Low temperature seriously hinders the normal growth and development of plants, limits the geographical distribution of vegetation, and affects agricultural production. In recent years, with the global climate change, extreme climate occurs frequently. As a global natural disaster, the low temperature and cold disaster threatens the growth and survival of crops and causes huge losses to agricultural production. Therefore, it is of great theoretical significance and practical value to study the molecular mechanism of plant response to low temperature stress.
Yang Shuhua research team of China Agricultural University has been engaged in the research of molecular mechanism of plant perception and response to low temperature stress for a long time, and has made a series of important progress in this field in recent years. Relevant research results have been published in academic journals such as molecular cell, developmental cell, the plant cell, molecular plant, PNAs, the EMBO journal, trends in plant science, etc. We have summarized some of the work of the team in order to help the readers who are engaged in the research of low temperature stress.
In April 2020, Yang Shuhua's team published the topic "cold induced cbf-pif3 interaction enhancements freeing tolerance by stabilizing the phyB thermosensor in mobile plant" The research paper of Arabidopsis (Dr. Jiang bochen and Associate Professor Shi Yiting are the co first authors, and Professor Yang Shuhua is the corresponding author) reported the molecular mechanism of the interaction between low-temperature signal transcription factor CBFS and light signal transcription factor PIF3, stabilizing red light and temperature receptor phyB, so as to improve the freezing resistance of plants.
It was found that there was a direct interaction between CBFS and PIF3 at low temperature, which inhibited the co degradation of PIF3 and phyB. PhyB is regulating the freezing resistance of plants by regulating the low temperature response and the expression of growth and development related genes. The freezing resistance of phyB mutant decreased under long red light or white light, and the freezing resistance of phyB overexpressed plants increased significantly under red light or white light. It was also found that the enhanced stability of phyB protein at low temperature could promote the degradation of pif1, pif4 and pif5 protein, while low temperature also inhibited the expression of pif1, pif4 and pif5 genes. Therefore, CBF protein induced by low temperature can fine regulate low temperature signal through feedback regulation mechanism, so that plants can resist low temperature environment. It is found that CBFS and PIF3 interact to integrate low temperature signal and phyB mediated light signal, which elucidates the important role of phyB in plant adaptation to low temperature stress.
Molecular model diagram of cbfs-pif3-phyb module regulating plant low temperature response
Paper link:
https://www.sciencedirect.com/science/article/pii/S1674205220301076
In February 2020, Yang Shuhua's team published a review article entitled "molecular regulation of plant responses to environmental temperatures" in the molecular plant, combing and summarizing the latest progress in the field of thermomorphogenesis, vernalization and the tolerance mechanism of plants to extreme temperature, and also putting forward the direction of future research in related fields.
This paper is divided into five parts: the perception of plant to temperature, the response of plant to low temperature stress, the response of plant to heat stress, the thermomorphogenesis and the Vernalization of plant. In this review, the research progress in these fields, especially the related molecular regulatory mechanism, is discussed in detail.
Please refer to: https://doi.org/10.1016/j.molp.2020.02.004
In September 2019, Yang Shuhua's team published a research paper entitled pub25 and pub26 promote plant freezing tolerance by grading the cold signaling negative regulator MYB15 online in the development cell (Wang Xi, a doctoral student of China Agricultural University, is the first author of the paper, and Professor Yang Shuhua is the corresponding author). This study revealed that pub25 / 26, an E3 ligase in Arabidopsis, participates in the response of plants to low temperature signals by regulating the protein stability of MYB15, a negative regulatory transcription factor in CBF signaling pathway. This study found new components in CBF signaling pathway and further elucidated the molecular mechanism of CBFS rapid induction in plant early cold response.
In this study, the U-box E3 ligase pub25 / 26 was found to be involved in plant response to low temperature by screening E3 T-DNA insertion mutant library. In the double mutant pub25 pub26, the cold induced level of CBFS was significantly lower than that of the wild type, and the plants showed a cold sensitive phenotype. Further study showed that pub25 / 26 interacted with MYB15 and participated in the degradation process of MYB15 in the early stage of low temperature treatment. At the same time, the T95 / T94 site of pub25 / 26 is the action site of protein kinase OST1. Low temperature activated OST1 kinase activity, activated OST1 phosphorylated pub25 / 26, enhanced the E3 ligase activity of pub25 / 26, promoted its ubiquitin degradation of MYB15 protein, and thus positively regulated the induced expression of CBFS at low temperature and the freezing resistance of plants. This study revealed the molecular mechanism that UPS mediated by pub25 / 26 participated in the regulation of plant frost resistance. Under the joint action of ost1-pu25 / 26, the homeostasis of MYB15 protein was balanced, and finally the fine regulation of plant low temperature response was realized.
Figure: low temperature activated OST1 kinase phosphorylates pub25 / 26, enhances the E3 activity of pub25 / 26, and promotes the degradation of MYB15 at low temperature; at the same time, OST1 phosphorylates ICE1 and enhances its protein stability and transcription activity, ultimately promoting the expression of CBFS, and enhancing the frost resistance of plants.
Paper link:
https://doi.org/10.1016/j.devcel.2019.08.008
In August 2019, Yang Shuhua's team published a research paper in the plant cell entitled brassinostroid-insensive2 indirectly regulations the stability of transcription factor ICE1 in response to cold stress in Arabidopsis. This study reported that protein phosphatase BIN2 (brassinostroid-insensive2) can regulate the expression of CBF, a key gene of cold exercise, by affecting the protein stability of ICE1 transcription factor, which provides new information for elucidating the fine regulation mechanism of genes during cold exercise in plants.
