The Role of Plant Hormones in the Interaction of Colletotrichum Species with Their Host Plants

Colletotrichum is a plant pathogenic fungus which is able to infect virtually every economically important plant species. Up to now no common infection mechanism has been identified comparing different plant and Colletotrichum species. Plant hormones play a crucial role in plant-pathogen interactions regardless whether they are symbiotic or pathogenic. In this review we analyze the role of ethylene, abscisic acid, jasmonic acid, auxin and salicylic acid during Colletotrichum infections. Different Colletotrichum strains are capable of auxin production and this might contribute to virulence. In this review the role of different plant hormones in plant—Colletotrichum interactions will be discussed and thereby auxin biosynthetic pathways in Colletotrichum spp. will be proposed.     

OsBRKq1, Related Grain Size Mapping,and Identification of Grain Shape Based on QTL Mapping in Rice

The world population is growing rapidly, and food shortage remains a critical issue. Quantitative trait locus (QTL) mapping is a statistical analytical method that uses both phenotypic and genotypic data. The purpose of QTL mapping is to determine the exact gene location for various complex traits. Increasing grain weight is a way to increase yield in rice. Genes related to grain size were mapped using the Samgang/Nagdong double haploid (SNDH) populations. Grain sizes were diversely distributed in SNDH 113 populations, and OsBRKq1 was detected on chromosome 1 in an analysis of QTL mapping that used 1000 grain weight, grain length, and grain width. OsBRKq1 exhibited high sequence similarity with the brassinosteroid leucine-rich repeat-receptor kinases of Arabidopsis thaliana and Zea mays. It was also predicted to have a similar function because of its high homology. OsBRKq1 interacts with various grain-size control genes. Among the SNDH populations, the analysis of the relative expression level during the panicle formation stage of OsBRKq1 in panicles of SNDH117, which has the largest grain size, and SNDH6, which has the smallest grain size, the relative expression level was significantly increased in SNDH117 panicles. SNDH populations have been advancing generations for 10 years; various genetic traits have been fixed and are currently being used as bridging parents. Therefore, the stable expression level of OsBRKq1 was confirmed via QTL mapping. In the future, OsBRKq1 can be effectively used to increase the yield of rice and solve food problems by increasing the size of seeds.     

Photodynamic and Antibiotic Therapy in Combination to Fight Biofilms and Resistant Surface Bacterial Infections

Although photodynamic therapy (PDT), a therapeutic approach that involves a photosensitizer, light and O₂, has been principally considered for the treatment of specific types of cancers, other applications exist, including the treatment of infections. Unfortunately, PDT does not always guarantee full success since it exerts lethal effects only in cells that have taken up a sufficient amount of photosensitizer and have been exposed to adequate light doses, conditions that are not always achieved. Based on our previous experience on the combination PDT/chemotherapy, we have explored the possibility of fighting bacteria that commonly crowd infected surfaces by combining PDT with an antibiotic, which normally does not harm the strain at low concentrations. To this purpose, we employed 5-aminolevulinic acid (5-ALA), a pro-drug that, once absorbed by proliferating bacteria, is converted into the natural photosensitizer Protoporphyrin IX (PpIX), followed by Gentamicin. Photoactivation generates reactive oxygen species (ROS) which damage or kill the cell, while Gentamicin, even at low doses, ends the work. Our experiments, in combination, have been highly successful against biofilms produced by several Gram positive bacteria (i.e., Staphylococcus aureus, Staphylococcus epidermidis, etc.). This original approach points to potentially new and wide applications in the therapy of infections of superficial wounds and sores.     

Efficient Neuroprotective Rescue of Sacsin-Related Disease Phenotypes in Zebrafish

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is a multisystem hereditary ataxia associated with mutations in SACS, which encodes sacsin, a protein of still only partially understood function. Although mouse models of ARSACS mimic largely the disease progression seen in humans, their use in the validation of effective therapies has not yet been proposed. Recently, the teleost Danio rerio has attracted increasing attention as a vertebrate model that allows rapid and economical screening, of candidate molecules, and thus combines the advantages of whole-organism phenotypic assays and in vitro high-throughput screening assays. Through CRISPR/Cas9-based mutagenesis, we generated and characterized a zebrafish sacs-null mutant line that replicates the main features of ARSACS. The sacs-null fish showed motor impairment, hindbrain atrophy, mitochondrial dysfunction, and reactive oxygen species accumulation. As proof of principle for using these mutant fish in high-throughput screening studies, we showed that both acetyl-DL-leucine and tauroursodeoxycholic acid improved locomotor and biochemical phenotypes in sacs^−/− larvae treated with these neuroprotective agents, by mediating significant rescue of the molecular functions altered by sacsin loss. Taken together, the evidence here reported shows the zebrafish to be a valuable model organism for the identification of novel molecular mechanisms and for efficient and rapid in vivo optimization and screening of potential therapeutic compounds. These findings may pave the way for new interventions targeting the earliest phases of Purkinje cell degeneration in ARSACS.     

