State Key Laboratory of Crop Biology, Agronomy College, Shandong Agricultural University, Tai'an 271018, China.
Int J Mol Sci. 2022 May 14;23(10):5495. doi: 10.3390/ijms23105495.
Low-temperature stress delays seed germination in maize. Different maize inbred lines display various low-temperature resistance, but the dynamic changes in seed germination under low-temperature stress in maize remain unknown, especially at the transcriptome level. In this study, low-temperature-resistant maize (RM) inbred line 04Qun0522-1-1 had a significantly faster germination speed than low-temperature-sensitive maize (SM) line B283-1 under low-temperature stress. Moreover, the total antioxidant capacity, superoxide dismutase, and peroxidase activities were notably higher in the RM line than in the SM line from 3 to 6 d. In contrast, the SM line showed significantly higher malondialdehyde (MDA) content than the RM line at 6 d. Gene ontology (GO) enrichment analysis showed that in 2dvs0d, both SM and RM lines displayed the downregulation of ribosome-related genes. Moreover, photosystem II and heat shock protein binding-related genes were also downregulated in the SM line. In 4dvs2d, the RM line showed a higher degree of upregulation of the ribosome and peroxidase (POD)-related genes than the SM line. In 6dvs4d, POD-related genes were continuously upregulated in both SM and RM lines, but the degree of upregulation of the genes was higher in the SM line than in the RM line. Moreover, vitamin B6-related genes were specifically upregulated in the RM line. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis showed that in 6dvs4d, phenylpropanoid biosynthesis was the most significantly enriched pathway in both SM and RM lines. Moreover, phenylpropanoid biosynthesis was also enriched in the RM line in 4dvs2d. More than half of the differentially expressed genes (DEGs) in phenylpropanoid biosynthesis were peroxidase, and the DEGs were similar to the GO enrichment analysis. The results provide new insights into maize seed germination in response to low-temperature stress.
低温胁迫会延迟玉米种子的萌发。不同的玉米自交系表现出不同的抗低温能力，但玉米种子在低温胁迫下的萌发动态变化，尤其是在转录组水平上，仍不清楚。在本研究中，与低温敏感型玉米（SM）自交系 B283-1 相比，低温抗性玉米（RM）自交系 04Qun0522-1-1 在低温胁迫下具有更快的萌发速度。此外，从第 3 天到第 6 天，RM 系的总抗氧化能力、超氧化物歧化酶和过氧化物酶活性明显高于 SM 系。相比之下，SM 系在第 6 天的丙二醛（MDA）含量明显高于 RM 系。基因本体（GO）富集分析表明，在 2dvs0d 时，SM 和 RM 系均下调核糖体相关基因。此外，SM 系的光系统 II 和热休克蛋白结合相关基因也下调。在 4dvs2d 时，RM 系的核糖体和过氧化物酶（POD）相关基因的上调程度高于 SM 系。在 6dvs4d 时，SM 和 RM 系的 POD 相关基因持续上调，但 SM 系的上调程度高于 RM 系。此外，RM 系特异性地上调了维生素 B6 相关基因。京都基因与基因组百科全书（KEGG）富集分析表明，在 6dvs4d 时，SM 和 RM 系中苯丙烷生物合成是最显著富集的途径。此外，在 4dvs2d 时，RM 系中苯丙烷生物合成也得到了富集。苯丙烷生物合成中超过一半的差异表达基因（DEGs）是过氧化物酶，这些 DEGs与 GO 富集分析相似。这些结果为玉米种子对低温胁迫的萌发反应提供了新的见解。
