biostudies-literatureDing Cthe National Key Research and Development Program of Chinathe Priority Academic Program Development of Jiangsu Higher Education Institutionsthe Natural Science Foundation of the Jiangsu Higher Education Institutions of Chinathe National Natural Science Foundation of China4537https://www.ebi.ac.uk/biostudies/studies/S-EPMC9100975biostudies-literatureUnknown23(9)Lignin and cellulose are the most abundant natural organic polymers in nature. MiRNAs are a class of regulatory RNAs discovered in mammals, plants, viruses, and bacteria. Studies have shown that miRNAs play a role in lignin and cellulose biosynthesis by targeting key enzymes. However, the specific miRNAs functioning in the phloem and developing xylem of <i>Populus deltoides</i> are still unknown. In this study, a total of 134 miRNAs were identified via high-throughput small RNA sequencing, including 132 known and two novel miRNAs, six of which were only expressed in the phloem. A total of 58 differentially expressed miRNAs (DEmiRNAs) were identified between the developing xylem and the phloem. Among these miRNAs, 21 were significantly upregulated in the developing xylem in contrast to the phloem and 37 were significantly downregulated. A total of 2431 target genes of 134 miRNAs were obtained via high-throughput degradome sequencing. Most target genes of these miRNAs were transcription factors, including <i>AP2</i>, <i>ARF</i>, <i>bHLH</i>, <i>bZIP</i>, <i>GRAS</i>, <i>GRF</i>, <i>MYB</i>, <i>NAC</i>, <i>TCP</i>, and <i>WRKY</i> genes. Furthermore, 13 and nine miRNAs were involved in lignin and cellulose biosynthesis, respectively, and we validated the miRNAs via qRT-PCR. Our study explores these miRNAs and their regulatory networks in the phloem and developing xylem of <i>P.</i><i>deltoides</i> and provides new insight into wood formation.International journal of molecular sciencesIntegrated Degradome and Srna Sequencing Revealed miRNA-mRNA Regulatory Networks between the Phloem and Developing Xylem of Poplar.PMC9100975PAPD2021YFD220120519KJB18000131971679Pan HXu MDing CZhang HShen TRan NSu XfalseIntegrated Degradome and Srna Sequencing Revealed miRNA-mRNA Regulatory Networks between the Phloem and Developing Xylem of Poplar.Lignin and cellulose are the most abundant natural organic polymers in nature. MiRNAs are a class of regulatory RNAs discovered in mammals, plants, viruses, and bacteria. Studies have shown that miRNAs play a role in lignin and cellulose biosynthesis by targeting key enzymes. However, the specific miRNAs functioning in the phloem and developing xylem of <i>Populus deltoides</i> are still unknown. In this study, a total of 134 miRNAs were identified via high-throughput small RNA sequencing, including 132 known and two novel miRNAs, six of which were only expressed in the phloem. A total of 58 differentially expressed miRNAs (DEmiRNAs) were identified between the developing xylem and the phloem. Among these miRNAs, 21 were significantly upregulated in the developing xylem in contrast to the phloem and 37 were significantly downregulated. A total of 2431 target genes of 134 miRNAs were obtained via high-throughput degradome sequencing. Most target genes of these miRNAs were transcription factors, including <i>AP2</i>, <i>ARF</i>, <i>bHLH</i>, <i>bZIP</i>, <i>GRAS</i>, <i>GRF</i>, <i>MYB</i>, <i>NAC</i>, <i>TCP</i>, and <i>WRKY</i> genes. Furthermore, 13 and nine miRNAs were involved in lignin and cellulose biosynthesis, respectively, and we validated the miRNAs via qRT-PCR. Our study explores these miRNAs and their regulatory networks in the phloem and developing xylem of <i>P.</i><i>deltoides</i> and provides new insight into wood formation.2022-01-01T00:00:00Z2022 Apr2025-04-04T20:36:13.825Z2025-04-04T20:36:13.825ZS-EPMC91009753556292810.3390/ijms23094537