Raw materials used for black garlic (BG) processing were collected from the major garlic production areas in Northern Thailand. Five of those were identified as of Thai origin (accession G1–G5), and accession G6 was of the Chinese variety. They were initially analyzed for varietal differences using morphological characteristics and genetic variation. Fresh materials from each accession were dried to the same moisture content (55%–60%) and BG processed at 75°C, 90% relative humidity (RH) for 15 days. Thereafter, physiochemical and chemical profiles were analyzed and compared. The dendrogram from random amplified polymorphic DNA fingerprints grouped G2, G3, G4, and G5 as closely related while G1 and G6 were out‐groups. Prior to BG processing, the pH of fresh garlic was approximately 6.3 and decreased to 3.7, thereafter. The contents of chemical properties were independent with genotypes. BG processing improved phenolic, flavonoid, and antioxidant but the content of thiosulfinate was minimized in all BG samples. Overall, result indicated that garlics grown in Northern Thailand were genotypically variable. BG processing altered physical and chemical appearance, and these changes were independent with the genotypes.

Fourteen medicinal plants from northern Thailand, which dominate and form large colonies, were dried, powdered, and evaluated for growth inhibitory activity using a modified sandwich method. All the plants showed inhibitory activities on the growth of lettuce seedlings: Cymbopogon nardus had the strongest activity, completely inhibiting the growth of the lettuce hypocotyls and radicles; Piper retrofractum completely inhibited the hypocotyl growth and 93.5% of the radicle growth; and the remaining plants inhibited hypocotyl and radicle growth by 30.9 57.4% and 44.1 75.3%, respectively. Inhibitory active compounds may have been released from the plants into the sandwich method medium and inhibited the growth of the lettuce seedlings. The present results suggest that C. nardus and P. retrofractum are possible candidates for developing alternative natural herbicides in sustainable agriculture because of their strong inhibitory activity.

We detected tobacco mosaic virus (TMV), a member of the genus Tobamovirus and one of the most significant plant-infecting viruses, for the first time in a chrysanthemum in Thailand using reverse-transcription polymerase chain reaction (RT–PCR). The TMV-infected chrysanthemum leaves exhibited mosaic symptoms. We conducted a sequence analysis of the coat protein (CP) gene and found that the TMV detected in the chrysanthemum had 98% identity with other TMV isolates in GenBank. We carried out bioassays and showed that TMV induced mosaic and stunting symptoms in inoculated chrysanthemums. We observed the rigid rod structure of TMV under a transmission electron microscope (TEM). To enhance the speed and sensitivity of detection, we developed a colorimetric RT loop-mediated isothermal amplification (LAMP) technique. We achieved LAMP detection after 30 min incubation in isothermal conditions at 65 °C, and distinguished the positive results according to the color change from pink to yellow. The sensitivity of the LAMP technique was 1000-fold greater than that of RT–PCR, and we found no cross-reactivity with other viruses or viroids. This is the first reported case of a TMV-infected chrysanthemum in Thailand, and our colorimetric RT–LAMP TMV detection method is the first of its kind.

No abstract

The order Mucorales typically includes fast-growing saprotrophic and plant pathogenic fungi. Flower rot of red-fleshed dragon fruit (Hylocereus polyrhizus) caused by Mucor-like fungi was observed in a field in Phatthalung province, southern Thailand.Agglomeration of sporangiophores and sporangia on the wet rotten tissues of the red-fleshed dragon fruit flower was detected. Fungal isolates obtained from symptomatic tissues were cultured on potato dextrose agar for macroscopic and microscopic observations. Based on the growth rate and morphology of sporangia and sporangiospores, the fungus was identified as Gilbertella persicaria, which was further confirmed using phylogenetic analyses of the internal transcribed spacer and nuclear large subunit ribosomal DNA sequences. Pathogenicity tests revealed that the fungal isolate G. persicaria caused flower rot, similar to that observed in the field. This study is the first report of flower rot disease in H. polyrhizus caused by G. persicaria in Thailand.

Chrysanthemum chlorotic mottle viroid (CChMVd) is a serious pathogen infecting chrysanthemum worldwide. To improve and enhance the detection procedure, the colorimetric loop-mediated isothermal amplifi cation (LAMP) technique was developed. Six LAMP primers were newly designed and tested the optimal conditions using a recombinant plasmid of CChMVd as a DNA template. The optimal conditions for colorimetric LAMP were incubation at 65°C for 60 min. At these conditions, the ladder-liked pattern LAMP products were detected along with the change of color from pink to yellow in the positive reactions. The sensitivity of colorimetric LAMP was up to 2.18 × 103 copies of recombinant plasmid concentration which was 104-fold greater than that of polymerase chain reaction (PCR). The developed colorimetric LAMP was not cross reacted to other viruse s and viroid. Effi ciency of colorimetric reverse transcription (RT)-LAMP for detecting CChMVd in chrysanthemum plantlets obtained from meristem tip culture was evaluated to verify and ensure CChMVd-free plantlets production. The results showed that 18 chrysanthemum plantlets were free of CChMVd contamination. Therefore, the colorimetric RT-LAMP can be used to detect CChMVd routinely due to its accuracy, rapidness and sensitivity.

Anthracnose caused by Colletotrichum gloeosporioides is the most significant postharvest disease of mangos and negatively affect handling and marketing of mango fruits in Vietnam. A mixture of bee-carnauba wax and propionic acid has successfully inhibited linear growth and spore germination of C. gloeosporioides (in vitro) and prevented anthracnose diseases of mango fruits (in vivo). A complete reduction in mycelial growth and spore germination was observed when a mixture of 0.09% propionic acid and 8% bee-carnauba wax was used. Similar results were shown on mango fruits treated with 0.12% propionic acid which obtained a highly protective effect against anthracnose disease. The results of this study revealed that propionic acid could be used as a safe fungicide alternative against anthracnose disease, which causes economic losses during transportation, marketing and storage.

Endophytic Streptomyces sp. CEN26 produces 2,5-bis(hydroxymethyl)furan monoacetate (BHMF-OAc), which is a compound that inhibits the infection process of Alternaria brassicicola in cabbage. Such an antifungal property would allow for the use of the BHMF-OAc as an alternative to chemical fungicides.