Identification of novel and conserved miRNAs involved in pollen development in Brassica campestris ssp. chinensi s by high-throughput sequencing and degradome analysis

Abstract

BackgroundmicroRNAs (miRNAs) are endogenous, noncoding, small RNAs that have essential regulatory functions in plant growth, development, and stress response processes. However, limited information is available about their functions in sexual reproduction of flowering plants. Pollen development is an important process in the life cycle of a flowering plant and is a major factor that affects the yield and quality of crop seeds.ResultsThis study aims to identify miRNAs involved in pollen development. Two independent small RNA libraries were constructed from the flower buds of the male sterile line (Bcajh97-01A) and male fertile line (Bcajh97-01B) of Brassica campestris ssp. chinensis. The libraries were subjected to high-throughput sequencing by using the Illumina Solexa system. Eight novel miRNAs on the other arm of known pre-miRNAs, 54 new conserved miRNAs, and 8 novel miRNA members were identified. Twenty-five pairs of novel miRNA/miRNA* were found. Among all the identified miRNAs, 18 differentially expressed miRNAs with over two-fold change between flower buds of male sterile line (Bcajh97-01A) and male fertile line (Bcajh97-01B) were identified. qRT-PCR analysis revealed that most of the differentially expressed miRNAs were preferentially expressed in flower buds of the male fertile line (Bcajh97-01B). Degradome analysis showed that a total of 15 genes were predicted to be the targets of seven miRNAs.ConclusionsOur findings provide an overview of potential miRNAs involved in pollen development and interactions between miRNAs and their corresponding targets, which may provide important clues on the function of miRNAs in pollen development.

Genetic and Biochemical Mechanisms of Pollen Wall Development

“…Brassica rapa) [95], suggesting their possible roles in pollen wall development. Notably, silencing of BcMF11, a non-coding RNA gene in Chinese cabbage (Brassica campestris), leads to aborted pollen [96].…”

“…Recent cryo-fixation studies from rice, maize [69], and Arabidopsis [12] have already demonstrated the power of cryo-fixation in obtaining novel ultrastructural features, mainly owing to improved sample preservation. Moreover, previous omics studies indicate the appearance of stage-specific or tissue-specific proteins [11], genes [95], and metabolites [43,56] during pollen wall development, highlighting the importance of systems biology in research on pollen wall development. Together with in vivo imaging, scanning, and cell-specific expression systems, omics studies may help us to fully understand the dynamic molecular and ultrastructural nature of pollen wall development.…”

Small RNA Sequencing Reveals Differential miRNA Expression in the Early Development of Broccoli (Brassica oleracea var. italica) Pollen

“…Most novel miRNAs detected in other plants or in the diverse biological processes of different plants also showed low expression abundance. Furthermore, these novel miRNAs are usually specific to a species or developmental phase (Wei et al, 2011; Peng et al, 2012; Jiang et al, 2014; Li et al, 2015; Qu et al, 2016). These results indicated that the predicted novel miRNAs were evolutionarily young with important roles in maintaining species-specificity regardless of their expression levels.…”

Identification and Functional Analysis of microRNAs Involved in the Anther Development in Cotton Genic Male Sterile Line Yu98-8A

“…Recently, several similar results have been reported in Brassica campestris ssp. Chinensis [24,25], radish [26] and soybean [27]. …”