Professor Bai Lianyang’s team cracked the new molecular mechanism of plant ABC transporter resistance to glyphosate
By: Date: 2021-04-14 Categories: foodtechnology Tags: ,
  Glyphosate is a kind of biocidal herbicide. Due to long-term and large-scale application of glyphosate, at least 48 types of weeds in crop fields have become resistant to glyphosate. Glyphosate is mainly transported throughout the body and spread throughout the meristem of plants to exert its herbicidal effect. Therefore, any mechanism that prevents glyphosate from reaching its target enolpyruvylshikimitin phosphate synthase (EPSPS) can cause plants Resistance to glyphosate. More than twenty years ago, the first discovered glyphosate-resistant weeds in the world were caused by their weakened transport capacity, and this is also the most common non-target resistance mechanism in glyphosate-resistant weeds. At present, the research on the resistance mechanism of weeds against glyphosate-resistant targets (EPSPS) is increasingly deep, but the molecular mechanism of resistance related to non-target or glyphosate transport is still unclear. ATP-binding cassette (ABC) transporter is a type of membrane-positioned carrier protein that depends on ATP hydrolysis for energy. It can transport hormones, lipid secondary metabolites, exogenous toxic substances, etc., but whether it is in the plant to glyphosate The role played in drug resistance remains unclear.
   On April 13, 2021, the team of Professor Bai Lianyang and Professor Yu Qin from the University of Western Australia in Australia, etc. formally published in the authoritative journal Proceedings of the National Academy of Sciences of the United States of America (PNAS) Published a research paper entitled”An ABCC-type transporter endowing glyphosate resistance in plants”. The study found that EcABCC8, a transporter of barnyardgrass, can transport glyphosate that enters the membrane to the outside of the membrane to produce resistance on the plasma membrane, revealing a new mechanism for plant resistance to glyphosate, and further elucidating the ABC in plants The function of transporter.
   Barnyardgrass is a worldwide malignant weed. It is the most important weed in many crop fields, which seriously affects crop yield. At the same time, it is also listed as the first of 15 serious weeds in farmland in my country. At present, the prevention of this weed must rely on chemical herbicides. Barnyardgrass has developed resistance to many herbicides. At present, herbicide resistance is a worldwide problem, which seriously threatens crop production. In this study, RNA-Seq was used to analyze the expression differences of sensitive and resistant single plants from the glyphosate-resistant barnyardgrass population, and successfully identified and cloned the glyphosate resistance-related gene EcABCC8. Transgenic rice further proves that overexpression of this gene can lead to resistance to glyphosate. Using gene editing to knock out the homologous gene of the EcABCC8 gene in rice can increase its sensitivity to glyphosate. It was also confirmed that the overexpression of the homologous gene of EcABCC8 gene in legume soybeans, grasses rice, and corn can also lead to resistance to glyphosate in transgenic plants, indicating that this function is likely to be widespread in higher plants. By analyzing the methylation levels of resistant and sensitive barnyardgrass populations, it was found that the transcriptional variation of EcABCC8 may be caused by differences in methylation levels. The internal biological mechanism of ABCC8-mediated plant resistance to glyphosate was further explored. Unlike the vacuolar membrane ABC transporter that has been studied more in the past, this study found that ABCC8 is mainly located on the plasma membrane and will enter the intracellular at the cellular level. Glyphosate is transported to the outside of the plasma membrane to reduce toxicity. This principle is similar to the drug resistance mechanism of human cancer cells. The molecular simulation method analyzed the structural interaction between the glyphosate molecule and the EcABCC8 protein of barnyardgrass, and confirmed this mechanism of action. This research is an important progress in the field of weed resistance and ABC transporter research. It not only enriches the basic theory of weed resistance, but also provides a theoretical basis for the application of genetic means to reverse the resistance of weeds to glyphosate. Genetic improvement for glyphosate tolerance also has important guiding value.
Professor Bai Lianyang’s team cracked the new molecular mechanism of plant ABC transporter resistance to glyphosateimage
  EcABCC8 transports glyphosate and produces resistance mechanism
   PNAS magazine nominated the research in the “In This Issue” section. The scientific writer/editor Janelle Weaver of PNAS magazine said that “plant transporters can pump toxic substances from cells to cause herbicide resistance” (Transporter co nfers herbicide resistance in plants by extruding toxin from cells), and pointed out that “Pan Lang et al. provided evidence that ABC transporters can participate in plant resistance to herbicides, and they also interact with human anticancer drugs.”Lang Pan et al. provide evidence that herbicide resistance in plants can be mediated by ABC transporters, which are also implicated in anticancer drug resistance in humans);”This molecular mechanism is similar to that used by cancer cells. This molecular mechanism is similar to that used by cancer cells, which use ABC transporters to extrude and resist chemotherapeutic drugs.
   The first unit of the research is the Hunan Academy of Agricultural Sciences. Professor Bai Lianyang is the corresponding author, Bai Lianyang’s postdoctoral fellow Pan Lang is the first author of the paper, and Professor Yu Qin and Professor Stephen Powles of the University of Western Australia are the joint correspondence. Author. The research was funded by the National Natural Science Foundation of China, the National Industrial Technology System, and the Australian Grain Research and Development Organization.