Kevin Ng Kit Siong
@frim.gov.my
Senior Researcher and Forest Biotechnology Division/Genetics Laboratory
Forest Research Institute Malaysia
EDUCATION
1999 - BSc (Hons) Universiti Malaysia Sabah
2004 - PhD - University of Malaya
RESEARCH INTERESTS
Population Genetics; Conservation Genetics; Tropical Forests; Genomics
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Lee Hong Tnah, Soon Leong Lee, Chai Ting Lee, Kevin Kit Siong Ng, Chin Hong Ng, and Ngah Zawiah
Springer Science and Business Media LLC
Chin Hong Ng, Kevin Kit Siong Ng, Soon Leong Lee, Rempei Suwa, Chai Ting Lee, and Lee Hong Tnah
Springer Science and Business Media LLC
AbstractMany tree planting programmes have long been initiated to increase forest cover to mitigate the effects of global climate change. Successful planting requires careful planning at the project level, including using suitable species with favourable traits. However, there is a paucity of improvement data for tropical tree species. An experimental common garden of Shorea leprosula was established to study traits related to growth performance which are key factors in planting success. Seedlings of S. leprosula were collected from nine geographical forest reserves. To study the effects of genetic variation, seedlings were planted in a common environment following a randomized complete block design. From performance data collected 2017‒2019, one population showed the highest coefficient for relative height growth, significantly higher than most of the other populations. Interestingly, this population from Beserah also exhibited the lowest coefficient for scale insect infestation. This study provides preliminary results on growth performance and susceptibility to scale insect infestation in S. leprosula and the first common garden experiment site conducted on dipterocarp species. It lays a foundation for future genome-wide studies.
Lee Hong Tnah, Chai Ting Lee, Chin Hong Ng, Kevin Kit Siong Ng, Zakaria Nurul Farhanah, and Soon Leong Lee
Springer Science and Business Media LLC
Chin Hong Ng, Kevin Kit Siong Ng, Soon Leong Lee, Nurul-Farhanah Zakaria, Chai Ting Lee, and Lee Hong Tnah
Springer Science and Business Media LLC
AbstractInternational timber trade communities are increasingly demanding that timber in the wood supply chain be sourced from sustainably harvested forests and certified plantations. This is to combat illegal logging activities to prevent further depletion of our precious forests worldwide. Hence, timber tracking tools are important to support law enforcement officials in ensuring only sustainably harvested timbers are traded in the market. In this study, we developed chloroplast DNA (cpDNA) and simple sequence repeat (SSR) databases as tracking tools for an important tropical timber tree species, Shorealeprosula from Peninsular Malaysia. A total of 1410 individual trees were sampled from 44 natural populations throughout Peninsular Malaysia. Four cpDNA regions were used to generate a cpDNA haplotype database, resulting in a haplotype map comprising 22 unique haplotypes derived from 28 informative intraspecific variable sites. This cpDNA database can be used to trace the origin of an unknown log at the regional level. Ten SSR loci were used to develop the SSR allele frequency database. Bayesian cluster analysis divided the 44 populations into two genetic clusters corresponding to Region A and Region B. Based on conservativeness evaluation of the SSR databases for individual identification, the coancestry coefficients (θ) were adjusted to 0.1900 and 0.1500 for Region A and B, respectively. These databases are useful tools to complement existing timber tracking systems in ensuring only legally sourced timbers are allowed to enter the wood supply chain.
Soon Leong Lee, Nurul-Farhanah Zakaria, Lee Hong Tnah, Chin Hong Ng, Kevin Kit Siong Ng, Chai Ting Lee, Kah Hoo Lau, and Lillian Swee Lian Chua
Elsevier BV
Masato Ohtani, Naoki Tani, Saneyoshi Ueno, Kentaro Uchiyama, Toshiaki Kondo, Soon Leong Lee, Kevin Kit Siong Ng, Norwati Muhammad, Reiner Finkeldey, Oliver Gailing,et al.
