Comparative Insights into the ERECTA-YODA Pathway in Arabidopsis thaliana

Mitogen-activated protein kinase (MAPK) pathways are highly conserved signaling cascades in eukaryotes and play a key role in plant growth, development, reproduction and stress responses. In Arabidopsis, its role in cell differentiation has drawn close attention in the past two decades, with a body of research focusing on the ERECTA-YODA (ER-YDA) pathway in embryogenesis and stomata development. ER-YDA signaling essentially comprises three transduction steps: 1) extracellular ligands are recognized by the upstream ER family (ERf) receptor complex which contains two receptor-like cytoplasmic kinases BRASSINOSTEROID-SIGNALING KINASE 1/2 (BSK1/2) at the membrane; 2) signals from the ERf receptor complex through BSK1/2 activate the YODAMKK4/5-MPK3/6 phosphorylation cascade; 3) the MAPK phosphorylation activates the downstream transcription factor WRKY2 in the embryo or represses the heterodimer complex of two basic helix-loop-helix (bHLH) transcription factors SPEECHLESS (SPCH) and SCREAM (SCRM) in stomata. Previous publications revealed details of the ER-YDA pathway in these two developmental contexts and indicated conserved upstream receptor components and distinct downstream targets. However, former genetic analysis is yet to demonstrate any functional difference in BSK1 and BSK2 as vital upstream signal relays connecting the ER receptor complex and the YDA cascade, and little is known about the conserved mechanism in the regulation of downstream regulators during cell proliferation. This project aims to fill the gaps mentioned above and to gain a better understanding of the ER-YDA pathway from a comparative point of view. To accomplish this, we generated the new loss-of-function mutants of BSK1 and BSK2 using CRISPR/Cas9 and conducted detailed phenotypic analyses which showed that BSK1 contributes mainly to the cell polarity in the embryo and stomata, while BSK2 plays a prominent role in the growth of rosette leaves. Confocal microscopy and co-immunoprecipitation coupled with mass spectrometry (CoIP-MS) assays in YPet-tagged BSK1/2 transgenic lines further identified the differences in expression patterns, new phosphorylation sites and interacting proteins for BSK1 and BSK2 in vivo. These functional differences between BSK1 and BSK2 suggest an evolutionary divergence and support us to propose a collaborative working model. Furthermore, we disclose that SCREAM (SCRM), a well-known target of the ER-YDA pathway in stomata, functions as a regulator of embryo development. However, the regulation of SCRM by the ER-YDA pathway switches from phosphorylation-dependent degradation in stomata to phosphorylation-dependent activation in the embryo. Further studies verified that SCRM works in synergy with WRKY2 to upregulate WUSCHEL RELATED HOMEOBOX 8 (WOX8) in the apical-basal axis formation during embryogenesis. Finally, we conducted a phenotypic screen and found bHLH35, a paralogue of SCRM subfamily, is a potential interacting partner of SCRM in early embryos. This work provides a comparative insight into the ER-YDA pathway, enabling us to have a more comprehensive understanding of the MAPK cascade. Two aspects of this thesis, the overlapping but differential functions of BSK1/2 and the altered regulation of the conserved target SCRM, together exhibit the conservation and diversity of the ER-YDA pathway, further expanding the knowledge on how the MAPK pathway delicately controls the signal for cell differentiation and proliferation.Die Dissertation ist gesperrt bis zum 23. November 2024

Square one: zygote polarity and early embryogenesis in flowering plants

In the last two decades, work on auxin signaling has helped to understand many aspects of the fundamental process underlying the specification of tissue types in the plant embryo. However, the immediate steps after fertilization including the polarization of the zygote and the initial body axis formation remained poorly understood. Valuable insight into these enigmatic processes has been gained by studying fertilization in grasses. Recent technical advances in transcriptomics of developing embryos with high spatial and temporal resolution give an emerging picture of the rapid changes of the zygotic developmental program. Together with the use of live imaging of novel fluorescent marker lines, these data are now the basis of unraveling the very first steps of the embryonic patterning process

Blue carbon cooperation in the Maritime Silk Road with network game model and simulation

The blue carbon cooperation is a joint effort of the countries along the Maritime Silk Road (MSR) to utilize marine activities and organisms to absorb and store carbon dioxide in the atmosphere, an initiative that has great strategic value for coping with the most important environmental problems in the 21st century and promoting the building of a community with shared aspirations for mankind's future. This research combines the decision-making structure model with the reality of the blue carbon cooperation game of the MSR to make conditional assumptions and carry out model construction. It uses the simulation method to test the influencing factors such as decision-maker type, initial input cost, continuous input maintenance cost, rate of return, carbon tax rate and others. The results suggest that initial and continuous input costs, returns, and neighbor subsidies have positive impacts on blue carbon cooperation, while carbon tax rates and income discount rates have negative impacts on blue carbon cooperation. To promote blue carbon cooperation along the MSR, emphasis should be placed on the design of incentive and subsidy mechanisms, together with the appropriate punishment mechanisms.</p

