The molecular nature of gene expression during the initiation and progress of diplosporous apomixis is still unknown. Moreover, the basis of the close correlation between diplospory and polyploidy is not clarified yet. A comparative expression analysis was performed based on expressed sequence tags (ESTs) sequencing and differential display in an Eragrostis curvula diplosporous tetraploid genotype (T, 4x apo), a sexual diploid derivative obtained from tissue culture (D, 2x sex) and an artificial sexual tetraploid obtained from the diploid seeds after colchicine treatment (C, 4x sex). From a total of 8,884 unigenes sequenced from inflorescence-derived libraries, 112 (1.26%) showed significant differential expression in individuals with different ploidy level and/or variable reproductive mode. Independent comparisons between plants with different reproductive mode (same ploidy) or different ploidy level (same reproductive mode) allowed the identification of genes modulated in response to diplosporous development or polyploidization, respectively. Surprisingly, a group of genes (Group 3) were differentially expressed or silenced only in the 4x sex plant, presenting similar levels of expression in the 4x apo and the 2x sex genotypes. A group of randomly selected differential genes was validated by QR-PCR. Differential display analysis showed that in general the 4x apo and 4x sex expression profiles were more related and different from the 2x sex one, but confirmed the existence of Group 3-type genes, in both inflorescences and leaves. The possible biological significance for the occurrence of this particular group of genes is discussed. In silico mapping onto the rice genome was used to identify candidates mapping to the region syntenic to the diplospory locus.

Eragrostis curvula (Schrad.) Nees is a forage grass native to the semiarid regions of Southern Africa, which reproduces mainly by pseudogamous diplosporous apomixis. A collection of ESTs was generated from four cDNA libraries, three of them obtained from panicles of near-isogenic lines with different ploidy levels and reproductive modes, and one obtained from 12 days-old plant leaves. A total of 12,295 high-quality ESTs were clustered and assembled, rendering 8,864 unigenes, including 1,490 contigs and 7,394 singletons, with a genome coverage of 22%. A total of 7,029 (79.11%) unigenes were functionally categorized by BLASTX analysis against sequences deposited in public databases, but only 37.80% could be classified according to Gene Ontology. Sequence comparison against the cereals genes indexes (GI) revealed 50% significant hits. A total of 254 EST-SSRs were detected from 219 singletons and 35 from contigs. Di- and tri- motifs were similarly represented with percentages of 38.95 and 40.16%, respectively. In addition, 190 SNPs and Indels were detected in 18 contigs generated from 3 to 4 libraries. The ESTs and the molecular markers obtained in this study will provide valuable resources for a wide range of applications including gene identification, genetic mapping, cultivar identification, analysis of genetic diversity, phenotype mapping and marker assisted selection.

No abstract

showed that achenes produced in the cold climates of North America normally contain 70% or more linoleic Knowledge of the effects of temperature and geographic variables acid in oil while those produced in more southern lation the oleic acid content of sunflower (Helianthus annuus L.) oil allows us to predict the type of oil that will be produced in a particular tudes show levels as low as 30%.area. This study was designed to establish a simple empirical model,The genetic modification of sunflower oil fatty acids which uses available variables of previously established effects, to eshas also been a subject of research. Soldatov (1976) obtimate the final oleic acid composition of sunflower oil. Over two growtained a stable sunflower mutant by dimethyl sulfateing seasons, sunflower seeds were collected from Spain's main producinduced mutagenesis that gave rise to oil levels exceeding areas, and the oleic acid concentration of oil extracted from these ing 80% oleic acid. This high-oleic mutant showed no samples was analytically determined. The effects of two types of varisubstantial variation in fatty acid composition in reables (geographical position and temperature) on oil oleic acid content sponse to changes in environmental conditions (Fick, were determined according to three models based on the input vari-1984). ables: latitude, longitude, and altitude (Model I); mean minimum and Sunflower cultivars differ in the sensitivity of their maximum temperatures during the phenological stages of sunflower seed development and maturation (Model II); and a combination of oil properties to the environment. This sensitivity has both types of data (Model III). Through stepwise regression, it was es-been exploited both from a theoretical perspective, such tablished that best results were obtained using the temperature model as by enzyme inactivation induced by temperature changes (Model II) and the variables' mean minimum development and mean under natural conditions, as well as from an applied minimum and maximum maturation temperatures (r 2 ϭ 0.99, P Ͻ standpoint because it is possible to produce oil of differ-0.001, n ϭ 88). Of the three variables included in this model, the ent characteristics at different latitudes. mean minimum maturation temperature provided the closest estimate Robertson et al. (1978) showed that fatty acid compoof percentage oleic acid content. This regression model was statistically sition was highly correlated with latitude. Although they validated and is proposed as a method for crop managers to estimate found that saturated fatty acids showed scarce variation oleic acid content based on local temperatures. associated with the environment, oleic acid ranged from 14 to 50% between north and south while linoleic acid levels changed from 41 to 75% in the reverse direction.329

