Over-expression of miR158 causes pollen abortion in Brassica campestris ssp. chinensis

Abstract

We identified and cloned the two precursors of miR158 and its target gene in Brassica campestris ssp. chinensis, which both had high relative expression in the inflorescences. Further study revealed that over-expression of miR158 caused reduced pollen varbility, which was caused by the degradation of pollen contents from the binucleate microspore stage. These results first suggest the role of miR158 in pollen development of Brassica campestris ssp. chinensis. MicroRNAs (miRNAs) play crucial roles in many important growth and development processes both in plants and animals by regulating the expression of their target genes via mRNA cleavage or translational repression. In this study, miR158, a Brassicaceae specific miRNA, was functionally characterized with regard to its role in pollen development of non-heading Chinese cabbage (Brassica campestris ssp. chinensis). Two family members of miR158 in B. campestris, namely bra-miR158a1 and bra-miR158a2, and their target gene bra027656, which encodes a pentatricopeptide repeat (PPR) containing protein, were identified. Then, qRT-PCR analysis and GUS-reporter system revealed that both bra-miR158 and its target gene had relatively high expression levels in the inflorescences. Further study revealed that over-expression of miR158 caused reduced pollen varbility and pollen germination ratio, and the degradation of pollen contents from the binucleate microspore stage was also found in those deformed pollen grains, which led to pollen shrinking and collapse in later pollen development stage. These results first shed light on the importance of miR158 in pollen development of Brassica campestris ssp. chinensis.

Joint RNA-Seq and miRNA Profiling Analyses to Reveal Molecular Mechanisms in Regulating Thickness of Pod Canopy in Brassica napus

“…MiR158 has been proven to regulate pollen development in non-heading Chinese cabbage ( Brassica campestris ssp. chinensis ) [72]. MiR159 and miR845 are involved in the control of stem length in rice [73] and crop resistance [74,75], respectively.…”

Abolished miR158 activity leads to 21-nucleotide tertiary phasiRNA biogenesis that targetsNHX2inArabidopsis thaliana

“…Abolished miR158 activity triggers PDP biogenesis following "two-hit, two-cleavage" model Earlier it was reported that miR158 targets a PPR and thereby regulates pollen development in Brassica campestris (Ma et al, 2017). However, our repeated attempts failed to identify the PPR as the target of miR158 in A. thaliana.…”

“…More recently it has been shown that miR158 play role in pollen development by regulating PPR in Brassica campestris (Ma et al, 2017).…”

Identification of microRNAs and their targets in inflorescences of an Ogura-type cytoplasmic male-sterile line and its maintainer fertile line of turnip (Brassica rapa ssp. rapifera) via high-throughput sequencing and degradome analysis

“…PPR-containing proteins constitute an important class of fertility restorer proteins that are required for generating a functional male gametophyte in CMS plants [ 14 , 19 ]. PPR-containing proteins have been previously confirmed as targets of miR158, miR161, miR475 and miR476 [ 69 , 78 , 79 ]. Here, miR5654 and miR1507 were also predicted to target PPR-containing proteins ( Table 5 ).…”