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BioRxiv : the Preprint Server For... May 2024In response to environmental stress, chloroplasts generate reactive oxygen species, including singlet oxygen (O), which regulates nuclear gene expression (retrograde...
In response to environmental stress, chloroplasts generate reactive oxygen species, including singlet oxygen (O), which regulates nuclear gene expression (retrograde signaling), chloroplast turnover, and programmed cell death (PCD). Yet, the central signaling mechanisms and downstream responses remain poorly understood. The () mutant conditionally accumulates O and involves Plant U-Box 4 (PUB4), a cytoplasmic E3 ubiquitin ligase, in propagating these signals. To gain insights into O signaling pathways, we compared transcriptomes of and mutants. The accumulation of O in plants broadly repressed genes involved in chloroplast function and photosynthesis, while O induced genes and transcription factors involved in abiotic and biotic stress, the biosynthesis of jasmonic acid (JA), and Salicylic acid (SA). Elevated JA and SA levels were observed in stressed plants, but were not responsible for PCD. reversed the majority of O-induced gene expression in and reduced the JA content, but maintained elevated levels of SA even in the absence of O stress. Reducing SA levels in restored O signaling and light sensitivity. Together, this work demonstrates that SA plays a protective role during photo-oxidative stress and that PUB4 mediates O signaling by modulating its levels.
PubMed: 38798329
DOI: 10.1101/2024.05.13.593788 -
Plants (Basel, Switzerland) May 2024The family Chenopodiaceae Vent. (Amaranthaceae .) is known for its taxonomic complexity, comprising species of significant economic and ecological importance. Despite...
The family Chenopodiaceae Vent. (Amaranthaceae .) is known for its taxonomic complexity, comprising species of significant economic and ecological importance. Despite its significance, the availability of plastid genome data for this family remains limited. This study involved assembling and characterizing the complete plastid genomes of four Thunb. species within the tribe Salsoleae ., utilizing next-generation sequencing technology. We compared genome features, nucleotide diversity, and repeat sequences and conducted a phylogenetic analysis of ten Salsoleae . species. The size of the plastid genome varied among four species, ranging from 150,777 bp () to 151,307 bp (). Each studied plastid genome encoded 133 genes, including 114 unique genes. This set of genes includes 80 protein-coding genes, 30 tRNA genes, and 4 rRNA genes. Eight divergent regions (, , , , , , , and ) were identified in ten Salsoleae . plastid genomes, which could be potential DNA-barcoding markers. Additionally, 1106 repeat elements were detected, consisting of 814 simple sequence repeats, 92 tandem repeats, 88 forward repeats, 111 palindromic repeats, and one reverse repeat. The phylogenetic analysis provided robust support for the relationships within species. These data represent a valuable resource for future phylogenetic studies within the genus.
PubMed: 38794403
DOI: 10.3390/plants13101332 -
International Journal of Molecular... May 2024In plants, nucleotide-binding site and leucine-rich repeat proteins (NLRs) play pivotal roles in effector-triggered immunity (ETI). However, the precise mechanisms...
Unveiling the Role of RNA Recognition Motif Proteins in Orchestrating Nucleotide-Binding Site and Leucine-Rich Repeat Protein Gene Pairs and Chloroplast Immunity Pathways: Insights into Plant Defense Mechanisms.
In plants, nucleotide-binding site and leucine-rich repeat proteins (NLRs) play pivotal roles in effector-triggered immunity (ETI). However, the precise mechanisms underlying NLR-mediated disease resistance remain elusive. Previous studies have demonstrated that the NLR gene pair confers resistance to rice blast disease by interacting with the transcription factor OsBIHD1, consequently leading to the upregulation of hormone pathways. In the present study, we identified an RNA recognition motif (RRM) protein, OsRRM2, which interacted with Pik-H4 and Pik-H4 in vesicles and chloroplasts. OsRRM2 exhibited a modest influence on -mediated rice blast resistance by upregulating resistance genes and genes associated with chloroplast immunity. Moreover, the RNA-binding sequence of OsRRM2 was elucidated using systematic evolution of ligands by exponential enrichment. Transcriptome analysis further indicated that OsRRM2 promoted RNA editing of the chloroplastic gene . Collectively, our findings uncovered a chloroplastic RRM protein that facilitated the translocation of the NLR gene pair and modulated chloroplast immunity, thereby bridging the gap between ETI and chloroplast immunity.
