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The anaerobic fermentation pathway is thought to play an important role under flooding conditions. The pyruvate decarboxylase 2 (pdc2) gene that encodes the first enzyme of this pathway has been cloned and characterized from rice. This gene has an open reading frame that putatively encodes a 603 amino-acid-residue protein with a molecular mass of 64 kDa. pdc2 has five introns dispersed throughout the coding region, which is also true for rice pdc1. Although the length of these introns in rice pdc2 are different from those in rice pdc1, they are located in exactly the same positions based on the deduced amino-acid sequences. The temporal and spatial expression patterns of pdc1 and pdc2 show that pdc2 is induced to a higher level during the early period (1.5–12 h) of anoxia than pdc1, which is induced more after longer time periods (24–72 h) of anoxia in both shoots and roots. The map positions of the three pdc genes have also been determined. Rice pdc1 is located on chromosome 5 between BCD454A and RZ67, pdc2 is located on chromosome 3 between RZ329 and RZ313, and pdc3 is mapped on chromosome 7 distal to RG351.

One of the major abiotic stresses that affect plant growth and development is anoxia or hypoxia. Plants respond to anoxia by regulation of gene expression at both the transcriptional and translational levels. Genes involved in such regulation are expected to be expressed soon after onset of anoxia. To date, however, anaerobically regulated genes that have been characterized predominantly encode enzymes for sugar phosphate metabolism, and are induced after several hours of anaerobic conditions. Early induced genes, those responding after 1-2 h of anoxia, have not been studied extensively. To study the early anaerobic response we investigated the most flooding-tolerant variety of rice, FR13A (flood-resistant). We used differential display techniques to identify cDNA fragments representing mRNAs that are induced within 90 min of anoxia. We isolated two cDNA fragments and one full-length cDNA that were induced to high levels. These cDNAs were found to be members of a family of 2-3 genes, which were called the aie (anaerobically inducible early) gene family. Northern blot analyses showed that the mRNA levels of aie genes peaked after 1.5 to 3 h of anoxia and were still at high levels after 72 h of anoxia. RNase protection assays showed 4-5 different protected bands indicating multiple transcripts from the aie gene family. Sequence analyses of the full-length cDNA showed an open reading frame that putatively encodes a 14 kDa protein of 127 amino acid residues. Neither the nucleotide nor the deduced amino acid sequences of this gene showed any significant homology to any known genes or proteins present in the GenBank or SwissProt databases. This novel gene, that is induced so early under anoxia in plants, may play an important role in plant metabolism under anaerobic conditions.

Trees known to produce two distinct textural forms of jackfruit, in which the fruit either remained firm when ripe or became soft and pulpy, were sampled when fruit was immature (10–11 weeks after anthesis) and when judged ripe (15–16 weeks after anthesis). The dry matter content of the edible perianth increased with maturity from 125 to 215 and 140 to 240 g kg −1 wet weight perianth in the firm and soft fruits respectively. Perianth from immature fruits had a high water-insoluble content (840–890 g kg −1 dry matter) consisting largely of cell wall material (450–530 g kg −1 dry matter) and starch (approximately 330 g kg −1 dry matter). Microscopic examination of fruit at this stage showed the perianth to contain thin-walled cells packed with starch granules, some organised into distinct clusters. In ripe fruits the starch (20–110 g kg −1 dry matter) and cell wall (170–200 g kg −1 dry matter) contents were substantially reduced, the extent of hydrolysis being greatest in the soft form. Cell maceration and starch dissolution were evident in both forms of the fruit when examined by light microscopy, but were more pronounced in the soft form. Concomitant with the decrease in water-insoluble dry matter was a substantial increase of water-soluble material (660–790 g kg −1 dry matter) which included fructose (76–113 g kg −1 dry matter) and sucrose (approximately 95 g kg −1 dry matter). Mannitol (22–68 g kg −1 dry matter) was also found in ripe but not immature fruits. Concentration of low molecular weight carbohydrate was greatest in the soft form. Polygalacturonase and pectin esterase activities were 12-fold and 40-fold higher in ripe fruits of the soft form compared to those of the firm form. This was reflected in the greater extent of tissue maceration and loss of homogalacturonan in the soft form. Since both forms of fruit demonstrated a common pattern of ripening, textural differences evidently related to the extent of change which was greatest in the soft form. The firm form of jackfruit may represent fruit in which cell wall degradation is arrested or delayed during ripening and possibly this was related to a reduced capacity to produce pectic and other cell wall degrading enzymes.