In this study, the interaction between BIN2 protein and ICE1, the upstream transcription factor of CBFS gene, was found by yeast library screening, and confirmed by a series of experiments. Further studies showed that as a protein kinase, BIN2 can phosphorylate ICE1, promote the degradation of ICE1, and ultimately reduce the expression of CBFS gene. BIN2 can reduce the expression of CBFS gene by negatively regulating transcription factors bzr1 and cesta, indicating that BIN2 is the key negative regulator of CBFS gene. Further study showed that the kinases activity of BIN2 decreased significantly in the early stage of cold stress, but returned to the level before stress in the later stage. This shows that plants can inhibit the effect of BIN2 through some mechanism after they feel the cold signal, release multiple transcription factors to induce CBF gene expression, so as to enhance the plant's ability of low temperature tolerance; in the later stage, the kinase activity of BIN2 recovers to prevent over response from causing damage to the plant itself. This study proves that BIN2 is an important switch in plant cold response process, which is of great significance to reveal the molecular mechanism of plant response to cold stress.
Paper link: www.plantcell.org/content/early/2019/08/13/tpc.19.00058
In November 2018, Yang Shuhua's team published a research paper entitled Egr2 phosphorase regulations OST1 kinase activity and freezing tolerance in Arabidopsis online in the EMBO Journal (Dr. Ding Yanglin is the first author, and Professor Yang Shuhua is the corresponding author). This study reported that the protein phosphatase Egr2 (clade-e growth regulating 2) is the key component of regulating the low temperature activation of OST1, which provides an important theoretical basis and possible research direction for clarifying the mechanism of plant response to low temperature signal.
In this study, Egr2, a protein phosphatase family of PP2C type E family, was identified to be involved in the regulation of low-temperature activation of OST1. Under normal temperature, Egr2 interacts with nmt1 and is modified by myristoylation, which is necessary for its low temperature response. The interaction of m-egr2 and OST1 can inhibit the kinase activity of OST1, which is beneficial to the normal growth of plants. When plants are exposed to low temperature stress, the interaction between Egr2 and nmt1 is weakened, which makes plants synthesize a large number of new Egr2 (u-egr2). At the same time, the interaction between m-egr2 and OST1 was disturbed by the newly synthesized u-egr2 at low temperature. The above dual factors make OST1 activated by low temperature, so as to phosphorylate the downstream components ICE1 and btf3 and enhance the frost resistance of plants (Figure 1). This study not only revealed the molecular mechanism of low-temperature activation of OST1, but also suggested that myristic switch may be involved in the plant's perception and transduction of low-temperature signal.
Paper link: https://doi.org/10.15252/embj.201899819
In March 2018, Yang Shuhua's team published a research paper entitled OST1 mediated btf3l photosynthesis positional regulations CBFS during plant cold responses online in the EMBO Journal (Dr. Ding Yanglin is the first author and Yang Shuhua is the corresponding author). This study found that btf3l (basic transcription factor 3 like), a β subunit of the new peptide chain coupled protein complex, is regulating the response to low temperature in plants. This study revealed the molecular mechanism of ost1-btf3l protein complex regulating plant response to low temperature stress, and deepened our understanding of the regulatory mechanism of plant response to low temperature.
Previous studies have shown that protein kinase OST1 is activated by low temperature, phosphorylating ICE1, an important transcription factor of low temperature signal, and inhibiting the ubiquitination and degradation of ICE1, thus enhancing the freezing resistance of plants (developmental cell, 2015). In order to further study the molecular mechanism of OST1 regulating plant low temperature response, Yang Shuhua's team demonstrated that btf3 and btf3l are the interacting proteins of OST1 through protein mass spectrometry, yeast two hybrid, pull down experiment in vitro, BiFC and co IP experiments. Further studies have shown that btf3l can be phosphorylated by the activated OST1 protein under low temperature, thus enhancing its interaction with CBFS protein. The results showed that the stability of CBF protein was enhanced, the expression of low temperature response gene cor was high, and the frost resistance of plants was enhanced. In addition, btf3l protein can indirectly regulate the expression of CBFS gene to enhance the ability of freezing resistance of plants. In this study, we found and elucidated the molecular mechanism of btf3l, a new component of low-temperature response, in plant response to low-temperature stress.
Figure: low temperature activated protein kinase OST1 activity, activated OST1 phosphorylated btf3s. The interaction between phosphorylated btf3s protein and CBFS protein is enhanced, thus enhancing the stability of CBFS protein. In addition, btf3s protein indirectly and positively regulates the expression of CBFS gene. The dual regulation of btf3s on CBFS ultimately improves the plant's frost resistance.
Paper link: https://doi.org/10.15252/embj.201798228
In 2018, Yang Shuhua's team was invited to publish a review paper entitled molecular regulation of CBF signaling in cold acclimation in trends in Plant Science (Shi Yiting and Ding Yanglin are the co first authors, and Professor Yang Shuhua is the corresponding author). In this paper, the adverse effects of low temperature on plants, the overview of low temperature exercise, the transcriptional regulation of low temperature exercise, the feeling of low temperature signal, post-translational modification of low temperature signal, the balance between plant growth and low temperature tolerance are summarized, and the future research direction of low temperature research is proposed.
Paper link: https://doi.org/10.1016/j.tplants.2018.04.002
In October 2017, Yang Shuhua's team published "MPK3 - and mpk6 mediated ICE1 phosphorylation negatively regulated ICE1 stability and freezing tolerance" in the development cell