Stingless bee honey (SBH) is an astounding ‘miracle liquid’ with countless medicinal properties for various diseases such as gastroenteritis, cataracts, as well as for wound-healing. However, knowledge regarding it is still rather scarce. Henceforth, it is intriguing for us to contemplate on the less-studied stingless bee and its honey in particular. First and foremost, the antimicrobial ability of honey from eight different stingless bee species was tested to further proven its health benefit. Homotrigona fimbriata honey showed the highest antimicrobial activity with inhibition against five bacteria; Serratia marcescens, Escherichia coli, Bacillus subtilis, Alcaligenes faecalis and Staphylococcus aureus. The next aim of our study is to characterize their honey bacterial community via the use of 16S rRNA amplicon sequencing technology. A total of eight bacterial phyla, 71 families, 155 genera and 70 species were identified from our study and two of the stingless bee species honey were determined to have the highest bacterial diversity compared to other six stingless bee species, namely Heterotrigona erythrogastra and Tetrigona melanoleuca. Furthermost, Lactobacillus malefermentans was thought to be the native dominant bacteria of SBH due to its predominant presence throughout all studied species. The aforementioned SBH’s antimicrobial results and characterization study of its bacterial diversity are hoped to carve the pathway towards extending its probiotic ability into our everyday lives.

Hoya R.Br. is a genus of ornamental plants with an attractive flower shape and unique scents. Anatomical studies are required to understand their structure that produces, and stores, the metabolites released by plants. The present study was conducted to determine the type and position of floral glands in three Hoya species: Hoya cagayanensis C.M Burton, Hoya lacunosa Blume, and Hoya coriacea Blume. The investigations were carried out using light microscopy (LM), scanning electron microscopy (SEM), and histochemical staining tests. Secondary nectaries were present in the corona lobe portion, while simple trichomes (unicellular) were found in the petals’ adaxial epidermis of all the studied species. Conical trichomes were found in H. cagayanensis, cylindrical trichomes in H. lacunosa, and falcate trichomes in H. coriacea. In the cells of secondary nectaries, this study revealed proteins, lipids, polysaccharides, and starch grains; however, only lipids and proteins were observed in simple trichomes. Secondary nectaries and simple trichomes were described for the first time in all the studied species, contributing new insight into Hoya’s anatomical and micromorphological floral glands.

Cosmos caudatus Kunth. or “king’s salad” contains high values of nutritional compounds that act as health promoters. Although widely consumed for its medicinal value, information on phytochemical contents and their biosynthesis in the species is scarce. Among the interesting compounds are the anthocyanins that possess a dual role; an antioxidant and natural colorant. A complete anthocyanin biosynthetic pathway in C. caudatus was elucidated using transcriptomics, metabolomics, and anatomical approaches in this study. The transcriptomic analysis revealed genes encoding enzymes in the anthocyanin biosynthetic pathway and the genes encoding the transcription factors relevant to the latter pathway. A total of 11 anthocyanins of cyanidin, pelargonidin, and delphinidin derivatives that are significantly abundant in the species were identified, correlating with the anthocyanin mainstream gene pathway. The occurrence of anthocyanin was further validated by light microscopy. Anthocyanin pigments in C. caudatus were detected at the epidermal layer of the leaf, stem, and flower, and at the cortex of stem and root. To our knowledge, this is the first work that has delineated the complete anthocyanin biosynthetic pathway in Malaysia’s underutilized plant, C. caudatus Kunth. This study correlated multi-omics data that will help integrate systems biology and synthetic biology, for a detailed understanding of the molecular mechanism and characterization of the anthocyanin biosynthesis using heterologous expression studies.