Topics: Chloroplasts; Plant Immunity; Plant Proteins; Gene Expression Regulation, Plant; Oryza; Leucine-Rich Repeat Proteins; Binding Sites; RNA Recognition Motif Proteins; Plant Diseases; Disease Resistance; NLR Proteins; RNA Editing
PubMed: 38791594
DOI: 10.3390/ijms25105557 -
International Journal of Molecular... May 2024ROS-dependent induction of oxidative damage can be used as a trigger initiating genetically determined non-specific protection in plant cells and tissues. Plants are...
ROS-dependent induction of oxidative damage can be used as a trigger initiating genetically determined non-specific protection in plant cells and tissues. Plants are potentially able to withstand various specific (toxic, osmotic) factors of abiotic effects, but do not have sufficient or specific sensitivity to form an adequate effective response. In this work, we demonstrate one of the possible approaches for successful cold acclimation through the formation of effective protection of photosynthetic structures due to the insertion of the heterologous gene into the tobacco genome under the control of the constitutive promoter and equipped with a signal sequence targeting the protein to plastid. The increased enzymatic activity of superoxide dismutase in the plastid compartment of transgenic tobacco plants enables them to tolerate the oxidative factor of environmental stresses scavenging ROS. On the other hand, the cost of such resistance is quite high and, when grown under normal conditions, disturbs the arrangement of the intrachloroplastic subdomains leading to the modification of stromal thylakoids, probably significantly affecting the photosynthesis processes that regulate the efficiency of photosystem II. This is partially compensated for by the fact that, at the same time, under normal conditions, the production of peroxide induces the activation of ROS detoxification enzymes. However, a violation of a number of processes, such as the metabolism of accumulation, and utilization and transportation of sugars and starch, is significantly altered, which leads to a shift in metabolic chains. The expected step for further improvement of the applied technology could be both the use of inducible promoters in the expression cassette, and the addition of other genes encoding for hydrogen peroxide-scavenging enzymes in the genetic construct that are downstream in the metabolic chain.
Topics: Nicotiana; Oxidative Stress; Plastids; Superoxide Dismutase; Plants, Genetically Modified; Reactive Oxygen Species; Cold Temperature; Photosynthesis; Plant Proteins
PubMed: 38791585
DOI: 10.3390/ijms25105544 -
International Journal of Molecular... May 2024To explore the possible novel microRNA (miRNA) regulatory pathways in Zhengmai 1860, a newly cultivated drought-tolerant wheat ( L.) cultivar, miRNA transcriptome...
To explore the possible novel microRNA (miRNA) regulatory pathways in Zhengmai 1860, a newly cultivated drought-tolerant wheat ( L.) cultivar, miRNA transcriptome sequencing of the flag leaves of Zhengmai 1860, drought-sensitive variety Zhoumai 18, and drought-resistant variety Bainong 207 was performed during the grain filling stage. We also observed changes in the chloroplast ultrastructure, phytohormone levels, and antioxidant- and photosynthesis-related physiological indicators in three wheat varieties. The results showed that the flag leaves of the drought-tolerant variety Zhengmai 1860 had higher chlorophyll contents and net photosynthetic rates than those of Zhoumai 18 under drought stress during the grain filling stage; in addition, the chloroplast structure was more complete. However, there was no significant difference between Zhengmai 1860 and Bainong 207. MiRNA transcriptome analysis revealed that the differential expression of the miRNAs and mRNAs exhibited variable specificity. The KEGG pathway enrichment results indicated that most of the genes were enriched in the MAPK signaling pathway, plant hormone signal transduction, photosynthetic antennae protein, and amino acid and carbohydrate metabolism. In the drought-tolerant cultivar Zhengmai 1860, tae-miR408 was targeted to regulate the allene oxide synthase (AOS) gene, inhibit its expression, reduce the AOS content, and decrease the synthesis of jasmonic acid (JA) and abscisic acid (ABA). The results of this study suggest that Zhengmai 1860 could improve the photosynthetic performance of flag leaves by inhibiting the expression of genes involved in the JA pathway through miRNAs under drought conditions. Moreover, multiple miRNAs may target chlorophyll, antioxidant enzymes, phytohormone signal transduction, and other related pathways; thus, it is possible to provide a more theoretical basis for wheat molecular breeding.
