33 research outputs found
Prospeccions arqueològiques a la cinglera del Castell de Cabrera (Cabrera d'Igualada, Anoia): Estudi de les evidències gràfiques
The 2-C-methylerythritol 4-phosphate pathway in melon is regulated by specialized isoforms for the first and last steps
The 2-C-methyl-d-erythritol-4-phosphate (MEP) pathway provides the precursors for the biosynthesis of plastidial isoprenoids, which include the carotenoid pigments of many fruits. We have analysed the genes encoding the seven enzymes of the MEP pathway in melon (Cucumis melo L.) and determined that the first one, 1-deoxyxylulose 5-phosphate synthase (DXS), and the last one, 1-hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate reductase (HDR), are represented in the genome as a small gene family and paralogous pair, respectively. In the case of DXS, three genes encode functional DXS activities which fall into previously established type I (CmDXS1) and II (CmDXS2a and CmDXS2b) categories, while a fourth DXS-like gene belonging to the type III group did not encode a protein with DXS activity. Their expression patterns and phylogenies suggest that CmDXS1 is functionally specialized for developmental and photosynthetic processes, while CmDXS2a and CmDXS2b are induced in flowers and ripening fruit of orange- (but not white-) fleshed varieties, coinciding with β-carotene accumulation. This is the first instance connecting type II DXS genes to specialized isoprenoid biosynthesis in the fruit of an agronomically important species. Two HDR paralogues were shown to encode functional enzymes, although only CmHDR1 was highly expressed in the tissues and developmental stages tested. Phylogenetic analysis showed that in cucurbits such as melon, these HDR paralogues probably arose through individual gene duplications in a common angiosperm ancestor, mimicking a prior division in gymnosperms, while other flowering plants, including apple, soy, canola, and poplar, acquired HDR duplicates recently as homoeologues through large-scale genome duplications. We report the influence of gene duplication history on the regulation of the MEP pathway in melon and the role of specialized MEP-pathway isoforms in providing precursors for β-carotene production in orange-fleshed melon varieties
A MEM1-like motif directs mesophyll cell-specific expression of the gene encoding the C4 carbonic anhydrase in Flaveria
The first two reactions of C4 photosynthesis are catalysed by carbonic anhydrase (CA) and phosphoenolpyruvate carboxylase (PEPC) in the leaf mesophyll (M) cell cytosol. Translatome experiments using a tagged ribosomal protein expressed under the control of M and bundle-sheath (BS) cell-specific promoters showed transcripts encoding CA3 from the C4 species Flaveria bidentis were highly enriched in polysomes from M cells relative to those of the BS. Localisation experiments employing a CA3-green fluorescent protein fusion protein showed F. bidentis CA3 is a cytosolic enzyme. A motif showing high sequence homology to that of the Flaveria M expression module 1 (MEM1) element was identified approximately 2 kb upstream of the F. bidentis and F. trinervia ca3 translation start sites. MEM1 is located in the promoter of C4Flaveria ppcA genes, which encode the C4-associated PEPC, and is necessary for M-specific expression. No MEM1-like sequence was found in the 4 kb upstream of the C3 species F. pringlei ca3 translation start site. Promoter–reporter fusion experiments demonstrated the region containing the ca3 MEM1-like element also directs M-specific expression. These results support the idea that a common regulatory switch drives the expression of the C4Flaveria ca3 and ppcA1 genes specifically in M cells.Funding from the Australian Research Council to ML (award number
DP150101037) and the Deutsche Forschungsgemeinschaft through the
Excellence Cluster EXC 1028 (From Complex Traits Towards Synthetic
Modules) to PW is gratefully acknowledged. We also thank the Australian
Research Council Centre of Excellence for Translational Photosynthesis, and
Oliver Berkowitz for supplying the pMDC83 vector
Analysis of the melon (Cucumis melo) small RNAome by high-throughput pyrosequencing
Abstract Background Melon (Cucumis melo L.) is a commercially important fruit crop that is cultivated worldwide. The melon research community has recently benefited from the determination of a complete draft genome sequence and the development of associated genomic tools, which have allowed us to focus on small RNAs (sRNAs). These are short, non-coding RNAs 21-24 nucleotides in length with diverse physiological roles. In plants, they regulate gene expression and heterochromatin assembly, and control protection against virus infection. Much remains to be learned about the role of sRNAs in melon. Results We constructed 10 sRNA libraries from two stages of developing ovaries, fruits and photosynthetic cotyledons infected with viruses, and carried out high-throughput pyrosequencing. We catalogued and analysed the melon sRNAs, resulting in the identification of 26 known miRNA families (many conserved with other species), the prediction of 84 melon-specific miRNA candidates, the identification of trans-acting siRNAs, and the identification of chloroplast, mitochondrion and transposon-derived sRNAs. In silico analysis revealed more than 400 potential targets for the conserved and novel miRNAs. Conclusion We have discovered and analysed a large number of conserved and melon-specific sRNAs, including miRNAs and their potential target genes. This provides insight into the composition and function of the melon small RNAome, and paves the way towards an understanding of sRNA-mediated processes that regulate melon fruit development and melon-virus interactions.This work was supported by grants AGL2009-07552/AGR, BIO2006-13107 (Ministerio de Ciencia e Innovación, Spain) and MELONOMICS (Fundación Genoma España, Spain).Peer Reviewe