Mechanism of copper electrodeposition in the presence of picolinic acid

The influence of picolinic acid (PA) on copper deposition from a slightly acidic sodium sulphate electrolyte has been studied over a wide range of concentration and pH by cyclic voltammetry. The mechanism by which the copper electrodeposition process in the presence of PA takes place, depends on the chemistry and electrochemistry characteristics of the additive. Depending on the PA concentration and pH of the solution, five different cathodic current peaks are obtained, which are assigned to different steps involving copper deposition from free-Cu²⁺ ions and [Cu(PA)_n]²⁺ complex species as well as H⁺ ions electroeduction. Fine-grained, highly adherent and bright copper deposits were obtained.     

Proteomic Analyses of Courtship Pheromones in the Redback Salamander,Plethodon cinereus

The evolutionary success of plethodontid salamanders for ~100 MY is due partly to the use of courtship pheromones that regulate female receptivity. In ~90 % of plethodontid species, males deliver pheromones by “scratching” a female’s dorsum, where pheromones diffuse transdermally into the bloodstream. However, in a single clade, representing ~10 % of Plethodon spp., males apply pheromones to the female’s nares for olfactory delivery. Molecular studies have identified three major pheromone families: Plethodontid Receptivity Factor (PRF), Plethodontid Modulating Factor (PMF), and Sodefrin Precursor-like Factor (SPF). SPF and PMF genes are relatively ancient and found in all plethodontid species; however, PRF is found exclusively in the genus Plethodon – which includes species with transdermal, olfactory, and intermediate delivery behaviors. While previous proteomic analyses suggested PRF and PMF are dominant in slapping species and SPF is dominant in non-Plethodon scratching species, it was unclear how protein expression of different pheromone components may vary across delivery modes within Plethodon. Therefore, the aim of this study was to proteomically characterize the pheromones of a key scratching species in this evolutionary transition, Plethodon cinereus. Using mass spectrometry-based techniques, our data support the functional replacement of SPF by PRF in Plethodon spp. and an increase in PMF gene duplication events in both lineage-dependent and delivery-dependent manners. Novel glycosylation was observed on P. cinereus PRFs, which may modulate the metabolism and/or mechanism of action for PRF in scratching species. Cumulatively, these molecular data suggest that the replacement of pheromone components (e.g., SPF by PRF) preceded the evolutionary transition of the functional complex from transdermal to olfactory delivery.     

The THO/TREX Complex Active in Alternative Splicing Mediates Plant Responses to Salicylic Acid and Jasmonic Acid

Salicylic acid (SA) and jasmonic acid (JA) are essential plant immune hormones, which could induce plant resistance to multiple pathogens. However, whether common components are employed by both SA and JA to induce defense is largely unknown. In this study, we found that the enhanced disease susceptibility 8 (EDS8) mutant was compromised in plant defenses to hemibiotrophic pathogen Pseudomonas syringae pv. maculicola ES4326 and necrotrophic pathogen Botrytis cinerea, and was deficient in plant responses to both SA and JA. The EDS8 was identified to be THO1, which encodes a subunit of the THO/TREX complex, by using mapping-by-sequencing. To check whether the EDS8 itself or the THO/TREX complex mediates SA and JA signaling, the mutant of another subunit of the THO/TREX complex, THO3, was tested. THO3 mutation reduced both SA and JA induced defenses, indicating that the THO/TREX complex is critical for plant responses to these two hormones. We further proved that the THO/TREX interacting protein SERRATE, a factor regulating alternative splicing (AS), was involved in plant responses to SA and JA. Thus, the AS events in the eds8 mutant after SA or JA treatment were determined, and we found that the SA and JA induced different alternative splicing events were majorly modulated by EDS8. In summary, our study proves that the THO/TREX complex active in AS is involved in both SA and JA induced plant defenses.     

