Phytochrome A Antagonizes PHYTOCHROME INTERACTING FACTOR 1 to Prevent Over-Activation of Photomorphogenesis

Phytochrome A (phyA) is crucial to initiate the early steps of the transition between skoto- and photomorphogenesis upon light exposure and to complete this process under far-red light (typical of dense vegetation canopies). However, under prolonged red or white light, phyA mutants are hyper-photomorphogenic in many respects. To investigate this issue, we analyzed the late response of the transcriptome of the phyA mutant to red light. Compared to the wildtype(WT), hyper-responsive genes outnumbered the genes showing reduced response to red light in phyA. A network analysis revealed the co-expression of PHYTOCHROME INTERACTING FACTOR 1 (PIF1) with those genes showing hyperpromotion by red light in phyA. The enhanced responses of gene expression, cotyledon unfolding, hypocotyl growth, and greening observed in the phyA mutant compared to the WT were absent in the phyA pif1 double mutant compared to pif1, indicating that the hyper-photomorphogenic phenotype of phyA requires PIF1. PIF1 directly binds to gene promoters that displayed PIF1-mediated enhanced response to red light. Expression of mutant PIF1 deficient in interactions with phyA and phyB enhanced the long-term growth response to red light but reduced the expression of selected genes in response to red light. We propose that phytochrome-mediated degradation of PIF1 prevents over-activation of photomorphogenesis during early seedling development.Fil: Krzymuski, Martin Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; ArgentinaFil: Cerdan, Pablo Diego. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Zhu, Ling. University of Texas at Austin; Estados UnidosFil: Vinh, Amanda. University of Texas at Austin; Estados UnidosFil: Chory, Joanne. Salk Institute. Plant Biology Laboratory; Estados UnidosFil: Huq, Enamul. University of Texas at Austin; Estados UnidosFil: Casal, Jorge José. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura. Universidad de Buenos Aires. Facultad de Agronomía. Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura; Argentin

Flash flood susceptibility assessment and zonation by integrating analytic hierarchy process and frequency ratio model with diverse spatial data

Flash floods are the most dangerous kinds of floods because they combine the destructive power of a flood with incredible speed. They occur when heavy rainfall exceeds the ability of the ground to absorb it. The main aim of this study is to generate flash flood maps using Analytical Hierarchy Process (AHP) and Frequency Ratio (FR) models in the river’s floodplain between the Jhelum River and Chenab rivers. A total of eight flash flood-causative physical parameters are considered for this study. Six parameters are based on remote sensing images of the Advanced Land Observation Satellite (ALOS), Digital Elevation Model (DEM), and Sentinel-2 Satellite, which include slope, elevation, distance from the stream, drainage density, flow accumulation, and land use/land cover (LULC), respectively. The other two parameters are soil and geology, which consist of different rock and soil formations, respectively. In the case of AHP, each of the criteria is allotted an estimated weight according to its significant importance in the occurrence of flash floods. In the end, all the parameters were integrated using weighted overlay analysis in which the influence value of drainage density was given the highest weight. The analysis shows that a distance of 2500 m from the river has values of FR ranging from 0.54, 0.56, 1.21, 1.26, and 0.48, respectively. The output zones were categorized into very low, low, moderate, high, and very high risk, covering 7354, 5147, 3665, 2592, and 1343 km2, respectively. Finally, the results show that the very high flood areas cover 1343 km2, or 6.68% of the total area. The Mangla, Marala, and Trimmu valleys were identified as high-risk zones of the study area, which have been damaged drastically many times by flash floods. It provides policy guidelines for risk managers, emergency and disaster response services, urban and infrastructure planners, hydrologists, and climate scientists

Razvoj normaliziranog indeksa tla za urbane studije upotrebom podataka daljinskih mjerenja

