Modulation of calcium, callose synthesis, membrane permeability and pectin methyl-esterase activity affect cell wall composition and embryo yield during Brassica napus microspore embryogenesis.

Background And Aims: Microspore embryogenesis is a convenient inducible system to study the changes associated with the developmental reprogramming of cells. In this work, Brassica napus microspore cultures were used to study the role in the embryogenic switch of callose and pectin cell wall composition, which depends on Ca2+ levels.

Methods: We used different chemicals to modulate Ca2+, callose and pectin methyl-esterification, including Ca(NO3)2, inositol 1,4,5-trisphosphate, 2-deoxy-d-glucose, benzyl alcohol, chitosan, epigallocatechin gallate and pectin methyl-esterase.

Calcium levels modulate embryo yield in microspore embryogenesis.

Calcium (Ca) is a universal signaling cation with a prominent role as second messenger in many different plant processes, including sexual reproduction. However, there is much less knowledge about the involvement of Ca during embryogenesis processes. In this work we performed a study of Ca levels during the different stages of microspore embryogenesis in , with special attention to how Ca can influence the occurrence of different embryogenic structures with different embryogenic potential.

: A Halophyte Model to Study Salt Tolerance Mechanisms and Potential Useful Crop for Sustainable Saline Agriculture in the Context of Climate Change.

Salinity is an increasing problem for agriculture. Most plant species tolerate low or, at best, moderate soil salinities. However, a small (<1%) proportion of species, termed halophytes, can survive and complete their life cycle in natural habitats with salinities equivalent to 200 mM NaCl or more.

Salt Tolerance of Sea Flax ( L.), a Rare Species with Conservation Interest in Eastern Spain.

Seldom found in saltmarshes, is a halophyte of great conservation interest in the eastern Iberian Peninsula. Although the species has been reported in different plant communities, there is no information on its range of salinity tolerance or mechanisms of response to environmental stress factors. In this study, plants were subjected to increasing salt concentrations in controlled conditions in a greenhouse.

The Highly Embryogenic DH4079 Line Is Recalcitrant to -Mediated Genetic Transformation.

is a species of high agronomic interest, used as a model to study different processes, including microspore embryogenesis. The DH4079 and DH12075 lines show high and low embryogenic response, respectively, which makes them ideal to study the basic mechanisms controlling embryogenesis induction. Therefore, the availability of protocols for genetic transformation of these two backgrounds would help to generate tools to better understand this process.

Calcium dynamics and modulation in carrot somatic embryogenesis.

Free calcium (Ca) is a pivotal player in different and morphogenic processes. In the induction of somatic embryogenesis, its role has been demonstrated in different species. In carrot, however, this role has been more controversial.

Calcium Dynamics, WUSCHEL Expression and Callose Deposition during Somatic Embryogenesis in Immature Zygotic Embryos.

In this work, we studied the induction of somatic embryogenesis in using IZEs as explants. We characterized the process at the light and scanning electron microscope level and studied several specific aspects such as WUS expression, callose deposition, and principally Ca dynamics during the first stages of the process of embryogenesis induction, by confocal FRET analysis with an line expressing a calcium sensor. We also performed a pharmacological study with a series of chemicals know to alter calcium homeostasis (CaCl, inositol 1,4,5-trisphosphate, ionophore A23187, EGTA), the calcium-calmodulin interaction (chlorpromazine, W-7), and callose deposition (2-deoxy-D-glucose).

Constitutive and Adaptive Traits of Environmental Stress Tolerance in the Threatened Halophyte Erben (Plumbaginaceae).

is a halophyte endemic to the E and SE Iberian Peninsula with interest in conservation. Salt glands represent an important adaptive trait in recretohalophytes like this and other species, as they allow the excretion of excess salts, reducing the concentration of toxic ions in foliar tissues. This study included the analysis of the salt gland structure, composed of 12 cells, 4 secretory and 8 accessory.

Cell Wall Composition and Structure Define the Developmental Fate of Embryogenic Microspores in .

Microspore cultures generate a heterogeneous population of embryogenic structures that can be grouped into highly embryogenic structures [exine-enclosed (EE) and loose bicellular structures (LBS)] and barely embryogenic structures [compact callus (CC) and loose callus (LC) structures]. Little is known about the factors behind these different responses. In this study we performed a comparative analysis of the composition and architecture of the cell walls of each structure by confocal and quantitative electron microscopy.

Doubled Haploids in Eggplant.

Eggplant is a solanaceous crop cultivated worldwide for its edible fruit. Eggplant breeding programs are mainly aimed to the generation of F1 hybrids by crossing two highly homozygous, pure lines, which are traditionally obtained upon several self crossing generations, which is an expensive and time consuming process. Alternatively, fully homozygous, doubled haploid (DH) individuals can be induced from haploid cells of the germ line in a single generation.

