121 research outputs found
Plant miRNA Cross-Kingdom Transfer Targeting Parasitic and Mutualistic Organisms as a Tool to Advance Modern Agriculture
MicroRNAs (miRNAs), defined as small non-coding RNA molecules, are fine regulators of
gene expression. In plants, miRNAs are well-known for regulating processes spanning
from cell development to biotic and abiotic stress responses. Recently, miRNAs have
been investigated for their potential transfer to distantly related organisms where they may
exert regulatory functions in a cross-kingdom fashion. Cross-kingdom miRNA transfer has
been observed in host-pathogen relations as well as symbiotic or mutualistic relations. All
these can have important implications as plant miRNAs can be exploited to inhibit
pathogen development or aid mutualistic relations. Similarly, miRNAs from eukaryotic
organisms can be transferred to plants, thus suppressing host immunity. This two-way
lane could have a significant impact on understanding inter-species relations and, more
importantly, could leverage miRNA-based technologies for agricultural practices.
Additionally, artificial miRNAs (amiRNAs) produced by engineered plants can be
transferred to plant-feeding organisms in order to specifically regulate their crosskingdom
target genes. This minireview provides a brief overview of cross-kingdom
plant miRNA transfer, focusing on parasitic and mutualistic relations that can have an
impact on agricultural practices and discusses some opportunities related to miRNAbased
technologies. Although promising, miRNA cross-kingdom transfer remains a
debated argument. Several mechanistic aspects, such as the availability, transfer, and
uptake of miRNAs, as well as their potential to alter gene expression in a cross-kingdom
manner, remain to be addressed
Transcriptomics View over the Germination Landscape in Biofortified Rice
Hidden hunger, or micronutrient deficiency, is a worldwide problem. Several approaches are employed to alleviate its effects (e.g., promoting diet diversity, use of dietary supplements, chemical fortification of processed food), and among these, biofortification is considered as one of the most cost-effective and highly sustainable. Rice is one of the best targets for biofortification since it is a staple food for almost half of the worldâs population as a high-energy source but with low nutritional value. Multiple biofortified rice lines have been produced during the past decades, while few studies also reported modifications in germination behavior (in terms of enhanced or decreased germination percentage or speed). It is important to underline that rapid, uniform germination, and seedling establishment are essential prerequisites for crop productivity. Combining the two traits, biofortified, highly-nutritious seeds with improved germination behavior can be envisaged as a highly-desired target for rice breeding. To this purpose, information gathered from transcriptomics studies can reveal useful insights to unveil the molecular players governing both traits. The present review aims to provide an overview of transcriptomics studies applied at the crossroad between biofortification and seed germination, pointing out potential candidates for trait pyramiding
Unraveling the response of plant cells to cytotoxic saponins: role of metallothionein and nitric oxide
A wide range of pharmacological
properties are ascribed to natural
saponins, in addition to their biological
activities against herbivores, plant soilborne
pathogens and pests. As for animal
cells, the cytotoxicity and the chemopreventive
role of saponins are mediated by
a complex network of signal transduction
pathways which include reactive oxygen
species (ROS) and nitric oxide (NO).
The involvement of other relevant components
of the saponin-related signaling
routes, such as the Tumor Necrosis
Factor (TNF)α, the interleukin (IL)-6
and the Nuclear Transcription FactorÎșB
(NFÎșB), has been highlighted in animal
cells. By contrast, information concerning
the response of plant cells to saponins
and the related signal transduction pathways
is almost missing. To date, there are
only a few common features which link
plant and animal cells in their response
to saponins, such as the early burst in
ROS and NO production and the induction
of metallothioneins (MTs), small
cysteine-rich, metal-binding proteins.
