Genome-Wide Analysis of Glycoside Hydrolase Family 1 β-glucosidase Genes in Brassica rapa and Their Potential Role in Pollen Development

Abstract

Glycoside hydrolase family 1 (GH1) β-glucosidases (BGLUs) are encoded by a large number of genes, and are involved in many developmental processes and stress responses in plants. Due to their importance in plant growth and development, genome-wide analyses have been conducted in model plants (Arabidopsis and rice) and maize, but not in Brassica species, which are important vegetable crops. In this study, we systematically analyzed B. rapa BGLUs (BrBGLUs), and demonstrated the involvement of several genes in pollen development. Sixty-four BrBGLUs were identified in Brassica databases, which were anchored onto 10 chromosomes, with 10 tandem duplications. Phylogenetic analysis revealed that 64 genes were classified into 10 subgroups, and each subgroup had relatively conserved intron/exon structures. Clustering with Arabidopsis BGLUs (AtBGLUs) facilitated the identification of several important subgroups for flavonoid metabolism, the production of glucosinolates, the regulation of abscisic acid (ABA) levels, and other defense-related compounds. At least six BrBGLUs might be involved in pollen development. The expression of BrBGLU10/AtBGLU20, the analysis of co-expressed genes, and the examination of knocked down Arabidopsis plants strongly suggests that BrBGLU10/AtBGLU20 has an indispensable function in pollen development. The results that are obtained from this study may provide valuable information for the further understanding of β-glucosidase function and Brassica breeding, for nutraceuticals-rich Brassica crops.

Aethionema arabicum genome annotation using PacBio full‐length transcripts provides a valuable resource for seed dormancy and Brassicaceae evolution research

“…Other species‐specific genes were annotated as cytochrome P450 (27), cysteine/histidine‐rich C1 (32), domain of unknown function (DUF) (76), glycoside hydrolase (22), NAC domains (14), peptidases (40), protein kinases (15), WRKY (15), and zinc finger proteins (35). Many of these putatively function in development and defense (Hwang et al ., 2014; Singh et al ., 2014; Xu et al ., 2015; Dong et al ., 2019) or might be related to seed germination and dormancy (Papi et al ., 2000; Christianson et al ., 2009; Joseph et al ., 2014; Santamaria et al ., 2014; Raineri et al ., 2016; Zhou et al ., 2020), as expected as many seed samples (234 of 294) were included for RNA‐seq data used in this annotation. Since Ae.…”

MS1, a direct target of MS188, regulates the expression of key sporophytic pollen coat protein genes in Arabidopsis

“…For instance, the ANTHER27/BETA GLUCOSIDASE 20 ( ATA27/BGLU20 ), which locates to Cluster #7, has no homology with any of the adjacent lipases, but shows co-expression with EXL4–EXL6 ( Reimegård et al , 2017 ). ATA27/BGLU20 has tapetum-specific expression and has been proposed as playing an indispensable role in pollen development ( Rubinelli et al , 1998 ; Dong et al , 2019 ). ATA27/BGLU20 is predicted to be localized to the endoplasmic reticulum (ER) lumen, which makes this protein less likely to be a sporophytic pollen coat protein (sPCP); however, the co-regulation of this gene with the clustered EXLs may indicate an important role in pollen coat metabolism ( Rubinelli et al , 1998 ).…”

Genome-Wide Comparative Analysis of the β-glucosidase Family in Five Rosaceae Species and their Potential Role on Lignification of Stone Cells in Chinese White Pear

“…Conserved motif analysis of PbBGLUs found that all the PbBGLUs contain Motif1, 48 PbBGLUs contain motif9, speculated that the two motifs may be related to catalytic activity. To adapt different new functions that are suitable for changes in the environment, gene structure was commonly diversi ed during the evolution of multigene families [47], for Arabidopsis BGLU genes family 13 exon-12 intron organization was considered as the ancestral gene structure, and the pattern with 13 exons was the most common [1,37]. In this study, we had analyzed exon-intron Structures of PbBGLUs and the results suggested that PbBGLU23 and PbBGLU24 contain only one exon, PbBGLU33 contains the most exons (21) and most gene exons range between 10-15, the result suggested that compared with AtBGLUs, PbBGLUs may have some genetic structure diversity.…”

“…2 , except that PbBGLU23 and PbBGLU24 have only one exon, the rest contain 7 or more exons, of which PbBGLU33 contains the most exons (21) and most gene exons range between 10-15. These results indicating the possible occurrence of alternative splicing during gene expression, which in turn leads to functional differences between these closely related PbBGLUs [37].…”

“…It is speculated that these Motifs may have special signi cance. Previous studies implied that gene structural diversity can lead to the evolution of multigene families [37]. To better characterize and understand the structural diversity of the PbBGLUs, gene exon-intron analysis was carried out Fig.…”