Abstract
The plant U-box (PUB) protein family plays an important role in plant growth and development. The U-box gene family has been well studied in Arabidopsis thaliana, Brassica rapa, rice, etc., but there have been no systematic studies in Brassica oleracea. In this study, we performed genome-wide identification and evolutionary analysis of the U-box protein family of B. oleracea. Firstly, based on the Brassica database (BRAD) and the Bolbase database, 99 Brassica oleracea PUB genes were identified and divided into seven groups (I–VII). The BoPUB genes are unevenly distributed on the nine chromosomes of B. oleracea, and there are tandem repeat genes, leading to family expansion from the A. thaliana genome to the B. oleracea genome. The protein interaction network, GO annotation, and KEGG pathway enrichment analysis indicated that the biological processes and specific functions of the BoPUB genes may mainly involve abiotic stress. RNA-seq transcriptome data of different pollination times revealed spatiotemporal expression specificity of the BoPUB genes. The differential expression profile was consistent with the results of RT-qPCR analysis. Additionally, a large number of pollen-specific cis-acting elements were found in promoters of differentially expressed genes (DEG), which verified that these significantly differentially expressed genes after self-pollination (SP) were likely to participate in the self-incompatibility (SI) process, including gene encoding ARC1, a well-known downstream protein of SI in B. oleracea. Our study provides valuable information indicating that the BoPUB genes participates not only in the abiotic stress response, but are also involved in pollination.
Highlights
Plant self-incompatibility exists mainly to prevent inbreeding and promote outcrossing [1], while the decline of self-inbreeding makes outcrossing more urgent
The arm repeat–containing protein 1 (ARC1) arm repeat region interacts with the S-locus receptor kinase (SRK) kinase domain and M-locus protein kinase (MLPK) to cause ARC1 activation, and its
Chromosome localization and collinear analysis showed that members of the U-box family were purified and selected during long-term evolution, and these genes may be products of amplification from the same ancestral gene
Summary
Plant self-incompatibility exists mainly to prevent inbreeding and promote outcrossing [1], while the decline of self-inbreeding makes outcrossing more urgent. When self-fertilized pollen falls on the stigma, the S-locus cysteine rich protein (SCR) in the pollen, combined with the extracellular domain of the S-locus receptor kinase (SRK) of the stigma mastoid cell, the SRK intracellular kinase domain, and the M-locus protein kinase (MLPK) are phosphorylated. At this time, arm repeat–containing protein 1 (ARC1) is located near the membrane of the nucleus [2]. With the assistance of E1 and E2, Exo70A1 is ubiquitinated to a certain extent, guided by the U-box at the N-terminus of ARC1 to 26S proteasome, and degraded [3].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
