographically identified groups: group 1 in the area including Kanto and Tokai regions, the Kii Peninsula and the Muroto-misaki Cape on the Pacific coast; group 2 in the Bungo-suido Channel area; and group 3 in southern Kyushu and Okinawa. Populations in the Seto Inland Sea were divided into two groups: one was included in group 1 and appears to have originated from last glacial maximum (LGM) refugia located in the Kii Peninsula, while the other was included in group 2 and appears to have originated from LGM refugia located in southern Kyushu. These groups can be considered as conservation units for the preservation of unique seashore ecosystems, or as a seed source to foster coastal protection forests and next-generation production forests. Considerable care should be taken to protect isolated populations that may be specialized to unique local environments, such as those on the islands of Koshikijima and Izenajima.