This paper presents two novel spectral soil area indices to identify bare soil area and distinguish it more accurately from the urban impervious surface area (ISA). This study designs these indices based on medium spatial resolution remote sensing data from Landsat 8 OLI dataset. Extracting bare soil or urban ISA is more challenging than extracting water bodies or vegetation in multispectral Remote Sensing (RS). Bare soil and the urban ISA area often were mixed because of their spectral similarity in multispectral sensors. This study proposes Normalized Soil Area Index 1 (NSAI1) and Normalized Soil Area Index 2 (NSAI2) using typical multispectral bands. Experiments show that these two indices have an overall accuracy of around 90%. The spectral similarity index (SDI) shows these two indices have higher separability between soil area and ISA than previous indices. The result shows that percentile thresholds can effectively classify bare soil areas from the background. The combined use of both indices measured the soil area of the study area over 71 km2. Most importantly, proposed soil indices can refine urban ISA measurement accuracy in spatiotemporal studies.Ovaj rad prikazuje dva nova spektralna indeksa tla kako bi se identificiralo golo tlo te kako bi se bolje razlikovalo od urbanih nepropusnih površina (ISA). Ti indeksi su definirani na temelju srednje prostorne rezolucije daljinskih podataka Landsat 8 OLI skupa podataka. U multispektralnim daljinskim mjerenjima (RS) prepoznavanje golog tla ili urbane ISA podloge je složenije od prepoznavanja vodenih tijela ili podloge s vegetacijom. Zbog sličnosti spektara dobivenih multispektralnim senzorima golo tlo i urbana ISA površina često se ne razlučuju. Ova studija predlaže dva normalizirana indeksa tla (NSAI1 i NSAI2) korištenjem tipičnih multispektralnih pojaseva. Eksperimenti pokazuju da ta dva indeksa imaju sveukupnu točnost od približno 90%. Indeks spektralne sličnosti (SDI) pokazuje da ta dva indeksa razlikuju golo tlo od urbane ISA podloge bolje nego dosadašnji indeksi. Rezultati pokazuju da percentilni pragovi mogu efikasno razlučiti površine s golim tlom od pozadine. Kombiniranom upotrebom oba indeksa izmjerena je površina tla veća od 71 km2. Najznačajniji rezultat je taj da predloženi indeksi tla mogu poboljšati točnost mjerenja urbanih ISA u u prostorno-vremenskim studijama

KELCH F-BOX Protein Positively Influences Arabidopsis Seed Germination by Targeting PHYTOCHROME-INTERACTING FACTOR1

Seeds employ sensory systems that assess various environmental cues over time to maximize the successful transition from embryo to seedling. Here we show that the Arabidopsis F-BOX protein COLD TEMPERATURE-GERMINATING (CTG)-10, identified by activation tagging, is a positive regulator of this process. When overexpressed (OE), CTG10 hastens aspects of seed germination. CTG10 is expressed predominantly in the hypocotyl, and the protein is localized to the nucleus. CTG10 interacts with PHYTOCHROME-INTERACTING FACTOR 1 (PIF1) and helps regulate its abundance in planta. CTG10-OE accelerates the loss of PIF1 in light, increasing germination efficiency, while PIF1-OE lines fail to complete germination in darkness, which is reversed by concurrent CTG10-OE. Double-mutant (pif1 ctg10) lines demonstrated that PIF1 is epistatic to CTG10. Both CTG10 and PIF1 amounts decline during seed germination in the light but reaccumulate in the dark. PIF1 in turn down-regulates CTG10 transcription, suggesting a feedback loop of CTG10/PIF1 control. The genetic, physiological, and biochemical evidence, when taken together, leads us to propose that PIF1 and CTG10 coexist, and even accumulate, in the nucleus in darkness, but that, following illumination, CTG10 assists in reducing PIF1 amounts, thus promoting the completion of seed germination and subsequent seedling development

Assessing vulnerability for inhabitants of Dhaka City considering flood-hazard exposure

