Distinct Hormone Signalling-Modulation Activities Characterize Two Maize Endosperm-Specific Type-A Response Regulators.

ZmTCRR1 and 2 are type-A response regulators expressed in the maize endosperm transfer cells (TC). While type-B response regulators transcriptionally control canonical type-A response regulators, as part of the cytokinin signal transduction mechanism, the ZmTCRRs are regulated by ZmMRP1, a master regulator of TC identity. In addition, the corresponding proteins are not detected in the TC, accumulating in the inner endosperm cells instead.

Cell wall invertase activity regulates the expression of the transfer cell-specific transcription factor ZmMRP-1.

Studies in cell wall bound invertase mutants indicate that the promoter of the transfer cell-specific transcription factor, ZmMRP - 1 , is modulated by the carbohydrate balance. Transfer cells are highly specialized plant cells located at the surfaces that need to support an intensive exchange of nutrients, such as the entrance of fruits, seeds and nodules or the young branching points along the stem. ZmMRP-1 is a one-domain MYB-related transcription factor specifically expressed at the transfer cell layer of the maize endosperm.

zmsbt1 and zmsbt2, two new subtilisin-like serine proteases genes expressed in early maize kernel development.

Two subtilisin-like proteases show highly specific and complementary expression patterns in developing grains. These genes label the complete surface of the filial-maternal interface, suggesting a role in filial epithelial differentiation. The cereal endosperm is the most important source of nutrition and raw materials for mankind, as well as the storage compartment enabling initial growth of the germinating plantlets.

A PCR-based forward genetics screening, using expression domain-specific markers, identifies mutants in endosperm transfer cell development.

Mutant collections are an invaluable source of material on which forward genetic approaches allow the identification of genes affecting a wide variety of biological processes. However, some particular developmental stages and morphological structures may resist analysis due to their physical inaccessibility or to deleterious effects associated to their modification. Furthermore, lethal mutations acting early in development may escape detection.

Robust and efficient genotyping of factor V and prothrombin alleles using amplicon high-resolution melting and synthetic DNA controls: validation of the test with three different commercial chemistries.

Objectives: Developing robust HRM (amplicon High Resolution Melting) analysis valid for different commercial reaction mixes, using synthetic control DNA samples and the RotorGeneQ (Qiagen) instrument.

Design And Methods: 126 samples were analyzed for the presence of the factor Leiden and the 20210G>A prothrombin alleles. The four alleles were cloned and used to prepare synthetic controls.

Atypical response regulators expressed in the maize endosperm transfer cells link canonical two component systems and seed biology.

Background: Two component systems (TCS) are phosphotransfer-based signal transduction pathways first discovered in bacteria, where they perform most of the sensing tasks. They present a highly modular structure, comprising a receptor with histidine kinase activity and a response regulator which regulates gene expression or interacts with other cell components. A more complex framework is usually found in plants and fungi, in which a third component transfers the phosphate group from the receptor to the response regulator.

Transcriptional activation of the maize endosperm transfer cell-specific gene BETL1 by ZmMRP-1 is enhanced by two C2H2 zinc finger-containing proteins.

ZmMRP-1 is a single MYB-domain transcription factor specifically expressed in the transfer cell layer of the maize endosperm, where it directly regulates the expression of a number of transfer cell specific genes and very likely contributes to the regulation of the transfer cell differentiation process. It is still a matter of debate, however, how this type of transcription factors interact with the promoter sequences they regulate. In this work we have investigated the existence of proteins interacting with ZmMRP-1 in the transfer cell nuclei.

The maize transcription factor myb-related protein-1 is a key regulator of the differentiation of transfer cells.

Transfer cells are highly modified plant cells specialized in the transport of solutes. They differentiate at many plant exchange surfaces, including phloem loading and unloading zones such as those present in the sink organs and seeds. In maize (Zea mays) seeds, transfer cells are located at the base of the endosperm.

Molecular dissection of the interaction between the transcriptional activator ZmMRP-1 and the promoter of BETL-1.

The interaction between the transfer cell specific transcriptional activator ZmMRP-1 and the promoter of the transfer cell specific gene BETL-1 constitutes an exceptionally robust system. Reporter constructs containing the BETL-1 promoter are virtually silent in a variety of cell types, from maize leaves to yeast. The introduction of ZmMRP-1 in co-transformation assays leads to the transactivation of the reporter construct by up to two orders of magnitude.

The maize transfer cell-specific type-A response regulator ZmTCRR-1 appears to be involved in intercellular signalling.

Response regulators are signal-transduction molecules present in bacteria, yeast and plants, acting as relays for environmental challenges. This paper reports the characterization of a Zea mays gene, ZmTCRR-1, that codes for a member of the type-A response regulator class of proteins. The gene was found to be expressed exclusively in the endosperm transfer-cell layer 8-14 days after pollination, when transfer-cell differentiation is most active.

Mapping of QTLs for androgenetic response based on a molecular genetic map of x Triticosecale Wittmack.

Quantitative trait loci (QTLs) for androgenetic response were mapped in a doubled haploid (DH) population derived from the F1 hybrid of 2 unrelated varieties of triticale, 'Torote' and 'Presto'. A molecular marker linkage map of this cross was previously constructed using 73 DH lines. This map contains 356 markers (18 random amplified 5 polymorphic DNA, 40 random amplified microsatellite polymorphics, 276 amplified fragment length polymorphisms, and 22 simple sequence repeats) and was used for QTL analysis.

ZmLrk-1, a receptor-like kinase induced by fungal infection in germinating seeds.

We report here on the identification and characterization of ZmLrk-1, a member of the Lrk class of receptor-like kinases in Zea mays. This gene was found to be located at the bin21.40 region on the short arm of maize chromosome 8, closely linked to the previously reported pseudogene of the same class psiZmLrk (originally called Zm2Lrk).

A protective role for the embryo surrounding region of the maize endosperm, as evidenced by the characterisation of ZmESR-6, a defensin gene specifically expressed in this region.

A Zea mays cDNA clone, ZmESR-6, was isolated as a gene specifically expressed at the basal region of immature kernels. ZmESR-6 cDNA encoded for a small (11.1 kDa) protein homologous to plant defensins.