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Barley (Hordeum vulgare) is an important global cereal crop and a model in genetic studies. Despite advances in characterising barley genomic resources, few mutant studies have identified genes controlling root architecture and anatomy, which plays a critical role in capturing soil resources. Our phenotypic screening of a TILLING mutant collection identified line TM5992 exhibiting a short-root phenotype compared with wild-type (WT) Morex background. Outcrossing TM5992 with barley variety Proctor and subsequent SNP array-based bulk segregant analysis, fine mapped the mutation to a cM scale. Exome sequencing pinpointed a mutation in the candidate gene HvPIN1a, further confirming this by analysing independent mutant alleles. Detailed analysis of root growth and anatomy in Hvpin1a mutant alleles exhibited a slower growth rate, shorter apical meristem and striking vascular patterning defects compared to WT. Expression and mutant analyses of PIN1 members in the closely related cereal brachypodium (Brachypodium distachyon) revealed that BdPIN1a and BdPIN1b were redundantly expressed in root vascular tissues but only Bdpin1a mutant allele displayed root vascular defects similar to Hvpin1a. We conclude that barley PIN1 genes have sub-functionalised in cereals, compared to Arabidopsis (Arabidopsis thaliana), where PIN1a sequences control root vascular patterning., (© 2024 The Author(s). New Phytologist © 2024 New Phytologist Foundation.)

Root angle is a critical factor in optimizing the acquisition of essential resources from different soil depths. The regulation of root angle relies on the auxin-mediated root gravitropism machinery. While the influence of ethylene on auxin levels is known, its specific role in governing root gravitropism and angle remains uncertain, particularly when Arabidopsis (Arabidopsis thaliana) core ethylene signaling mutants show no gravitropic defects. Our research, focusing on rice (Oryza sativa L.) and maize (Zea mays), clearly reveals the involvement of ethylene in root angle regulation in cereal crops through the modulation of auxin biosynthesis and the root gravitropism machinery. We elucidated the molecular components by which ethylene exerts its regulatory effect on auxin biosynthesis to control root gravitropism machinery. The ethylene-insensitive mutants ethylene insensitive2 (osein2) and ethylene insensitive like1 (oseil1), exhibited substantially shallower crown root angle compared to the wild type. Gravitropism assays revealed reduced root gravitropic response in these mutants. Hormone profiling analysis confirmed decreased auxin levels in the root tips of the osein2 mutant, and exogenous auxin (NAA) application rescued root gravitropism in both ethylene-insensitive mutants. Additionally, the auxin biosynthetic mutant mao hu zi10 (mhz10)/tryptophan aminotransferase2 (ostar2) showed impaired gravitropic response and shallow crown root angle phenotypes. Similarly, maize ethylene-insensitive mutants (zmein2) exhibited defective gravitropism and root angle phenotypes. In conclusion, our study highlights that ethylene controls the auxin-dependent root gravitropism machinery to regulate root angle in rice and maize, revealing a functional divergence in ethylene signaling between Arabidopsis and cereal crops. These findings contribute to a better understanding of root angle regulation and have implications for improving resource acquisition in agricultural systems., Competing Interests: Conflict of interest statement. The authors declare that they have no competing interests., (© The Author(s) 2024. Published by Oxford University Press on behalf of American Society of Plant Biologists. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Root angle in crops represents a key trait for efficient capture of soil resources. Root angle is determined by competing gravitropic versus antigravitropic offset (AGO) mechanisms. Here we report a root angle regulatory gene termed ENHANCED GRAVITROPISM1 ( EGT1 ) that encodes a putative AGO component, whose loss-of-function enhances root gravitropism. Mutations in barley and wheat EGT1 genes confer a striking root phenotype, where every root class adopts a steeper growth angle. EGT1 encodes an F-box and Tubby domain-containing protein that is highly conserved across plant species. Haplotype analysis found that natural allelic variation at the barley EGT1 locus impacts root angle. Gravitropic assays indicated that Hvegt1 roots bend more rapidly than wild-type. Transcript profiling revealed Hvegt1 roots deregulate reactive oxygen species (ROS) homeostasis and cell wall-loosening enzymes and cofactors. ROS imaging shows that Hvegt1 root basal meristem and elongation zone tissues have reduced levels. Atomic force microscopy measurements detected elongating Hvegt1 root cortical cell walls are significantly less stiff than wild-type. In situ analysis identified HvEGT1 is expressed in elongating cortical and stele tissues, which are distinct from known root gravitropic perception and response tissues in the columella and epidermis, respectively. We propose that EGT1 controls root angle by regulating cell wall stiffness in elongating root cortical tissue, counteracting the gravitropic machinery's known ability to bend the root via its outermost tissues. We conclude that root angle is controlled by EGT1 in cereal crops employing an antigravitropic mechanism.

The barley cellulose synthase-like F (CslF) genes encode putative cell wall polysaccharide synthases. They are related to the cellulose synthase (CesA) genes involved in cellulose biosynthesis, and the CslD genes that influence root hair development. Although CslD genes are implicated in callose, mannan and cellulose biosynthesis, and are found in both monocots and eudicots, CslF genes are specific to the Poaceae. Recently the barley CslF3 (HvCslF3) gene was shown to be involved in the synthesis of a novel (1,4)-β-linked glucoxylan, but it remains unclear whether this gene contributes to plant growth and development. Here, expression profiling using qRT-PCR and mRNA in situ hybridization revealed that HvCslF3 accumulates in the root elongation zone. Silencing HvCslF3 by RNAi was accompanied by slower root growth, linked with a shorter elongation zone and a significant reduction in root system size. Polymer profiling of the RNAi lines revealed a significant reduction in (1,4)-β-linked glucoxylan levels. Remarkably, the heterologous expression of HvCslF3 in wild-type (Col-0) and root hair-deficient Arabidopsis mutants (csld3 and csld5) complemented the csld5 mutant phenotype, in addition to altering epidermal cell fate. Our results reveal a key role for HvCslF3 during barley root development and suggest that members of the CslD and CslF gene families have similar functions during root growth regulation., (© 2022 The Authors. The Plant Journal published by Society for Experimental Biology and John Wiley & Sons Ltd.)

