The Chinese and foreign teams revealed the key mechanisms of the fertilization process of the plant

fertilization process of the bee plant is a key link in seed formation. Preventing multiple sperm cells from binding to egg cells, i.e. polysemination, is an important thing to keep the genomes of future generations stable.
March 19, Nature published the latest results from Shandong Agricultural University and the University of Massachusetts Amster. After years of effort, they discovered the molecular mechanism by which beaded plants prevent multiple pollen tubes from entering the embryo.
Qiaohong, the first author of the paper and a professor at Shandong Agricultural University's School of Horticultural Science and Engineering, told China Science Daily that it is the feronia-subject kinase that plays this important role. It has a "dual regulatory mechanism" in the interaction between pollen tube and embryo beads: it is responsible for regulating the mechanism by which pollen tubes break up after entering the beads to release sperm cells, and it is also responsible for preventing other pollen tubes from entering embryos that are already "famous flowers".in the long-term evolution, flowering plants have evolved the phenomenon of pollen fertilization, which is through pollen tubes to transfer in motionable sperm to the egg cells in the embryo. Yang Weicai, a researcher at the Institute of Genetics and Developmental Biology of the Chinese Academy of Sciences, told the China Science Journal: "This evolution has made fertilization less dependent on the water environment, so it is essential for flowering plants to adapt to the land environment." At the same time, pollen fertilization has a genus-specific (reproductive isolation) and a one-to-one relationship between pollen tubes and female ligands. This means that only one pollen tube is allowed into a female match.
Yu Lijia, a professor at Peking University's School of Life Sciences, told the China Science Daily that in a plant, sperm cells can only be passively transported from pollen tubes to female ligators for fertilization as "goods" because sperm cells no longer have whiplash as a "power system". Pollen tubes are attracted by a variety of attractors secreted by the beads and are precisely directed into the female lithology."in the natural state of pollination process, pollen is usually excessive, so the number of pollen tubes entering the female python always greatly exceeds the number of embryo beads." Nevertheless, under normal circumstances, pollen tubes can always successfully "bypass" the embryo beads that have been "occupied" and look for those that have not yet been "occupied".
" phenomenon not only prevents plants from multi-pollen tube fertilization, but also ensures maximum reproductive efficiency and seed yield, and is therefore of great significance to agricultural production. She said.
past few decades, scientists have studied the mechanisms by which plants avoid "polysemination" and made a number of assumptions.
"FERONIA, a protein kinase that is expressed in many organs in plants, affects many important biological processes, including plant growth and development, response to biological and absolamation, sexual reproduction, etc. It can be said that it is like a 'star-like body'. Duan Qiaohong told China Science Daily that they started studying FER a long time ago.
2014, they found that in FER's missing mutant embryo beads, the reactive oxygen content was lower, pollen tubes could not break after entering the embryonic cells, and grew "in a circle" inside the embryo beads. They determined that FER regulates the accumulation of reactive oxygen at the embryonic bead silk, which causes the pollen tube to rupture and release the sperm cells., it became common for multiple pollen tubes to enter the same embryo bead in ferring-missing mutants. It also makes them realize that FER has more than one regulatory mechanism for pollen tubes.
"When the subject protein FERONIA is missing, pollen tubes can be attracted to the female ligand and continue to grow, but do not break to release the sperm they carry, along with multiple pollen tubes into the same female ligand." This shows that FERONIA is important for the timely release of sperm and to prevent the entry of excess pollen tubes, but its mechanism is not clear. Yang Weicai said.pollen falls on the female's column head, it begins to grow pollen tubes. A pollen tube is a single-celled tube structure that grows at the top, growing in the female to the egg cells in the embryo beads, and the sperm cells are constantly transported forward.
