PGBV - Universidade Federal de Lavras - UFLA, CEP 37200-000, Lavras, MG, Brazil.
Embrapa Agroenergia, CEP 70770-901, Brasília, DF, Brazil.
BMC Plant Biol. 2021 Nov 8;21(1):518. doi: 10.1186/s12870-021-03296-9.
Several mechanisms regulating gene expression contribute to restore and reestablish cellular homeostasis so that plants can adapt and survive in adverse situations. MicroRNAs (miRNAs) play roles important in the transcriptional and post-transcriptional regulation of gene expression, emerging as a regulatory molecule key in the responses to plant stress, such as cold, heat, drought, and salt. This work is a comprehensive and large-scale miRNA analysis performed to characterize the miRNA population present in oil palm (Elaeis guineensis Jacq.) exposed to a high level of salt stress, to identify miRNA-putative target genes in the oil palm genome, and to perform an in silico comparison of the expression profile of the miRNAs and their putative target genes.
A group of 79 miRNAs was found in oil palm, been 52 known miRNAs and 27 new ones. The known miRNAs found belonged to 28 families. Those miRNAs led to 229 distinct miRNA-putative target genes identified in the genome of oil palm. miRNAs and putative target genes differentially expressed under salinity stress were then selected for functional annotation analysis. The regulation of transcription, DNA-templated, and the oxidation-reduction process were the biological processes with the highest number of hits to the putative target genes, while protein binding and DNA binding were the molecular functions with the highest number of hits. Finally, the nucleus was the cellular component with the highest number of hits. The functional annotation of the putative target genes differentially expressed under salinity stress showed several ones coding for transcription factors which have already proven able to result in tolerance to salinity stress by overexpression or knockout in other plant species.
Our findings provide new insights into the early response of young oil palm plants to salinity stress and confirm an expected preponderant role of transcription factors - such as NF-YA3, HOX32, and GRF1 - in this response. Besides, it points out potential salt-responsive miRNAs and miRNA-putative target genes that one can utilize to develop oil palm plants tolerant to salinity stress.
几种调节基因表达的机制有助于恢复和重建细胞内稳态，使植物能够适应和在不利情况下生存。MicroRNAs（miRNAs）在基因表达的转录和转录后调控中发挥着重要作用，作为植物应对冷、热、干旱和盐胁迫等应激反应的关键调节分子而出现。这项工作是对暴露在高盐胁迫下的油棕（Elaeis guineensis Jacq.）进行的大规模 miRNA 分析，旨在描述油棕中存在的 miRNA 群体，鉴定油棕基因组中 miRNA 的假定靶基因，并对 miRNA 和其假定靶基因的表达谱进行计算机模拟比较。
在油棕中发现了一组 79 个 miRNA，其中 52 个是已知的 miRNA，27 个是新的 miRNA。发现的已知 miRNA 属于 28 个家族。这些 miRNA 导致在油棕基因组中鉴定出 229 个不同的 miRNA 假定靶基因。然后选择盐胁迫下差异表达的 miRNA 和假定靶基因进行功能注释分析。转录、DNA 模板和氧化还原过程是假定靶基因具有最高命中数的生物学过程，而蛋白质结合和 DNA 结合是具有最高命中数的分子功能。最后，细胞核是具有最高命中数的细胞成分。盐胁迫下差异表达的假定靶基因的功能注释表明，几个基因编码转录因子，这些转录因子在其他植物物种中通过过表达或敲除已经被证明能够耐受盐胁迫。
我们的研究结果为幼龄油棕植物对盐胁迫的早期响应提供了新的见解，并证实了转录因子（如 NF-YA3、HOX32 和 GRF1）在这种响应中的预期主导作用。此外，它还指出了潜在的盐响应 miRNA 和 miRNA 假定靶基因，人们可以利用这些基因来培育耐受盐胁迫的油棕植物。