The ARP2/3 complex, a highly conserved nucleator of F-actin, and its activator, the SCAR complex, are essential for growth in plants and animals. In this article, we present a pathway through which roots of Arabidopsis thaliana directly perceive light to promote their elongation. The ARP2/3-SCAR complex and the maintenance of longitudinally aligned F-actin arrays are crucial components of this pathway. The involvement of the ARP2/3-SCAR complex in light-regulated root growth is supported by our finding that mutants of the SCAR complex subunit BRK1/HSPC300, or other individual subunits of the ARP2/3-SCAR complex, showed a dramatic inhibition of root elongation in the light, which mirrored reduced growth of wild-type roots in the dark. SCAR1 degradation in dark-grown wild-type roots by constitutive photomorphogenic 1 (COP1) E3 ligase and 26S proteasome accompanied the loss of longitudinal F-actin and reduced root growth. Light perceived by the root photoreceptors, cryptochrome and phytochrome, suppressed COP1-mediated SCAR1 degradation. Taken together, our data provide a biochemical explanation for light-induced promotion of root elongation by the ARP2/3-SCAR complex.

Transcription factors are modular in nature in all organisms. In general, they have a DNA binding domain, one or more transcription activation and/or repressor domain, and often a dimerization domain. In many cases, transcription factors also have other protein-protein interaction domain(s). Mapping these functional domains in transcription factors is critical in understanding their molecular function. In this chapter, protocols for mapping the DNA binding domain and the transcription activation domain of a bHLH class of transcription factor are described. In principle, these protocols can be applied to other classes of transcription factors for mapping their functional domains.

The phytochrome family of sensory photoreceptors interacts with phytochrome interacting factors (PIFs), repressors of photomorphogenesis, in response to environmental light signals and induces rapid phosphorylation and degradation of PIFs to promote photomorphogenesis. However, the kinase that phosphorylates PIFs is still unknown. Here we show that CK2 directly phosphorylates PIF1 at multiple sites. α1 and α2 subunits individually phosphorylated PIF1 weakly in vitro. However, each of four β subunits strongly stimulated phosphorylation of PIF1 by α1 or α2. Mapping of the phosphorylation sites identified seven Ser/Thr residues scattered throughout PIF1. Ser/Thr to Ala scanning mutations at all seven sites eliminated CK2-mediated phosphorylation of PIF1 in vitro. Moreover, the rate of degradation of the Ser/Thr to Ala mutant PIF1 was significantly reduced compared with wild-type PIF1 in transgenic plants. In addition, hypocotyl lengths of the mutant PIF1 transgenic plants were much longer than the wild-type PIF1 transgenic plants under light, suggesting that the mutant PIF1 is suppressing photomorphogenesis. Taken together, these data suggest that CK2-mediated phosphorylation enhances the light-induced degradation of PIF1 to promote photomorphogenesis.

Phytochrome Interacting Factor 1 (PIF1), a basic helix-loop-helix (bHLH) protein, functions as a negative regulator of various facets of photomorphogenesis. To indentify PIF1-interacting proteins, we performed yeast two-hybrid screening using PIF1 as a bait and identified a group of proteins including PIF1 itself, PIF3 and long hypocotyl in far-red 1 (HFR1), an atypical HLH protein. Directed yeast two-hybrid interaction assays showed that PIF1 can form heterodimers with all other PIFs as well as with HFR1. PIF1 and PIF3 interacted with each other in both in vitro and in vivo co-immunoprecipitation assays. PIF1-PIF3 heterodimer also bound to a G-box DNA sequence element in vitro. To understand the biological significance of these interactions, a pif1pif3 double mutant was obtained and characterized. Analyses of the single and double mutants showed that PIF3 plays a prominent role in repressing photomorphogenesis under continuous blue light conditions. pif1 and pif3 showed additive phenotypes more prominently under discontinuous blue light conditions. Similar to PIF1, PIF3 was also rapidly phosphorylated, poly-ubiquitylated and degraded in response to blue light. PIF3 also interacted with phytochromes in response to blue light. A PIF3 mutant defective in interaction with both phyA and phyB displayed reduced degradation under blue light, suggesting that phy-interaction was necessary for the blue light-induced degradation of PIF3. Taken together, these data suggest a combinatorial control of photomorphogenesis by bHLH proteins in response to light in Arabidopsis.