This aspect is discussed in the present
paper in view of the recent hypothesis
that MTs and NO are part of a novel signal
transduction pathway participating
in the cell response to oxidative stress
Metabolic signatures of germination triggered by kinetin in Medicago truncatula
In the present work, non-targeted metabolomics was used to investigate the seed response to kinetin, a phytohormone with potential roles in seed germination, still poorly explored. The aim of this study was to elucidate the metabolic signatures of germination triggered by kinetin and explore changes in metabolome to identify novel vigor/stress hallmarks in Medicago truncatula. Exposure to 0.5 mM kinetin accelerated seed germination but impaired seedling growth. Metabolite composition was investigated in seeds imbibed with water or with 0.5 mM kinetin collected at 2 h and 8 h of imbibition, and at the radicle protrusion stage. According to Principal Component Analysis, inositol pentakisphosphate, agmatine, digalactosylglycerol, inositol hexakisphosphate, and oleoylcholine were the metabolites that mostly contributed to the separation between 2 h, 8 h and radicle protrusion stage, irrespective of the treatment applied. Overall, only 27 metabolites showed significant changes in mean relative contents triggered by kinetin, exclusively at the radicle protrusion stage. The observed metabolite depletion might associate with faster germination or regarded as a stress signature. Results from alkaline comet assay, highlighting the occurrence of DNA damage at this stage of germination, are consistent with the hypothesis that prolonged exposure to kinetin induces stress conditions leading to genotoxic injury.publishersversionpublishe
Changes in Medicago truncatula seed proteome along the rehydrationâdehydration cycle highlight new players in the genotoxic stress response
IntroductionSeveral molecular aspects underlying the seed response to priming and the resulting vigor profile are still poorly understood. Mechanisms involved in genome maintenance deserve attention since the balance between stimulation of germination and DNA damage accumulation versus active repair is a key determinant for designing successful seed priming protocols.MethodsChanges in the Medicago truncatula seed proteome were investigated in this study, using discovery mass spectrometry and label-free quantification, along the rehydration-dehydration cycle of a standard vigorization treatment (hydropriming plus dry-back), and during post-priming imbibition.Resuts and discussionFrom 2056 to 2190 proteins were detected in each pairwise comparison, among which six were differentially accumulated and 36 were detected only in one condition. The following proteins were selected for further investigation: MtDRP2B (DYNAMIN-RELATED PROTEIN), MtTRXm4 (THIOREDOXIN m4), and MtASPG1 (ASPARTIC PROTEASE IN GUARD CELL 1) showing changes in seeds under dehydration stress; MtITPA (INOSINE TRIPHOSPHATE PYROPHOSPHORYLASE), MtABA2 (ABSCISIC ACID DEFICIENT 2), MtRS2Z32 (SERINE/ARGININE-RICH SPLICING FACTOR RS2Z32), and MtAQR (RNA HELICASE AQUARIUS) that were differentially regulated during post-priming imbibition. Changes in the corresponding transcript levels were assessed by qRT-PCR. In animal cells, ITPA hydrolyses 2â-deoxyinosine triphosphate and other inosine nucleotides, preventing genotoxic damage. A proof of concept was performed by imbibing primed and control M. truncatula seeds in presence/absence of 20 mM 2â-deoxyinosine (dI). Results from comet assay highlighted the ability of primed seeds to cope with dI-induced genotoxic damage. The seed repair response was assessed by monitoring the expression profiles of MtAAG (ALKYL-ADENINE DNA GLYCOSILASE) and MtEndoV (ENDONUCLEASE V) genes that participate in the repair of the mismatched I:T pair in BER (base excision repair) and AER (alternative excision repair) pathways, respectively
Changes in genotoxic stress response, ribogenesis and PAP (3â-phosphoadenosine 5â-phosphate) levels are associated with loss of desiccation tolerance in overprimed Medicago truncatula seeds
