UBC18 mediates ERF1 degradation under light-dark cycles.

Ethylene Response Factor 1 (ERF1) plays a crucial role in biotic and abiotic stress responses. Previous studies have shown that ERF1 regulates stress-responsive gene expression by binding to different cis-acting elements in response to various stress signals. ERF1 was also reported to be unstable in the dark, and it regulates hypocotyl elongation.

ORA47 (octadecanoid-responsive AP2/ERF-domain transcription factor 47) regulates jasmonic acid and abscisic acid biosynthesis and signaling through binding to a novel cis-element.

ORA47 (octadecanoid-responsive AP2/ERF-domain transcription factor 47) of Arabidopsis thaliana is an AP2/ERF domain transcription factor that regulates jasmonate (JA) biosynthesis and is induced by methyl JA treatment. The regulatory mechanism of ORA47 remains unclear. ORA47 is shown to bind to the cis-element (NC/GT)CGNCCA, which is referred to as the O-box, in the promoter of ABI2.

Increased glutathione contributes to stress tolerance and global translational changes in Arabidopsis.

Although glutathione is well known for its reactive oxygen species (ROS) scavenging function and plays a protective role in biotic stress, its regulatory function in abiotic stress still remains to be elucidated. Our previous study showed that exogenously applied reduced glutathione (GSH) could improve abiotic stress tolerance in Arabidopsis. Here, we report that endogenously increased GSH also conferred tolerance to drought and salt stress in Arabidopsis.

The Arabidopsis ETHYLENE RESPONSE FACTOR1 regulates abiotic stress-responsive gene expression by binding to different cis-acting elements in response to different stress signals.

ETHYLENE RESPONSE FACTOR1 (ERF1) is an upstream component in both jasmonate (JA) and ethylene (ET) signaling and is involved in pathogen resistance. Accumulating evidence suggests that ERF1 might be related to the salt stress response through ethylene signaling. However, the specific role of ERF1 in abiotic stress and the molecular mechanism underlying the signaling cross talk still need to be elucidated.

Functional characterization of an abiotic stress-inducible transcription factor AtERF53 in Arabidopsis thaliana.

AP2/ERF proteins play crucial roles in plant growth and development and in responses to biotic and abiotic stresses. ETHYLENE RESPONSE FACTOR 53 (AtERF53) belongs to group 1 in the ERF family and is induced in the early hours of dehydration and salt treatment. The functional study of AtERF53 is hampered because its protein expression in Arabidopsis is vulnerable to degradation in overexpressed transgenic lines.

Arabidopsis RGLG2, functioning as a RING E3 ligase, interacts with AtERF53 and negatively regulates the plant drought stress response.

Transcriptional activities of plants play important roles in responses to environmental stresses. ETHYLENE RESPONSE FACTOR53 (AtERF53) is a drought-induced transcription factor that belongs to the AP2/ERF superfamily and has a highly conserved AP2 domain. It can regulate drought-responsive gene expression by binding to the GCC box and/or the dehydration-responsive element in the promoter of downstream genes.

Drought and salt stress tolerance of an Arabidopsis glutathione S-transferase U17 knockout mutant are attributed to the combined effect of glutathione and abscisic acid.

Although glutathione S-transferases (GSTs) are thought to play major roles in oxidative stress metabolism, little is known about the regulatory functions of GSTs. We have reported that Arabidopsis (Arabidopsis thaliana) GLUTATHIONE S-TRANSFERASE U17 (AtGSTU17; At1g10370) participates in light signaling and might modulate various aspects of development by affecting glutathione (GSH) pools via a coordinated regulation with phytochrome A. Here, we provide further evidence to support a negative role of AtGSTU17 in drought and salt stress tolerance.

Structural and functional assays of AtTLP18.3 identify its novel acid phosphatase activity in thylakoid lumen.

The membrane protein AtTLP18.3 of Arabidopsis (Arabidopsis thaliana) contains a domain of unknown function, DUF477; it forms a polysome with photosynthetic apparatuses in the thylakoid lumen. To explore the molecular function of AtTLP18.

Historical spatial range expansion and a very recent bottleneck of Cinnamomum kanehirae Hay. (Lauraceae) in Taiwan inferred from nuclear genes.

Background: Species in the varied geographic topology of Taiwan underwent obvious demographic changes during glacial periods. Cinnamomum kanehirae has been exploited for timber and to obtain medicinal fungi for the past 100 years. Understanding anthropogenic factors influencing the demography of this species after the last glacial maximum (LGM) is critically important for the conservation of this species.

Duplication of the class I cytosolic small heat shock protein gene and potential functional divergence revealed by sequence variations flanking the {alpha}-crystallin domain in the genus Rhododendron (Ericaceae).

Background And Aims: Positive selection in the -crystallin domain (ACD) of the chloroplast small heat shock protein (CPsHSP) gene was found in a previous study and was suggested to be related to the ecological adaptation of Rhododendron species in the subgenus Hymenanthes. Consequently, it was of interest to examine whether gene duplication and subsequent divergence have occurred in other sHSP genes, for example class I cytosolic sHSP genes (CT1sHSPs) in Rhododendron in Taiwan, where many endemic species have evolved as a result of habitat differentiation.

Methods: A phylogeny of CT1sHSP amino acid sequences was built from Rhododendron, Arabidopsis thaliana, Oryza sativa, Populus trichocarpa, Vitis vinifera and other species for elucidation of the phylogenetic relationships among CT1sHSPs.

