Transcriptome Analysis Revealed the Regulation of Gibberellin and the Establishment of Photosynthetic System Promote Rapid Seed Germination and Early Growth of Seedling in Pearl Millet

Abstract

Background：Seed germination is the most important stage for the formation of a new plant. This process starts when the dry seeds begin to absorb water and ends when the radicles sticks out. The germination rate of different plant seeds varies differently. Most energy plants that usually grow on marginal land, the rapid germination of seeds is more conducive to its superiority in competition with surrounding plants, which is also the guarantee of normal plant development and high yield. Pearl millet is an important cereal crop that shares widespread applications in the world. It has the advantages of fast growth, high yield, and low maintenance cost. It can also be used to extract bioethanol to solve the increasingly prominent energy problems. Previous germination experiments are the evidence of very fast seed germination rate of pearl millet, but the molecular mechanisms behind it is still unclear.Results: Through the germination test and the measurement of the germs and radicles length of the seedlings, we found that pearl millet seeds germinated very quickly after 24 hours of swelling of the dry seeds. By using transcriptome sequencing technology, we characterized the gene expression patterns of dry seeds, water imbibed seeds, germs and radicles of seedlings, and found the more DEGs in radicles than germs. Further analysis showed that different genome clusters function specifically at different tissues and time periods. WGCNA and KEGG enrichment analysis showed that that many genes that positively regulate plant growth and development are highly enriched and expressed, especially the gibberellin signaling pathway that can promote seed germination. We speculated that the activation of these key genes promotes the germination of pearl millet seeds and the growth of seedlings. To verify this inference, we measured the content of the main effect hormone gibberellin and found that the gibberellin content after seed imbibition rose sharply and remained at a high level.Conclusions：This study explored the expression patterns of genes involved in pearl millet growth from the germination of dry seeds to the early growth stages. Also identifies the key genes involved in the regulation of seed germination and seedling growth. The activation of key genes in these pathways may contribute to the rapid germination and growth of seeds and seedlings in pearl millet. These results provide new insights to solve the problem for the plants with slow seed germination and seedling growth.

Combination of Single-Molecule Long-Read Sequencing and Illumina Sequencing Revealed the Mechanism of Anthocyanins Accumulation in an Ornamental Grass, Pennisetum Setaceum ‘Rubrum’

“…Br.) has revealed by combining phenotype, physiology and transcriptome (Sun et al, 2021;Wu et al, 2021). As well as Zhu et al (2020) performed NGS transcriptome sequencing of P. setaceum 'Rubrum'.…”