Genotype and organ effect on the occupancy of phyllosphere prokaryotes in different rice landraces.

Bacteria community provides essential ecological services to rice plants. The bacterial diversity of rice varies across host plant genotype and organs. This study employed 16S rDNA amplicon sequencing to characterise the bacterial community associated with three rice landraces using leaf blade and stem samples. The prokaryotic community found in these rice landraces comprised of two kingdoms, 12 phyla, 25 classes, 40 orders, 80 families, and 118 genera. Proteobacteria (53.9%) was the most abundant phylum. The most abundant genus was an undefined genus under Cyanobacteria (33.0%). Homogeneity of prokaryotic community was observed across the three rice landraces, which may suggest a high similarity in biological and genetical properties of the rice landraces. The difference in prokaryotic composition between leaf blade and stem was depicted based on principal coordinate analysis. This study observed that the prokaryotic inhabitants in rice plants is predominantly determined by rice plant organs.

Infestation Pattern and Population Dynamics of the Tropical Bed Bug, Cimex hemipterus (F.) (Hemiptera: Cimicidae) Based on Novel Microsatellites and mtDNA Markers.

The tropical bed bug, Cimex hemipterus (F.), has now emerged as an important public health pest in the tropics. Despite its alarming infestation rate, the information on its population genetics remains scarce. Here, we described the infestation structure and population dynamics of C. hemipterus in the tropics, especially Malaysia and Singapore, based on eight novel microsatellites and two mtDNA markers, including cytochrome c oxidase I (COI) and 16S rRNA genes. Across populations, microsatellite data revealed high genetic diversity with significant genetic differentiation and restricted gene flow. Analysis within populations revealed evidence of a recent bottleneck. Nonetheless, elevated genetic diversity in nearly all populations suggests that the propagule in C. hemipterus populations were much diverse, distantly related (mean r = 0.373), and not significantly inbred (mean FIS = 0.24) than that observed in Cimex lectularius from previous studies. We observed seven mtDNA haplotypes across the 18 populations studied (Hd = 0.593) and several populations displayed more than one matrilineal descent. The two markers were generally congruent in suggesting a common, genetically diverse (especially at the nuclear region) source population with possibilities of multiple introductions for the bed bug populations in the present study.