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L. is a popular regional characteristic plant in China, cultivated for its attractive flower colors, extended bloom time, and medicinal properties. To enhance molecular breeding and gene function studies, we conducted transcriptome analysis and identified valuable genes in previous research. Nonetheless, the current inefficient and labor-intensive transformation techniques have hindered their applications. Virus-induced gene silencing (VIGS) provides a precise and effective strategy for post-transcriptional down-regulation of endogenous gene expression. We investigated the performance of tobacco rattle virus (TRV) as a tool for targeting and silencing the gene encoding the protein involved in chloroplast development, cloroplastos alterados 1 (altered chloroplast; ), of through -mediated infiltration. By effectively suppressing the gene associated with chloroplast development in the TRV-VIGS system, we have illustrated the inaugural implementation of VIGS in this species. Quantitative RT-PCR proved that expression in agro-infiltrated plants was lower than in the mock-infiltrated (mock) and the control (CK) plants. Phenotypic observations corroborated the albino phenotype in leaves following successful silencing. Our study showcases TRV-VIGS as a potential gene silencing tool for , facilitating functional genomics studies and molecular breeding efforts in this species.

Almond kernels can be mixed with apricot (Prunus armeniaca L.) seeds while preparing certain almond-based products such as marzipan, without an identifiable alteration in the final product's sensory attributes. Consequently, apricot kernels are the most commonly utilized almond substitutes for the economic adulteration of almonds. In the present work, the trnH-psbA intergenic spacer was evaluated as a potential PCR-based authenticity marker of almond. The barcode enabled the straightforward discrimination of almond and apricot in their blends, based on diagnostic length polymorphisms between the two closely related Prunus species. The proposed assay simultaneously amplifies and distinguishes almond- and apricot-specific trnH-psbA barcode fragments from mixed samples. The barcode size of almond segregates significantly from peach as well, which is a secondary source for the economic adulteration of almond kernels. The proposed trnH-psbA genotyping assay is easy and selective for the discrimination of almond from its potential adulterants when present as admixtures.

Identifying factors governing the origin, distribution, and maintenance of Neotropical plant diversity is an enduring challenge. To explore the complex and dynamic historical processes that shaped contemporary genetic patterns for a Central American plant species, we investigated the spatial distribution of chloroplast haplotypes of a geographically and environmentally widespread epiphytic bromeliad with wind‐dispersed seeds, Catopsis nutans, in Costa Rica. We hypothesized that genetic discontinuities occur between northwestern and southwestern Pacific slope populations, resembling patterns reported for other plant taxa in the region. Using non‐coding chloroplast DNA from 469 individuals and 23 populations, we assessed the influences of geographic and environmental distance as well as historical climatic variation on the genetic structure of populations spanning >1200 m in elevation. Catopsis nutans revealed seven haplotypes with low within‐population diversity (mean haplotype richness = 1.2) and moderate genetic structure (FST = 0.699). Pairwise FST was significantly correlated with both geographic and environmental distance. The frequency of dominant haplotypes was significantly correlated with elevation. A cluster of nine Pacific lowland populations exhibited a distinct haplotype profile and contained five of the seven haplotypes, suggesting historical isolation and limited seed‐mediated gene flow with other populations. Paleodistribution models indicated lowland and upland habitats in this region were contiguous through past climatic oscillations. Based on our paleodistribution analysis and comparable prior phylogeographic studies, the genetic signature of recent climatic oscillations are likely superimposed upon the distribution of anciently divergent lineages. Our study highlights the unique phylogeographic history of a Neotropical plant species spanning an elevation gradient.

Sieb. et Zucc. is a semi-mangrove plant used for the ecological restoration of saline-alkali land, coastal afforestation and urban landscaping. The genetic transformation is currently inefficient and laborious, restricting gene functional studies on this species. In plants, virus-induced gene silencing provides a pathway to rapidly and effectively create targeted gene knockouts for gene functional studies. In this study, we tested the efficiency of a tobacco rattle virus vector in silencing the cloroplastos alterados 1 ( ) gene through agroinfiltration. The leaves of showed white streaks typical of gene silencing three weeks after agroinfiltration. In agroinfiltrated plants, the expression levels in leaves with white streaks were all significantly lower than those in leaves from mock-infected and control plants. The system presented here can efficiently silence genes in and may be a powerful tool for large-scale reverse-genetic analyses of gene functions in .

We examined ultrastructural changes of the cell organelles of Arabidopsis stems in response to gamma irradiation. Seedlings treated with 0 to 5 Gy developed normally, while height growth in plants exposed to 50 Gy was significantly inhibited. Based on TEM observations, the chloroplasts were extremely sensitive to such irradiation. In particular, the thylakoids were heavily swollen, some portions of the mitochondria and endoplasmic reticulum were structurally altered, and the plasmalemma had pulled away from the cell wall in places.