Globalna opasnost od poplave postupno se povećava. Iako ih je nemoguće izbjeći, gubici i šteta od opasnosti (npr. poplave, cikloni i potresi) mogu se učinkovito smanjiti smanjenjem ranjivosti kućanstava odgovarajućim mjerama. Cilj ove studije je kvantitativno mjerenje ranjivosti kućanstava obzirom na opasnosti od poplave kao alata za njihovo ublažavanje. Također je predložen jedinstveni pristup za kvantificiranje ugroženosti kućanstava obzirom na opasnosti od poplave, a kao primjer predstavljena je primjena u gradu Dhaki sklonom poplavama. Podaci su prikupljeni i sa siromašnih i bogatih područja kako bi bilo pokriveno cijelo urbano područje te kako bi se usporedila razina ugroženosti od poplava. Ukupno 300 kućanstava anketirano je strukturiranim upitnikom na temelju pet čimbenika (ekonomskih, socijalnih, okolišnih, strukturnih i institucionalnih) ugroženosti od poplava. Analitički hijerarhijski postupak (AHP) primijenjen je za mjerenje pojedinačnih rezultata ranjivosti kućanstva korištenjem relativne težine varijabli i pokazatelja uz pravilnu standardizaciju. Analitički rezultati pokazali su da je 63,06% siromašnih kućanstava i 20,02% bogatih kućanstava vrlo osjetljivo na poplave. Uz to, ovaj je rad utvrdio i procijenio čimbenike odgovorne za ranjivost kućanstava u Dhaki. Što se tiče strukturne ranjivosti, rezultati su pokazali da je 82% kućanstava u siromašnim krajevima bilo visoko ranjivo, a 95,3% kućanstava koja nisu iz siromašnih četvrti bilo je umjereno ranjivo. Društveno, 67,3% siromašnih i 78,7% kućanstava koja nisu iz siromašnih naselja bila su umjereno i slabo ranjiva. Većina kućanstava u siromašnoj i nesiromašnoj četvrti (84%, odnosno 59,3%) pokazala je visoku i umjerenu ekonomsku ranjivost. Štoviše, za 69,3% siromašnih i 65,3% nesiromašnih kućanstava institucionalna ranjivost je bila visoka. Od stanovnika siromašnih naselja, 63,3% je bilo izloženo ekološkom riziku, a 78% staništa koja nisu u siromašnim područjima bilo je u kategoriji niske ranjivosti. Uz odgovarajuću prilagodbu ovdje predložen učinkoviti alat za mjerenje ranjivosti koji je ovdje prilagođen specifičnoj lokaciji, primjenjiv je i za mjerenje ranjivosti drugih gradova u svijetu. Na temelju ove studije moglo bi se provesti buduće istraživanje s više čimbenika, varijabli i pokazatelja ljudske ranjivosti na prirodne ili umjetne opasnosti / katastrofe. Budući rad mogao bi pružiti bolju sliku stanja ranjivosti od pojedinačne / višestruke opasnosti / katastrofe.Global flood hazard is gradually increasing. Though it is impossible to avoid them, losses and damage of hazards (e.g., floods, cyclones, and earthquakes) could be efficiently reduced by reducing household vulnerability with appropriate measures. This study aims to quantitatively measure the household vulnerability of flood hazards as a mitigation tool. It also proposed a unique approach to quantify flood-hazard household vulnerability, and shows its application in the flood prone city of Dhaka as an example case. Data were collected from both slum and non-slum areas to cover the entire urban habitat, and to compare their level of flood vulnerability. A total of 300 households were surveyed by structured questionnaire on the basis of five factors (economic, social, environmental, structural, and institutional) of flood vulnerability. The analytical hierarchy process (AHP) was applied to measure individual household vulnerability scores by using the relative weightage of variables and indicators with proper standardisation. Analytical results demonstrated that 63.06% slum and 20.02% non-slum households were highly vulnerable to floods. In addition, this paper determined and assessed responsible factors for household flood vulnerability in Dhaka. For structural vulnerability, results exhibited that 82% of slum households were highly vulnerable, and 95.3% of non-slum households were moderately vulnerable. Socially, 67.3% of slum and 78.7% of non-slum households were moderately and low-vulnerable. The majority of slum and non-slum households (84% and 59.3%, respectively) showed high and moderate vulnerability with respect to economic vulnerability. Moreover, 69.3% of slum and 65.3% of nonslum household institutional vulnerability levels were high. Of slum inhabitants, 63.3% were environmentally at high risk, and 78% of non-slum habitats were in the low-vulnerability category. However, as an effective tool to measure location-specific vulnerability, it is applicable for the measuring vulnerability of other cities in the world with proper customisation. On the basis of this study, future research could be conducted with more factors, variables, and indicators of human vulnerability to natural or artificial hazards/disasters. Future work may provide a better reflection of the vulnerability status of single/multiple hazard(s)/disaster(s)

