Unlocking the pineapple’s secrets

The pineapple, enjoyed by people world-wide in slices, chunks, juice, piña coladas, and Hawaiian pizza, is finally giving up its genetic secrets.

COSTA RICA (DOLE) – Scientists say they have sequenced the genome of the pineapple, learning about the genetic underpinning of the plant’s drought tolerance and special form of photosynthesis, the process plants use to convert light into chemical energy.

The genome provides a foundation for developing cultivated varieties that are improved for disease and insect resistance, quality, productivity and prolonged shelf life, according to Qingyi Yu, a plant and molecular biologist at Texas A&M University.

Pineapples, domesticated about 6,000 years ago in what is now south-west Brazil and eastern Paraguay and currently grown in tropical and subtropical regions worldwide, are big business. They are the second most important tropical fruit crop behind bananas, and are grown in more than 80 countries, with an annual value of more than $8 billion.

Pineapples are the most economically important crop that uses a type of photosynthesis called CAM, or crassulacean acid metabolism, that evolved in arid locales for high water-use efficiency. It is one of three types of photosynthesis and differs from the forms in the vast majority of plants.

“A CAM plant can adapt to a very dry area so it has a very high water-use efficiency. Compared with the C3 plant, CAM plants only use 20 percent of water,” said Yu.

Mindful of global climate change forecasts, the researchers said understanding the pineapple genome may help to engineer drought tolerance into other crops and even engineer C3 photosynthesis crops like rice and wheat to use CAM photosynthesis.

“Our discovery confirms that it is possible to engineer C3 into CAM photosynthesis which can give it higher water usage efficiency,” said Yu.

Some of the pineapple’s photosynthesis genes are governed by its circadian clock genes, which enable plants to distinguish between day and night and adapt their metabolism accordingly. Ming said this makes sense because CAM photosynthesis lets plants close pores in their leaves during daytime and open them at night, helping retain moisture.

The research appears in the journal Nature Genetics.