Species with Haploid or Doubled Haploid Protocols.

In this chapter, we present a list of species (and few interspecific hybrids) where haploids and/or doubled haploids have been published, including the method by which they were obtained and the corresponding references. This list is an update of the compilation work of Maluszynski et al. published in 2003, including new species for which protocols were not available at that time, and also novel methodologies developed during these years.

Doubled Haploid Production in High- and Low-Response Genotypes of Rapeseed (Brassica napus) Through Isolated Microspore Culture.

Rapeseed (Brassica napus) is one of the most important oilseed crops worldwide. It is also a model system to study the process of microspore embryogenesis, due to the high response of some B. napus lines, and to the refinements of the protocols.

Division Plane Orientation Defects Revealed by a Synthetic Double Mutant Phenotype.

TANGLED1 (TAN1) and AUXIN-INDUCED-IN-ROOTS9 (AIR9) are microtubule-binding proteins that localize to the division site in plants. Their function in Arabidopsis () remained unclear because neither nor single mutants have a strong phenotype. We show that double mutants have a synthetic phenotype consisting of short, twisted roots with disordered cortical microtubule arrays that are hypersensitive to a microtubule-depolymerizing drug.

A DII Domain-Based Auxin Reporter Uncovers Low Auxin Signaling during Telophase and Early G1.

A sensitive and dynamically responsive auxin signaling reporter based on the DII domain of the INDOLE-3-ACETIC ACID28 (IAA28, DII) protein from Arabidopsis (Arabidopsis thaliana) was modified for use in maize (Zea mays). The DII domain was fused to a yellow fluorescent protein and a nuclear localization sequence to simplify quantitative nuclear fluorescence signal. DII degradation dynamics provide an estimate of input signal into the auxin signaling pathway that is influenced by both auxin accumulation and F-box coreceptor concentration.

Pathogen and circadian controlled 1 (PCC1) protein is anchored to the plasma membrane and interacts with subunit 5 of COP9 signalosome in Arabidopsis.

The Pathogen and Circadian Controlled 1 (PCC1) gene, previously identified and further characterized as involved in defense to pathogens and stress-induced flowering, codes for an 81-amino acid protein with a cysteine-rich C-terminal domain. This domain is essential for homodimerization and anchoring to the plasma membrane. Transgenic plants with the ß-glucuronidase (GUS) reporter gene under the control of 1.

Diverse functional interactions between nitric oxide and abscisic acid in plant development and responses to stress.

The extensive support for abscisic acid (ABA) involvement in the complex regulatory networks controlling stress responses and development in plants contrasts with the relatively recent role assigned to nitric oxide (NO). Because treatment with exogenous ABA leads to enhanced production of NO, it has been widely considered that NO participates downstream of ABA in controlling processes such as stomata movement, seed dormancy, and germination. However, data on leaf senescence and responses to stress suggest that the functional interaction between ABA and NO is more complex than previously thought, including not only cooperation but also antagonism.

Pathogen and Circadian Controlled 1 (PCC1) regulates polar lipid content, ABA-related responses, and pathogen defence in Arabidopsis thaliana.

Pathogen and Circadian Controlled 1 (PCC1) was previously characterized as a regulator of defence against pathogens and stress-activated transition to flowering. Plants expressing an RNA interference construct for the PCC1 gene (iPCC1 plants) showed a pleiotropic phenotype. They were hypersensitive to abscisic acid (ABA) as shown by reduced germination potential and seedling establishment, as well as reduced stomatal aperture and main root length in ABA-supplemented media.

A permeable cuticle is associated with the release of reactive oxygen species and induction of innate immunity.

Wounded leaves of Arabidopsis thaliana show transient immunity to Botrytis cinerea, the causal agent of grey mould. Using a fluorescent probe, histological staining and a luminol assay, we now show that reactive oxygen species (ROS), including H(2)O(2) and O(2) (-), are produced within minutes after wounding. ROS are formed in the absence of the enzymes Atrboh D and F and can be prevented by diphenylene iodonium (DPI) or catalase.

Genome-wide analyses of the transcriptomes of salicylic acid-deficient versus wild-type plants uncover Pathogen and Circadian Controlled 1 (PCC1) as a regulator of flowering time in Arabidopsis.

Salicylic acid (SA) has been characterized as an activator of pathogen-triggered resistance of plants. SA also regulates developmental processes such as thermogenesis in floral organs and stress-induced flowering. To deepen our knowledge of the mechanism underlying SA regulation of flowering time in Arabidopsis, we compared the transcriptomes of SA-deficient late flowering genotypes with wild-type plants.