March 9 (UPI) -- Scientists have discovered genes that help wild peaches tolerate a variety of climate stressors. The genes could be reintroduced to domesticated peaches to help the stone fruits adapt to climate change.
For the study, scientists sequenced and analyzed the genomes of wild peaches and landraces -- varieties that have adapted over hundreds of years to specific climate conditions -- across seven regions of China.
The survey, published Tuesday in the journal Genome Research, revealed the genes that help the wild relatives of the domestic peach, Prunus persica, survive cold spells, drought and elevated levels of ultraviolet radiation.
"Our study provides many candidate genes, showing how peach has adapted to all kinds of environmental stresses and stimuli," study co-author Zhangjun Fei said in a press release.
"Breeders can use this information to develop more resilient domesticated peach trees that cope better with temperature extremes, drought and other harsh, changing conditions imposed by climate change," said Fei, a researcher at the Boyce Thompson Institute and an adjunct professor of plant sciences at Cornell University.
China is the world's leading peach producer, growing roughly 60 percent of the industry's total output. The value of the global fresh peach market is estimated at roughly $50 billion.
But while efforts to engineer more resilient varieties of staples like rice, soybeans and other crops have yielded promising breakthroughs, less attention has been paid to stone fruits.
Though peaches grow best in warmer climates, unseasonably warm winters can devastate stone fruit cops.
Through decades of domestication, as plant breeders have focused on selecting for flavor, sweetness and other marketable traits, genes linked with environmental resiliency have been lost. As a result, domestic peaches are less able to cope with climate stress than they might have been 100 years ago.
For the new study, scientists analyzed the genomes of 263 wild relatives and landraces, isolating more than 2,700 locations linked with 51 different environmental factors relevant to local climate conditions.
For example, the analysis showed the genomes of peaches grown in regions with low winter temperatures featured a unique genetic variation in the histidine phosphotransfer protein AHP5.
Scientists found peaches from more arid regions carried several genetic variations in the abscisic acid biosynthesis pathway, which regulates drought response. The same peaches boasted variations in the pathways responsible for starch production and sugar metabolism.
When scientists subjected peaches from arid regions to dry conditions, they upped their abscisic acid production, which increased the synthesis of sucrose-producing enzymes. The experiments helped explain why peaches from arid regions are often sweeter than non-arid varieties.
"When a fruiting plant like peach is growing under a stressful condition like drought, its fruit gets sweeter," Fei said. "In this study, we have found the direct genetic link between drought and the sugar content of peach."
Researchers also identified genetic variations that help peaches growing at higher elevations on the Tibetan Plateau tolerate higher levels of UV rays.
"Overall, the genetic information we found could help people breed peach trees that grow in many different and harsh environments, expanding peach's geographic range to new regions," Fei said. "Breeders could develop cultivars that thrive on otherwise unused land, bolstering the local economy and bringing more good food to local markets."
Additionally, by comparing the genomes of peach samples collected across three decades from a single region in China, researchers confirmed that peach trees are flowering earlier and earlier each year.
Researchers were able to link the change to a variation in a circadian clock gene, LNK1, the expression of which is boosted by warming temperatures.
"This finding could eventually let breeders control the bloom date of their trees, so that the peach crop is ready for harvest when the grower and the market are ready," Fei said.