Bacterial communities associated with invasive populations of Bactrocera dorsalis (Diptera: Tephritidae) in China.

The oriental fruit fly Bactrocera dorsalis (Hendel) is a destructive insect pest of a wide range of fruits and vegetables. This pest is an invasive species and is currently distributed in some provinces of China. To recover the symbiotic bacteria of B. dorsalis from different invasion regions in China, we researched the bacterial diversity of this fruit fly among one laboratory colony (Guangdong, China) and 15 wild populations (14 sites in China and one site in Thailand) using DNA-based approaches. The construction of 16S rRNA gene libraries allowed the identification of 24 operational taxonomic units of associated bacteria at the 3% distance level, and these were affiliated with 3 phyla, 5 families, and 13 genera. The higher bacterial diversity was recovered in wild populations compared with the laboratory colony and in samples from early term invasion regions compared with samples from late term invasion regions. Moreover, Klebsiella pneumoniae and Providencia sp. were two of the most frequently recovered bacteria, present in flies collected from three different regions in China where B. dorsalis is invasive. This study for the first time provides a systemic investigation of the symbiotic bacteria of B. dorsalis from different invasion regions in China.

Photorespiration studies in Cycas circinalis L. and Cycas beddomei Dyer.

Photosynthetic carboxylating enzymes and the effects of light and temperature on (14)CO2 efflux in two species of gymnosperm leaves were studied. The activity of RuBP carboxylase was high and that of PEP carboxylase was very low when compared to C4 plants. The CO2 compensation point was high. (14)CO2 efflux was greater in light than in darkness and the ratio (L/D) increased with increase in temperature and light intensity. The inhibitors of glycolate metabolism showed decreased (14)CO2 evolution in light while dark respiration was unaffected. It is concluded that both Cycas circinalis, L. and Cycas beddomei Dyer are C3 plants.