The Chinese Herb Jianpijiedu Contributes to the Regulation of OATP1B2 and ABCC2 in a Rat Model of Orthotopic Transplantation Liver Cancer Pretreated with Food Restriction and Diarrhea

Traditional Chinese Medicine Jianpijiedu decoction (JPJD) could improve the general status of liver cancer patients in clinics, especially the symptoms of decreased food intake and diarrhea. In this study, our results showed that the survival rate of the liver cancer with food restriction and diarrhea (FRD-LC) rats was lower than the liver cancer (LC) rats, and the tumor volume of the FRD-LC rats was higher than the LC rats. It was also shown that the high dose of JPJD significantly improved the survival rate, weight, and organ weight when compared with FRD-LC-induced rats. Moreover, JPJD administration upregulated the mRNA and protein levels of ABCC2 and downregulated the mRNA and protein levels of OATP1B2 in liver tissues. However, opposite results were observed in the cancer tissues. In conclusion, the study indicated that the Chinese Medicine JPJD could contribute to the rats with liver cancer which were pretreated with food restriction and diarrhea by regulating the expression of ABCC2 and OATP1B2 in liver tissues and cancer tissues

Study on Microstructure and Properties of Ni60A/WC Composite Coating by Alternating-Magnetic-Field-Assisted Laser Cladding

Ni60A/WC composite coating is prepared on 45 steel substrate by alternating-magnetic-field-assisted laser cladding. We compare the effects of different magnetic field intensity on WC particle distribution, microstructure, phase composition, microhardness and wear; in addition, the mechanism of alternating magnetic fields on cladding layers is briefly analyzed. The results show that an alternating magnetic field can significantly homogenize the distribution of WC particles. WC particles at the bottom are stirred and dispersed to the middle and upper area of the laser pool. The distribution of WC in the bottom region 6 of the coating decreases from 19.1% to 10%, the distribution of WC in the bottom region 5 decreases from 46.46% to 33.3%, the WC distribution in the top region 1 of the coating increases from 0 to 7.7% and the WC distribution in the top region 2 of the coating increases from 8.08% to 12.2%. The stirring of alternating magnetic fields strengthens the solute convection in the laser pool, refines the snowflake-shaped carbide hard phase and improves the coating microhardness and wear property, and adhesive wear and abrasive wear decrease gradually with increasing magnetic field strength

Psoralen Inhibited Apoptosis of Osteoporotic Osteoblasts by Modulating IRE1-ASK1-JNK Pathway

Osteoporosis is a common disease causing fracture in older populations. Abnormal apoptosis of osteoblasts contributes to the genesis of osteoporosis. Inhibiting apoptosis of osteoblasts provides a promising strategy to prevent osteoporosis. The proliferation of osteoblasts isolated from osteoporotic patients or healthy subjects was determined by MTT assay. Apoptosis was determined by Annexin V/PI assay. Protein expression was measured by western blot. The proliferation of osteoblasts isolated from osteoporotic patients was inhibited and the apoptosis level of these cells was higher than the osteoblasts from healthy subjects. Incubation with psoralen or estradiol significantly enhanced the proliferation and decreased the apoptosis level of osteoporotic osteoblasts. Western blot demonstrated that psoralen or estradiol treatment downregulated the expression of IRE1, p-ASK, p-JNK, and Bax. Meanwhile, expression of Bcl-2 was upregulated. Pretreatment by IRE1 agonist tunicamycin or JNK agonist anisomycin attenuated the effect of psoralen on osteoporotic osteoblasts. Psoralen inhibited apoptosis of osteoporotic osteoblasts by regulating IRE1-ASK1-JNK pathway

The Building of a New Countryside in Poverty-stricken Mountainous Area:A case of Hongyan Village, Haizijie Town of Bijie City

The essential drive of building a new countryside lies in scientific and technological innovation. Through expounding the scientific and technological demonstration benefits and roles of new countryside building in poverty-stricken mountainous area, the major problems and hardships of new countryside building in poverty-stricken area are analyzed and the new breakthroughs which should be focused on during the building of a new countryside are put forward. These breakthroughs include transforming the philosophy and approach of rural work; highlighting the construction of rural operation mode and rural socialized service system, and improving the quality of rural labors