Topics: MicroRNAs; Triticum; Photosynthesis; Gene Expression Regulation, Plant; Droughts; Stress, Physiological; Gene Expression Profiling; Transcriptome; Plant Growth Regulators; Edible Grain; Chloroplasts; Plant Leaves
PubMed: 38791558
DOI: 10.3390/ijms25105518 -
Genes Apr 2024Kohlrabi is an important swollen-stem cabbage variety belonging to the Brassicaceae family. However, few complete chloroplast genome sequences of this genus have been...
Kohlrabi is an important swollen-stem cabbage variety belonging to the Brassicaceae family. However, few complete chloroplast genome sequences of this genus have been reported. Here, a complete chloroplast genome with a quadripartite cycle of 153,364 bp was obtained. A total of 132 genes were identified, including 87 protein-coding genes, 37 transfer RNA genes and eight ribosomal RNA genes. The base composition analysis showed that the overall GC content was 36.36% of the complete chloroplast genome sequence. Relative synonymous codon usage frequency (RSCU) analysis showed that most codons with values greater than 1 ended with A or U, while most codons with values less than 1 ended with C or G. Thirty-five scattered repeats were identified and most of them were distributed in the large single-copy (LSC) region. A total of 290 simple sequence repeats (SSRs) were found and 188 of them were distributed in the LSC region. Phylogenetic relationship analysis showed that five subspecies were clustered into one group and the kohlrabi chloroplast genome was closely related to that of var. Our results provide a basis for understanding chloroplast-dependent metabolic studies and provide new insight for understanding the polyploidization of Brassicaceae species.
Topics: Genome, Chloroplast; Phylogeny; Brassica; Microsatellite Repeats; Base Composition; Codon Usage; Chloroplasts; Whole Genome Sequencing
PubMed: 38790180
DOI: 10.3390/genes15050550 -
Genes Apr 2024is a dominant desert shrub in Xinjiang, China, with high economic and ecological value. However, molecular systematics research on is lacking. To resolve the genetic... (Comparative Study)
Comparative Study
is a dominant desert shrub in Xinjiang, China, with high economic and ecological value. However, molecular systematics research on is lacking. To resolve the genetic composition of within Amaranthaceae and its systematic relationship with related genera, we used a second-generation Illumina sequencing system to detect the chloroplast genome of and analyze its assembly, annotation, and phylogenetics. Total length of the chloroplast genome of reached 152,287 bp, with 84 protein-coding genes, 36 tRNAs, and eight rRNAs. Codon usage analysis showed the majority of codons ending with base A/U. Mononucleotide repeats were the most common (85.42%) of the four identified simple sequence repeats. A comparison with chloroplast genomes of six other Amaranthaceae species indicated contraction and expansion of the inverted repeat boundary region in , with some genes (, , ) differing in length and distribution. Among the seven species, the variation in non-coding regions was greater. Phylogenetic analysis revealed , , , and to have a close monophyletic relationship. By sequencing the chloroplast genome, this research resolves the relatedness among 35 Amaranthaceae species, providing molecular insights for germplasm utilization, and theoretical support for studying evolutionary relationships.
Topics: Genome, Chloroplast; Phylogeny; Amaranthaceae; Codon Usage; Microsatellite Repeats; Evolution, Molecular; Chloroplasts; China; Molecular Sequence Annotation
PubMed: 38790176
DOI: 10.3390/genes15050546 -
Genes Apr 2024is considered the closest relative to the invasive weed in China, making it an important native species for studying the invasive mechanisms and adaptations of .... (Comparative Study)
Comparative Study
is considered the closest relative to the invasive weed in China, making it an important native species for studying the invasive mechanisms and adaptations of . Chloroplasts play a crucial role in a plant's environmental adaptation, with their genomes being pivotal in the evolution and adaptation of both invasive and related species. However, the chloroplast genome of has remained unknown until now. In this study, we sequenced and assembled the complete chloroplast genome of using high-throughput sequencing. The chloroplast genome is 151,935 base pairs long, comprising two inverted repeat regions, a large single copy region, and a small single copy region. This chloroplast genome contains 128 genes, including 8 rRNA-coding genes, 37 tRNA-coding genes, 4 pseudogenes, and 83 protein-coding genes. When compared to the chloroplast genome of the invasive weed and other Amaranthaceae species, we observed significant variations in the , , and regions in the chloroplast genome. Moreover, two genes, and , were found to be undergoing rapid evolution due to positive selection pressure. The phylogenetic trees were constructed for the Amaranthaceae family, estimating the time of independent species formation between and to be approximately 3.5186-8.8242 million years ago. These findings provide a foundation for understanding the population variation within invasive species among the genus.