Transcription factors are modular in nature in all organisms. In general, they have a DNA binding domain, one or more transcription activation and/or repressor domain, and often a dimerization domain. In many cases, transcription factors also have other protein-protein interaction domain(s). Mapping these functional domains in transcription factors is critical in understanding their molecular function. In this chapter, protocols for mapping the DNA binding domain and the transcription activation domain of a bHLH class of transcription factor are described. In principle, these protocols can be applied to other classes of transcription factors for mapping their functional domains.

Chloroplast DNA (cpDNA) is under great photooxidative stress, yet its evolution is very conservative compared with nuclear or mitochondrial genomes. It can be expected that DNA repair mechanisms play important roles in cpDNA survival and evolution, but they are poorly understood. To gain insight into how the most severe form of DNA damage, a double-strand break (DSB), is repaired, we have developed an inducible system in Arabidopsis that employs a psbA intron endonuclease from Chlamydomonas , I-CreII, that is targeted to the chloroplast using the rbcS1 transit peptide. In Chlamydomonas , an I-CreII-induced DSB in psbA was repaired, in the absence of the intron, by homologous recombination between repeated sequences (20–60 bp) abundant in that genome; Arabidopsis cpDNA is very repeat poor, however. Phenotypically strong and weak transgenic lines were examined and shown to correlate with I-CreII expression levels. Southern blot hybridizations indicated a substantial loss of DNA at the psbA locus, but not cpDNA as a whole, in the strongly expressing line. PCR analysis identified deletions nested around the I-CreII cleavage site indicative of DSB repair using microhomology (6–12 bp perfect repeats, or 10–16 bp with mismatches) and no homology. These results provide evidence of alternative DSB repair pathways in the Arabidopsis chloroplast that resemble the nuclear, microhomology-mediated and nonhomologous end joining pathways, in terms of the homology requirement. Moreover, when taken together with the results from Chlamydomonas , the data suggest an evolutionary relationship may exist between the repeat structure of the genome and the organelle's ability to repair broken chromosomes.

Carotenoids are key for plants to optimize carbon fixing using the energy of sunlight. They contribute to light harvesting but also channel energy away from chlorophylls to protect the photosynthetic apparatus from excess light. Phytochrome-mediated light signals are major cues regulating carotenoid biosynthesis in plants, but we still lack fundamental knowledge on the components of this signaling pathway. Here we show that phytochrome-interacting factor 1 (PIF1) and other transcription factors of the phytochrome-interacting factor (PIF) family down-regulate the accumulation of carotenoids by specifically repressing the gene encoding phytoene synthase (PSY), the main rate-determining enzyme of the pathway. Both in vitro and in vivo evidence demonstrate that PIF1 directly binds to the promoter of the PSY gene, and that this binding results in repression of PSY expression. Light-triggered degradation of PIFs after interaction with photoactivated phytochromes during deetiolation results in a rapid derepression of PSY gene expression and a burst in the production of carotenoids in coordination with chlorophyll biosynthesis and chloroplast development for an optimal transition to photosynthetic metabolism. Our results also suggest a role for PIF1 and other PIFs in transducing light signals to regulate PSY gene expression and carotenoid accumulation during daily cycles of light and dark in mature plants., This work was funded by grants from the Spanish Ministerio de Ciencia e Innovación (BIO2008-00432 and CSD2007-00036) and Generalitat de Catalunya (SGR and XaRBa programs) to M.R.C. and the National Science Foundation (IOS-0822811 and IOS-0849287) to E.H. G.T.O. was funded by the “Juan de la Cierva” program of the Ministerio de Ciencia e Innovación and by an EMBO Short-Term fellowship that covered her stay at the University of Texas, Austin.