Molecular population genetics and gene expression analysis of duplicated CBF genes of Arabidopsis thaliana.

Background: CBF/DREB duplicate genes are widely distributed in higher plants and encode transcriptional factors, or CBFs, which bind a DNA regulatory element and impart responsiveness to low temperatures and dehydration.

Results: We explored patterns of genetic variations of CBF1, -2, and -3 from 34 accessions of Arabidopsis thaliana. Molecular population genetic analyses of these genes indicated that CBF2 has much reduced nucleotide diversity in the transcriptional unit and promoter, suggesting that CBF2 has been subjected to a recent adaptive sweep, which agrees with reports of a regulatory protein of CBF2.

Molecular evolution of the Pi-ta gene resistant to rice blast in wild rice (Oryza rufipogon).

Rice blast disease resistance to the fungal pathogen Magnaporthe grisea is triggered by a physical interaction between the protein products of the host R (resistance) gene, Pi-ta, and the pathogen Avr (avirulence) gene, AVR-pita. The genotype variation and resistant/susceptible phenotype at the Pi-ta locus of wild rice (Oryza rufipogon), the ancestor of cultivated rice (O. sativa), was surveyed in 36 locations worldwide to study the molecular evolution and functional adaptation of the Pi-ta gene.

Constitutive components and induced gene expression are involved in the desiccation tolerance of Selaginella tamariscina.

Selaginella tamariscina, one of the most primitive vascular plants, can remain alive in a desiccated state and resurrect when water becomes available. To evaluate the nature of desiccation tolerance in this plant, we compared the composition of soluble sugars and saturation ratios of phospholipids (PLs) between hydrated and desiccated tissues of S. tamariscina using gas chromatography.

Divergent evolution of the chloroplast small heat shock protein gene in the genera Rhododendron (Ericaceae) and Machilus (Lauraceae).

Background And Aims: Evolutionary and ecological roles of the chloroplast small heat shock protein (CPsHSP) have been emphasized based on variations in protein contents; however, DNA sequence variations related to the evolutionary and ecological roles of this gene have not been investigated. In the present study, a basal angiosperm, Machilus, together with the eudicot Rhododendron were used to illustrate the evolutionary dynamics of gene divergence in CPsHSPs.

Methods: Degenerate primers were used to amplify CPsHSP-related sequences from 16 Rhododendron and eight Machilus species that occur in Taiwan.

Uniform genetic diversity, low differentiation, and neutral evolution characterize contemporary refuge populations of Taiwan fir (Abies kawakamii, Pinaceae).

Based on fossil pollen, the distribution range of Taiwan fir [Abies kawakamii (Hay.) Ito] (Pinaceae) is smaller than it was 50 000 years ago. To characterize the present refuge populations of A.

Phylogeographic study reveals the origin and evolutionary history of a Rhododendron species complex in Taiwan.

This study infers a single origin and a once-widespread distribution of the Rhododendron pseudochrysanthum species complex in Taiwan based on chloroplast DNA (cpDNA) variation. In total, 124 individuals from five endemic Rhododendron species were used for amplifications of two chloroplast intergenic spacers: trnL-trnF and atpB-rbcL. The haplotype and nucleotide diversities were much lower for the R.

Allozyme variation of populations of Castanopsis carlesii (Fagaceae) revealing the diversity centres and areas of the greatest divergence in Taiwan.

Background And Aims: The genetic variation and divergence estimated by allozyme analysis were used to reveal the evolutionary history of Castanopsis carlesii in Taiwan. Two major questions were discussed concerning evolutionary issues: where are the diversity centres, and where are the most genetically divergent sites in Taiwan?

Methods: Twenty-two populations of C. carlesii were sampled throughout Taiwan.

Source populations of Quercus glauca in the last glacial age in Taiwan revealed by nuclear microsatellite markers.

In this work, we attempted to study genetic differentiation between populations of Quercus glauca in Taiwan using nuclear microsatellite markers to infer the potential refugium in the last glaciation stage. Four microsatellite loci for 20 individuals each in 10 populations of Taiwan were analyzed. We found that Q.

Potential refugia in Taiwan revealed by the phylogeographical study of Castanopsis carlesii Hayata (Fagaceae).

In this study, we examined spatial patterns of chloroplast DNA (cpDNA) variation in a total of 30 populations of Castanopsis carlesii Hayata (Fagaceae), a subtropical and temperate tree species, including 201 individuals sampled throughout Taiwan. By sequencing two cpDNA fragments using universal primers (the trnL intron and the trnV-trnM intergenic spacer), we found a total of 1663 bp and 21 polymorphic sites. These gave rise to a total of 28 cpDNA haplotypes.

Postglacial population growth of Cunninghamia konishii (Cupressaceae) inferred from phylogeographical and mismatch analysis of chloroplast DNA variation.

Phylogeographical and mismatch analysis of chloroplast DNA (cpDNA) variation were used to infer the temporal dynamics of distributional and demographic history of Taiwan fir (Cunninghamia konishii). We examined 64 and 52 trees from 17 populations of C. konishii and 14 provenances of C.

Spatial pattern of chloroplast DNA variation of Cyclobalanopsis glauca in Taiwan and East Asia.

This study examined the spatial pattern of chloroplast DNA (cpDNA) variation in Cyclobalanopsis glauca (Thunb. ex Murray) Oerst. (Fagaceae) in 140 trees from Taiwan (25 populations), Japan (three), Ryukyus (two), Hong Kong (one) and Mainland China (one).