Transcriptomic Signatures of Ash (Fraxinus spp.) Phloem

Ash (Fraxinus spp.) is a dominant tree species throughout urban and forested landscapes of North America (NA). The rapid invasion of NA by emerald ash borer (Agrilus planipennis), a wood-boring beetle endemic to Eastern Asia, has resulted in the death of millions of ash trees and threatens billions more. Larvae feed primarily on phloem tissue, which girdles and kills the tree. While NA ash species including black (F. nigra), green (F. pennsylvannica) and white (F. americana) are highly susceptible, the Asian species Manchurian ash (F. mandshurica) is resistant to A. planipennis perhaps due to their co-evolutionary history. Little is known about the molecular genetics of ash. Hence, we undertook a functional genomics approach to identify the repertoire of genes expressed in ash phloem.Using 454 pyrosequencing we obtained 58,673 high quality ash sequences from pooled phloem samples of green, white, black, blue and Manchurian ash. Intriguingly, 45% of the deduced proteins were not significantly similar to any sequences in the GenBank non-redundant database. KEGG analysis of the ash sequences revealed a high occurrence of defense related genes. Expression analysis of early regulators potentially involved in plant defense (i.e. transcription factors, calcium dependent protein kinases and a lipoxygenase 3) revealed higher mRNA levels in resistant ash compared to susceptible ash species. Lastly, we predicted a total of 1,272 single nucleotide polymorphisms and 980 microsatellite loci, among which seven microsatellite loci showed polymorphism between different ash species.The current transcriptomic data provide an invaluable resource for understanding the genetic make-up of ash phloem, the target tissue of A. planipennis. These data along with future functional studies could lead to the identification/characterization of defense genes involved in resistance of ash to A. planipennis, and in future ash breeding programs for marker development

CDPKs CPK6 and CPK3 Function in ABA Regulation of Guard Cell S-Type Anion- and Ca(2+)- Permeable Channels and Stomatal Closure

Abscisic acid (ABA) signal transduction has been proposed to utilize cytosolic Ca(2+) in guard cell ion channel regulation. However, genetic mutants in Ca(2+) sensors that impair guard cell or plant ion channel signaling responses have not been identified, and whether Ca(2+)-independent ABA signaling mechanisms suffice for a full response remains unclear. Calcium-dependent protein kinases (CDPKs) have been proposed to contribute to central signal transduction responses in plants. However, no Arabidopsis CDPK gene disruption mutant phenotype has been reported to date, likely due to overlapping redundancies in CDPKs. Two Arabidopsis guard cell–expressed CDPK genes, CPK3 and CPK6, showed gene disruption phenotypes. ABA and Ca(2+) activation of slow-type anion channels and, interestingly, ABA activation of plasma membrane Ca(2+)-permeable channels were impaired in independent alleles of single and double cpk3cpk6 mutant guard cells. Furthermore, ABA- and Ca(2+)-induced stomatal closing were partially impaired in these cpk3cpk6 mutant alleles. However, rapid-type anion channel current activity was not affected, consistent with the partial stomatal closing response in double mutants via a proposed branched signaling network. Imposed Ca(2+) oscillation experiments revealed that Ca(2+)-reactive stomatal closure was reduced in CDPK double mutant plants. However, long-lasting Ca(2+)-programmed stomatal closure was not impaired, providing genetic evidence for a functional separation of these two modes of Ca(2+)-induced stomatal closing. Our findings show important functions of the CPK6 and CPK3 CDPKs in guard cell ion channel regulation and provide genetic evidence for calcium sensors that transduce stomatal ABA signaling

The L17 ribosomal protein of Bacillus subtilis binds preferentially to curved DNA.

International audienceWe searched in Bacillus subtilis for proteins that bind preferentially to curved DNA. Two proteins of 9 and 15 kDa displaying this property were purified from exponentially growing cells of B. subtilis strain 168. Sequencing of N-terminal amino acids identified them as the proteins HBsu and L17 respectively. The overproduction of L17 from B. subtilis in Escherichia coli was shown to have a strong effect on nucleoid morphology and segregation

Etude structurale et fonctionnelle des aspartokinases-homoserine deshydrogenases d'E. coli

SIGLECNRS-CDST / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Thoracic sarcopenia as a predictive factor of SARS-COV2 evolution

Purpose: Evaluation of CT sarcopenia as a predictor of intensive care hospitalization during SARS-COV2 infection.Materials and methods: Single-center retrospective study of patients admitted to hospital with SARS-COV2 infection. The estimation of muscle mass (skeletal muscle index (SMI)) for sarcopenia, measure-ment of muscle density for muscle quality and body adiposity, were based on CT views on the T4 and L3 levels measured at admission. Demographic data, percentage of pulmonary parenchymal involvement as well as the orientation of patients during hospitalization and the risk of hospitalization in intensive care were collected.Results: A total of 162 patients hospitalized for SARS-COV2 infection were included (92 men and 70 women, with an average age of 64.6 years and an average BMI of 27.4). The muscle area measured at the level of L3 was significantly associated with the patient's unfavorable evolution (124.4cm2 [97; 147] vs 141.5 cm2 [108; 173]) (p 1/4 0.007), as was a lowered SMI (p < 0.001) and the muscle area measured in T4 (OR 1/4 0.98 [0.97; 0.99]), (p 1/4 0.026). Finally, an abdominal visceral fat area measured at the level of L3 was also associated with a risk of hospitalization in intensive care (249.4cm2 [173; 313] vs 147.5cm2 [93.1; 228] (p < 0.001).Conclusion: This study demonstrates that thoracic and abdominal sarcopenia are independently asso-ciated with an increased risk of hospitalization in an intensive care unit, suggesting the need to assess sarcopenia on admission during SARS-COV2 infection