No abstract

Fatty acid desaturases (FADs) catalyze the introduction of a double bond into acyl chains. Two FAD groups have been identified in plants: acyl-acyl carrier proteins (ACPs) and acyl-lipid or membrane-bound FAD. The former catalyze the conversion of 18:0 to 18:1 and to date have only been identified in plants. The latter are found in eukaryotes and bacteria and are responsible for multiple desaturations. In this study, we identified 82 desaturase gene and protein sequences from 10 grass species deposited in GenBank that were analyzed using bioinformatic approaches. Subcellular localization predictions of desaturase family revealed their localization in plasma membranes, chloroplasts, endoplasmic reticula, and mitochondria. The in silico mapping showed multiple chromosomal locations in most species. Furthermore, the presence of the characteristic histidine domains, the predicted motifs, and the finding of transmembrane regions strongly support the protein functionality. The identification of putative regulatory sites in the promotor and the expression profiles revealed the wide range of pathways in which fatty acid desaturases are involved. This study is an updated survey on desaturases of grasses that provides a comprehensive insight into diversity and evolution. This characterization is a necessary first step before considering these genes as candidates for new biotechnological approaches.

Novel species of fungi described in this study include those from various countries as follows: Argentina, Colletotrichum araujiae on leaves, stems and fruits of Araujia hortorum. Australia, Agaricus pateritonsus on soil, Curvularia fraserae on dying leaf of Bothriochloa insculpta, Curvularia millisiae from yellowing leaf tips of Cyperus aromaticus, Marasmius brunneolorobustus on well-rotted wood, Nigrospora cooperae from necrotic leaf of Heteropogon contortus, Penicillium tealii from the body of a dead spider, Pseudocercospora robertsiorum from leaf spots of Senna tora, Talaromyces atkinsoniae from gills of Marasmius crinis-equi and Zasmidium pearceae from leaf spots of Smilax glyciphylla. Brazil, Preussia bezerrensis from air. Chile, Paraconiothyrium kelleni from the rhizosphere of Fragaria chiloensis subsp. chiloensis f. chiloensis. Finland, Inocybe udicola on soil in mixed forest with Betula pendula, Populus tremula, Picea abies and Alnus incana. France, Myrmecridium normannianum on dead culm of unidentified Poaceae. Germany, Vexillomyces fraxinicola from symptomless stem wood of Fraxinus excelsior. India, Diaporthe limoniae on infected fruit of Limonia acidissima, Didymella naikii on leaves of Cajanus cajan, and Fulvifomes mangroviensis on basal trunk of Aegiceras corniculatum. Indonesia, Penicillium ezekielii from Zea mays kernels. Namibia, Neocamarosporium calicoremae and Neocladosporium calicoremae on stems of Calicorema capitata, and Pleiochaeta adenolobi on symptomatic leaves of Adenolobus pechuelii. Netherlands, Chalara pteridii on stems of Pteridium aquilinum, Neomackenziella juncicola (incl. Neomackenziella gen. nov.) and Sporidesmiella junci from dead culms of Juncus effusus. Pakistan, Inocybe longistipitata on soil in a Quercus forest. Poland, Phytophthora viadrina from rhizosphere soil of Quercus robur, and Septoria krystynae on leaf spots of Viscum album. Portugal (Azores), Acrogenospora stellata on dead wood or bark. South Africa, Phyllactinia greyiae on leaves of Greyia sutherlandii and Punctelia anae on bark of Vachellia karroo. Spain, Anteaglonium lusitanicum on decaying wood of Prunus lusitanica subsp. lusitanica, Hawksworthiomyces riparius from fluvial sediments, Lophiostoma carabassense endophytic in roots of Limbarda crithmoides, and Tuber mohedanoi from calcareus soils. Spain (Canary Islands), Mycena laurisilvae on stumps and woody debris. Sweden, Elaphomyces geminus from soil under Quercus robur. Thailand, Lactifluus chiangraiensis on soil under Pinus merkusii, Lactifluus nakhonphanomensis and Xerocomus sisongkhramensis on soil under Dipterocarpus trees. Ukraine, Valsonectria robiniae on dead twigs of Robinia hispida. USA, Spiralomyces americanus (incl. Spiralomyces gen. nov.) from office air. Morphological and culture characteristics are supported by DNA barcodes.

The purpose of this research was to study the effect of vernalization on flowering time in thirty accessions of Triticum turgidum spp. durum. To this end, screening of allelic variation at VRN‐1 loci was carried out using PCR‐based markers and DNA sequencing, and gene expression analysis was performed in two and four developmental stages, with and without cold treatment. In non‐vernalized plants, average days to flowering ranged from 34 to 99 days and only one accession was observed to remain at the vegetative stage. Three accessions were found to accelerate flowering after cold treatment. At VRN‐A1 locus, three alleles previously characterized, Vrn‐A1b, Vrn‐A1c and vrn‐A1, were detected. No polymorphisms at VRN‐B1 locus were observed. The differences in vernalization response among the genotypes studied could be explained by allelic variation and VRN‐A1 transcript levels. Variability in flowering time and sensitivity to vernalization in a collection of durum wheat, both potentially useful to the development of new varieties, were observed. This information is key to directing breeding cultivars for adaptation.