" pollen tube advances between cell walls and does not enter the cell's interior until it enters the embryo. "Until it reached the female lithosome of the embryo, there was a structure called a silky device, the junction of the cell membrane and cell wall that the two cells together formed, the site where the FERONIA protein was expressed in large numbers, and the lure protein that attracted pollen tubes into the embryobeads." The ribbon is where these events take place. Our research is here. Duan Qiaohong said.as long as the embryo beads do not accept pollen tube, the embryo beads will continue to secrete induced protein LURE through a silky device, can adhere to 2-3 days. Once the pollen tube passes through the cell wall into the embryo beads, a series of chain reactions are activated, Duan said.
first change is the low methyl esterified phosphate on the ribbon. The subject kinase FER regulates the low methylsteride glial glial, which turns it into multiple small molecules. These small molecules further induce the accumulation of nitric oxide in the ribbon.
previous studies have shown that nitric oxide has nitrosylation. In this study, we found that nitric oxide did nitrosize the induced protein LURE and acted on two bits. Duan Qiaohong said that the modification of these two points, on the one hand to prevent the continued secretion of LURE, on the other hand, make LURE lose the activity of induced pollen tube, other pollen tubes therefore can not enter the "famous flower has the main" embryo beads.
" is that plants 'choose' nitric oxide in this mechanism, and gases can spread rapidly. Nitric oxide has the potential to reach LURE, which has been secreted to the far end, allowing the entire mechanism to function quickly. Duan Qiaohong said that when the remote induced protein LURE infested, "late" pollen tube will be in time to turn to other embryos that have not yet been "occupied." in FER's missing mutant embryo beads, the content of low methyl esterified gel and nitric oxide in the silky device site was significantly lower than that of wild embryo beads, confirming the above mechanism. In-body experiments have also shown that the treatment of embryo beads with low methyl esterified glial can stimulate the production of nitric oxide.
" findings suggest that when the first pollen tube arrives, it changes the embryo bead state, unencumbers the pollen tube and prevents subsequent pollen tubes from entering, avoiding polysemination. This study reveals a new mechanism for FERONIA to regulate polyseed phenomena. Yang Weicai said. " in the process of plant sexual reproduction, the signal communication between males and females has a strong space-time specificity, so it is very difficult to study the molecular mechanisms that regulate sexual reproduction processes. The work spanned a decade, and the work spanned a decade, with a precise division of pollen tube guidance, avoidance of "multi-fertilization" and fertilization compensation, as well as a number of different but linked, overlapping biological processes that linked star-like ferrings to cell wall groups, pollen tubes to attract signal transductivity, and gases, he said. Molecular nitric oxide and other factors are linked together, at the molecular level revealed a new control network in the plant to prevent polyflower tube fertilization, greatly deepened people's understanding of cell-cell communication in plant sexual reproduction process, is a major breakthrough in the field of plant reproductive biology research. Alice Y. Cheung, co-author of the
paper and a professor at massachusetts State University amster, said the study sheds light on molecular and biochemic levels how the beads coordinate the biological processes of "pollen tube rupture" and "prevent multiple pollen tubes from entering the embryo beads", providing important inspiration for further study of the regulatory mechanisms of the fertilization process of plants.
" discovery reveals the molecular mechanism of sperm release and avoidance of multiple pollen tubes in flowering plants, and enriches and perfects the human understanding of the phenomenon of pollen fertilization. Yang Weicai said.
plants evolved to form an inters species reproductive isolation mechanism, that is, pollen from one plant, and even if a pollen tube is grown, it is difficult to accurately enter the embryo beads of another plant. For the embryo beads of the athropomorthic mustard, it is difficult to accurately direct the pollen tube of the leeks belonging to the crusader department.
some wild plants may contain good genes, such as drought resistance, salt resistance, etc. Scientists have long wanted to break the isolation of plant species and genus through distant hybridization, introduce these features into crops, and obtain new crop varieties. One of the main causes of hybridization disorders is the effective identification of male and female licquer.
" with this result, we are one step closer to the realization of distant hybridization. Duan Qiaohong said. In the future, however, there are still some scientific problems to be solved in the study of plant fertilization processes. This includes what is the degradation mechanism of induced protein LURE? In addition to the MECHANISM of FER subject regulation to make LURE "no longer attract" late pollen tubes, is there any other mechanism to "stop" or even "exclude" late pollen tubes?
believe that there are still many issues that remain to be resolved throughout the fertilization process, " he said. Duan Qiaohong said.
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