24 nt TEs-siRNAs were found to be up-regulated in embryo sac but down-regulated in pollen development. 21 nt-phasiRNAs were detected during both pollen and embryo sac development, while 24 nt-phasiRNAs were found only in pollen development, which displayed down-regulation in autotetraploid compared to diploid rice and their spatial-temporal expression patterns were similar to osa-miR2275d. Of these DEM, osa-miR1436_L + 3_1ss5CT and osa-miR167h-3p were associated with the female meiosis, while osa-miR159a.1 and osa-MIR159a-p5 were related with the male meiosis.

The expression levels of 39 DEM, which revealed interaction with meiosis-related genes, showed opposite expression patterns during pollen and embryo sac development. Gene Ontology enrichment analysis on the targets of DEM associated with embryo sac and pollen development revealed 30 prominent functional gene classes, such as cell differentiation and signal transduction during embryo sac development, while only 7 prominent functional gene classes, such as flower development and transcription factor activity, were detected during pollen development in autotetraploid rice. ResultsĪ total of 321 and 368 differentially expressed miRNAs (DEM) were detected during pollen and embryo sac development in autotetraploid rice, respectively. In the present study, WE-CLSM (whole-mount eosin B-staining confocal laser scanning microscopy) and high-throughput sequencing technology was employed to examine the cytological variations and to analyze small RNAs changes during pollen and embryo sac development in autotetraploid rice compared with its diploid counterpart. However, knowledge on comparative analysis between the development of pollen and embryo sac by small RNAs in autotetraploid rice is still unknown. Our previous study revealed that small RNAs changes may associate with pollen fertility in autotetraploid rice. Partial pollen and embryo sac sterilities are the two main reasons for low fertility in autotetraploid rice.

Mother cells definition