Phytochrome interacting factors (PIFs) are nuclear basic helix-loop-helix (bHLH) transcription factors that negatively regulate photomorphogenesis both in the dark and in the light in Arabidopsis. The phytochrome (phy) family of photoreceptors induces the rapid phosphorylation and degradation of PIFs in response to both red and far-red light conditions to promote photomorphogenesis. Although phys have been shown to function under blue light conditions, the roles of PIFs under blue light have not been investigated in detail. Here we show that PIF1 negatively regulates photomorphogenesis at the seedling stage under blue light conditions. pif1 seedlings displayed more open cotyledons and slightly reduced hypocotyl length compared to wild type under diurnal (12 hr light/12 hr dark) blue light conditions. Double-mutant analyses demonstrated that pif1phyA, pif1phyB, pif1cry1, and pif1cry2 have enhanced cotyledon opening compared to the single photoreceptor mutants under diurnal blue light conditions. Blue light induced the rapid phosphorylation, polyubiquitination, and degradation of PIF1 through the ubi/26S proteasomal pathway. PIF1 interacted with phyA and phyB in a blue light-dependent manner, and the interactions with phys are necessary for the blue light-induced degradation of PIF1. phyA played a dominant role under pulses of blue light, while phyA, phyB, and phyD induced the degradation of PIF1 in an additive manner under prolonged continuous blue light conditions. Interestingly, the absence of cry1 and cry2 enhanced the degradation of PIF1 under blue light conditions. Taken together, these data suggest that PIF1 functions as a negative regulator of photomorphogenesis under blue light conditions and that blue light-activated phys induce the degradation of PIF1 through the ubi/26S proteasomal pathway to promote photomorphogenesis.

[Background]: An important contributing factor to the success of terrestrial flowering plants in colonizing the land was the evolution of a developmental strategy, termed skotomorphogenesis, whereby postgerminative seedlings emerging from buried seed grow vigorously upward in the subterranean darkness toward the soil surface., [Results]: Here we provide genetic evidence that a central component of the mechanism underlying this strategy is the collective repression of premature photomorphogenic development in dark-grown seedlings by several members of the phytochrome (phy)-interacting factor (PIF) subfamily of bHLH transcription factors (PIF1, PIF3, PIF4, and PIF5). Conversely, evidence presented here and elsewhere collectively indicates that a significant component of the mechanism by which light initiates photomorphogenesis upon first exposure of dark-grown seedlings to irradiation involves reversal of this repression by rapid reduction in the abundance of these PIF proteins, through degradation induced by direct interaction of the photoactivated phy molecule with the transcription factors., [Conclusions]: We conclude that bHLH transcription factors PIF1, PIF3, PIF4, and PIF5 act as constitutive repressors of photomorphogenesis in the dark, action that is rapidly abrogated upon light exposure by phy-induced proteolytic degradation of these PIFs, allowing the initiation of photomorphogenesis to occur., This work was supported by a postdoctoral fellowship from the Spanish Ministry of Education and Science to P.L., by a “Ramon y Cajal” contract and a Spanish Ministry of Education and Science Grant BIO2006-09254 to E.M., by a Research Fellowship of the Japan Society for the Promotion of Science for Young Scientists to Y.O., by National Science Foundation Grants IBN-0418653 and IOS-0822811 to E.H., and by National Institutes of Health Grant GM-47475, Department of Energy Grant DEFG03-87ER13742, and USDA Agricultural Research Service Current Research Information System Grant 5335-21000-017-00D to P.H.Q.

To adapt to the surrounding environment, plants constantly monitor and respond to changes in the red and far-red regions of the light spectrum through the phytochrome family of photoreceptors. Extensive efforts using genetic, molecular and photobiological techniques have led to the identification of a group of basic helix–loop–helix transcription factors called the Phytochrome Interacting Factors, PIFs, which directly bind to the photoactivated phytochromes. Members of the PIF family have been shown to control light-regulated gene expression directly and indirectly. PIF1, PIF3, PIF4 and PIF5 are degraded in response to light signals, and physical interaction of PIF3 with phytochromes is necessary for the light-induced phosphorylation and degradation of PIF3. PIFs constitute an excellent model for the investigation of the biochemical mechanisms of signal transfer from photoactivated phytochromes and the light-regulation of gene expression that controls photomorphogenesis in plants.