Genes induced under anaerobic conditions in rice

Anaerobiosis is one of the major stresses that affect plant growth and development. A lack of oxygen becomes a serious problem when plants are submerged for periods of one to two weeks. Plants respond to anoxia by regulation of gene expression at both the transcriptional and translational levels. The research presented in this dissertation involved isolation and characterization of two types of genes that are induced under anaerobic conditions. The first was a gene family that encodes the pyruvate decarboxylase (PDC) enzymes in rice. PDC is the first enzyme in the alcoholic fermentation pathway which is thought to play an important role in plant survival when plants are flooded. I isolated two pdc genes and their cDNAs, and investigated their temporal and spatial expression patterns under anaerobic conditions. The two genes were found to be regulated differently in shoots and roots of rice at different time periods of anoxia. These genes are now being used to modify their levels of expression in rice in order to assess whether a correlation exists between expression levels and flooding tolerance. The second class of genes investigated includes the anaerobically induced early, or aie, genes those responding after 1-2 hours of anoxia. These genes have not been studied extensively in plants. I used differential display techniques to identify cDNA fragments which were induced within 90 minutes of anoxia. I isolated two partial cDNA fragments that were induced to high levels. These two partial cDNAs have 96% sequence homology and are members of a multigene family. Southern blots of genomic DNA and RNase protection assays showed that there were at least 2 to 3 different members present in the rice genome. Each member of this family was induced at different levels after different time periods of anaerobic conditions. The anaerobic induction of both pdc and aie genes is down-regulated by translational inhibitors indicating that these genes require new protein synthesis for their induction. Sequencing of a full-length aie cDNA showed that this gene putatively encodes a 14 kD protein with 127 amino acid residues. The DNA and deduced amino acid sequence of this gene did not show any significant homology to any known genes or proteins present in the GenBank or SwissProt databases. This is the first report of a gene that is induced early under anoxia in rice. Both pdc and aie gene families may play important roles in plant metabolism under anaerobic conditions

A protein-based genetic screening uncovers mutants involved in phytochrome signaling in Arabidopsis

Plants perceive red and far-red region of the light spectrum to regulate photomorphogenesis through a family of photoreceptors called phytochromes. Phytochromes transduce the light signals to trigger a cascade of downstream gene regulation in part via a subfamily of bHLH transcription factors called Phytochrome Interacting Factors (PIFs). As the repressors of light signaling pathways, most PIFs are phosphorylated and degraded through the ubiquitin/26S proteasome pathway in response to light. The mechanisms involved in the phosphorylation and degradation of PIFs have not been fully understood yet. Here we used an EMS mutagenesis and luminescent imaging system to identify mutants defective in the degradation of one of the PIFs, called PIF1. We identified five mutants named stable PIF (spf) that showed reduced degradation of PIF1 under light treatment in both luminescent imaging and immunoblot assays. The amounts of PIF1 in spf3, spf4 and spf5 were similar to a PIF1 missense mutant (PIF1-3M) that lacks interactions between PIF1 and phyA/phyB under light. The hypocotyl lengths of spf1 and spf2 were slightly longer under red light compared to the LUC-PIF1 control, while only spf1 displayed weak phenotype under far-red light conditions. Interestingly, the spf3, spf4 and spf5 displayed high abundance of PIF1, yet the hypocotyl lengths were similar to the wild type under these conditions. Cloning and characterization of these mutants will help identify key players in the light signaling pathways including, the light-regulated kinase(s) and the E3 ligase(s) necessary for the light-induced degradation of PIFs

Spatial regulation of thermomorphogenesis by HY5 and PIF4 in Arabidopsis

Plants undergo morphological changes collectively termed thermomorphogenesis when exposed to elevated temperature. Here the authors show that the SPA1 kinase regulates distinct thermomorphogenic responses according to tissue type by interactions with PIF4 and HY5 in shoots and roots, respectively