A team of researchers from different scientific institutions successfully carried out a genome sequencing of the pineapple in order to isolate the specific genes and pathways that allow the plant to exist even in areas where there is limited water supply.
In a study featured in the Nature Genetics journal, scientists from the University of Illinois and other research organizations set out to understand the evolutionary history of certain species of grass that share distant ancestry with the pineapple such as rice and sorghum.
Pineapples have been used by humans as a food source for more than 6,000 years. The first crops were cultivated in the South American region that is now occupied by the modern-day states of Paraguay and Brazil.
The fruit can now be found in more than 85 different countries, which produce around 25 million metric tons of crops annually and contribute to an international industry worth close to $9 billion.
Scientists have discovered that early pineapple and grass species experienced numerous doublings of their genomes as part of a process known as whole-genome duplications.
By tracing the pathways of these duplications, researchers hope to have a better understanding of the plants' independent and shared evolutionary histories.
Sequencing Pineapple Genome
Prof. Ray Ming, a plant biologist at Illinois and lead author of the study, said their findings suggest that the genome of the pineapple contains one less genome duplication compared to grass species that share its ancestry.
He said this trait makes the pineapple an ideal point of comparison for research on the genomes of cereal crops.
Ming and his colleagues were able to identify two instances of whole-genome duplications in the evolutionary history of the pineapple. This also validated the findings of earlier studies in which three duplications were found in grasses.
While most other plants use a type of the photosynthesis called C3 to build up its tissues, pineapples have been found to employ a variation of the process known as crassulacean acid metabolism (CAM).
Ming explained that plants that use the CAM process typically use as much as 20 percent of water supplies used by C3 plants. CAM plants are also capable of thriving in arid, marginal areas where most other plants would not be able to survive in.
Some genes related to this form of photosynthesis have been found to be controlled by the pineapple's genetic circadian clock, which allows it to differentiate daytime from nighttime and make necessary adjustments to its metabolism.
"This is the first time scientists have found a link between regulatory elements of CAM photosynthesis genes and circadian clock regulation," Ming pointed out.
"This makes sense, because CAM photosynthesis allows plants to close the pores in their leaves during the day and open them at night."
Ming added that the trait contributes to the resilience of the pineapple in harsh climates, allowing the plant to lose only small amounts of moisture through its leaves during daytime.
The researchers believe understanding the evolution of photosynthesis can help improve efforts in developing more productive and drought-tolerant versions of essential crops.
Ming said that adapting food crops to become more resistant to droughts could also help secure food supplies in the coming years.
Photo: Derek Rose | Flickr