Springer Science and Business Media LLC
Kevin Kit Siong Ng, Masaki J. Kobayashi, Jeffrey A. Fawcett, Masaomi Hatakeyama, Timothy Paape, Chin Hong Ng, Choon Cheng Ang, Lee Hong Tnah, Chai Ting Lee, Tomoaki Nishiyama,et al.
Springer Science and Business Media LLC
AbstractHyperdiverse tropical rainforests, such as the aseasonal forests in Southeast Asia, are supported by high annual rainfall. Its canopy is dominated by the species-rich tree family of Dipterocarpaceae (Asian dipterocarps), which has both ecological (e.g., supports flora and fauna) and economical (e.g., timber production) importance. Recent ecological studies suggested that rare irregular drought events may be an environmental stress and signal for the tropical trees. We assembled the genome of a widespread but near threatened dipterocarp, Shorea leprosula, and analyzed the transcriptome sequences of ten dipterocarp species representing seven genera. Comparative genomic and molecular dating analyses suggested a whole-genome duplication close to the Cretaceous-Paleogene extinction event followed by the diversification of major dipterocarp lineages (i.e. Dipterocarpoideae). Interestingly, the retained duplicated genes were enriched for genes upregulated by no-irrigation treatment. These findings provide molecular support for the relevance of drought for tropical trees despite the lack of an annual dry season.
C T Lee, L H Tnah, Z H Humaira’, Z Nurul-Farhanah, S L Lee, K K S Ng, C H Ng, A Nur-Nabilah, B Norlia, A Noorsiha,et al.
IOP Publishing
Abstract Located at Bersia Timur, the Rafflesia Conservation and Interpretive Centre (RCIC) was initiated by the Forest Research Institute Malaysia (FRIM) and FELDA to boost research and conservation efforts of the iconic Rafflesia species in the state of Perak. It also plays a role in supporting the economy of local communities by promoting local eco-tourism, providing trainings to local tour-guides and involving them in conserving the Rafflesia population. As part of the R & D and conservation effort, genetic diversity assessment of Rafflesia cantleyi from RCIC and Gerik Forest Reserve (FR) was carried out. Bract samples from a total of eight and 35 R. cantleyi individuals of different flowering / anthesis stages were collected from RCIC and Gerik FR, respectively. We used nine polymorphic microsatellite markers for genotyping. Despite the small sample size (∼75% lesser compared with Gerik FR), the total number of alleles observed in RCIC is > 50% than that of Gerik FR, i.e., 33 compared to 57. The genetic diversity measure in terms of observed (Ho) and expected (He) heterozygosities from both sites are comparable (RCIC: Ho = 0.5298, He = 0.5347; Gerik FR: Ho = 0.5145, He = 0.5868). Our findings suggest that the R. cantleyi population in Gerik FR is a suitable source for future translocation activities.
Masaki J. KOBAYASHI, Kevin Kit Siong NG, Soon Leong LEE, Norwati MUHAMMAD, and Naoki TANI
Japan International Research Center for Agricultural Sciences
Abstract Understanding internode elongation in woody species is the basis of stable timber production. Although trees exhibit coordinated growth between leaves and internodes, it is unclear whether their coordinated growth occurs simply because both organs receive a common signal that triggers their growth or because the growth of one organ is regulated by the other. To test the latter possibility, we defined simple developmental stages and assessed the effect of leaves on the regulation of internode elongation at the phytomer level in the tropical tree Shorea leprosula, which is an important timber tree species in Southeast Asia. Our observation of phytomers showed that leaves and internodes grew coordinately in S. leprosula. A spatiotemporal analysis of internode elongation indicated that internode elongation occurred around young expanding leaves. Furthermore, the excision of expanding leaves significantly reduced internode elongation. These results suggest that expanding leaves positively regulate internode elongation. Therefore, the growth interactions between leaves and internodes must be considered in order to better understand the mechanism of internode elongation in S. leprosula. These results will also form the basis of future studies aimed at sustainable timber production using this species.
