Abstract：
Due to continuous plantation of poplar, its growth and biomass accumulation may be negatively affected by the accumulation of allelochemicals such as para-hydroxybenzoic acid (pHBA) in soil. As photosynthesis is the most fundamental process in plants, it can be negatively impacted by pHBA stress. Therefore, it is crucial to improve photosynthetic capacity under pHBA stress to facilitate poplar plant growth. The mitogen-activated protein kinase (MAPK) cascade pathway is widely involved in environmental stress responses in plants. However, the regulation mechanisms of photosynthesis-related pathways by MAPK pathway genes under pHBA stress are still unclear. In this study, through transcriptome analysis and weighted gene co-expression network analysis, we observed that PeMPK7 overexpression in poplar can regulate the expression of photosynthesis-related genes and transcription factor genes, namely, WRKY1, WRKY33, and ERF3, during the early stage of pHBA stress. In addition, PeMPK7 can improve photosynthesis in poplar under long-term pHBA stress. Moreover, yeast two-hybrid and pull-down assays confirmed the interaction between PeMPK7 and PeMKK7/10. Based on these results, a schematic diagram of the pathways involved in the regulation of photosynthesis by PeMPK7 was constructed. This study provided novel insights into the molecular mechanisms of regulation of pHBA stress via MAPK cascade pathway.
摘要：
由于杨树的连续种植，土壤中对羟基苯甲酸（pHBA）等化感物质的积累可能会对其生长和生物量积累产生负面影响。光合作用是植物最基本的过程,它可能会受到pHBA压力的负面影响。因此,在pHBA胁迫下提高光合能力对促进杨树植物生长至关重要。丝裂原活化蛋白激酶（MAPK）级联途径广泛参与植物的环境胁迫反应。然而,pHBA胁迫下MAPK通路基因对光合作用相关通路的调控机制尚不清楚。在这项研究中,通过转录组分析和加权基因共表达网络分析，我们观察到PeMPK7在杨树中的过表达可以调节光合作用相关基因和转录因子基因的表达,即,在pHBA胁迫的早期阶段，WRKY1，WRKY33和ERF3。此外,在长期pHBA胁迫下，PeMPK7可以改善杨树的光合作用。此外，酵母双杂交和下拉测定证实了PeMPK7和PeMKK7/10之间的相互作用。基于这些结果,构建了PeMPK7调节光合作用的途径示意图。本研究为通过MAPK级联途径调控pHBA应激的分子机制提供了新的见解。
