Identification of novel aphid-killing bacteria to protect plants

Aphids, including the peach-potato aphid, Myzus persicae, are major insect pests of agriculture and horticulture, and aphid control measures are limited. There is therefore an urgent need to develop alternative and more sustainable means of control. Recent studies have shown that environmental microbes have varying abilities to kill insects. We screened a range of environmental bacteria isolates for their abilities to kill target aphid species. Tests demonstrated the killing aptitude of these bacteria against six aphid genera (including Myzus persicae). No single bacterial strain was identified that was consistently toxic to insecticide-resistant aphid clones than susceptible clones, suggesting resistance to chemicals is not strongly correlated with bacterial challenge. Pseudomonas fluorescens PpR24 proved the most toxic to almost all aphid clones whilst exhibiting the ability to survive for over three weeks on three plant species at populations of 5–6 log CFU cm⁻² leaf. Application of PpR24 to plants immediately prior to introducing aphids onto the plants led to a 68%, 57% and 69% reduction in aphid populations, after 21 days, on Capsicum annuum, Arabidopsis thaliana and Beta vulgaris respectively. Together, these findings provide new insights into aphid susceptibility to bacterial infection with the aim of utilizing bacteria as effective biocontrol agents.     

Tetratricopeptide Repeat Domain 9A Negatively Regulates Estrogen Receptor Alpha Activity

Tetratricopeptide repeat domain 9A (TTC9A) is a target gene of estrogen and progesterone. It is over-expressed in breast cancer. However, little is known about the physiological function of TTC9A. The objectives of this study were to establish a Ttc9a knockout mouse model and to study the consequence of Ttc9a gene inactivation. The Ttc9a targeting vector was generated by replacing the Ttc9a exon 1 with a neomycin cassette. The mice homozygous for Ttc9a exon 1 deletion appear to grow normally and are fertile. However, further characterization of the female mice revealed that Ttc9a deficiency is associated with greater body weight, bigger thymus and better mammary development in post-pubertal mice. Furthermore, Ttc9a deficient mammary gland was more responsive to estrogen treatment with greater mammary ductal lengthening, ductal branching and estrogen target gene induction. Since Ttc9a is induced by estrogen in estrogen target tissues, these results suggest that Ttc9a is a negative regulator of estrogen function through a negative feedback mechanism. This is supported by in vitro evidence that TTC9A over-expression attenuated ERα activity in MCF-7 cells. Although TTC9A does not bind to ERα or its chaperone protein Hsp90 directly, TTC9A strongly interacts with FKBP38 and FKBP51, both of which interact with ERα and Hsp90 and modulate ERα activity. It is plausible therefore that TTC9A negatively regulates ERα activity through interacting with co-chaperone proteins such as FKBP38 and FKBP51.     

1H NMR metabolomics reveals increased glutaminolysis upon overexpression of NSD3s or Pdp3 in Saccharomyces cerevisiae

NSD3s, the proline-tryptophan-tryptophan-proline (PWWP) domain-containing, short isoform of the human oncoprotein NSD3, displays high transforming properties. Overexpression of human NSD3s or the yeast protein Pdp3 in Saccharomyces cerevisiae induces similar metabolic changes, including increased growth rate and sensitivity to oxidative stress, accompanied by decreased oxygen consumption. Here, we set out to elucidate the biochemical pathways leading to the observed metabolic phenotype by analyzing the alterations in yeast metabolome in response to NSD3s or Pdp3 overexpression using ¹H nuclear magnetic resonance (NMR) metabolomics. We observed an increase in aspartate and alanine, together with a decrease in arginine levels, on overexpression of NSD3s or Pdp3, suggesting an increase in the rate of glutaminolysis. In addition, certain metabolites, including glutamate, valine, and phosphocholine were either NSD3s or Pdp3 specific, indicating that additional metabolic pathways are adapted in a protein-dependent manner. The observation that certain metabolic pathways are differentially regulated by NSD3s and Pdp3 suggests that, despite the structural similarity between their PWWP domains, the two proteins act by unique mechanisms and may recruit different downstream signaling complexes. This study establishes for the first time a functional link between the human oncoprotein NSD3s and cancer metabolic reprogramming.     

A non‐canonical role of the p97 complex in RIG‐I antiviral signaling

RIG‐I is a well‐studied sensor of viral RNA that plays a key role in innate immunity. p97 regulates a variety of cellular events such as protein quality control, membrane reassembly, DNA repair, and the cell cycle. Here, we report a new role for p97 with Npl4‐Ufd1 as its cofactor in reducing antiviral innate immune responses by facilitating proteasomal degradation of RIG‐I. The p97 complex is able to directly bind both non‐ubiquitinated RIG‐I and the E3 ligase RNF125, promoting K48‐linked ubiquitination of RIG‐I at residue K181. Viral infection significantly strengthens the interaction between RIG‐I and the p97 complex by a conformational change of RIG‐I that exposes the CARDs and through K63‐linked ubiquitination of these CARDs. Disruption of the p97 complex enhances RIG‐I antiviral signaling. Consistently, administration of compounds targeting p97 ATPase activity was shown to inhibit viral replication and protect mice from vesicular stomatitis virus (VSV) infection. Overall, our study uncovered a previously unrecognized role for the p97 complex in protein ubiquitination and revealed the p97 complex as a potential drug target in antiviral therapy.     

Generation of enzymatically competent SARS-CoV-2 decoy receptor ACE2-Fc in glycoengineered Nicotiana benthamiana

Human angiotensin-converting enzyme 2 (ACE2) is the primary host cell receptor for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) binding and cell entry. Administration of high concentrations of soluble ACE2 can be utilized as a decoy to block the interaction of the virus with cellular ACE2 receptors and potentially be used as a strategy for treatment or prevention of coronavirus disease 2019. Human ACE2 is heavily glycosylated and its glycans impact on binding to the SARS-CoV-2 spike protein and virus infectivity. Here, we describe the production of a recombinant soluble ACE2-fragment crystallizable (Fc) variant in glycoengineered Nicotiana benthamiana. Our data reveal that the produced dimeric ACE2-Fc variant is glycosylated with mainly complex human-type N-glycans and functional with regard to enzyme activity, affinity to the SARS-CoV-2 receptor-binding domain, and wild-type virus neutralization.     

Mapping quantitative trait loci (QTLs) for fatty acid composition in an interspecific cross of oil palm

Background  

Marker Assisted Selection (MAS) is well suited to a perennial crop like oil palm, in which the economic products are not produced until several years after planting. The use of DNA markers for selection in such crops can greatly reduce the number of breeding cycles needed. With the use of DNA markers, informed decisions can be made at the nursery stage, regarding which individuals should be retained as breeding stock, which are satisfactory for agricultural production, and which should be culled. The trait associated with oil quality, measured in terms of its fatty acid composition, is an important agronomic trait that can eventually be tracked using molecular markers. This will speed up the production of new and improved oil palm planting materials.     

Ecdysteroids and meiotic reinitiation in Palaemon serratus (Crustacea Decapoda Natantia) and in Locusta migratoria (Insecta orthoptera). A comparative study

Summary

Meiotic reinitiation has been studied in Locusta migratoria and Palaemon serratus in relation to the titre of free ecdysteroids present in the maturing oocyte. In both species meiotic reinitiation is characterized by two meiotic arrests, in prophase I and in metaphase I, and the first meiotic resumption which leads to germinal vesicle breakdown (GVBD) is correlated with increasing titres of ecdysteroids in the oocyte. Meiotic reinitiation has been successfully triggered in the oocytes of both species by incubation with physiological doses of ecdysteroids.