Ecker 5 Ethylene signal transduction in flowers and fruits: Harry J.

This review summarizes biosynthesis and signal transduction of jasmonates with emphasis on new findings in relation to enzymes, their crystal structure, new compounds detected in the oxylipin and jasmonate families, and newly found functions.

Hormone binding and signal transduction-- K.R.

HORMONE SIGNAL TRANSDUCTION1 Auxin signal transduction Gretchen Hagen, Tom J.

BT - Plant Hormones: Biosynthesis, Signal Transduction, Action!

Since the first isolation of JAME as a constituent of the oil of Jasminum grandiflorum (), numerous jasmonate compounds have been detected in diverse plant phyla (). Jasmonates occur in algae, mosses, fungi, gymnosperms and angiosperms. The capacity to form or to convert various jasmonates is remarkably high in fungi; for example, more than 20 jasmonates were detected in culture filtrate of Fusarium oxysporum (, whilst Aspergillus niger grown on liquid medium could form more than 25 jasmonate compounds upon application of JA, 9,10-dihydro-JA and their methyl esters (). Some fungi, such as Botryodiplodia theobromae, are able to accumulate up to 500 µg mL−1 of culture medium of (+)-7-iso-JA, the initial product in JA biosynthesis (). Whereas in fungi the biological function of various jasmonates is unknown, application of jasmonates and their structural analogs to higher plants led to the first insights into their structural requirements for biological activity. Based on different assays, such as alkaloid formation (), tendril coiling (), tuber formation (), or gene expression (), the following structural requirements have been found ().

Plant Hormones: Biosynthesis, Signal Transduction, …

One of the best-studied signal-transduction pathways of jasmonates is that of wound-response, which was initially studied mainly in tomato. Briefly, a sequential action of the 18-aa peptide systemin, cleaved from prosystemin upon local wounding, activates JA biosynthetic enzymes such as AOC and leads to local rise in JA (). An amplification in JA formation has been suggested due to JA-dependent PROSYSTEMIN expression, a systemin-dependent AOC expression, and their common location in vascular bundles (; ). It is possible that JA acts as a systemic signal, leading also to systemic expression of genes encoding proteinase inhibitors (PINs) and other foliar compounds with negative effects on herbivore performance. Consequently the plant becomes immunized against a subsequent herbivore attack. Grafting experiments with JA-deficient and JA-signalling mutants in G. Howe's laboratory have shown that JA signalling – but not JA biosynthesis – is necessary in the systemic leaf. The numerous data on the wound response pathway have been reviewed repeatedly, including discussions on cross-talk to other signals, further elements of the wound-response pathway such as MAP kinases, and additional herbivore-induced compounds such as volatiles and their consequences for diverse plant–insect interactions, together with overlap to plant pathogen–interactions (, ; ; ). Here, I want to mention only few important new developments.

Kieber4 Ethylene signal transduction in stem elongation: Ramlah Nehring and Joseph R.
Clark6 Abscisic acid signal transduction in stomatal responses: Sarah M.

from book Plant hormones: Biosynthesis, signal transduction, ..

Wasternack C and Hause B (2013) Jasmonates: biosynthesis, perception, signal transduction and action in plant stress response, growth and development. An update to the 2007 review in Annals of Botany. Annals of Botany 111: 1021–1058.

AssmannUpdate: The Abscisic Acid Receptor7 Brassinosteroid signal transduction: Steven D.

Plant Hormones Biosynthesis, Signal Transduction, ..

Begonia contains 1820 species and is amongst the world’s largest angiosperm genera. The genus has a pantropical distribution, characterised by extremely high rates of narrow endemism. The distribution of Begonia species richness is representative of rainforest diversity generally, being markedly greater in the Neotropics and tropical Asia, and suggests the family is a good proxy for investigating tropical diversification. Much of the research into the generation of large-scale patterns of tropical diversity has focused on trees, however herbaceous layer genera such as Begonia represent an ecologically contrasting aspect of tropical vegetation and need to be included if we are to have a complete understanding of tropical ecosystems. The prevalence of Begonia across the tropics suggests a highly successful strategy in exploiting the niches available to tropical herbs. In order to understand the generation of such a large radiation, we need insights into the interplay of niche evolution, physiology and genome evolution, building on the foundations of a sound taxonomy and robust phylogenetic hypotheses. Preliminary phylogenetic hypotheses for Begonia have been constructed, based on a small number of genome regions. Insights from next generation approaches need to be explored to show us what extent these represent species trees in the light of data on hybridisation and organelle capture. In addition we need to understand the degree of niche differentiation between species with respect to both phylogeny and genomic evolution. In this symposium we aim to bring together a variety of disciplines to give insight into the evolution of Begonia diversity, drawing on recent advances in research of niche evolution, genome dynamism, reproductive biology, photosynthetic physiology, biogeography, and management of biodiversity data. The building of a synthetic picture of evolution in the mega-diverse genus Begonia has the potential to provide a template for understanding broader patterns tropical herbaceous diversity.

Zhao Y (2010) Auxin biosynthesis and its role in plant development. Annual Review of Plant Biology 61: 49.

Auxin Signal Transduction | Request PDF

One of the first biological activities observed for jasmonates was the senescence-promoting effect (; ). Although it occurs ubiquitously following JA treatment, monocotyledonous plants are more sensitive. Senescence is the last stage in plant development. Consequently, genes expressed during leaf senescence (senescence-associated genes, SAGs) code for proteins with functions in sink/source relationships, photosynthesis, intermediary metabolism, proteolysis and plant defence (cf. ; ). The role of JA in senescence is linked to (1) downregulation of housekeeping proteins encoded by photosynthetic genes and (2) upregulation of genes active in defence reactions against biotic and abiotic stresses (, ). Several microarray analyses have led to more detailed information, including cross-talk between plant hormones (; ; ). A direct role of JA in leaf senescence of A. thaliana was shown by expression-analysis of JA biosynthetic genes (). Another molecular explanation for the role of JA in leaf senescence was given by identification of a novel nuclear-localized CCCH-type zinc finger protein in rice (). This protein acts as a negative regulator of the JA pathway and leads to a delay in the onset of leaf senescence. Another negative regulator of senescence is ORE9, an F-box protein (). However, there are also JA-independent processes in leaf senescence, as shown by identification of NAC family transcription factors that have an important role in leaf senescence ().