Seasonal patterns in butterfly abundance and species diversity in five characteristic habitats in Sites of Community Importance in Sicily (Italy)

Sicily (Italy) is one of the richest European regions in animal biodiversity. Butterflies offer good opportunities for studies on biodiversity , population and community ecology. Many species are strictly seasonal, preferring only a particular set of habitats. Five typical Mediterranean habitats: olive grove (conducted following organic farm management), mixed wood, ampelodesmos prairie (with dominance of Ampelodesmos mauritanicus), Mediterranean shrub and shrub at the coastal areas, were monitored for diversity and seasonal patterns in butterfly communities for 2 years. All habitats were inside protected areas indicated as Sites of Community Importance. Butterfly species richness was highest in ampelodesmos prairie and in olive grove. Pieris brassicae, Lasiommata megera, Maniola jurtina, Pararge aegeria have been reported in all habitats, although with different abundance whilst other species were observed only in one particular habitat. Melanargia pherusa, endemic species, and Hipparchia statil-inus, listed in the IUCN Red List, respectively as " Least Concern " and " Near Threatened " , were observed in the ampelodesmos prairie. The morphotype Coenonympha pamphilus f. lyllus was reported in olive grove and ampelodesmos prairie. The majority of species showed abundance peaks in June and July, however many species showed a longer flight period than reported in literature with detection of specimens until November or December. The analysis of the similarity of communities among habitats shows a similarity between ampelodesmos prairie and olive grove and between Mediterranean shrub and Mediterranean shrub at the coastal areas, while the butterfly community in mixed wood is substantially different. The results of several diversity indexes suggest that ampelodesmos prairie has an important ecological role, as it supports butterfly abundance and species diversity

Transcriptome analysis of Phoenix canariensis Chabaud in response to Rhynchophorus ferrugineus Olivier attacks

Red Palm Weevil (RPW, Rhynchophorus ferrugineus Olivier) threatens most palm species worldwide. Until now, no studies have analyzed the gene regulatory networks of Phoenix canariensis (Chabaud) in response to RPW attacks. The aim of this study was to fill this knowledge gap. Providing this basic knowledge is very important to improve its management.Results: A deep transcriptome analysis was performed on fully expanded leaves of healthy non-infested trees and attacked trees at two symptom stages (middle and late infestation). A total of 54 genes were significantly regulated during middle stage. Pathway enrichment analysis showed that phenylpropanoid-related pathways were induced at this stage. More than 3300 genes were affected during late stage of attacks. Higher transcript abundances were observed for lipid fatty acid metabolism (fatty acid and glycerolipids), tryptophan metabolism, phenylpropanoid metabolism. Key RPW-modulated genes involved in innate response mediated by hormone crosstalk were observed belonging to auxin, jasmonate and salicylic acid (SA) pathways. Among transcription factors, some WRKYs were clearly induced. qRT-PCR validation confirmed the upregulation of key genes chosen as validation of transcriptomic analysis.Conclusion: A subset of these genes may be further analyzed in future studies to confirm their specificity to be induced by RPW infestations.The present research work was financially supported by Propalma project funded by the “Ministero delle Politiche Agricole, Alimentari e Forestali.”Peer reviewedPeer Reviewe

Members of the WRKY gene family are upregulated in Canary palms attacked by Red Palm Weevil

The Red Palm Weevil (RPW), Rhynchophorus ferrugineus, is one of the major pests affecting several palm species all around the world. The aim of this work was to identify palm genes that are responsive to RPW infestations as a valuable diagnostic tool to detect the insect attack. We have analysed a total of 15 genes that were divided in two subsets: (1) 7 genes previously linked with RPW attacks, but not involved in biotic stress responses, and (2) 8 genes encoding members of the WRKY family, a class of transcription factors well-known to be linked with both abiotic and biotic stress responses. The analysis was conducted on 4-year-old Canary palms comparing uninfested plants and infested plants at 30 and 45 days after RPW oviposition. Principal component analysis of gene expression data showed that the overall analysis of WRKYs partially distinguished the three groups of plants. No separation of the three groups was observed when PCA was conducted using genes that were not linked with biotic stress responses. Among the 8 analysed WRKYs, 4 genes (WRKY2, WRKY28, WRKY14, WRKY51) were significantly induced by RPW attacks at 45 days after the beginning of the infestation. These four WRKYs could be further investigated to confirm if they may be used to help diagnosis of RPW infestations in palm

Preliminary selection of non-target Lepidoptera species for ecological risk assessment of Bt canola in Sicily

It is essential to assess the environmental risk that Bt canola resistant to Lepidopteran pests may hold and to study its effect on species assemblages that fulfil a variety of ecosystem functions. Environmental risk assessment can be improved through the use of an ecological model which can be applied to a specific environment, so that local species can be classified functionally and prioritized to identify potential test species. Several other Lepidoptera species are also directly exposed to Bt toxin. In this paper an ecological approach was followed for selection of non-target Lepidoptera species for ecological risk assessment of Bt canola in Sicily, using data collected over a one-year period on Lepidoptera biodiversity on different habitats. Non-target Lepidoptera most likely to be affected were identified and prioritized for future testing and inclusion in risk assessments. Through use of the selection matrix, knowledge gaps were identified for future research and guidance for the design of ecologically realistic experiments

Transcriptome analysis of phoenix canariensis chabaud in response to rhynchophorus ferrugineus olivier attacks