Hoya’s R.Br. attractive flower shapes and unique scents make it suitable to be exploited as a new source of tropical fragrance. Therefore, this study aims to elucidate the biosynthesis of secondary metabolites using phytochemical and transcriptomic approaches to understand the mechanisms of scents biosynthesis, especially terpenoid in Hoya. Three Hoya flower species were selected in this study: Hoya cagayanensis, Hoya lacunosa, and Hoya coriacea. The secondary metabolite profiles characterizing scents on flowers were performed using head space solid phase microextraction (HS-SPME). Gas chromatography-mass spectrometry (GC-MS) revealed 23 compounds from H. cagayanensis, 14 from H. lacunose, and 36 from H. coriacea. Volatiles from the three species had different fragrance profiles, with β-ocimene and methyl salicylate compounds dominating the odor in H. cagayanensis. The 1-octane-3-ol was found highest in H. lacunosa, and (Z)-acid butyric, 3-hexenyl ester was found highest in H. coriacea. Subsequent studies were conducted to identify the biosynthesis pathway of secondary metabolites responsible for the aroma profile released by Hoya flowers through transcriptome sequencing using the Illumina Hiseq 4000 platform. A total of 109,240 (75.84%) unigenes in H. cagayanensis, 42,479 (69.00%) in H. lacunosa and 72,610 (70.55%) in H. coriacea of the total unigenes were successfully annotated using public databases such as NCBI-Nr, KEGG, InterPro, and Gene Ontology (GO). In conclusion, this study successfully identified the complete outline of terpenoid biosynthesis pathways for the first time in Hoya. This discovery could lead to the exploitation of new knowledge in producing high-value compounds using the synthetic biology approach.

Bacterial leaf streak (BLS) caused by bacterium Xanthomonas oryzae pv. oryzicola (Xoc) is one of the most prominent rice diseases. BLS causes a significant reduction in paddy yields. However, there are limited studies and a lack of information regarding the mechanisms and cells affected on leaf tissues severed from this disease. Therefore, in this study, sensitive paddy variety IR24 was inoculated against BLS, and the pathogen colonised mesophyll cells and some bundle sheath cells. The infection spreads rapidly towards the base and apex of the leaf, but rather slowly to the left and right sides of the leaf veins. Another experiment was performed to unravel anatomical characteristics in sensitive paddy varieties (TN1, IR24, IR5) and resistant paddy varieties (IR26, Dular, IR36) against BLS. Susceptible paddy varieties have less thick midrib and leaf lamina, a high number of bundle sheath cells at primary vascular tissue (midrib), one layer of sclerenchyma cells at the secondary vein, and more than two metaxylems at the primary vein. Resistant paddy varieties, on the other hand, consist of a relatively thickened midrib and leaf lamina, fewer bundle sheath cells at the primary vascular tissue (midrib), more than one sclerenchyma layers at the secondary vein, and two metaxylems at the primary vein. This study contributes new knowledge in identifying the level of infection in paddy fields, and helps breeders in producing resistant paddies to this disease.

Hoya R.Br. is an epiphytic plant known as an exotic ornamental plant with distinctive, unique, and fragrant flowers. Investigating its floral structure is crucial for understanding how these structures may contribute to the production and storage of secondary metabolites emitted by Hoya. This study aimed to identify the type and position of floral glands in Hoya pentaphlebia. The investigations began by identifying the type and position of the floral glands, utilizing light microscopy, electron microscopy, and histochemical staining techniques. Secondary nectaries (sn) were discovered in the corona lobe, while conical-shaped glandular trichomes (unicellular) (ct) were at the adaxial epidermis of the corolla. The secretory activity of proteins, lipids, polysaccharides, and starch grains was found in sn, whereas ct detected only lipids and proteins. Subsequent studies to identify the secondary metabolite profiles characterizing aroma emitted from H. pentaphlebia flowers using gas chromatography-mass spectrometry (GC-MS) showed 26 compounds were identified, with the methyl salicylate (MeSA) compounds being the most abundant. In conclusion, this study successfully identified the floral glands and secondary metabolites present as aromas in the species studied. Sn and ct were discovered to be present for the first time in H. pentaphlebia, providing new information into the Hoya’s floral structures. The presence of floral glands indicates the existence of secondary aromatic metabolites that play a role in the interaction between plants and numerous environmental elements.