Topics: Genome, Chloroplast; Amaranthaceae; Phylogeny; Introduced Species; Plant Weeds; Chloroplasts; High-Throughput Nucleotide Sequencing; Evolution, Molecular
PubMed: 38790173
DOI: 10.3390/genes15050544 -
BMC Plant Biology May 2024Baolia H.W.Kung & G.L.Chu is a monotypic genus only known in Diebu County, Gansu Province, China. Its systematic position is contradictory, and its morphoanatomical...
BACKGROUND
Baolia H.W.Kung & G.L.Chu is a monotypic genus only known in Diebu County, Gansu Province, China. Its systematic position is contradictory, and its morphoanatomical characters deviate from all other Chenopodiaceae. Recent study has regarded Baolia as a sister group to Corispermoideae. We therefore sequenced and compared the chloroplast genomes of this species, and resolved its phylogenetic position based on both chloroplast genomes and marker sequences.
RESULTS
We sequenced 18 chloroplast genomes of 16 samples from two populations of Baolia bracteata and two Corispermum species. These genomes of Baolia ranged in size from 152,499 to 152,508 bp. Simple sequence repeats (SSRs) were primarily located in the LSC region of Baolia chloroplast genomes, and most of them consisted of single nucleotide A/T repeat sequences. Notably, there were differences in the types and numbers of SSRs between the two populations of B. bracteata. Our phylogenetic analysis, based on both complete chloroplast genomes from 33 species and a combination of three markers (ITS, rbcL, and matK) from 91 species, revealed that Baolia and Corispermoideae (Agriophyllum, Anthochlamys, and Corispermum) form a well-supported clade and sister to Acroglochin. According to our molecular dating results, a major divergence event between Acroglochin, Baolia, and Corispermeae occurred during the Middle Eocene, approximately 44.49 mya. Ancestral state reconstruction analysis showed that Baolia exhibited symplesiomorphies with those found in core Corispermoideae characteristics including pericarp and seed coat.
CONCLUSIONS
Comparing the chloroplast genomes of B. bracteata with those of eleven typical Chenopodioideae and Corispermoideae species, we observed a high overall similarity and a one notable noteworthy case of inversion of approximately 3,100 bp. of DNA segments only in two Atriplex and four Chenopodium species. We suggest that Corispermoideae should be considered in a broader sense, it includes Corispermeae (core Corispermoideae: Agriophyllum, Anthochlamys, and Corispermum), as well as two new monotypic tribes, Acroglochineae (Acroglochin) and Baolieae (Baolia).
Topics: Phylogeny; Genome, Chloroplast; Amaranthaceae; Microsatellite Repeats; China; DNA, Chloroplast; Sequence Analysis, DNA; Genetic Markers
PubMed: 38789931
DOI: 10.1186/s12870-024-05164-8 -
Nature Communications May 2024Photosynthetic organisms have evolved an essential energy-dependent quenching (qE) mechanism to avoid any lethal damages caused by high light. While the triggering...
Photosynthetic organisms have evolved an essential energy-dependent quenching (qE) mechanism to avoid any lethal damages caused by high light. While the triggering mechanism of qE has been well addressed, candidates for quenchers are often debated. This lack of understanding is because of the tremendous difficulty in measuring intact cells using transient absorption techniques. Here, we have conducted femtosecond pump-probe measurements to characterize this photophysical reaction using micro-sized cell fractions of the green alga Chlamydomonas reinhardtii that retain physiological qE function. Combined with kinetic modeling, we have demonstrated the presence of an ultrafast excitation energy transfer (EET) pathway from Chlorophyll a (Chl a) Q to a carotenoid (car) S state, therefore proposing that this carotenoid, likely lutein1, is the quencher. This work has provided an easy-to-prepare qE active thylakoid membrane system for advanced spectroscopic studies and demonstrated that the energy dissipation pathway of qE is evolutionarily conserved from green algae to land plants.
Topics: Chlamydomonas reinhardtii; Energy Transfer; Carotenoids; Thylakoids; Photosynthesis; Light-Harvesting Protein Complexes; Chlorophyll A; Light; Kinetics; Chlorophyll; Chlamydomonas
PubMed: 38789432
DOI: 10.1038/s41467-024-48789-x