Mar 10 2021
A team of researchers, headed by Boyce Thompson Institute (BTI), has identified genes that allow peaches and their wild relatives to withstand stressful conditions—a discovery that can help domesticated peaches acclimatize to climate change.
A behmi tree (Prunus mira), which is a wild relative of the domesticated peach, grows in its native habitat next to a glacier on the Tibetan Plateau. Image Credit: Yong Li, from Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences.
The research work, which was co-headed by BTI faculty member Zhangjun Fei, analyzed the genes of the wild relatives and landraces of the domesticated peach. Over time, these varieties have adapted to certain local conditions—from seven areas in China.
The researchers identified genes that account for the peach’s adaptation to various environmental factors, such as drought, cold and even ultraviolet (UV-B) radiation levels at high altitudes.
Our study provides many candidate genes, showing how peach has adapted to all kinds of environmental stresses and stimuli. 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.
Zhangjun Fei, Faculty Member, Boyce Thompson Institute
Fei is also an adjunct professor in the School of Integrative Plant Science at Cornell University.
The study was described in an article published in the Genome Research journal on March 9th, 2020, and was contributed by authors from BTI, the U.S. Department of Agriculture, the Chinese Academy of Agricultural Sciences, Huazhong Agricultural University, and the Institute of Agrifood Research and Technology in Barcelona.
Lirong Wang, a professor from the Chinese Academy of Agricultural Sciences, has co-headed the study with Fei.
In the last few years, several food crops had become less productive due to climate change, and this fact underscores a greater need to render these crops more resistant to climate stressors.
Several analyses have detected the genes that allow soybean, rice and other similar food crops to acclimatize to their local surroundings. However, only a few analyses have actually looked at important fruit crops, such as the domesticated peach (Prunus persica), which yields 24.5 million tons per year.
Most of the adaptation genes in the domesticated peach were lost as humans cultivated the plant to focus on sweetness, flavor and other characteristics.
But the wild relatives and landraces of the domesticated peach have remarkable genetic diversity that could offer resources for enhancing the resilience of their domesticated cousin.
Cold, Dry and Mile-High Adaptations
The investigators collected a total of 263 peach wild relatives and landraces—45 from the Tibetan Plateau and 218 from the National Peach Germplasm Repository of China.
They subsequently performed genome-wide environmental association analyses on these specimens and detected over 2,700 spots in the gene that are associated with 51 environmental factors impacting the local climates of those areas.
For instance, a genetic variation was identified in AHP5—the histidine phosphotransfer protein—in peaches grown in a region with very low winter temperatures. This indicates that this genetic variant provided the peach tree with the capacity to tolerate cold conditions.
The researchers confirmed this concept by demonstrating that the protein levels increased when the plants were exposed to low temperatures.
Plants from an extreme arid region contained multiple gene variants in the abscisic acid (ABA) biosynthesis pathway that controls responses to drought stress, and in 12 genes on pathways that control the metabolism of sugar and starch.
Additional experimentation demonstrated that ABA induced higher concentrations of a sucrose-producing enzyme in response to drought stress. This, therefore, explains why fruits from the peach trees grown in the extreme arid region have consistently more sugar contents when compared to those grown in less arid regions.
When a fruiting plant like peach is growing under a stressful condition like drought, its fruit gets sweeter. In this study, we have found the direct genetic link between drought and the sugar content of peach.
Zhangjun Fei, Faculty Member, Boyce Thompson Institute
In the peach trees grown in the Tibetan Plateau, the researchers detected a variant in chalcone synthase 2 known to withstand the extreme UV-B radiation of that high altitude area. This variant boosted the production of the purple-colored flavonoid anthocyanin in the new shoots of the plant, protecting them from damage caused by UV-B radiation.
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. Breeders could develop cultivars that thrive on otherwise unused land, bolstering the local economy and bringing more good food to local markets.
Zhangjun Fei, Faculty Member, Boyce Thompson Institute
Spring Forward
Climate change has impacted several temperate flowering and fruiting plant species, such as peach, by making them bloom earlier. The researchers also looked at 89 peach samples covering 30 years (1983-2011) from a single region in China and observed that bloom dates had progressed by around 10 days over that time.
The team also came up with a plausible genetic explanation for this advance—a difference in a circadian clock gene, called LNK1, which is highly expressed during blooming and up-regulated by warm 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,” concluded Fei.
The study was funded by grants from the U.S. National Science Foundation (IOS-1339287 and IOS-1855585), the National Natural Science Foundation of China (31572094), the Agricultural Science and Technology Innovation Program (CAAS-ASTIP-2020-ZFRI-01), and the Crop Germplasm Resources Conservation Project (2016NWB041).
Science in Seconds - Gene discovery may help peaches tolerate climate stress
Video Credit: Boyce Thompson Institute.
Journal Reference:
Li, Y., et al. (2021) Genomic analyses provide insights into peach local adaptation and responses to climate change. Genome Research. doi.org/10.1101/gr.261032.120.