Evolutionary analysis of angiosperm dehydrin gene family reveals three orthologues groups associated to specific protein domains

Cell death in bryophytes: emerging models to study core regulatory modules and conserved pathways

This review summarizes recent progress in our current understanding of the mechanisms underlying the cell death pathways in bryophytes, focusing on conserved pathways and particularities in comparison to angiosperms. Regulated cell death (RCD) plays key roles during essential processes along the plant life cycle. It is part of specific developmental programmes and maintains homeostasis of the organism in response to unfavourable environments. Bryophytes could provide valuable models to study developmental RCD processes as well as those triggered by biotic and abiotic stresses. Some pathways analogous to those present in angiosperms occur in the gametophytic haploid generation of bryophytes, allowing direct genetic studies. In this review, we focus on such RCD programmes, identifying core conserved mechanisms and raising new key questions to analyse RCD from an evolutionary perspective.

Identification of Dof transcription factors in Dendrobium huoshanense and expression pattern under abiotic stresses

Introduction: DNA-binding with one finger (Dof) transcription factors (TFs) are a unique family of TFs found in higher plants that regulate plant responses to light, hormones, and abiotic stresses. The specific involvement of Dof genes in the response to environmental stresses remains unknown in D. huoshanense. Methods: A total of 22 Dof family genes were identified from the D. huoshanense genome. Results: Chromosome location analysis showed that DhDof genes were distributed on 12 chromosomes, with the largest number of Dof genes located on chromosome 8. The phylogenetic tree revealed that DhDofs could be categorized into 11 distinct subgroups. In addition to the common groups, DhDof4, DhDof5, DhDof17, and the AtDof1.4 ortholog were clustered into the B3 subgroup. Group E was a newly identified branch, among which DhDof6, DhDof7, DhDof8, and DhDof9 were in an independent branch. The conserved motifs and gene structure revealed the differences in motif number and composition of DhDofs. The dof domain near the N-terminus was highly conserved and contained a C2-C2-type zinc finger structure linked with four cysteines. Microsynteny and interspecies collinearity revealed gene duplication events and phylogenetic tree among DhDofs. Large-scale gene duplication had not occurred among the DhDofs genes and only in one pair of genes on chromosome 13. Synteny blocks were found more often between D. huoshanense and its relatives and less often between Oryza sativa and Arabidopsis thaliana. Selection pressure analysis indicated that DhDof genes were subject to purifying selection. Expression profiles and correlation analyses revealed that the Dof gene under hormone treatments showed several different expression patterns. DhDof20 and DhDof21 had the highest expression levels and were co-expressed under MeJA induction. The cis-acting element analysis revealed that each DhDof had several regulatory elements involved in plant growth as well as abiotic stresses. qRT-PCR analysis demonstrated that DhDof2 was the main ABA-responsive gene and DhDof7 was the main cold stress-related gene. IAA suppressed the expression of some Dof candidates, and SA inhibited most of the candidate genes. Discussion: Our results may provide new insights for the further investigation of the Dof genes and the screening of the core stress-resistance genes.

Modulation of early gene expression responses to water deprivation stress by the E3 ubiquitin ligase ATL80: implications for retrograde signaling interplay

BACKGROUND

Primary response genes play a pivotal role in translating short-lived stress signals into sustained adaptive responses. In this study, we investigated the involvement of ATL80, an E3 ubiquitin ligase, in the dynamics of gene expression following water deprivation stress. We observed that ATL80 is rapidly activated within minutes of water deprivation stress perception, reaching peak expression around 60 min before gradually declining. ATL80, despite its post-translational regulation role, emerged as a key player in modulating early gene expression responses to water deprivation stress.

RESULTS

The impact of ATL80 on gene expression was assessed using a time-course microarray analysis (0, 15, 30, 60, and 120 min), revealing a burst of differentially expressed genes, many of which were associated with various stress responses. In addition, the diversity of early modulation of gene expression in response to water deprivation stress was significantly abolished in the atl80 mutant compared to wild-type plants. A subset of 73 genes that exhibited a similar expression pattern to ATL80 was identified. Among them, several are linked to stress responses, including ERF/AP2 and WRKY transcription factors, calcium signaling genes, MAP kinases, and signaling peptides. Promoter analysis predicts enrichment of binding sites for CAMTA1 and CAMTA5, which are known regulators of rapid stress responses. Furthermore, we have identified a group of differentially expressed ERF/AP2 transcription factors, proteins associated with folding and refolding, as well as pinpointed core module genes which are known to play roles in retrograde signaling pathways that cross-referenced with the early ATL80 transcriptome.