Phenotypic and Molecular Convergence of 2q23.1 Deletion Syndrome with Other Neurodevelopmental Syndromes Associated with Autism Spectrum Disorder

Roughly 20% of autism spectrum disorders (ASD) are syndromic with a well-established genetic cause. Studying the genes involved can provide insight into the molecular and cellular mechanisms of ASD. 2q23.1 deletion syndrome (causative gene, MBD5) is a recently identified genetic neurodevelopmental disorder associated with ASD. Mutations in MBD5 have been found in ASD cohorts. In this study, we provide a phenotypic update on the prevalent features of 2q23.1 deletion syndrome, which include severe intellectual disability, seizures, significant speech impairment, sleep disturbance, and autistic-like behavioral problems. Next, we examined the phenotypic, molecular, and network/pathway relationships between nine neurodevelopmental disorders associated with ASD: 2q23.1 deletion Rett, Angelman, Pitt-Hopkins, 2q23.1 duplication, 5q14.3 deletion, Kleefstra, Kabuki make-up, and Smith-Magenis syndromes. We show phenotypic overlaps consisting of intellectual disability, speech delay, seizures, sleep disturbance, hypotonia, and autistic-like behaviors. Molecularly, MBD5 possibly regulates the expression of UBE3A, TCF4, MEF2C, EHMT1 and RAI1. Network analysis reveals that there could be indirect protein interactions, further implicating function for these genes in common pathways. Further, we show that when MBD5 and RAI1 are haploinsufficient, they perturb several common pathways that are linked to neuronal and behavioral development. These findings support further investigations into the molecular and pathway relationships among genes linked to neurodevelopmental disorders and ASD, which will hopefully lead to common points of regulation that may be targeted toward therapeutic intervention.     

In situ synthesis,fabrication and Rietveld refinement of the hydroxyapatite/titania composite coatings on 316 L SS

The development of Hydroxyapatite (HAP)/Titania (TiO₂) composite coatings on metallic implants have received a great deal of attention during the recent years owing to their superior advantages in biomedical applications. The present study has focused on the in situ formation of HAP/TiO₂ composite powders through aqueous precipitation technique. Five different HAP/TiO₂ composite powders of varied HAP to TiO₂ ratios has been synthesized in the present study and the results were compared with the stoichiometric HAP, Rutile TiO₂ and Anatase TiO₂ which also have been synthesized by adapting a similar synthetic procedure. All the synthesized powders have been analyzed using X-ray diffraction (XRD) and X-ray fluorescence (XRF) techniques. Rietveld Refinement technique has been employed to generate quantitative information about the structural characteristics and phase content in all the powder samples. Further, the electrophoretic deposition (EPD) method has been employed to fabricate HAP/TiO₂ composite coatings on 316 L SS and the resultant coatings were analyzed for its quantitative structural characteristics. The results from the present investigation has confirmed that concentration of TiO₂ in the HAP/TiO₂ composites and heat treatment temperatures have played a major role in the degradation of HAP to β-Tricalcium phosphate and also in the conversion of Anatase to Rutile TiO₂ phase.     

Double Gamers—Can Modified Natural Regulators of Higher Plants Act as Antagonists against Phytopathogens? The Case of Jasmonic Acid Derivatives

As key players in biotic stress response of plants, jasmonic acid (JA) and its derivatives cover a specific and prominent role in pathogens-mediated signaling and hence are promising candidates for a sustainable management of phytopathogenic fungi. Recently, JA directed antimicrobial effects on plant pathogens has been suggested, supporting the theory of oxylipins as double gamers in plant-pathogen interaction. Based on these premises, six derivatives (dihydrojasmone and cis-jasmone, two thiosemicarbazonic derivatives and their corresponding complexes with copper) have been evaluated against 13 fungal species affecting various economically important herbaceous and woody crops, such as cereals, grapes and horticultural crops: Phaeoacremonium minimum, Neofusicoccum parvum, Phaeomoniella chlamydospora, Fomitiporia mediterranea, Fusarium poae, F. culmorum, F. graminearum, F. oxysporum f. sp. lactucae, F. sporotrichioides, Aspergillus flavus, Rhizoctonia solani, Sclerotinia spp. and Verticillium dahliae. The biological activity of these compounds was assessed in terms of growth inhibition and, for the two mycotoxigenic species A. flavus and F. sporotrichioides, also in terms of toxin containment. As expected, the inhibitory effect of molecules greatly varied amongst both genera and species; cis-jasmone thiosemicarbazone in particular has shown the wider range of effectiveness. However, our results show that thiosemicarbazones derivatives are more effective than the parent ketones in limiting fungal growth and mycotoxins production, supporting possible applications for the control of pathogenic fungi.     