Reâestablishment of desiccation tolerance is essential for the survival of germinated seeds facing water deficit in the soil. The molecular and ultrastructural features of desiccation tolerance maintenance and loss within the nuclear compartment are not fully resolved. In the present study, the impact of desiccationâinduced genotoxic stress on nucleolar ultrastructure and ribogenesis was explored along the rehydrationâdehydration cycle applied in standard seed vigorization protocols. Primed and overprimed Medicago truncatula seeds, obtained through hydropriming followed by desiccation (dryâback), were analysed. In contrast to desiccationâtolerant primed seeds, overprimed seeds enter irreversible germination and do not survive dryâback. Reactive oxygen species, DNA damage and expression profiles of antioxidant/DNA Damage Response genes were measured, as main hallmarks of the seed response to desiccation stress. Nuclear ultrastructural features were also investigated. Overprimed seeds subjected to dryâback revealed altered rRNA accumulation profiles and upâregulation of genes involved in ribogenesis control. The signal molecule PAP
(3âČâphosphoadenosine 5âČâphosphate) accumulated during dryâback only in primed seeds, as a distinctive feature of desiccation tolerance. The presented results show the molecular and ultrastructural landscapes of the seed desiccation response, including substantial changes in nuclear organization
Arterial vascularization of the colon; a guide to surgical resection
Background. Colorectal cancer is a commonly diagnosed neoplasia in men and women worldwide. This study aims to rigorously map the arterial distribution of the colon in order to assess the implications of vascular patterns in surgical resection. Methods. Cadaveric dissections were performed to explore the arterial distribution (including collateral blood flow) of the colon. The study used standard dissection tools and photographic documentation to detail the vascular architecture supporting the large intestine. Results. The dissection revealed important arterial branches and anastomoses in the area of the superior and inferior mesenteric arteries, which are able to ensure continuous local blood supply especially in cases of arterial ischemia. An important arterial anastomosis was identified between the right branch of the middle colic artery and the ascending branch of the right colic artery, as well as the specific distribution of the marginal artery of Drummond and Haller-Riolan anastomotic arch. Conclusions. The blood supply of the colon derived from both mesenteric arteries includes redundant arterial anastomoses, but which are critical in specific situations such as the approach and results of surgical resection. Understanding these vascular patterns and collateral pathways, as well as careful intraoperative surgical exploration, are essential for oncologic surgeons to ensure successful colic resections with minimal complications and morbidity
DNA profiling, telomere analysis and antioxidant properties as tools for monitoring ex situ seed longevity
Background and Aims The germination test currently represents the most used method to assess seed viability in germplasm banks, despite the difficulties caused by the occurrence of seed dormancy. Furthermore, seed longevity can vary considerably across species and populations from different environments and studies related to the eco-physiological processes underlying such variations are still limited in their depth. The aim of the present work was the identification of reliable molecular markers that might help monitoring seed deterioration.
Methods Dry seeds were subjected to artificial aging and collected at different time points for molecular/biochemical analyses. DNA damage was measured using the RAPD (Random Amplified Polymorphic DNA) approach while the seed antioxidant profile was obtained using both the DPPH (1,1-diphenyl, 2-picrylhydrazyl) assay and the Folin Ciocalteu reagent method. Electron Paramagnetic Resonance (EPR) provided profiles of free radicals. Quantitative RealTime-Polymerase Chain Reaction (QRT-PCR) was used to assess the expression profiles of the antioxidant genes MT2 (Type 2 Metallothionein) and SOD (Superoxide Dismutase). A modified QRT-PCR protocol was used to determine telomere length.
Key Results The RAPD profiles highlighted different capacities of the two Silene species to overcome DNA damage induced by artificial aging. The antioxidant profiles of dry and rehydrated seeds revealed that the high-altitude taxon Silene acaulis was characterised by a lower antioxidant specific activity. Significant up-regulation of the MT2 and SOD genes was observed only in the rehydrated seeds of the low-altitude species. Rehydration resulted in telomere lengthening in both Silene species.
Conclusions Different seed viability markers have been selected for plant species showing inherent variation of seed longevity. RAPD analysis, quantification of redox activity of non enzymatic antioxidant compounds and gene expression profiling provide deeper insights to study seed viability during storage. Telomere lengthening is a promising tool to discriminate between short- and long-lived species
- âŠ