"Peaches and plums are all over the world" genetic evidence found

Chinese people often use "peach plums all over the world" as a metaphor for the many elite juniors cultivated by elders or teachers all over the world.

On March 10, "Genome Research" (Genome Research) published online the genetic analysis of the influence of multiple environmental factors on the peach genome, led by Wang Lirong, a researcher at the Zhengzhou Institute of Fruit Research, Chinese Academy of Agricultural Sciences, and gave the "peach plums all over the world" heredity The scientific meaning can help breeders establish new models for adapting to climate change.

Pressure from climate change

Different ecotypes of peach fruits have rich genetic diversity.

By analyzing the long-term monitoring data of 89 peach germplasm in the resource nursery, Wang Lirong's team found that the flowering time of peaches was 10 days earlier than 30 years ago.

"Peaches are very sensitive to environmental changes, and the early flowering period will be threatened by the'lower spring cold'.

Many studies have identified genes that adapt rice, soybeans and other food crops to the local environment.

Can current peach tree species adapt to future climate change? This gave Wang Lirong the idea of ​​studying how peach, a highly adaptable fruit tree, interacts with the environment.

She told China Science Daily that peach originated in my country and has strong adaptability.

In addition, "the peach genome is small, diploid, and low in ploidy; peach trees self-pollinate and bear fruit, so the genome heterozygosity is low; the child period is short, only 2 to 3 years, and the breeding time is shorter than other fruit trees; There has not been a whole genome duplication event in the evolutionary history of peach.

The special status and characteristics of peach trees make the conclusions obtained in the study of peach trees possible to provide reference for other fruit tree research.

"Gene is the key to molecular breeding.

The paper’s co-corresponding author and Cornell University professor Fei Zhangjun told the Chinese Journal of Science that studying the genetic basis of the interaction between peach trees and the environment can help people cultivate new varieties of peach trees that grow in many different harsh environments.

Tracing the native environment of peaches

Because people focus on flavor, sweetness, and other taste qualities, genes related to environmental adaptation in many peach varieties have been lost.

Fei Zhangjun said, however, there are many wild relatives and local varieties of peaches, and they have long been adapted to specific local conditions and have huge genetic diversity, which can provide resources for improving the adaptability of their "cousins.

But, how can these genes be found faster?

Usually, scientists study the interaction between crops and the environment, and choose to plant several germplasm resources in several different typical environments at the same time, and observe and record the different phenotypic traits of these crop germplasms in three to five years.
, And then through big data analysis and genome analysis, the corresponding relationship between phenotype and genotype is obtained, so as to screen out related genes that adapt to the environment.

If the above methods are used to study the interaction between peach trees and the environment, the cost is high and the cycle is long.

"Our germplasm resource bank has preserved very complete basic information.
" Wang Lirong said that every peach germplasm can be traced back to its collection site, which means that scientists can use this to know where its suitable environment is.

Traditionally, peach varieties are divided into 7 types according to their geographical distribution and traits, which are Yunnan-Guizhou Plateau ecotype, South China subtropical ecotype, Yangtze River mid-lower ecotype, North China Plain ecotype, Northeast Alpine ecotype, Northwest arid ecotype, Ecotype of the Qinghai-Tibet Plateau.

Wang Lirong believes that by using local climatic conditions and the genotypes of local breeds to conduct an association analysis, one can find relevant genes that adapt to the local environment.
This greatly reduces the difficulty of the experiment and can also ensure the accuracy of the experimental results.

2700 environmentally relevant sites

As a result, the team of researchers conducted a genome-wide environmental association study (GWEAS) on 263 peach germplasm resources covering the above seven geographic regions.

The results confirmed that these germplasm can indeed be divided into 7 taxa that match the geographical distribution.
Li Yong, the first author of the paper, told the China Science Daily to further analyze the correlation between environment, genome and geographic location, and found that environment and genome have a high correlation, indicating that the differences between genomes are caused by the environment.
Yes, the genome changes with changes in the environment.

Comparison of different distribution environments of peaches Photo courtesy of Zheng Guo Institute, Chinese Academy of Agricultural Sciences

"That is to say, due to the natural selection of the environment, peaches have undergone different mutations in order to adapt to different environments, resulting in different genome characteristics of the seven ecotypes of peach varieties, forming a genome model that adapts to different environmental conditions.
" Li Yong said .

They also identified more than 2,700 environmental-associated gene loci, which are closely related to 51 environmental factors that affect the climate of these regions.

Analysis of Peach Adaptability Related Genes and Their Functions Photo courtesy of Zheng Guo Institute, Chinese Academy of Agricultural Sciences

For example, it was discovered that peach trees from the northeast alpine region have a unique genetic variation in the histidine phosphotransfer protein gene AHP5, which gives these varieties the ability to withstand severe cold.

In peach trees from arid regions, a series of genes in the ABA regulatory pathway closely related to drought resistance are subject to natural selection.
Further experiments showed that under drought stress, abscisic acid induced a higher level of sucrose synthase, which explained why the sugar content of peach fruits in arid regions is higher than that in peaches in other regions.

Fei Zhangjun said: “When fruit trees like peaches grow under stress conditions such as drought, the fruit becomes sweeter.
In this study, we found a direct genetic link between drought and sugar content in peaches.
”

In the peach samples from the Qinghai-Tibet Plateau, the research team discovered a mutation in the chalcone synthase gene CHS2, which makes it resistant to strong ultraviolet radiation in high altitude areas.
The high expression of this gene increases the content of anthocyanins in new plant tissues, thereby protecting them from ultraviolet radiation.

They also proposed a potential genetic explanation for the early flowering of peach trees: mutations in the circadian rhythm gene LNK1.
This mutation up-regulates expression when the temperature rises, which leads to the blooming of flowers.
Fei Zhangjun said: "This discovery may eventually allow breeders to control the flowering time of fruit trees so that they can harvest peaches when the growers and the market are ready.
"

Thousand Peach Genome Project

"Our research has provided many candidate genes to show how peaches can adapt to various environmental pressures and stimuli.
" Lirong Wang said, "Breeders can use this information to breed peach varieties with a wider range of adaptability, so as to better cope with extremes.
Temperature, drought and climate change.
"

This work is one of the phased achievements of the "1000 Peach Genome" project initiated by Wang Lirong's team.
Wang Lirong told reporters that the plan uses more than 1,000 copies of peach wild relatives, landraces, and cultivars distributed globally as materials to sequence the whole genome of them, and explore the control of important agronomic traits, resistance traits and environmental adaptability.
Key genes, analyze the evolution and domestication mechanism of peach, the formation mechanism of important agronomic traits, and the genetic basis of environmental adaptability, develop practical molecular breeding markers, and lay the foundation for molecular design breeding.

Previously, the team has made important progress in peach genome variation characteristics, artificial selection of peach genome modification, domestication, and association analysis of agronomic traits.

This latest study mainly reveals the influence of natural selection on the peach genome and the genetic basis of peach adaptation to different environments.

Wang Lirong said that in the next step, they will use the rich germplasm resources to carry out genetic research on how Rosaceae fruit trees adapt to the environment, and lay a theoretical foundation for cultivating new varieties of fruit trees that adapt to climate change.
(Source: China Science News Li Chen)

Related paper information: org/10.
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