Amelia Azman, Kevin-Kit-Siong Ng, Chin-Hong Ng, Chai-Ting Lee, Lee-Hong Tnah, Nurul-Farhanah Zakaria, Suhaila Mahruji, Khairuddin Perdan, Md-Zaidey Abdul-Kadir, Acga Cheng,et al.
Springer Science and Business Media LLC
AbstractWorldwide, many mangrove species are experiencing significant population declines, including Rhizophora apiculata, which is one of the most widespread and economically important species in tropical Asia. In Malaysia, there has been an alarming decline in R. apiculata populations driven primarily by anthropogenic activities. However, the lack of genetic and demographic information on this species has hampered local efforts to conserve it. To address these gaps, we generated novel genetic information for R. apiculata, based on 1,120 samples collected from 39 natural populations in Peninsular Malaysia. We investigated its genetic diversity and genetic structure with 19 transcriptome and three nuclear microsatellite markers. Our analyses revealed a low genetic diversity (mean He: 0.352) with significant genetic differentiation (FST: 0.315) among populations of R. apiculata. Approximately two-third of the populations showed significant excess of homozygotes, indicating persistent inbreeding which might be due to the decrease in population size or fragmentation. From the cluster analyses, the populations investigated were divided into two distinct clusters, comprising the west and east coasts of Peninsular Malaysia. The western cluster was further divided into two sub-clusters with one of the sub-clusters showing strong admixture pattern that harbours high levels of genetic diversity, thus deserving high priority for conservation.
Masaki J. Kobayashi, Kevin Kit Siong Ng, Soon Leong Lee, Norwati Muhammad, and Naoki Tani
Wiley
Premise Leaf phenology is an essential developmental process in trees and an important component in understanding climate change. However, little is known about the regulation of leaf phenology in tropical trees. Methods To understand the regulation by temperature of leaf phenology in tropical trees, we performed daily observations of leaf production under rainfall‐independent conditions using saplings of Shorea leprosula and Neobalanocarpus heimii, both species of Dipterocarpaceae, a dominant tree family of Southeast Asia. We analyzed the time‐series data obtained using empirical dynamic modeling (EDM) and conducted growth chamber experiments. Results Leaf production by dipterocarps fluctuated in the absence of fluctuation in rainfall, and the peaks of leaf production were more frequent than those of day length, suggesting that leaf production cannot be fully explained by these environmental factors, although they have been proposed as regulators of leaf phenology in dipterocarps. Instead, EDM suggested a causal relationship between temperature and leaf production in dipterocarps. Leaf production by N. heimii saplings in chambers significantly increased when temperature was increased after long‐term low‐temperature treatment. This increase in leaf production was observed even when only nighttime temperature was elevated, suggesting that the effect of temperature on development is not mediated by photosynthesis. Conclusions Because seasonal variation in temperature in the tropics is small, effects on leaf phenology have been overlooked. However, our results suggest that temperature is a regulator of leaf phenology in dipterocarps. This information will contribute to better understanding of the effects of climate change in the tropics.
