First report of Pantoea anthophila causing shoot dieback disease of Ceylon ironwood (Mesua ferrea Linn.) in Malaysia

Ceylon ironwood (Mesua ferrea Linn.) or Penaga lilin is one of Asia's most popular tropical herbal plants, including Malaysia (Sharma et al., 2017). The trees are cultivated for their aesthetic value and pharmacological properties, especially as traditional remedies for asthma, dermatopathy, inflammation, and rheumatic conditions (Adib et al., 2019). In August 2022, a disease survey was conducted on Ceylon ironwood trees ranging from 5 to 12 years old in Botanical Park, Putrajaya, Malaysia, with 80% exhibiting shoot dieback disease of the 15 trees exhibiting shoot dieback disease. Symptoms include irregular, water-soaked with brown lesions on young leaves and shoots, where the small lesion coalesced and formed broad necrotic regions, subsequently causing dieback and gradual defoliation. Three infected shoots were collected from each tree, excised into small pieces (10 to 20 mm), immersed with 75% ethanol for 3 min, washed with 2% NaOCl solution for 1 min, and rinsed twice for 1 min in sterilized distilled water. A 10 µl aliquot of the sample suspension was streaked onto nutrient agar (NA) and incubated for 24 h to 48 h at 35 °C. A total of 15 isolates with similar morphology were obtained, and each isolate was re-streaked three times to obtain pure colonies that were round, smooth, with irregular edges, and produced yellow pigment in culture. All isolates were Gram-negative, negative for indole production, and utilized glucose, maltose, trehalose, sucrose, D-lactose, and pectin. Three representative isolates (C001, C002, and C003) with similar morphology were selected for further characterization. The total genomic DNA of all isolates was extracted from overnight cultures using Geneaid™ DNA Isolation Kit (Geneaid Biotech Ltd., Taiwan). PCR amplification of 16S rDNA (Zhou et al., 2015) and species-specific infB (Brady et al., 2008) genes was performed, and each of the ~1500 bp and ~900 bp amplicons were sequenced. BLASTn and phylogenetic analyses revealed all isolates were 100% identical to Pantoea anthophila (P. anthophila) LGM 2558 strains (Accession Nos. NR_116749 and NR_116113) for the 16S rDNA gene. They were 99% identical to P. anthophila CL1 strain (Accession Number CP110473) for infB gene. These sequences were later deposited in the GenBank (Accession Nos. OQ772233, OQ772234, and OQ772235 for 16S rDNA gene, and OQ803527, OQ803528, and OQ803529 for infB gene). For the pathogenicity test, healthy Ceylon ironwood seedlings' shoots were inoculated with 10 mL of each isolate suspension (1 x 108 CFU/ml) by spraying the inoculum on the young shoots using a sterilized spray bottle. Control seedlings were inoculated with sterile water. The inoculated shoots were covered with a sealed plastic bag to maintain the moisture and were kept in the greenhouse with temperatures ranging from 26 to 35 °C. The experiments were repeated twice, with three replicates for each treatment. Inoculated shoots showed dieback symptoms like natural infection, including irregular, water-soaked, and brown lesions on leaves and young shoots at 10 days post-inoculation. Control seedlings remained asymptomatic. The pathogen was re-isolated and identified via sequencing of the 16S rDNA and infB genes, thus fulfilling Koch's postulates. Previously, P. anthophila has been reported to cause soft rot in wampee plants in China (Zhou et al., 2015) and leaf blight of cotton in Pakistan (Tufail et al., 2020). To our knowledge, this is the first report of P. anthophila causing shoot dieback disease of Ceylon ironwood trees in Malaysia. Plant disease management strategies need to be established to reduce losses due to P. anthophila infection since the pathogen could limit Ceylon ironwood tree production in Malaysia.