Constitutive expression of the cold-regulated COR15a gene of Arabidopsis thaliana results in a significant increase in the survival of isolated protoplasts frozen over the range of -4.5 to -7 degree C. The increased freezing tolerance is the result of a decreased incidence of freeze-induced lamellar-to-hexagonal II phase transitions that occur in regions where the plasma membrane is brought into close apposition with the chloroplast envelope as a result of freeze-induced dehydration. Moreover, the mature polypeptide encoded by this gene. COR15am, increases the lamellar-to-hexagonal II phase transition temperature of dioleoylphosphatidylethanolamine and promotes formation of the lamellar phase in a lipid mixture composed of the major lipid species that comprise the chloroplast envelope. We propose that COR15am, which is located in the chloroplast stroma, defers freeze-induced formation of the hexagonal II phase to lower temperatures (lower hydrations) by altering the intrinsic curvature of the inner membrane of the chloroplast envelope

A number of studies have noted that nucleotide substitution rates at the chloroplast-encoded rbcL locus violate the molecular clock principle. Substitution rate variation at this plastic gene is particularly pronounced between palms and grasses; for example, a previous study estimated that substitution rates in rbcL sequences are approximately 5-fold faster in grasses than in palms. To determine whether a proportionate change in substitution rates also occurs in plant nuclear genes, we characterized nucleotide substitution rates in palm and grass sequences for the nuclear gene Adh. In this article, we report that palm sequences evolve at a rate of 2.61 X 10(-9) substitution per synonymous site per year, a rate which is slower than most plant nuclear genes. Grass Adh sequences evolve approximately 2.5-fold faster than palms at synonymous sites. Thus, synonymous rates in nuclear Adh genes show a marked decrease in palms relative to grasses, paralleling the pattern found at the plastic rbcL locus. This shared pattern indicates that synonymous rates are correlated between a nuclear and a plastid gene. Remarkably, nonsynonymous rates do not show this correlation. Nonsynonymous rates vary between two duplicated grass Adh loci, and nonsynonymous rates at the palm Adh locus are not markedly reduced relative to grasses

In nearly all eukaryotes, at least some individuals inherit mitochondrial and chloroplast genes from only one parent. There is no single mechanism of uniparental inheritance: organelle gene inheritance is blocked by a variety of mechanisms and at different stages of reproduction in different species. Frequent changes in the pattern of organelle gene inheritance during evolution suggest that it is subject to varying selective pressures. Organelle genes often fail to recombine even when inherited biparentally; consequently, their inheritance is asexual. Sexual reproduction is apparently less important for genes in organelles than for nuclear genes, probably because there are fewer of them. As a result organelle sex can be lost because of selection for special reproductive features such as oogamy or because uniparental inheritance reduces the spread of cytoplasmic parasites and selfish organelle DNA.

Little is known about the division of eukaryotic cell organelles and up to now neither in animals nor in plants has a gene product been shown to mediate this process. A cDNA encoding a homolog of the bacterial cell division protein FtsZ, an ancestral tubulin, was isolated from the eukaryote Physcomitrella patens and used to disrupt efficiently the genomic locus in this terrestrial seedless plant. Seven out of 51 transgenics obtained were knockout plants generated by homologous recombination; they were specifically impeded in plastid division with no detectable effect on mitochondrial division or plant morphology. Implications on the theory of endosymbiosis and on the use of reverse genetics in plants are discussed.

The application of a moderate water deficit (water potential of -1.3 MPa) to pea (Pisum sativum L. cv Lincoln) leaves led to a 75% inhibition of photosynthesis and to increases in zeaxanthin, malondialdehyde, oxidized proteins, and mitochondrial, cytosolic, and chloroplastic superoxide dismutase activities. Severe water deficit (-1.9 MPa) almost completely inhibited photosynthesis, decreased chlorophylls, beta-carotene, neoxanthin, and lutein, and caused further conversion of violaxanthin to zeaxanthin, suggesting damage to the photosynthetic apparatus. There were consistent decreases in antioxidants and pyridine nucleotides, and accumulation of catalytic Fe, malondialdehyde, and oxidized proteins. Paraquat (PQ) treatment led to similar major decreases in photosynthesis, water content, proteins, and most antioxidants, and induced the accumulation of zeaxanthin and damaged proteins. PQ decreased markedly ascorbate, NADPH, ascorbate peroxidase, and chloroplastic Fe-superoxide dismutase activity, and caused major increases in oxidized glutathione, NAD+, NADH, and catalytic Fe. It is concluded that, in cv Lincoln, the increase in catalytic Fe and the lowering of antioxidant protection may be involved in the oxidative damage caused by severe water deficit and PQ, but not necessarily in the incipient stress induced by moderate water deficit. Results also indicate that the tolerance to water deficit in terms of oxidative damage largely depends on the legume cultivar