Chin Ng, Kevin Ng, Chai Lee, Lee Tnah, Nurul Zakaria, Noorsiha Ayop, and Soon Lee
MDPI AG
Our study highlights the utilization of a genetic database for wood-origin identification in Intsia palembanica, a valuable heavy hardwood from the tropical forests. This forensic tool is essential for strengthening the verification of legality in the wood supply chain from the forest to the end-users. An increasing number of rules and regulations are being put in place to promote sustainable practice in the timber trade, one of which involves ensuring that importers declare the correct species name and source of geographic origin of the timber. We aimed to determine the origin of the I. palembanica seed source used in the early establishment on the Forest Research Institute Malaysia (FRIM) campus. DNA samples of I. palembanica individuals from the FRIM campus were obtained and analyzed using four chloroplast (cp) DNA markers to characterize the haplotype variants for population identification. In addition, the DNA samples were also genotyped at 14 short tandem repeat (STR) loci for individual identification. Individual assignment to the possible geographic origin was done through an assignment test. On the basis of our recently developed I. palembanica genetic databases, the I. palembanica seed source for the early establishment was inferred to be originated from a mixture of several sources, with a large portion from the southern region (89%) and a relatively small portion from the northern region (11%) of Peninsular Malaysia. The I. palembanica seed source used for the early establishment on the century old FRIM campus was inferred to be originated from several forest reserves located not far from the planting sites. This study proves the applicability of the DNA method in supply-chain verification, where an unknown I. palembanica tree can be traced to its geographic origin using genetic databases.
Sawitri, Naoki Tani, Mohammad Na’iem, Widiyatno, Sapto Indrioko, Kentaro Uchiyama, Rempei Suwa, Kevin Kit Siong Ng, Soon Leong Lee, and Yoshihiko Tsumura
MDPI AG
Shorea platyclados (Dark Red Meranti) is a commercially important timber tree species in Southeast Asia. However, its stocks have dramatically declined due, inter alia, to excessive logging, insufficient natural regeneration and a slow recovery rate. Thus, there is a need to promote enrichment planting and develop effective technique to support its rehabilitation and improve timber production through implementation of Genome-Wide Association Studies (GWAS) and Genomic Selection (GS). To assist such efforts, plant materials were collected from a half-sib progeny population in Sari Bumi Kusuma forest concession, Kalimantan, Indonesia. Using 5900 markers in sequences obtained from 356 individuals, we detected high linkage disequilibrium (LD) extending up to >145 kb, suggesting that associations between phenotypic traits and markers in LD can be more easily and feasibly detected with GWAS than with analysis of quantitative trait loci (QTLs). However, the detection power of GWAS seems low, since few single nucleotide polymorphisms linked to any focal traits were detected with a stringent false discovery rate, indicating that the species’ phenotypic traits are mostly under polygenic quantitative control. Furthermore, Machine Learning provided higher prediction accuracies than Bayesian methods. We also found that stem diameter, branch diameter ratio and wood density were more predictable than height, clear bole, branch angle and wood stiffness traits. Our study suggests that GS has potential for improving the productivity and quality of S. platyclados, and our genomic heritability estimates may improve the selection of traits to target in future breeding of this species.
KKS Ng, SL Lee, LH Tnah, CH Ng, CT Lee, Z Nurul-Farhanah, and A Amelia
Forest Research Institute Malaysia
Chin Hong Ng, Kevin Kit Siong Ng, Soon Leong Lee, Lee Hong Tnah, Chai Ting Lee, and Nurul-Farhanah Zakaria
Elsevier BV
Chin-Hong Ng, Soon-Leong Lee, Lee-Hong Tnah, Kevin K S Ng, Chai-Ting Lee, Bibian Diway, and Eyen Khoo
Oxford University Press (OUP)
AbstractSoutheast Asian rainforests at upper hill elevations are increasingly vulnerable to degradation because most lowland forest areas have been converted to different land uses. As such, understanding the genetics of upper hill species is becoming more crucial for their future management and conservation. Shorea platyclados is an important, widespread upper hill dipterocarp in Malaysia. To elucidate the genetic structure of S. platyclados and ultimately provide guidelines for a conservation strategy for this species, we carried out a comprehensive study of the genetic diversity and demographic history of S. platyclados. Twenty-seven populations of S. platyclados across its range in Malaysia were genotyped at 15 polymorphic microsatellite loci and sequenced at seven noncoding chloroplast DNA (cpDNA) regions. A total of 303 alleles were derived from the microsatellite loci, and 29 haplotypes were identified based on 2892 bp of concatenated cpDNA sequences. The populations showed moderately high genetic diversity (mean HE = 0.680 for microsatellite gene diversity and HT = 0.650 for total haplotype diversity) and low genetic differentiation (FST = 0.060). Bayesian clustering divided the studied populations into two groups corresponding to western and eastern Malaysia. Bottleneck analysis did not detect any recent bottleneck events. Extended Bayesian skyline analyses showed a model of constant size for the past population history of this species. Based on our findings, priority areas for in situ and ex situ conservation and a minimum population size are recommended for the sustainable utilization of S. platyclados.