Age and date for early arrival of the Acheulian in Europe (Barranc de la Boella, la Canonja, Spain)
The first arrivals of hominin populations into Eurasia during the Early Pleistocene are currently considered to have occurred
as short and poorly dated biological dispersions. Questions as to the tempo and mode of these early prehistoric settlements
have given rise to debates concerning the taxonomic significance of the lithic assemblages, as trace fossils, and the
geographical distribution of the technological traditions found in the Lower Palaeolithic record. Here, we report on the
Barranc de la Boella site which has yielded a lithic assemblage dating to ,1 million years ago that includes large cutting
tools (LCT). We argue that distinct technological traditions coexisted in the Iberian archaeological repertoires of the late
Early Pleistocene age in a similar way to the earliest sub-Saharan African artefact assemblages. These differences between
stone tool assemblages may be attributed to the different chronologies of hominin dispersal events. The archaeological
record of Barranc de la Boella completes the geographical distribution of LCT assemblages across southern Eurasia during
the EMPT (Early-Middle Pleistocene Transition, circa 942 to 641 kyr). Up to now, chronology of the earliest European LCT
assemblages is based on the abundant Palaeolithic record found in terrace river sequences which have been dated to the
end of the EMPT and later. However, the findings at Barranc de la Boella suggest that early LCT lithic assemblages appeared
in the SW of Europe during earlier hominin dispersal episodes before the definitive colonization of temperate Eurasia took
place.The research at Barranc de la Boella has been carried out with the financial support of the Spanish Ministerio de Economı´a y Competitividad (CGL2012-
36682; CGL2012-38358, CGL2012-38434-C03-03 and CGL2010-15326; MICINN project HAR2009-7223/HIST), Generalitat de Catalunya, AGAUR agence (projects
2014SGR-901; 2014SGR-899; 2009SGR-324, 2009PBR-0033 and 2009SGR-188) and Junta de Castilla y Leo´n BU1004A09. Financial support for Barranc de la Boella
field work and archaeological excavations is provided by the Ajuntament de la Canonja and Departament de Cultura (Servei d’Arqueologia i Paleontologia) de la
Generalitat de Catalunya. A. Carrancho’s research was funded by the International Excellence Programme, Reinforcement subprogramme of the Spanish Ministry
of Education. I. Lozano-Ferna´ndez acknowledges the pre-doctoral grant from the Fundacio´n Atapuerca. The funders had no role in study design, data collection
and analysis, decision to publish, or preparation of the manuscript
The 2-C-methylerythritol 4-phosphate pathway in melon is regulated by specialized isoforms for the first and last steps
The 2-C-methyl-d-erythritol-4-phosphate (MEP) pathway provides the precursors for the biosynthesis of plastidial isoprenoids, which include the carotenoid pigments of many fruits. We have analysed the genes encoding the seven enzymes of the MEP pathway in melon (Cucumis melo L.) and determined that the first one, 1-deoxyxylulose 5-phosphate synthase (DXS), and the last one, 1-hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate reductase (HDR), are represented in the genome as a small gene family and paralogous pair, respectively. In the case of DXS, three genes encode functional DXS activities which fall into previously established type I (CmDXS1) and II (CmDXS2a and CmDXS2b) categories, while a fourth DXS-like gene belonging to the type III group did not encode a protein with DXS activity. Their expression patterns and phylogenies suggest that CmDXS1 is functionally specialized for developmental and photosynthetic processes, while CmDXS2a and CmDXS2b are induced in flowers and ripening fruit of orange- (but not white-) fleshed varieties, coinciding with β-carotene accumulation. This is the first instance connecting type II DXS genes to specialized isoprenoid biosynthesis in the fruit of an agronomically important species. Two HDR paralogues were shown to encode functional enzymes, although only CmHDR1 was highly expressed in the tissues and developmental stages tested. Phylogenetic analysis showed that in cucurbits such as melon, these HDR paralogues probably arose through individual gene duplications in a common angiosperm ancestor, mimicking a prior division in gymnosperms, while other flowering plants, including apple, soy, canola, and poplar, acquired HDR duplicates recently as homoeologues through large-scale genome duplications. We report the influence of gene duplication history on the regulation of the MEP pathway in melon and the role of specialized MEP-pathway isoforms in providing precursors for β-carotene production in orange-fleshed melon varieties
