Background Suaeda glauca (S. glauca) is a halophyte widely distributed in saline and sandy beaches, with strong saline-alkali tolerance. It is also admired as a landscape plant with high development prospects and scientific research value. The S. glauca chloroplast (cp) genome has recently been reported; however, the mitochondria (mt) genome is still unexplored. Results The mt genome of S. glauca were assembled based on the reads from Pacbio and Illumina sequencing platforms. The circular mt genome of S. glauca has a length of 474,330 bp. The base composition of the S. glauca mt genome showed A (28.00%), T (27.93%), C (21.62%), and G (22.45%). S. glauca mt genome contains 61 genes, including 27 protein-coding genes, 29 tRNA genes, and 5 rRNA genes. The sequence repeats, RNA editing, and gene migration from cp to mt were observed in S. glauca mt genome. Phylogenetic analysis based on the mt genomes of S. glauca and other 28 taxa reflects an exact evolutionary and taxonomic status of S. glauca. Furthermore, the investigation on mt genome characteristics, including genome size, GC contents, genome organization, and gene repeats of S. gulaca genome, was investigated compared to other land plants, indicating the variation of the mt genome in plants. However, the subsequently Ka/Ks analysis revealed that most of the protein-coding genes in mt genome had undergone negative selections, reflecting the importance of those genes in the mt genomes. Conclusions In this study, we reported the mt genome assembly and annotation of a halophytic model plant S. glauca. The subsequent analysis provided us a comprehensive understanding of the S. glauca mt genome, which might facilitate the research on the salt-tolerant plant species.

In eukaryotes, genetic material is packaged into a dynamic but stable nucleoprotein structure called chromatin. Post-translational modification of chromatin domains affects the expression of underlying genes and subsequently the identity of cells by conveying epigenetic information from mother to daughter cells. SWI/SNF chromatin remodelers are ATP-dependent complexes that modulate core histone protein polypeptides, incorporate variant histone species and modify nucleotides in DNA strands within the nucleosome. The present review discusses the SWI/SNF chromatin remodeler family, its classification and recent advancements. We also address the involvement of SWI/SNF remodelers in regulating vital plant growth and development processes such as meristem establishment and maintenance, cell differentiation, organ initiation, flower morphogenesis and flowering time regulation. Moreover, the role of chromatin remodelers in key phytohormone signaling pathways is also reviewed. The information provided in this review may prompt further debate and investigations aimed at understanding plant-specific epigenetic regulation mediated by chromatin remodeling under continuously varying plant growth conditions and global climate change.

BackgroundAn efficient transformation protocol is a primary requisite to study and utilize the genetic potential of any plant species. A quick transformation system is also crucial for the functional analysis of genes along with the study of proteins and their interactions in vivo. Presently, however, quick and effective transformation systems are still lacking for many plant species including pineapple. This has limited the full exploration of the genetic repository of pineapple as well as the study of its genes, protein localization and protein interactions.ResultsTo address the above limitations, we have developed an efficient system for protoplast isolation and subcellular localization of desired proteins using pineapple plants derived from tissue culture. A cocktail of 1.5% (W/V) Cellulase R-10 and 0.5% (W/V) Macerozyme R-10 resulted in 51% viable protoplasts with 3 h digestion. Compared to previously reported protocols, our protoplast isolation method is markedly faster (saving 4.5 h), requires only a small quantity of tissue sample (1 g of leaves) and has high yield (6.5 × 105). The quality of the isolated protoplasts was verified using organelle localization in protoplasts with different organelle markers. Additionally, colocalization analysis of two pineapple Mg2+ transporter genes in pineapple protoplasts was consistent with the results in a tobacco transient expression system, confirming that the protoplast isolation method can be used to study subcellular localization. Further findings showed that the system is also suitable for protein–protein interaction studies.ConclusionBased on our findings, the presently described method is an efficient and effective strategy for pineapple protoplast isolation and transformation; it is convenient and time saving and provides a greater platform for transformation studies.

The plant-specific transcription factor gene family, YABBY, belongs to the subfamily of zinc finger protein superfamily and plays an essential regulatory role in lateral organ development. In this study, nine YABBY genes were identified in the pineapple genome. Seven of them were located on seven different chromosomes and the remaining two were located on scaffold 1235. Through protein structure prediction and protein multiple sequence alignment, we found that AcYABBY3, AcYABBY5 and AcYABBY7 lack a C2 structure in their N-terminal C2C2 zinc finger protein structure. Analysis of the cis-acting element indicated that all the seven pineapple YABBY genes contain multiple MYB and MYC elements. Further, the expression patterns analysis using the RNA-seq data of different pineapple tissues indicated that different AcYABBYs are preferentially expressed in various tissues. RT-qPCR showed that the expression of AcYABBY2, AcYABBY3, AcYABBY6 and AcYABBY7 were highly sensitive to abiotic stresses. Subcellular localization in pineapple protoplasts, tobacco leaves and Arabidopsis roots showed that all the seven pineapple YABBY proteins were nucleus localized. Overexpression of AcYABBY4 in Arabidopsis resulted in short root under NaCl treatment, indicating a negative regulatory role of AcYABBY4 in plant resistance to salt stress. This study provides valuable information for the classification of pineapple AcYABBY genes and established a basis for further research on the functions of AcYABBY proteins in plant development and environmental stress response.