Hong Kong Baptist UniversityUnravelling the mystery of invasive apple snails

Unravelling the mystery of invasive apple snails

Apple snails, in the family Ampullariidae, are invasive species that cause serious damage to crops and agriculture around the world. A study led by biologists from Hong Kong Baptist University (HKBU) has discovered that the apple snails have evolved to achieve broad environmental adaptability. The research findings were published in the international journal Molecular Biology and Evolution.

The four apple snail species involved in the study are the African Lanistes nyassanus, and the South American Pomacea canaliculataPomacea maculata, and Marisa cornuarietis. Among them, the two Pomacea species are the most invasive. In China, Japan, Thailand and the Philippines, Pomacea are considered the number one rice pest.

Led by Professor Qiu Jianwen of the Department of Biology at HKBU, the research team sequenced and assembled the genomes of the four apple snail species. By comparing the genomes of the apple snail species with other molluscs, the team found 28 gene families that were substantially expanded. This included some genes functionally related to chemoreception which are highly expressed in sensory tentacles, indicating that they may have enhanced environmental sensing ability.

The four apple snail species featured in the study: (clockwise from top left) Pomacea canaliculata, Pomacea maculata, Lanistes nyassanus and Marisa cornuarietis.

The team also found that these apple snail species encode multiple copies of cellulase genes which enables them to actively decompose cellulose, an important component of the cell wall of green plants. This ability may help explain why they can digest a broad range of plant materials and exploit variety of freshwater wetland habitats.

The researchers further found that the new acquisition of a calcium-binding protein (CaBP) allows Pomacea to form a hard eggshell. It therefore physically protects the egg and prevents them from drying out on land.

“Given that several invasive apple snail species are notorious agricultural pests, the genomic resources from this study can be used to develop effective control strategies, including the synthesis of chemical molluscicides and the design of genetic control measures using ribonucleic acid (RNA) interference,” said Professor Qiu.

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Faculty of Science
Department of Biology

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