Ethnobotanical study of medicinal plants used by the Kenyah community of Borneo

ETHNOPHARMACOLOGICAL RELEVANCE

Sarawak is located in one of the world's most biodiverse regions and is home to more than 40 sub-ethnic groups that each have their own distinct culture, language and lifestyle. This has given rise to numerous, unique ethnobotanical systems. However, due to rapid urbanization, this traditional knowledge is at a risk of extinction. Yet, ethnobotanical studies in Sarawak are almost non-existent, especially among Orang Ulu communities like the Kenyah.

AIM OF STUDY

Therefore, this study was conducted to document the ethnomedicinal knowledge of the Kenyah community. The main objectives of this study are: 1) To determine and document the diversity of medicinal plants used by the Kenyah community, 2) To determine whether the availability of modern medicine has affected Kenyah traditional medicine, and 3) To identify plants which have not been previously cited or used for previously unreported medical uses.

MATERIALS AND METHODS

We conducted repeated interviews and field surveys at the Asap-Koyan Resettlement Area, Belaga Sarawak. A total of 24 respondents from four Kenyah longhouses were interviewed in this study. Individuals possessing extensive traditional medicinal knowledge were identified via preliminary interviews or by viva voce. Translators were employed to ensure that there was no miscommunication. The results were evaluated based on the plant's total use-reports and number of respondents citing the plant. The data was also evaluated based on use-reports by ailment category.

RESULTS

Over 95% of the respondents were 40 years and older (58.21 years old ± 11.21). This was due to the younger members of the community (40 years old and below) admitting that they had almost no knowledge regarding traditional medicine, as they preferred relying on modern medicine. A total of 61 plant species were mentioned by the 24 respondents Seven plants had five or more respondents citing it, which was more than 20% of the respondents. These plants were Piper betle, Homalomena cordata, Senna alata, Annona muricata, Derris elliptica, Blumea balsamifera and Coscinium fenestratum.

CONCLUSION

Almost all of the cited plants had been previously recorded to be used in either Ayurvedic, Chinese herbal medicine, Malay traditional medicine or other Asian ethnomedicinal systems. However, there were four highly cited species that were used for treatments that were scarcely reported in past literature. These were piper betle (used by Kenyah to treat fever), Sauropus andrognus (used by Kenyah to treat fever), Derris elliptica (used by Kenyah to treat fever and influenza) and Coscinuim fenestratum (used by Kenyah to treat toxic effects from non-medical substances).

Addressing psychosocial issues caused by the COVID-19 lockdown: Can urban greeneries help?

The Coronavirus disease-2019 (COVID-19) pandemic has affected over 200 countries, forcing governments to impose lockdowns to contain the spread of the disease. Although effective in reducing infection rates, the lockdowns have also resulted in a severe negative impact on mental health throughout the world; Setting the foundation for mental illnesses to become the next "silent" pandemic. This study attempts to determine a self-care method of ensuring mental health during the COVID-19 pandemic, especially for those living under lockdown. We evaluated the potential of physical exercise (in a nature setting) and nature therapy in improving mental wellbeing, among young adults with either stress, anxiety or depression symptoms. The study involved thirty subjects, who were equally divided into a nature-exercise group and a nature therapy group. The participants were briefed on the activities that they were to perform on a daily basis, and both groups performed their assigned activities concurrently for one week (27th April 2020 to 3rd May 2020) at urban greeneries accessible to them (rooftop parks, neighbourhood parks, home gardens). We used the depression, anxiety and stress scale - 21 items (DASS-21) to evaluate the mental health status of participants, once before beginning the study (baseline readings) and once at the end of the study (after a week of nature-exercise/nature therapy). There was a statistically significant reduction in stress, anxiety and depression symptoms for both the nature-exercise and nature therapy groups. However, when evaluating the effectiveness of exercise and nature therapy in treating stress, anxiety and depression symptoms on a case-by-case basis, it was discovered that nature therapy was more effective in treating mental health issues. Hence, nature therapy has the potential to be a form of preventive medicine, namely in preserving mental health during the COVID-19 crisis.