Effect of cold storage and 1-MCP treatment on ethylene perception, signalling and synthesis: Influence on the development of the evergreen behaviour in ‘Conference’ pears
To further understand the response of ‘Conference’ pears to 1-methylcyclopropene (1-MCP) treatment and their ability to restore ripening after prolonged periods of cold storage, fruit were treated with 0, 300 nL L−1 1-MCP or 300 nL L−1 exogenous ethylene plus 600 nL L−1 1-MCP prior to storage. Changes in ethylene, ethylene precursors (ACC, MACC), ethylene-related enzyme activities (ACS, ACO) together with their transcript levels, and the expression of four ethylene receptors and one Raf kinase protein from the ethylene signalling pathway, were monitored before and after cold storage and during subsequent ripening at 20 °C. 1-MCP treatment acted on the ethylene pathway in two differentiated phases. In a first initiation occurring during cold storage, the 1-MCP treatment limited the up-regulation of both PcACS1 and PcACO1 observed in control fruit and promoted an up-regulation of PcETR1 leading to a complete inhibition of ACO activity during cold storage. These regulations resulted in fruit unable to produce ethylene upon removal and promoted the second phase (maintenance phase). This second phase was characterized by a down-regulation of PcACS1 and PcACS4 as well as PcACO1 together with a clear up-regulation of PcETR5 and better maintenance of PcCTR1 transcript levels, which were partially reversed with exogenous ethylene treatment. All these different regulations led in turn to a complete inhibition of the ripening processes, which may partially explain the occurrence of the evergreen behaviour in ‘Conference’ pear during shelf-life.MA Chiriboga was supported financially through a doctoral scholarship from the University of Lleida. The authors gratefully acknowledge the support from AgroFresh Inc. for supplying Smartfresh™ product and Dr. D Micheletti from the Centre for Research in Agricultural Genomics CSIC-IRTA-UAB-UB for technical assistance.Peer reviewe
The Evolutionary Origin of C4 photosynthesis in the Grass Subtribe Neurachninae
The Australian grass subtribe Neurachninae contains closely related species that use C3, C4, and C2 photosynthesis. To gain insight into the evolution of C4 photosynthesis in grasses, we examined leaf gas exchange, anatomy and ultrastructure, and tissue localization of Gly decarboxylase subunit P (GLDP) in nine Neurachninae species. We identified previously unrecognized variation in leaf structure and physiology within Neurachne that represents varying degrees of C3–C4 intermediacy in the Neurachninae. These include inverse correlations between the apparent photosynthetic carbon dioxide (CO2) compensation point in the absence of day respiration (C*) and chloroplast and mitochondrial investment in the mestome sheath (MS), where CO2 is concentrated in C2 and C4 Neurachne species; width of the MS cells; frequency of plasmodesmata in the MS cell walls adjoining the parenchymatous bundle sheath; and the proportion of leaf GLDP invested in the MS tissue. Less than 12% of the leaf GLDP was allocated to the MS of completely C3 Neurachninae species with C* values of 56–61 μmol mol−1, whereas two-thirds of leaf GLDP was in the MS of Neurachne lanigera, which exhibits a newly-identified, partial C2 phenotype with C* of 44 μmol mol−1. Increased investment of GLDP in MS tissue of the C2 species was attributed to more MS mitochondria and less GLDP in mesophyll mitochondria. These results are consistent with a model where C4 evolution in Neurachninae initially occurred via an increase in organelle and GLDP content in MS cells, which generated a sink for photorespired CO2 in MS tissues
Intergroup cannibalism in the European Early Pleistocene: The range expansion and imbalance of power hypotheses
In this paper, we compare cannibalism in chimpanzees, modern humans, and in archaeological cases
with cannibalism inferred from evidence from the Early Pleistocene assemblage of level TD6 of Gran
Dolina (Sierra de Atapuerca, Spain). The cannibalism documented in level TD6 mainly involves the
consumption of infants and other immature individuals. The human induced modifications on Homo
antecessor and deer remains suggest that butchering processes were similar for both taxa, and the
remains were discarded on the living floor in the same way. This finding implies that a group of hominins
that used the Gran Dolina cave periodically hunted and consumed individuals from another group.
However, the age distribution of the cannibalized hominins in the TD6 assemblage is not consistent with
that from other cases of exo-cannibalism by human/hominin groups. Instead, it is similar to the age
profiles seen in cannibalism associated with intergroup aggression in chimpanzees. For this reason, we
use an analogy with chimpanzees to propose that the TD6 hominins mounted low-risk attacks on
members of other groups to defend access to resources within their own territories and to try and
expand their territories at the expense of neighboring groups