Light signals perceived by the phytochrome (phy) family of sensory photoreceptors control multiple aspects of plant development. Recently, PIF1, a phy-interacting basic helix-loop-helix (bHLH) transcription factor, has been shown to negatively regulate facets of the photomorphogenesis of seedlings. Moreover, the transcriptional activation activity of PIF1 is reduced in a phy-dependent manner. In this study we use the luciferase (LUC) activity of the LUC-PIF1 fusion protein as an indicator of the stability of PIF1 in various light conditions. We found that the activity of LUC-PIF1 in both transient and stable transgenic lines is rapidly reduced in light, while the LUC-only control is stable under the same conditions, suggesting that PIF1 is degraded in response to light. Fluence-rate response curves indicate that PIF1 degradation is very sensitive to the quality and quantity of light. The half-life of PIF1 is about 16 min under 10 micromol m-2 sec-1 red light. PIF1 reaccumulates in the subsequent dark period after light-induced degradation, signifying that PIF1 not only functions in the dark and during the transition from etiolated to de-etiolated growth, but may also function during diurnal cycles. Inhibitors of the 26S proteasome increased the stability of PIF1, indicating that degradation of PIF1 is mediated by the ubiquitin-26S proteasome pathway. Further, de novo protein synthesis is not required for degradation of PIF1, as the presence of cycloheximide does not prevent degradation of PIF1 in the light. Taken together, these results suggest that the light signals perceived by phys induce the degradation of PIF1 and other phy-interacting factors to optimize photomorphogenesis.

The phytochrome (phy) family of sensory photoreceptors (phyA to phyE) in Arabidopsis thaliana control plant developmental transitions in response to informational light signals throughout the life cycle. The photoactivated conformer of the photoreceptor Pfr has been shown to translocate into the nucleus where it induces changes in gene expression by an unknown mechanism. Here, we have identified two basic helix-loop-helix (bHLH) transcription factors, designated PHYTOCHROME-INTERACTING FACTOR5 (PIF5) and PIF6, which interact specifically with the Pfr form of phyB. These two factors cluster tightly with PIF3 and two other phy-interacting bHLH proteins in a phylogenetic subfamily within the large Arabidopsis bHLH (AtbHLH) family. We have identified a novel sequence motif (designated the active phytochrome binding [APB] motif) that is conserved in these phy-interacting AtbHLHs but not in other noninteractors. Using the isolated domain and site-directed mutagenesis, we have shown that this motif is both necessary and sufficient for binding to phyB. Transgenic expression of the native APB-containing AtbHLH protein, PIF4, in a pif4 null mutant, rescued the photoresponse defect in this mutant, whereas mutated PIF4 constructs with site-directed substitutions in conserved APB residues did not. These data indicate that the APB motif is necessary for PIF4 function in light-regulated seedling development and suggest that conformer-specific binding of phyB to PIF4 via the APB motif is necessary for this function in vivo. Binding assays with the isolated APB domain detected interaction with phyB, but none of the other four Arabidopsis phys. Collectively, the data suggest that the APB domain provides a phyB-specific recognition module within the AtbHLH family, thereby conferring photoreceptor target specificity on a subset of these transcription factors and, thus, the potential for selective signal channeling to segments of the transcriptional network.

Photosynthetic organisms must achieve a delicate balance between the light energy absorbed by chlorophyll and their capacity to channel that energy into productive photochemical reactions. Release of excess absorbed energy in the cell can cause lethal photooxidative damage. We identified a basic helix-loop-helix (bHLH) transcription factor, designated PHYTOCHROME-INTERACTING FACTOR 1 (PIF1), that negatively regulates chlorophyll biosynthesis. pif1 mutant seedlings accumulate excess free protochlorophyllide when grown in the dark, with consequent lethal bleaching upon exposure to light. PIF1 interacts specifically with the photoactivated conformer of phytochromes A and B, suggesting a signaling pathway by which chlorophyll biosynthetic rates are tightly controlled during the critical initial emergence of seedlings from subterranean darkness into sunlight.

The phytochrome (phy) family of sensory photoreceptors (phyA to phyE in Arabidopsis) enables plants to optimize their growth and development under natural light environments. Subcellular localization studies have shown that the photoreceptor molecule is induced to translocate from cytosol to nucleus by light, but direct evidence of the functional relevance of this translocation has been lacking. Here, using a glucocorticoid receptor-based fusion protein system, we demonstrate that both photoactivation and nuclear translocation combined are necessary and sufficient for the biological function of phyB. Conversely, neither artificial nuclear translocation of non-photoactivated phyB nor artificial retention of photoactivated phyB in the cytosol provides detectable biological activity. Together these data indicate that signal transfer from photoactivated phyB to its primary signaling partner(s) is localized in the nucleus, and conversely suggest the absence of a cytosolic pathway from photoactivated phyB to light-responsive genes.