CONCLUSIONS

Based on these findings, we propose that ATL80 may target one or more components within the retrograde signaling pathways for degradation. In essence, ATL80 serves as a bridge connecting these signaling pathways and effectively functions as an alarm signal.

Deciphering the Plastomic Code of Chinese Hog-Peanut (Amphicarpaea edgeworthii Benth., Leguminosae): Comparative Genomics and Evolutionary Insights within the Phaseoleae Tribe

The classification and phylogenetic relationships within the Phaseoleae tribe (Leguminosae) have consistently posed challenges to botanists. This study addresses these taxonomic intricacies, with a specific focus on the Glycininae subtribe, by conducting a comprehensive analysis of the highly conserved plastome in Amphicarpaea edgeworthii Benth., a critical species within this subtribe. Through meticulous genomic sequencing, we identified a plastome size of 148,650 bp, composed of 128 genes, including 84 protein-coding genes, 36 tRNA genes, and 8 rRNA genes. Comparative genomic analysis across seven Glycininae species illuminated a universally conserved circular and quadripartite structure, with nine genes exhibiting notable nucleotide diversity, signifying a remarkable genomic variability. Phylogenetic reconstruction of 35 Phaseoleae species underscores the affinity of Amphicarpaea with Glycine, placing Apios as a sister lineage to all other Phaseoleae species, excluding Clitorinae and Diocleinae subtribes. Intriguingly, Apios, Butea, Erythrina, and Spatholobus, traditionally clumped together in the Erythrininae subtribe, display paraphyletic divergence, thereby contesting their taxonomic coherence. The pronounced structural differences in the quadripartite boundary genes among taxa with unresolved subtribal affiliations demand a reevaluation of Erythrininae's taxonomic classification, potentially refining the phylogenetic contours of the tribe.

Plant dehydrins and dehydrin-like proteins: characterization and participation in abiotic stress response

Abiotic stress has a significant impact on plant growth and development. It causes changes in the subcellular organelles, which, due to their stress sensitivity, can be affected. Cellular components involved in the abiotic stress response include dehydrins, widely distributed proteins forming a class II of late embryogenesis abundant protein family with characteristic properties including the presence of evolutionarily conserved sequence motifs (including lysine-rich K-segment, N-terminal Y-segment, and often phosphorylated S motif) and high hydrophilicity and disordered structure in the unbound state. Selected dehydrins and few poorly characterized dehydrin-like proteins participate in cellular stress acclimation and are also shown to interact with organelles. Through their functioning in stabilizing biological membranes and binding reactive oxygen species, dehydrins and dehydrin-like proteins contribute to the protection of fragile organellar structures under adverse conditions. Our review characterizes the participation of plant dehydrins and dehydrin-like proteins (including some organellar proteins) in plant acclimation to diverse abiotic stress conditions and summarizes recent updates on their structure (the identification of dehydrin less conserved motifs), classification (new proposed subclasses), tissue- and developmentally specific accumulation, and key cellular activities (including organellar protection under stress acclimation). Recent findings on the subcellular localization (with emphasis on the mitochondria and plastids) and prospective applications of dehydrins and dehydrin-like proteins in functional studies to alleviate the harmful stress consequences by means of plant genetic engineering and a genome editing strategy are also discussed.

Snapshot of four mature quinoa (Chenopodium quinoa) seeds: a shotgun proteomics analysis with emphasis on seed maturation, reserves and early germination

Chenopodium quinoa Willd. is a crop species domesticated over 5000 years ago. This species is highly diverse, with a geographical distribution that covers more than 5000 km from Colombia to Chile, going through a variety of edaphoclimatic conditions. Quinoa grains have great nutritional quality, raising interest at a worldwide level. In this work, by using shotgun proteomics and in silico analysis, we present an overview of mature quinoa seed proteins from a physiological context and considering the process of seed maturation and future seed germination. For this purpose, we selected grains from four contrasting quinoa cultivars (Amarilla de Maranganí, Chadmo, Sajama and Nariño) with different edaphoclimatic and geographical origins. The results give insight on the most important metabolic pathways for mature quinoa seeds including: starch synthesis, protein bodies and lipid bodies composition, reserves and their mobilization, redox homeostasis, and stress related proteins like heat-shock proteins (HSPs) and late embryogenesis abundant proteins (LEAs), as well as evidence for capped and uncapped mRNA translation. LEAs present in our analysis show a specific pattern of expression matching that of other species. Overall, this work presents a complete snapshot of quinoa seeds physiological context, providing a reference point for further studies.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12298-023-01295-8.