Scientists have unlocked the genome sequence of the pineapple, shedding light into the photosynthetic process that makes the drought-tolerant tropical fruit promising in areas like disease and insect resistance, enhanced productivity, and prolonged shelf life.
Writing in the journal Nature Genetics, a research team from the University of Illinois and other organizations found that pineapples used crassulacean acid metabolism (CAM), a special form of photosynthesis. This process has evolved in over 10,000 plant species, and pineapple emerged as the most economically important one.
Unlike most crops that use a kind of photosynthesis known as C3, CAM plants use a mere 20 percent of the water used by C3 plants, flourishing in dry lands unsuitable for most crops, explained lead author and plant biologist Prof. Ray Ming of University of Illinois.
The research also revealed that the pineapple’s circadian clock regulates certain genes contributing to CAM photosynthesis, allowing plants to tell between day and night and to regulate their metabolism properly. Now is the first time, according to the team, that such link was established.
"This makes sense, because CAM photosynthesis allows plants to close the pores in their leaves during the day and open them at night,” said Ming, adding it contributes to pineapples’ resilience during hot and arid conditions, losing very little moisture at daytime through its leaves.
What this type of photosynthesis lets the tropical plant do is absorb and process CO2 into molecules at night, concentrating it in the leaves and releasing it next day for the photosynthetic process. CAM plants, for instance, are able to keep their stomata closed at daytime, massively reducing water loss.
What implications does this unique process hold?
Drought is pointed out as a major culprit in crop loss worldwide. Thus, understanding plants’ water stress survival tactics proves to be “vital for engineering drought tolerance in crop species,” wrote the researchers.
The discovery is poised to help scientists develop cultivated varieties of essential crops for greater productivity and resistance to droughts.
For example, the U.S. energy department has spearheaded a project focusing on the genetic workings that make CAM photosynthesis and drought protection possible in desert-adapted crops. This is targeted to introduce the same traits to biofuel crops.
Climate change adaptation is another potential benefit. "Higher water-use efficiency is a highly desirable trait,” Ming highlighted, citing the necessity of doubling up food production by 2050 in the context of climate change.
Photo: Richard North | Flickr