The Cre/ lox site-specific recombination controls the excision of a target DNA segment by recombination between two loxsites flanking it, mediated by the Cre recombinase. We have studied the functional expression of the Cre/ lox system to excise a transgene from the rice genome. We developed transgenic plants carrying the target gene, hygromycin phosphotransferase ( hpt) flanked by two lox sites and transgenic plants harboring the Cre gene. Each lox plant was crossed with each Cre plant reciprocally. In the Cre /lox hybrid plants, the Cre recombinase mediates recombination between two lox sites, resulting in excision of the hpt gene. The recombination event could be detected because it places the CaMV 35S promoter of the hpt gene adjacent to a promoterless gusA gene; as a result the gusA gene is activated and its expression could be visualized. In 73 Cre /lox hybrid plants from various crosses of T0 transgenic plants, 19 expressed GUS, and in 132 Cre /lox hybrid plants from crosses of T2 transgenic plants, 77 showed GUS expression. Molecular data proved the excision event occurred in all the GUS(+) plants. Recombination occurred with high efficiency at the early germinal stage, or randomly during somatic development stages.

Plants sense and respond to red and far-red light using the phytochrome (phy) family of photoreceptors. However, the mechanism of light signal transduction is not well defined. Here, we report the identification of a new mutant Arabidopsis locus, srl2 (short under red-light 2), which confers selective hypersensitivity to continuous red, but not far-red, light. This hypersensitivity is eliminated in srl2phyB, but not srl2phyA, double mutants, indicating that this locus functions selectively and negatively in phyB signaling. The SRL2 gene encodes a bHLH factor, designated PIF4 (phytochrome-interacting factor 4), which binds selectively to the biologically active Pfr form of phyB, but has little affinity for phyA. Despite its hypersensitive morphological phenotype, the srl2 mutant displays no perturbation of light-induced expression of marker genes for chloroplast development. These data suggest that PIF4 may function specifically in a branch of the phyB signaling network that regulates a subset of genes involved in cell expansion. Consistent with this proposal, PIF4 localizes to the nucleus and can bind to a G-box DNA sequence motif found in various light-regulated promoters.

Regulatable transgene systems providing easily controlled, conditional induction or repression of expression are indispensable tools in biomedical and agricultural research and biotechnology. Several such systems have been developed for eukaryotes1,2,3,4,5,6. Most of these rely on the administration of either exogenous chemicals or heat shock. Despite the general success of many of these systems, the potential for problems, such as toxic, unintended, or pleiotropic effects of the inducing chemical or treatment, can impose limitations on their use. We have developed a promoter system that can be induced, rapidly and reversibly, by short pulses of light. This system is based on the known red light–induced binding of the plant photoreceptor phytochrome to the protein PIF3 and the reversal of this binding by far-red light7,8. We show here that yeast cells expressing two chimeric proteins, a phytochrome–GAL4-DNA-binding-domain fusion and a PIF3–GAL4-activation-domain fusion, are induced by red light to express selectable or “scorable” marker genes containing promoters with a GAL4 DNA-binding site, and that this induction is rapidly abrogated by subsequent far-red light. We further show that the extent of induction can be controlled precisely by titration of the number of photons delivered to the cells by the light pulse. Thus, this system has the potential to provide rapid, noninvasive, switchable control of the expression of a desired gene to a preselected level in any suitable cell by simple exposure to a light signal.

Light signals perceived by the phytochrome family of sensory photoreceptors are transduced to photoresponsive genes by an unknown mechanism. Here, we show that the basic helix-loop-helix transcription factor PIF3 binds specifically to a G-box DNA-sequence motif present in various light-regulated gene promoters, and that phytochrome B binds reversibly to G-box–bound PIF3 specifically upon light-triggered conversion of the photoreceptor to its biologically active conformer. We suggest that the phytochromes may function as integral light-switchable components of transcriptional regulator complexes, permitting continuous and immediate sensing of changes in this environmental signal directly at target gene promoters.

The pdc1 gene encoding pyruvate decarboxylase has been isolated and sequenced from an IR54 rice genomic library. In contrast to a previously isolated intron-less rice genomic pdc, pRgpdc3, this gene contains five intervening introns in the coding region and corresponds to a cDNA clone, pRcpdc1, isolated from an IR54-cDNA library constructed from anaerobically-induced mRNAs. Comparison of the deduced amino acid sequence of this gene with that of the rice pdc2 and pdc3 showed 88% and 89% similarity, and 78% and 79% identity, respectively. Southern blots indicated that more than three genes constitute the pdc gene family in rice. pdc1 is highly inducible under anaerobic conditions. Rice pdc2 is also inducible by anoxia but to a much lesser extent than pdc1.