SmSPL6 Induces Phenolic Acid Biosynthesis and Affects Root Development in Salvia miltiorrhiza

Salvia miltiorrhiza is a renowned model medicinal plant species for which 15 SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPL) family genes have been identified; however, the specific functions of SmSPLs have not been well characterized as of yet. For this study, the expression patterns of SmSPL6 were determined through its responses to treatments of exogenous hormones, including indole acetic acid (IAA), gibberellic acid (GA₃), methyl jasmonic acid (MeJA), and abscisic acid (ABA). To characterize its functionality, we obtained SmSPL6-ovexpressed transgenic S. miltiorrhiza plants and found that overexpressed SmSPL6 promoted the accumulation of phenolic acids and repressed the biosynthesis of anthocyanin. Meanwhile, the root lengths of the SmSPL6-overexpressed lines were significantly longer than the control; however, both the fresh weights and lateral root numbers decreased. Further investigations indicated that SmSPL6 regulated the biosynthesis of phenolic acid by directly binding to the promoter regions of the enzyme genes Sm4CL9 and SmCYP98A14 and activated their expression. We concluded that SmSPL6 regulates not only the biosynthesis of phenolic acids, but also the development of roots in S. miltiorrhiza.     

Constrained nonlinear optimization for solubility parameters of poly(lactic acid) and poly(glycolic acid)—validation and comparison

An optimization technique has been proposed to determine Hansen solubility parameters (HSP) and radius of interaction (R) of PLA and PGA; objective function to be minimized being radius of interaction (R), and the constraints being that the solvents should be within and nonsolvents outside the interaction sphere. The proposed method has been validated and found to be most reliable. The values of HSP (δ_d, δ_p, δ_h) and R for PLA have been obtained as ((18.50, 9.70, 6.00) and 10.50) (J/cc)^0.5 at 25 °C; and those of PGA as ((17.70, 6.21, 12.50) and 1.92) (J/cc)^0.5 at 80 °C. For formulating the nonlinear inequality constraints known HSP data for 20 solvents and seven nonsolvents have been used for PLA at 25 °C; similarly HSP data for three newly found solvents (phenol, m-cresol and 4-chlorophenol), and five nonsolvents have been used for PGA at 80 °C. Established methods have been used for comparison. HSP and R have been directly compared using the 3D intrinsic viscosity and classical methods. Indirectly the total solubility parameter δ has been compared with the values obtained from the intrinsic viscosity 1D approach and group contribution method using Fedors and van Krevelen correlations. The 1D approach has led to an empirical correlation for intrinsic viscosities of PLA and PGA.     

Genome Evolutionary Dynamics Meets Functional Genomics: A Case Story on the Identification of SLC25A44

Gene clusters are becoming promising tools for gene identification. The study reveals the purposive genomic distribution of genes toward higher inheritance rates of intact metabolic pathways/phenotypes and, thereby, higher fitness. The co-localization of co-expressed, co-interacting, and functionally related genes was found as genome-wide trends in humans, mouse, golden eagle, rice fish, Drosophila, peanut, and Arabidopsis. As anticipated, the analyses verified the co-segregation of co-localized events. A negative correlation was notable between the likelihood of co-localization events and the inter-loci distances. The evolution of genomic blocks was also found convergent and uniform along the chromosomal arms. Calling a genomic block responsible for adjacent metabolic reactions is therefore recommended for identification of candidate genes and interpretation of cellular functions. As a case story, a function in the metabolism of energy and secondary metabolites was proposed for Slc25A44, based on its genomic local information. Slc25A44 was further characterized as an essential housekeeping gene which has been under evolutionary purifying pressure and belongs to the phylogenetic ETC-clade of SLC25s. Pathway enrichment mapped the Slc25A44s to the energy metabolism. The expression of peanut and human Slc25A44s in oocytes and Saccharomyces cerevisiae strains confirmed the transport of common precursors for secondary metabolites and ubiquinone. These results suggest that SLC25A44 is a mitochondrion-ER-nucleus zone transporter with biotechnological applications. Finally, a conserved three-amino acid signature on the cytosolic face of transport cavity was found important for rational engineering of SLC25s.