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Fulltext Identification and characterization of jasmonic acid- and linolenic acid-mediated transcriptional regulation of secondary laticifer differentiation in Hevea brasiliensis

Loh SC, Othman AS, Veera Singham G

Sci Rep, 2019 10 04;9(1):14296.
PMID: 31586098 DOI: 10.1038/s41598-019-50800-1

Hevea brasiliensis remains the primary crop commercially exploited to obtain latex, which is produced from the articulated secondary laticifer. Here, we described the transcriptional events related to jasmonic acid (JA)- and linolenic acid (LA)-induced secondary laticifer differentiation (SLD) in H. brasiliensis clone RRIM 600 based on RNA-seq approach. Histochemical approach proved that JA- and LA-treated samples resulted in SLD in H. brasiliensis when compared to ethephon and untreated control. RNA-seq data resulted in 86,614 unigenes, of which 2,664 genes were differentially expressed in JA and LA-induced secondary laticifer harvested from H. brasiliensis bark samples. Among these, 450 genes were unique to JA and LA as they were not differentially expressed in ethephon-treated samples compared with the untreated samples. Most transcription factors from the JA- and LA-specific dataset were classified under MYB, APETALA2/ethylene response factor (AP2/ERF), and basic-helix-loop-helix (bHLH) gene families that were involved in tissue developmental pathways, and we proposed that Bel5-GA2 oxidase 1-KNOTTED-like homeobox complex are likely involved in JA- and LA-induced SLD in H. brasiliensis. We also discovered alternative spliced transcripts, putative novel transcripts, and cis-natural antisense transcript pairs related to SLD event. This study has advanced understanding on the transcriptional regulatory network of SLD in H. brasiliensis.
Identification of differentially expressed genes and signalling pathways in bark of Hevea brasiliensis seedlings associated with secondary laticifer differentiation using gene expression microarray

Loh SC, Thottathil GP, Othman AS

Plant Physiol Biochem, 2016 Oct;107:45-55.
PMID: 27236227 DOI: 10.1016/j.plaphy.2016.05.011

The natural rubber of Para rubber tree, Hevea brasiliensis, is the main crop involved in industrial rubber production due to its superior quality. The Hevea bark is commercially exploited to obtain latex, which is produced from the articulated secondary laticifer. The laticifer is well defined in the aspect of morphology; however, only some genes associated with its development have been reported. We successfully induced secondary laticifer in the jasmonic acid (JA)-treated and linolenic acid (LA)-treated Hevea bark but secondary laticifer is not observed in the ethephon (ET)-treated and untreated Hevea bark. In this study, we analysed 27,195 gene models using NimbleGen microarrays based on the Hevea draft genome. 491 filtered differentially expressed (FDE) transcripts that are common to both JA- and LA-treated bark samples but not ET-treated bark samples were identified. In the Eukaryotic Orthologous Group (KOG) analysis, 491 FDE transcripts belong to different functional categories that reflect the diverse processes and pathways involved in laticifer differentiation. In the Kyoto Encyclopedia of Genes and Genomes (KEGG) and KOG analysis, the profile of the FDE transcripts suggest that JA- and LA-treated bark samples have a sufficient molecular basis for secondary laticifer differentiation, especially regarding secondary metabolites metabolism. FDE genes in this category are from the cytochrome (CYP) P450 family, ATP-binding cassette (ABC) transporter family, short-chain dehydrogenase/reductase (SDR) family, or cinnamyl alcohol dehydrogenase (CAD) family. The data includes many genes involved in cell division, cell wall synthesis, and cell differentiation. The most abundant transcript in FDE list was SDR65C, reflecting its importance in laticifer differentiation. Using the Basic Local Alignment Search Tool (BLAST) as part of annotation and functional prediction, several characterised as well as uncharacterized transcription factors and genes were found in the dataset. Hence, the further characterization of these genes is necessary to unveil their role in laticifer differentiation. This study provides a platform for the further characterization and identification of the key genes involved in secondary laticifer differentiation.
Fulltext Physical Activity and Motor Performance: A Comparison Between Young Children With and Without Autism Spectrum Disorder

Sung YS, Loh SC, Lin LY

Neuropsychiatr Dis Treat, 2021;17:3743-3751.
PMID: 34984002 DOI: 10.2147/NDT.S343552

Purpose: This study aims to examine the differences in physical activity and motor performance between young children with autism spectrum disorder (ASD) and children with typical development (TD) and to investigate the relationships between the levels of physical activity and motor performance.
Patients and Methods: Twenty-five children with ASD (mean age = 59.3 ± 8.1 months) and 28 children with TD (mean age = 63.1 ± 8.6 months) were recruited. The Actigraph accelerometer, Movement Assessment Battery for Children-second edition, and Assessment of Preschool Children's Participation were used.
Results: Young children with ASD spent significantly less time in moderate and light physical activity and exhibited more sedentary behavior than did children with TD. Those children with ASD also had greater motor difficulties and engaged less frequently in physical recreation activities compared to their TD peers. Motor performance was significantly correlated with physical activity in all children.
Conclusion: This study highlighted the specificity of the levels of physical activity, motor difficulties, and participation diversity in children with ASD comparing performances on children with TD. Additional research is needed to provide valuable information for early interventions.
Fulltext A meta-analysis of the effect of the Early Start Denver Model in children with autism spectrum disorder

Wang Z, Loh SC, Tian J, Chen QJ

Int J Dev Disabil, 2022;68(5):587-597.
PMID: 36210899 DOI: 10.1080/20473869.2020.1870419

Objectives: To examine and analyse the intervention effects of the Early Start Denver Model (ESDM) on children with autism spectrum disorder (ASD). Methods: This meta-analysis evaluated the effect sizes in four major domains of measurement (autism symptoms, language, cognition, and social communication). A total of 624 participants with ASD were included in 11 high-quality randomized controlled trial studies. Results: The results indicated that the ESDM intervention resulted in significant improvement with moderate effect sizes in the cognition (g = 0.28), autism symptoms (g = 0.27), and language (g = 0.29) domains. The effect sizes of autism symptoms and language were moderated by country (Western versus Asian countries). However, there were no significant effects observed for the social communication domain. Conclusion: The ESDM intervention significantly improved autism symptoms, language, and cognition. The effect sizes of autism symptoms and language were larger in Asian countries than in Western countries.