Genetic variation studies in Oryctes rhinoceros (L.) (Coleoptera: Scarabaeidae) from oil palm plantations using random amplified microsatellite (RAMs) markers

Randomly amplified microsatellite markers were used to study the genetic variation among six populations of Oryctes rhinoceros L. which were collected from oil palm plantations in Selangor, Perak, Pahang and Medan. Samples were collected using light and pheromone trapping for the purpose of obtaining two populations per site study. Thirty individual beetles per population were screened using seven randomly amplified microsatellite primers. Beetles were not attracted to light traps at Pahang and Medan. This resulted in only pheromone populations being caught there. Distances calculated based on the similarity coefficient of Nei and Li (1979) ranged between 0.422 and 0.736. Seventy eight reproducible loci were generated using the seven primers and all the loci were polymorphic. The dendrogram constructed produced two major clusters. Based on the dendrogram, the clusterings were observed to be influenced by preference to trapping system as well as geographical distance. The separation of clustering between Perak Pheromone (PP) and Perak Light (PL) is important as it gives rise to the possibility for the presence of two groups of O. rhinoceros based on their preference toward light and pheromone trap. However, further studies using codominant markers especially single locus DNA microsatellite markers are required to understand the population genetic structure and to further validate the presence of a cryptic species complex.Keywords: Oryctes rhinoceros, RAMs, genetic variatio

Efficient in vitro regeneration of Zingiber zerumbet Smith (a valuable medicinal plant) plantlets from rhizome bud explants

This study was conducted to develop an efficient protocol for mass propagation of Zingiber zerumbet Smith. Explants from rhizome buds were cultured on Murashige and Skoog (MS) medium supplemented with 6-Benzylaminopurine (BAP) alone (0 to 5 mg/l) or a combination of BAP (0 to 5 mg/l) and indole 3- acetic acid (IAA) (0 to 2 mg/l). MS medium supplemented with a combination of 5.0 mg/l BAP and 2.0 mg/l IAA or 3.0 mg/l BAP and 0.5 mg/l IAA produced the highest mean number of shoots (5.6) per explant as compared to other concentrations. The best shoots length (9.44 cm) was obtained on the medium containing 1.0 mg/l of BAP and 2.0 mg/l IAA. Thus, combined effects of BAP and IAA improved significantly the shoot growth and proliferation. MS medium supplemented with a combination of 5.0 mg/l BAP and 2 mg/l IAA gave the highest number of roots (17). However, longest roots per explant were obtained with 1.0 mg/l BAP alone. The proliferated shoots were green and healthy in appearance. Finally, healthy and complete plants with well developed roots were hardened, acclimatized and planted in the field successfully with a survival rate of 80%.Key words: Zingiber zerumbet, shoot multiplication, micropropagation, in vitro, acclimatization, medicinal plants, Zingiberaceae

Differential expressions of putative genes in various floral organs of the Pigeon orchid (Dendrobium crumenatum) using GeneFishing

Nine Differentially Expressed Genes (DEGs) were detected in the five floral organs of Dendrobium crumenatum and three DEGs of relatively high expression in the column, were significantly homologous to the small Heat Shock Protein (HSP) differentially regulated during pollen development and heat stress in tobacco (DEG3-8), pectin methylesterase enzyme (PME) which was a male-flower specific gene in Salix gilgiana (DEG6-1) and the 14-3-3 protein which was differentially expressed and upregulated in Malus x domestica (DEG9-9) during fruit ripening. Generally, the differential expressions of the DEGs in the column and other floral organs were distinct, indicating the suppressive role of column DEGs on other floral organ DEGs. Interactions between the other floral DEGs (excluding column DEGs) indicated pattern expression specificity to each floral organ. Following this investigation, further molecular expression investigations are required and essential to develop and establish an orchid floral ontogenic model