The scientists' new findings provide an explanation for the phenomenon of "same pollen first"

Beijing, May 31 (Reporter Jin Haotian) Peking University School of Life Sciences, Peking University - Tsinghua Joint Center for Life Sciences Professor Yu Lijia task force 31 in the journal Science published online entitled "rich in cysteine small peptide signals to promote genetic isolation between species of amoeba. " This paper reveals the molecular signaling mechanisms of the reproductive isolation barrier within and between plants. The study is beneficial for future breeding efforts and could increase the gene pool by adding the desired agro-artistic features to crop plants.
that genetic isolation between species is the key to maintaining that one species does not mix with other species, and that there are a number of factors that can lead to genetic isolation between species. 160 years ago, Darwin said in his famous Origin of Species that he had personally tested the phenomenon of a plant's pollen "winning" in competition with pollen from other species, arguing that it was important to create genetic isolation between different species. A similar phenomenon has been found in animals, known as "same sperm first", which ensures that the sperm of one species is attracted to the egg cells of the same species, rather than other species, and thus completes subsequent fusion (fertilization) to preserve the pure genetics of the species. But for more than a century, little is known about the molecular mechanisms of this phenomenon.
Previous studies have shown that five members of a class of small peptide signals (AtLURE1s) secreted by cells in the female reproductive organs of flower plant amoeba can specifically attract the species' male cell pollen tubes, which contain sperm cells. Interestingly, however, whether it is the small peptide signal AtLURE1 or the receptor that feels the signal, the plant is able to successfully complete the pollen tube attraction and subsequent fertilization process after loss of function, and produce normal seeds. This phenomenon has inspired researchers to rethink the atLURE1-mediated pollen tube-oriented biological function.
The team at Peking University's School of Life Sciences first identified two AtLURE1s members with the same function as the five members above, and then used CRISPR/Cas9 gene knock-out technology to obtain the atlure1 mutants that all members of the AtLURE1 family had been knocked out, and found that mutant plants could still produce seeds normally. The results show that atLURE1s, a small peptide with species-specific pollen tube attraction activity, is not necessary to complete the pollen tube orientation and subsequent fertilization process. So what are the biological functions of AtLURE1s, the small peptide signals specific to amoeba? They further found that if the pollen of athropophymesan mustard was given to the column head of amortization mustard together with pollen of another species close to the athropophymeal mustard, the pollen tubes of athropophymeal mustard were given priority and competitiveness was significantly reduced in plants with a normal AtLURE1 signal; The above-mentioned studies show that AtLURE1s is not the only signal of attracting male pollen tubes secreted by the female organs of athropomorthic mustard, but rather a signal of genetic isolation by increasing the competitiveness of its own pollen tubes and promoting genetic isolation of closely related species;
Interestingly, the team further found that the female organs of the amoeba can also secrete four small peptide signals that do not have species-specific attracting pollen tubes, which not only attract the pollen tubes of the amoeba, but also attract other near edges. The pollen tubes of species such as Qinye amoeba and Haller's amoeba; they named these four species-specific peptides XIU (the Chinese pinyin for "Hydrangea", taken from the allusion of the ancient Chinese woman to be married to throw hydrangea to choose her husband). This also explains why, after all the AtLURE1s gene has been mutated, the pollen tube of the athropomorthic mustard can still find the embryo beads, complete fertilization and produce seeds. The discovery of the "hydrangea" small peptide signal greatly improves the model of the role of the small peptide signal in regulating the fertilization process of flower plants.
scientific review notes that the authors' conclusions will have a profound impact on the relevant research areas and mean that almost all textbooks and reviews published and published after 2009 may have to be rewritten. At the same time, it is an exciting idea that a pollen tube attraction substance (XIUQIU) that transcends species barriers exists in combination with a small peptide (AtLURE1s) that functions in reproductive isolation, which will affect the basic theory of plant biology and the practical application of horticulture/agriculture.
It is understood that Yu Lijia, a professor at Peking University's School of Life Sciences, is the co-author of the paper, as are Zhong Zhongsheng, an assistant laboratory researcher, Liu Meiling, a doctoral student at Peking University's School of Life Sciences, and Wang Zhixuan, a researcher at the Institute of Plant Research of the Chinese Academy of Sciences, Liu Pei, a professor at the School of Resources and Environment of the Agricultural University of China, Xiao Junyu, a researcher at Peking University's School of Life Sciences, and Gu Hongya, a professor. The research was funded by the National Natural Science Foundation of China and the Peking University-Tsinghua Joint Life Center.