L.H. Tnah, S.L. Lee, A.L. Tan, C.T. Lee, K.K.S. Ng, C.H. Ng, and Z. Nurul Farhanah
Elsevier BV
James R. Smith, Jaboury Ghazoul, David F. R. P. Burslem, Akira Itoh, Eyen Khoo, Soon Leong Lee, Colin R. Maycock, Satoshi Nanami, Kevin Kit Siong Ng, and Chris J. Kettle
Public Library of Science (PLoS)
Documenting the scale and intensity of fine-scale spatial genetic structure (FSGS), and the processes that shape it, is relevant to the sustainable management of genetic resources in timber tree species, particularly where logging or fragmentation might disrupt gene flow. In this study we assessed patterns of FSGS in three species of Dipterocarpaceae (Parashorea tomentella, Shorea leprosula and Shorea parvifolia) across four different tropical rain forests in Malaysia using nuclear microsatellite markers. Topographic heterogeneity varied across the sites. We hypothesised that forests with high topographic heterogeneity would display increased FSGS among the adult populations driven by habitat associations. This hypothesis was not supported for S. leprosula and S. parvifolia which displayed little variation in the intensity and scale of FSGS between sites despite substantial variation in topographic heterogeneity. Conversely, the intensity of FSGS for P. tomentella was greater at a more topographically heterogeneous than a homogeneous site, and a significant difference in the overall pattern of FSGS was detected between sites for this species. These results suggest that local patterns of FSGS may in some species be shaped by habitat heterogeneity in addition to limited gene flow by pollen and seed dispersal. Site factors can therefore contribute to the development of FSGS. Confirming consistency in species’ FSGS amongst sites is an important step in managing timber tree genetic diversity as it provides confidence that species specific management recommendations based on species reproductive traits can be applied across a species’ range. Forest managers should take into account the interaction between reproductive traits and site characteristics, its consequences for maintaining forest genetic resources and how this might influence natural regeneration across species if management is to be sustainable.
Lee CT, Norlia B, Tnah LH, Lee SL, Ng CH, Ng KKS, Nor-Hasnida H, Nurul-Farhanah Z, Suryani CS, and Nur-Nabilah A
Forest Research Institute Malaysia
Cheng Choon Ang, Michael J. O’Brien, Kevin Kit Siong Ng, Ping Chin Lee, Andy Hector, Bernhard Schmid, and Kentaro K. Shimizu
Informa UK Limited
Background: The impact of logging and restoration on species diversity has been well studied in tropical forests. However, little is known about their effects on genetic diversity within species. Aims: We assess the degree of genetic diversity among dipterocarp seedlings used for enrichment planting of selectively logged forests in Sabah, Malaysia, and compare it with diversity in naturally regenerating seedlings. Methods: We sampled young leaf tissues from seedlings of Shorea leprosula and Parashorea malaanonan for DNA genotyping, using microsatellite markers. Results: The levels of genetic diversity (expected heterozygosity and rarefied allelic richness) of naturally regenerating seedlings were statistically indistinguishable among unlogged, once logged and repeatedly logged forest areas. Enrichment-planted seedlings of P. malaanonan exhibited similar levels of genetic diversity to naturally regenerating seedlings whereas those of S. leprosula had significantly lower genetic diversity than natural seedlings. Interestingly, reduction of genetic variation was consistently observed in single-species plots relative to mixed-species plots among enrichment-planted seedlings. Conclusions: There was no reduction of genetic variation in naturally regenerating dipterocarp seedlings in areas of selective logging. However, genetic variation of enrichment-planted seedlings was lower in single-species plots relative to mixed-species plots. This suggests that enrichment-planting strategies should adopt diverse mixtures that should promote levels of both species richness and genetic diversity within species.
