The interaction between miR165/166 and miR160 regulates Arabidopsis thaliana seed size, weight, and number in a ROS-dependent manner.

Our data link the miR165/166- and miR160-mediated regulatory modules to ROS and seed formation. Trade-offs of seed size, weight, and number probably require control of the expression of miR165/166 by miR160, modulation of ROS metabolism by miR165/166, and miR160 abundance by ROS-induced oxidative modifications The cycle of plant life and its yield productivity depends fundamentally on the establishment of the trade-offs of seed size, weight, and number. For annual plants, seed number should simply be a positive function of vegetative biomass and a negative function of seed size and/or weight.

[ARGONAUTE proteins in cell biology and plant development].

ARGONAUTE (AGO) proteins are integral parts of regulatory pathways under the control of small RNA (sRNA) that are fundamental for the proper functioning of eukaryotic cells. AGOs, as highly specialized platforms binding specific sRNA, coordinate gene silencing through interaction with other protein factors (forming the RNA-induced silencing complex, RISC), contributing to endonucleolytic cleavage of the target mRNA and/or influencing the translation process. The increasing number of evidence confirms the participation of AGO proteins in several other cellular processes, such as i.

The novel activity of Argonautes in intron splicing: A transcriptome-wide survey in plants.

The importance of the evolutionarily conserved Argonaute (AGO) proteins has been well recognized for their involvement in the RNA interference pathways. Recent discoveries in animals demonstrated that AGOs also participate in alternative splicing (AS). Motivated by the question whether the AGO proteins are also functional in RNA splicing in plants, we searched for the introns excised through an AGO-dependent manner in Arabidopsis (Arabidopsis thaliana).

phyB and HY5 are Involved in the Blue Light-Mediated Alleviation of Dormancy of Seeds Possibly via the Modulation of Expression of Genes Related to Light, GA, and ABA.

Light is one of the most important environmental factors regulating seed germination. It is known that light inhibits seed germination of some monocotyledonous species and that it is mostly related to the blue wavelength of the spectrum received by cryptochromes (cry). Research has also found that the red light (R) stimulates germination of dicotyledonous seeds and that this reaction involves mainly phytochromes (phy).

Cellular Recycling of Proteins in Seed Dormancy Alleviation and Germination.

Each step of the seed-to-seed cycle of plant development including seed germination is characterized by a specific set of proteins. The continual renewal and/or replacement of these biomolecules are crucial for optimal plant adaptation. As proteins are the main effectors inside the cells, their levels need to be tightly regulated.

Phytohormones Signaling Pathways and ROS Involvement in Seed Germination.

Phytohormones and reactive oxygen species (ROS) are major determinants of the regulation of development and stress responses in plants. During life cycle of these organisms, signaling networks of plant growth regulators and ROS interact in order to render an appropriate developmental and environmental response. In plant's photosynthetic (e.

Large-Scale Phenomics Identifies Primary and Fine-Tuning Roles for CRKs in Responses Related to Oxidative Stress.

Cysteine-rich receptor-like kinases (CRKs) are transmembrane proteins characterized by the presence of two domains of unknown function 26 (DUF26) in their ectodomain. The CRKs form one of the largest groups of receptor-like protein kinases in plants, but their biological functions have so far remained largely uncharacterized. We conducted a large-scale phenotyping approach of a nearly complete crk T-DNA insertion line collection showing that CRKs control important aspects of plant development and stress adaptation in response to biotic and abiotic stimuli in a non-redundant fashion.

Promotion of testa rupture during garden cress germination involves seed compartment-specific expression and activity of pectin methylesterases.

Pectin methylesterase (PME) controls the methylesterification status of pectins and thereby determines the biophysical properties of plant cell walls, which are important for tissue growth and weakening processes. We demonstrate here that tissue-specific and spatiotemporal alterations in cell wall pectin methylesterification occur during the germination of garden cress (Lepidium sativum). These cell wall changes are associated with characteristic expression patterns of PME genes and resultant enzyme activities in the key seed compartments CAP (micropylar endosperm) and RAD (radicle plus lower hypocotyl).

Embryo growth, testa permeability, and endosperm weakening are major targets for the environmentally regulated inhibition of Lepidium sativum seed germination by myrigalone A.

Myrigalone A (MyA) is a rare flavonoid in fruit leachates of Myrica gale, a deciduous shrub adapted to flood-prone habitats. As a putative allelochemical it inhibits seed germination and seedling growth. Using Lepidium sativum as a model target species, experiments were conducted to investigate how environmental cues modulate MyA's interference with key processes of seed germination.

Myrigalone A inhibits Lepidium sativum seed germination by interference with gibberellin metabolism and apoplastic superoxide production required for embryo extension growth and endosperm rupture.

Myrica gale L. (sweet gale) fruit leachate contains myrigalone A (MyA), a rare C-methylated dihydrochalcone and putative allelochemical, which is known to be a phytotoxin impeding seedling growth. We found that MyA inhibited Lepidium sativum L.

Regulation of seed germination in the close Arabidopsis relative Lepidium sativum: a global tissue-specific transcript analysis.

The completion of germination in Lepidium sativum and other endospermic seeds (e.g. Arabidopsis [Arabidopsis thaliana]) is regulated by two opposing forces, the growth potential of the radicle (RAD) and the resistance to this growth from the micropylar endosperm cap (CAP) surrounding it.

The mechanisms involved in seed dormancy alleviation by hydrogen cyanide unravel the role of reactive oxygen species as key factors of cellular signaling during germination.

The physiological dormancy of sunflower (Helianthus annuus) embryos can be overcome during dry storage (after-ripening) or by applying exogenous ethylene or hydrogen cyanide (HCN) during imbibition. The aim of this work was to provide a comprehensive model, based on oxidative signaling by reactive oxygen species (ROS), for explaining the cellular mode of action of HCN in dormancy alleviation. Beneficial HCN effect on germination of dormant embryos is associated with a marked increase in hydrogen peroxide and superoxide anion generation in the embryonic axes.

Release of sunflower seed dormancy by cyanide: cross-talk with ethylene signalling pathway.

Freshly harvested sunflower (Helianthus annuus L.) seeds are considered to be dormant because they fail to germinate at relatively low temperatures (10 degrees C). This dormancy results mainly from an embryo dormancy and disappears during dry storage.

ROS production and protein oxidation as a novel mechanism for seed dormancy alleviation.

At harvest, sunflower (Helianthus annuus L.) seeds are dormant and unable to germinate at temperatures below 15 degrees C. Seed storage in the dry state, known as after-ripening, is associated with an alleviation of embryonic dormancy allowing subsequent germination at suboptimal temperatures.

Induction of oxidative stress by sunflower phytotoxins in germinating mustard seeds.

The aim of this study was to investigate the phytotoxic effect of sunflower on physiological and biochemical processes during germination of mustard seeds (Sinapis alba L. cv. Nakielska).