LIFE SCIENCE

A new mechanism for regulating drought tolerance and growth balance in wheat was found


A negative regulation model of wheat MPK3-PYL interaction module in ABA signaling pathway under normal and drought stress conditions. Courtesy of the Chinese Academy of Agricultural Sciences

Recently, the Research Group of Wheat Stress Resistance Molecular Breeding Innovation Research Group of Crop Sciences, Chinese Academy of Agricultural Sciences found that the MPK3-PYL module can be used as a negative regulation mechanism, which helps wheat balance drought stress response and normal plant growth and development, and provides a theoretical basis and genetic resources for drought resistance breeding of wheat. The results were published in The New Phytologist.

According to Ma Youzhi, a researcher at the Institute of Sciences of the Chinese Academy of Agricultural Sciences, protein kinase plays an important role in plant adversity responses, participating in many functions such as cell regulation and metabolism. The PYR1/PYL protein is an intracellular receptor of the plant hormone abscisic acid that positively regulates abscisic acid signaling. It is also an important target molecule that regulates plant absorcisic acid sensitivity and water use efficiency, and controlling its stability or activity will directly affect the conduction of abscisic acid signaling. The mitogen-activated protein kinase (MAPK) cascade pathway can connect multiple environments and plant developmental signals. However, under drought stress, the molecular mechanisms of abscisic acid signaling and MAPK cascade interactions remain unclear.

It was found that overexpression of the TamPK3 gene significantly reduced the drought tolerance and sensitivity to abscisic acid in wheat. Under drought stress at the seedling stage, overexpressed strains showed low survival rates; Under drought stress at the adult stage, the grain width and 1,000 grain weight of overexpressed TamPK3 wheat decreased. Interfering with the expression of taMPK3 gene can improve the drought tolerance of wheat under certain conditions. The interaction of MPK3 with the abscisic acid receptor protein PYL4 can inhibit the activity of PYL4 and negatively regulate abscisic acid signaling by degrading the PYL4 protein; MPK3-PYL interaction modules are also present in monocotyledonous rice and dicotyledonous Arabidopsis and soybean.

Under normal conditions, the inhibition of PYL4 by MPK3 interferes with the transmission of stress signals and prevents the effect of stress response on normal plant growth. Rapidly produced abscisic acid under drought stress can weaken MPK3-mediated degradation of PYL4, thereby promoting abscisic acid signaling and activating plant stress response. In order to limit the inhibition of plant growth by stress signals or to return to normal growth quickly after the stress stimulus has disappeared, plants may down-regulate the function of PYL4 in abscisic acid signaling by increasing the level of TamPK3. The study confirmed that wheat MPK3 can negatively regulate the drought tolerance of wheat by promoting the degradation of PYL4, and may play a balancing role between wheat drought stress response and normal growth signals.

The research was funded by the National Key R&D Program, the National Natural Science Foundation of China and the Yazhou Bay Seed Laboratory in Hainan. (Source: China Science Daily, Li Chen, Wei Fei)

Related paper information:https://doi.org/10.1111/nph.18326



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