Research Center for Eco-Environmental Engineering, Dongguan University of Technology, Dongguan 523808, China; Institute of Environmental Research at Greater Bay Area, Guangzhou University, Guangzhou 510006, China.
Sci Total Environ. 2024 Jun 10;928:172449. doi: 10.1016/j.scitotenv.2024.172449. Epub 2024 Apr 12.
Nanoplastic represents an emerging abiotic stress facing modern agriculture, impacting global crop production. However, the molecular response of crop plants to this stress remains poorly understood at a spatiotemporal resolution. We therefore used RNA sequencing to profile the transcriptome expressed in rice (Oryza sativa) root and leaf organs at 1, 2, 4, and 8 d post exposure with nanoplastic. We revealed a striking similarity between the rice biomass dynamics in aboveground parts to that in belowground parts during nanoplastic stress, but transcriptome did not. At the global transcriptomic level, a total of 2332 differentially expressed genes were identified, with the majority being spatiotemporal specific, reflecting that nanoplastics predominantly regulate three processes in rice seedlings: (1) down-regulation of chlorophyll biosynthesis, photosynthesis, and starch, sucrose and nitrogen metabolism, (2) activation of defense responses such as brassinosteroid biosynthesis and phenylpropanoid biosynthesis, and (3) modulation of jasmonic acid and cytokinin signaling pathways by transcription factors. Notably, the genes involved in plant-pathogen interaction were shown to be successively modulated by both root and leaf organs, particularly plant disease defense genes (OsWRKY24, OsWRKY53, Os4CL3, OsPAL4, and MPK5), possibly indicating that nanoplastics affect rice growth indirectly through other biota. Finally, we associated biomass phenotypes with the temporal reprogramming of rice transcriptome by weighted gene co-expression network analysis, noting a significantly correlation with photosynthesis, carbon metabolism, and phenylpropanoid biosynthesis that may reflect the mechanisms of biomass reduction. Functional analysis further identified PsbY, MYB, cytochrome P450, and AP2/ERF as hub genes governing these pathways. Overall, our work provides the understanding of molecular mechanisms of rice in response to nanoplastics, which in turn suggests how rice might behave in a nanoplastic pollution scenario.
纳米塑料是现代农业面临的一种新兴非生物胁迫，影响全球作物生产。然而，作物植物对这种胁迫的分子响应在时空分辨率上仍知之甚少。因此，我们使用 RNA 测序来描绘暴露于纳米塑料后 1、2、4 和 8 天水稻（Oryza sativa）根和叶器官表达的转录组。我们发现，纳米塑料胁迫下地上部分和地下部分的水稻生物量动态之间存在惊人的相似性，但转录组没有。在全局转录组水平上，共鉴定出 2332 个差异表达基因，其中大多数具有时空特异性，反映出纳米塑料主要调节水稻幼苗的三个过程：（1）下调叶绿素生物合成、光合作用和淀粉、蔗糖和氮代谢，（2）激活防御反应，如油菜素内酯生物合成和苯丙烷生物合成，（3）通过转录因子调节茉莉酸和细胞分裂素信号通路。值得注意的是，参与植物-病原体相互作用的基因被证明被根和叶器官相继调节，特别是植物疾病防御基因（OsWRKY24、OsWRKY53、Os4CL3、OsPAL4 和 MPK5），可能表明纳米塑料通过其他生物间接影响水稻生长。最后，我们通过加权基因共表达网络分析将生物量表型与水稻转录组的时间重编程相关联，注意到与光合作用、碳代谢和苯丙烷生物合成显著相关，这可能反映了生物量减少的机制。功能分析进一步确定了 PsbY、MYB、细胞色素 P450 和 AP2/ERF 作为控制这些途径的枢纽基因。总的来说，我们的工作提供了对水稻响应纳米塑料的分子机制的理解，这反过来又表明了水稻在纳米塑料污染情况下可能的行为。