Red Palm Weevil (RPW, Rhynchophorus ferrugineus Olivier) threatens most palm species worldwide. Until now, no studies have analyzed the gene regulatory networks of Phoenix canariensis (Chabaud) in response to RPW attacks. The aim of this study was to fill this knowledge gap. Providing this basic knowledge is very important to improve its management. Results: A deep transcriptome analysis was performed on fully expanded leaves of healthy non-infested trees and attacked trees at two symptom stages (middle and late infestation). A total of 54 genes were significantly regulated during middle stage. Pathway enrichment analysis showed that phenylpropanoid-related pathways were induced at this stage. More than 3300 genes were affected during late stage of attacks. Higher transcript abundances were observed for lipid fatty acid metabolism (fatty acid and glycerolipids), tryptophan metabolism, phenylpropanoid metabolism. Key RPW-modulated genes involved in innate response mediated by hormone crosstalk were observed belonging to auxin, jasmonate and salicylic acid (SA) pathways. Among transcription factors, some WRKYs were clearly induced. qRT-PCR validation confirmed the upregulation of key genes chosen as validation of transcriptomic analysis. Conclusion: A subset of these genes may be further analyzed in future studies to confirm their specificity to be induced by RPW infestations

Arbuscular mycorrhizal symbiosis mitigates the negative effects of salinity on durum wheat.

Arbuscular mycorrhizal (AM) symbiosis is generally considered to be effective in ameliorating the plant tolerance to salt stress. Unfortunately, the comprehension of the mechanisms implicated in salinity stress alleviation by AM symbiosis is far from being complete. Thus, an experiment was performed by growing durum wheat (Triticum durum Desf.) plants under salt-stress conditions to evaluate the influence of AM symbiosis on both the plant growth and the regulation of a number of genes related to salt stress and nutrient uptake. Durum wheat plants were grown outdoors in pots in absence or in presence of salt stress and with or without AM fungi inoculation. The inoculum consisted of a mixture of spores of Rhizophagus irregularis (formerly Glomus intraradices) and Funneliformis mosseae (formerly G. mosseae). Results indicate that AM symbiosis can alleviate the detrimental effects of salt stress on the growth of durum wheat plants. In fact, under salt stress conditions mycorrhizal plants produced more aboveground and root biomass, had higher N uptake and aboveground N concentration, and showed greater stability of plasma membranes compared to non-mycorrhizal plants. Inoculation with AM fungi had no effect on the expression of the N transporter genes AMT1.1, AMT1.2, and NAR2.2, either under no-stress or salt stress conditions, probably due to the fact that plants were grown under optimal N conditions; on the contrary, NRT1.1 was always upregulated by AM symbiosis. Moreover, the level of expression of the drought stress-related genes AQP1, AQP4, PIP1, DREB5, and DHN15.3 observed in the mycorrhizal stressed plants was markedly lower than that observed in the non-mycorrhizal stressed plants and very close to that observed in the non-stressed plants. Our hypothesis is that, in the present study, AM symbiosis did not increase the plant tolerance to salt stress but instead generated a condition in which plants were subjected to a level of salt stress lower than that of non-mycorrhizal plants

Metabolomics Suggests That Soil Inoculation with Arbuscular Mycorrhizal Fungi Decreased Free Amino Acid Content in Roots of Durum Wheat Grown under N-Limited, P-Rich Field Conditions.

Arbuscular mycorrhizal fungi (AMF) have a major impact on plant nutrition, defence against pathogens, a plant's reaction to stressful environments, soil fertility, and a plant's relationship with other microorganisms. Such effects imply a broad reprogramming of the plant's metabolic activity. However, little information is available regarding the role of AMF and their relation to other soil plant growth-promoting microorganisms in the plant metabolome, especially under realistic field conditions. In the present experiment, we evaluated the effects of inoculation with AMF, either alone or in combination with plant growth-promoting rhizobacteria (PGPR), on the metabolome and changes in metabolic pathways in the roots of durum wheat (Triticum durum Desf.) grown under N-limited agronomic conditions in a P-rich environment. These two treatments were compared to infection by the natural AMF population (NAT). Soil inoculation with AMF almost doubled wheat root colonization by AMF and decreased the root concentrations of most compounds in all metabolic pathways, especially amino acids (AA) and saturated fatty acids, whereas inoculation with AMF+PGPR increased the concentrations of such compounds compared to inoculation with AMF alone. Enrichment metabolomics analyses showed that AA metabolic pathways were mostly changed by the treatments, with reduced amination activity in roots most likely due to a shift from the biosynthesis of common AA to γ-amino butyric acid. The root metabolome differed between AMF and NAT but not AMF+PGPR and AMF or NAT. Because the PGPR used were potent mineralisers, and AMF can retain most nitrogen (N) taken as organic compounds for their own growth, it is likely that this result was due to an increased concentration of mineral N in soil inoculated with AMF+PGPR compared to AMF alone

RNA uridylation and decay in plants

RNA uridylation consists of the untemplated addition of uridines at the 30 extremity of an RNA molecule. RNA uridylation is catalysed by terminal uridylyltransferases (TUTases), which form a subgroup of the terminal nucleotidyltransferase family, to which poly(A) polymerases also belong. The key role of RNA uridylation is to regulate RNA degradation in a variety of eukaryotes, including fission yeast, plants and animals. In plants, RNA uridylation has been mostly studied in two model species, the green algae Chlamydomonas reinhardtii and the flowering plant Arabidopsis thaliana. Plant TUTases target a variety of RNA substrates, differing in size and function. These RNA substrates include microRNAs (miRNAs), small interfering silencing RNAs (siRNAs), ribosomal RNAs (rRNAs), messenger RNAs (mRNAs) and mRNA fragments generated during post-transcriptional gene silencing. Viral RNAs can also get uridylated during plant infection. We describe here the evolutionary history of plant TUTases and we summarize the diverse molecular functions of uridylation during RNA degradation processes in plants. We also outline key points of future research. This article is part of the theme issue '50 and 30 modifications controlling RNA degradation'