Chin Hong Ng, Soon Leong Lee, Lee Hong Tnah, Kevin Kit Siong Ng, Chai Ting Lee, and Maria Madon
Informa UK Limited
Background: Dipterocarpaceae is a pantropical tree family that plays an important role in our understanding of the ecology of Asian tropical rain forests. However, genome sizes for members of the Dipterocarpaceae are still poorly known. Aims: To report the genome size of 115 dipterocarp species and examine the variation and evolution of genome size in this family. Methods: Genome size was estimated using flow cytometry. Both the rpoB and trnL intron were sequenced to uncover the evolution of genome size within a phylogenetic framework. Results: The 1C genome size varied between 0.267 and 0.705 pg in Shorea hemsleyana and Shorea ovalis, respectively, a 2.64-fold variation across the family. Most dipterocarps are characterised by very small genomes with a mean 1C value of 0.416 pg (sd = 0.075) and five polyploids are recorded. The ancestral genome size for dipterocarps was reconstructed as 1Cx = 0.481 pg (95% CI = 0.433–0.534). Conclusions: Genome size variation in dipterocarps was characterised by very small values with a narrow range. Overall, genome size reduction from the ancestral state is a general trend in Dipterocarpaceae.
Toshiaki Kondo, Sen Nishimura, Naoki Tani, Kevin Kit Siong Ng, Soon Leong Lee, Norwati Muhammad, Toshinori Okuda, Yoshihiko Tsumura, and Yuji Isagi
Wiley
PREMISE OF THE STUDY
In tropical rainforests of Southeast Asia, a highly fecund thrips (Thrips spp.) responds rapidly to the mass flowering at multiple-year intervals characteristic of certain species such as the canopy tree studied here, Shorea acuminata, by feeding on flower resources. However, past DNA analyses of pollen adherent to thrips bodies revealed that the thrips promoted a very high level of self-pollination. Here, we identified the pollinator that contributes to cross-pollination and discuss ways that the pollination system has adapted to mass flowering.
METHODS
By comparing the patterns of floral visitation and levels of genetic diversity in adherent pollen loads among floral visitors, we evaluated the contribution of each flower visitor to pollination.
KEY RESULTS
The big-eyed bug, Geocoris sp., a major thrips predator, was an inadvertent pollinator, and importantly contributed to cross-pollination. The total outcross pollen adhering to thrips was approximately 30% that on the big-eyed bugs. Similarly, 63% of alleles examined in S. acuminata seeds and seedlings occurred in pollen adhering to big-eyed bugs; about 30% was shared with pollen from thrips.
CONCLUSIONS
During mass flowering, big-eyed bugs likely travel among flowering S. acuminata trees, attracted by the abundant thrips. Floral visitation patterns of big-eyed bugs vs. other insects suggest that these bugs can maintain their population size between flowering by preying upon another thrips (Haplothrips sp.) that inhabits stipules of S. acuminata throughout the year and quickly respond to mass flowering. Thus, thrips and big-eyed bugs are essential components in the pollination of S. acuminata.
Lee Hong Tnah, Soon Leong Lee, Ai Lee Tan, Chai Ting Lee, Kevin Kit Siong Ng, and Chin Hong Ng
Elsevier BV
Kevin Kit Siong Ng, Soon Leong Lee, Lee Hong Tnah, Zakaria Nurul-Farhanah, Chin Hong Ng, Chai Ting Lee, Naoki Tani, Bibian Diway, Pei Sing Lai, and Eyen Khoo
Elsevier BV