A report on the 10th International Congress of Plant Molecular Biology, Jeju, South Korea, October 21-26, 2012.

Phytochrome (phy) family of photoreceptors is a broad sensor of environmental light signals that promote photomorphogenic development of plants. Phytochrome Interacting Factors (PIFs), bHLH family of transcription factors, repress photomorphogenesis in the dark in an overlapping manner. Phytochromes interact with PIFs in response to light and induce rapid phosphorylation, poly-ubiquitylation and degradation of PIFs through the ubiquitin/26S proteasome pathway to promote photomorphogenesis. Structure-function analyses with PIF family members revealed that multiple domains are necessary for the light-induced phosphorylation and degradation of PIFs. CK2, a ubiquitious Ser/Thr kinase, phosphorylates PIF1 independent of light. In addition, PIF1 mutants deficient in CK2 phosphorylation sites are still robustly phosphorylated but not efficiently degraded in response to light. These data suggest that multiple kinases phosphorylate PIF1 to promote light-induced degradation and photomorphogenesis.

Considering the importance of the potentiality of leveraging big data for enhancing resilience for disaster management, this study focused on the recent technology explored by various scholars on big data -based disaster resilience which can help people in all stages of disaster management. This study reveals that disaster resilience is a combined function of the adaptive, absorptive and transformative capacity of an individual or society to withstand and cope with the adverse effects of the disaster. This study explores the potential of big data in various stages of disaster management which can ensure the resilience capacity of a social unit. This chapter also highlights the major principles of big data for effective use for disaster management like open source tools, strong infrastructure, developing local skills, context -specific data sources, data sharing with ethics, awareness about the right of data and learning from experience. It also argues that big data is a potential tool for policymakers, administrators and related stakeholders to take necessary actions during and after disasters like early warning system, weather forecasting, emergency evacuation, immediate responses, relief distribution, training need assessment and increasing trained individuals. For getting maximum benefit from big data approach for disaster resilience, this study suggests to solve the related problems such as challenges in data collection, analytics, infrastructure, gaps between human and technological capacity, ethical and political anomaly, poor coordination, privacy and accuracy. This study recommends implementing proper infrastructure, technologies, tools and expertise for ensuring proper utilization of big data for disaster resilience. This study also focuses on further research on big data approaches for enhancing disaster resilience in context -specific cases by collecting primary data which can help to extend the use of it over the world.

The adverse effect of climate change is gradually increasing all over the world and developing countries are more sufferer. The potential of big data can be an effective tool to make an appropriate adaptation strategy and enhance the resilience of the people. This study aims to explore the potential of big data for taking proper strategy against climate change effects as well as enhance people’s resilience in the face of the adverse effect of climate change. A systematic literature review has been conducted in the last ten years of existing kinds of literature. This study argues that resilience is a process of bounce back to the previous condition after facing any adverse effect. It also focuses on the integrated function of the adaptive, absorptive and transformative capacity of a social unit such as individual, community or state for facing any natural disaster. Big data technologies have the capacity to show the information regarding upcoming issues, current issues and recovery stages of the adverse effect of climate change. The findings of this study will enable policymakers and related stakeholders to take appropriate adaptation strategies for enhancing the resilience of the people of the affected areas.

Cyclisation of 3-methylcyclohex-2-enones and the derived epoxides containing alkene, alkyne, and aryl side-chains yields bicyclo[4.4.0]decane derivatives when the alkene or alkyne is electronically biased towards six-membered ring formation and when the alkene is electronically unbiased.

A series of C-2 substituted 3-methylcyclohex-2-enones has been prepared using the Hagemann ester route. A new synthesis of these compounds has been developed which involves the alkylation of the N,N-diethylaminoethyl ether of 1-hydroxy-5-methylcyclohexa-1,5-diene. The cyclohexenones have been converted into the corresponding α,β-epoxyketones using alkaline hydrogen peroxide.

It is shown that certain alk-2-enyl-2,3-epoxy-3-methylcyclohexanones can be cyclised in good yield with some Lewis acids to decalone derivatives, but use of weak Lewis acids and/or nonpolar solvents leads to ring contraction.