Background: Diet implementation with insect meal has aroused increased attention in aquaculture considering the advantages of this new protein source. The effect of Hermetia illucens meal (HI) inclusion in diets on rainbow trout physical-chemical and sensory properties was evaluated. Three diets were prepared: HI0, HI25, HI50, with 0, 25 and 50% of HI replacing fish meal, respectively. Fillet sensory profiles were described by descriptive analysis and temporal dominance of sensation methods. Cooking loss, Warner-Bratzler shear force, proximate analysis, and fatty acid composition were also determined., Results: Diets significantly affected fillets sensory profile. Descriptive analysis indicated significant changes in perceived intensity of aroma, flavour and texture descriptors as a function of diet composition. Temporal dominance of sensation evaluations provided information on dominance and evolution of sensations perceived in fillets from different diets. The first sensations perceived as dominant were related to texture attributes, followed by flavours. Dominance of fibrousnesses decreased with the increase of HI in the diet. Boiled fish, algae flavours and umami taste clearly dominated the HI0 dynamic profile. The onset of metallic flavour dominance characterised HI25 and HI50. No differences in physical parameters were detected. Principal component analysis highlighted the relationship between sensory attributes and physico-chemical parameters., Conclusion: The sensory description of fillets indicated that HI inclusion induces significant differences in the perceived profile. © 2016 Society of Chemical Industry., (© 2016 Society of Chemical Industry.)

In order to investigate the effect of n-hexane and its metabolites on the Central Nervous System (CNS), we treated mice with n-hexane and 2,5-hexanedione (2,5-HD) by intraperitoneal (i.p.) administration. Gascromatographic mass spectrometric (GCMS) analyses of striatum and cerebellum revealed a consistent increase of 2,5-HD concentration at 0.5 and 2 hours after treatment and a decline to baseline levels at 24 hours. Traces of 2,5-HD were detected in the brain of control animals. Biochemical analyses revealed a precocious, short lasting, significant increase of striatal dopamine (DA) and homovanillic acid (HVA) levels. A significant increase of striatal synaptosomal DA uptake, suggesting a DA releasing effect on the dopaminergic terminals, was also observed. These results support the hypothesis of a possible role of n-hexane and its metabolites in inducing parkinsonism in humans and animals.

The possibility that age-related changes in amino acid levels in various rat brain areas might correlate with modifications of monoamine oxidase (MAO) activity, already found with aging, has been examined. Taurine, aspartic acid and glutamic acid levels were found to be unchanged or decreased with age, whereas GABA and glutamine concentrations increased or remained unchanged. Serine and glycine (except in pons-medulla) levels were found to be unaffected by age. The increase in total MAO activity with aging in some brain areas might contribute to the changes in amino acid levels. Likewise, the possible influence of age-induced changes in activity of various enzymes involved in H2O2 and NH3 detoxication and in amino acid biosynthesis on rat brain amino acid levels are considered. Oral administration of clorgyline or 1-deprenyl to young rats did not significantly modify the concentrations of most brain amino acids.

The intrahippocampal injection of kainic acid cleared 50% of muscarinic receptors and favored the detection of a further 20% loss in hippocampal presynaptic muscarinic receptors produced by electrolytic lesion of the medial septal nucleus as determined by Scatchard analysis of the saturation isotherms of [3H]dexetimide binding. In accordance, a decrease of about 20% in the in vivo accumulation of [3H]dexetimide in the hippocampus was found in animals lesioned in the medial septal nucleus. This effect occurred at both the dose of 5 micrograms/kg and at the saturating dose of 100 micrograms/kg of [3H]dexetimide. The results suggest that the loss was due to decreased receptor number rather than decreased receptor affinity.

The ergot derivatives, bromocriptine, lisuride and quinpirole (Ly-171555), activators of D-2 receptors, increased striatal acetylcholine (ACh) content by about 40% and induced a 30% inhibition of ACh evoked release from striatal slices, similar to the effects of the dopaminergic agonist apomorphine. These actions were a consequence of dopaminergic activation since they were antagonized by pretreatment with the neuroleptic agent, pimozide. In contrast, pretreatment with L-sulpiride (100 mg/kg), a specific antagonist for the D-2 dopaminergic receptor only, prevented the rise of ACh levels induced by apomorphine or quinpirole but did not interfere with the lisuride- or bromocriptine- induced ACh increases. Similarly, inhibition of the ACh evoked release produced by lisuride (3 microM) was prevented by pimozide (1 mg/kg) but not by pretreatment with L-sulpiride. Addition of L-sulpiride (5 microM) to the Krebs solution had no effect on the inhibition of ACh-evoked release induced by lisuride, but a lower concentration (1 microM) antagonized the inhibition induced by quinpirole. Lisuride and bromocriptine responses were both insensitive to sulpiride. These results are discussed in terms of different interaction with the dopaminergic D-2 receptors by the drugs studied.