Flavonols and flavanones are important bioactive compounds with multiple pharmacological activities and health benefits.  Transcriptional activation of flavonol and flavanone biosynthesis has been studied extensively, while little is known about the negative regulators.  CRISPR/Cas9 gene-editing technology, with the advantage of precise genetic modification, is a desirable tool for breeding biofortified materials and exploring potential molecular mechanisms.  In this study, a transcriptional repressor, SlMYB32, was characterized in tomato fruit.  Phenotype and metabolomic analyses confirmed that knockout of SlMYB32 resulted in increased accumulation of flavonols and flavanones, especially about 1 mg g^–1 FW of quercetin 3-O-rutinoside (rutin).  Transcriptome analysis indicated that expression of key genes SlPAL6, Sl4CL3 and Sl4CL4 as well as five candidate SlUGTs were significantly up-regulated in slmyb32 mutants.  Dual-luciferase and EMSA assays indicated SlMYB32 could bind to and repress promoter activities of SlPAL6 and Sl4CL3.  Expression of 27 transcription factors belonging to 12 families was significantly changed in slmyb32 mutants, among which two SlMYBs, two SlNACs, two SlAP2s and one SlWRKY were clustered with known flavonoid regulators.  Our results provide new insights into improving bioactive compounds in fruit and understanding negative regulatory mechanisms in flavonol and flavanone biosynthesis.

Mating behavior is essential for sexual reproduction, and it is often modulated by key chemical cues.  In many moth species, males find compatible mates through the reception of sex pheromones which are released by females.  Pheromone receptors (PRs) are key elements in sensing these chemical signals.  Concurrently, male moths emit a complex blend of volatile compounds during courtship; however, the mechanisms for recognizing putative male pheromones remain poorly understood.  Here, we employed gas chromatography coupled with electroantennographic detection and mass spectrometry to analyze the volatile compounds produced by males of the cotton bollworm, Helicoverpa armigera.  Three candidate male sex pheromones were identified, with (Z)-7-dodecen-1-yl acetate (Z7-12:OAc) eliciting the most pronounced electrophysiological response in the male antenna.  The olfactory receptor neuron (ORN) ORN-a in Type A trichoid sensilla was shown to respond to Z7-12:OAc by conducting single sensillum recording (SSR) assays.  Additionally, we found that the OR13s from five Heliothinae species responded to Z7-12:OAc by using the Xenopus oocyte expression system and two-electrode voltage-clamp recording.  Our findings identified a candidate for evaluation in future behavioral studies of the poorly understood chemosensory recognition mechanisms underlying male sex pheromones.  If its relevance is supported by behavioral data, this knowledge may facilitate the design of novel olfactory regulators for effective pest control strategies involving mating disruption.

Nitrogen (N) enrichment is expected to induce a greater phosphorus (P) limitation, despite the acceleration of soil P cycling.  However, the changing patterns in plant P and soil available P after N enrichment, and their regulatory mechanisms, remain poorly understood in alpine meadows.  Here, we conducted a field experiment with four N addition rates (0, 5, 10, and 15 g N m^–2 yr^–1) in an alpine meadow, and investigated the P in plants, microorganisms, and soil to determine their patterns of change after short-term N addition.  Our results showed that N addition significantly increased plant biomass, and the plant P pool showed a non-linear response to the N addition gradient.  Soil available P initially increased and then declined with increasing N addition, whereas the occluded inorganic P decreased markedly.  The critical factors for soil available P varied with different N addition rates.  At lower N addition levels (0 and 5 g N m^–2 yr^–1), soil acidification facilitated the mobilization of occluded inorganic P to increase soil available P.  Conversely, at higher N addition levels (10 and 15 g N m^–2 yr^–1), the elevated soil microbial biomass P intensified the competition with plants for soil P, leading to a decline in soil available P.  This study highlights the non-linear responses of the plant P pool and soil available P concentration to N addition rates.  These responses suggest the need for developing ecosystem models to assess different effects of increasing N rates, which would enable more accurate predictions of the plant P supply and soil P cycling under N enrichment.

Spodoptera frugiperda is a highly destructive pest that has become a global problem due to its robust reproductive and migratory capabilities.  Transient receptor potential (TRP) channels, which constitute a vast ion channel family, play pivotal roles in sensing the external environment and maintaining internal homeostasis in insects.  TRP channels have been widely investigated for their critical roles in regulating various insect behaviors in recent years.  In this study, we identified 15 TRP gene loci encoding 26 transcripts in the genome of S. frugiperda and analyzed their expression profiles at different developmental stages.  The results revealed that S. frugiperda possesses four TRPC genes, six TRPA genes, one TRPM gene, two TRPV genes, one TRPN gene, and one TRPML gene, while a canonical TRPP is absent.  Moreover, the SfruTRPA1 was functionally characterized using the Xenopus oocyte expression system.  The results showed that SfruTRPA1 is activated by temperature increases from 20 to 45°C, and there is no significant desensitization after repeated stimuli within the same temperature range.  Additionally, SfruTRPA1 is activated by certain natural chemicals, including allyl isothiocyanate (AITC) and cinnamaldehyde (CA).  These findings provide valuable insights to the TRP genes in S. frugiperda.

Ovarian follicle development is associated with the physiological functions of granulosa cells (GCs), including proliferation and apoptosis.  The level of miR-24-3p in ovarian tissue of high-yielding Yorkshire×Landrace sows was significantly higher than that of low-yielding sows.  However, the functions of miR-24-3p on GCs are unclear.  In this study, using flow cytometry, 5-ethynyl-2´-de-oxyuridine (EdU) staining, and cell count, we showed that miR-24-3p promoted the proliferation of GCs increasing the proportion of cells in the S phase and upregulating the expression of cell cycle genes, moreover, miR-24-3p inhibited GC apoptosis.  Mechanistically, on-line prediction, bioinformatics analysis, a luciferase reporter assay, RT-qPCR, and Western blot results showed that the target gene of miR-24-3p in proliferation and apoptosis is cyclin-dependent kinase inhibitor 1B (P27/CDKN1B).  Furthermore, the effect of miR-24-3p on GC proliferation and apoptosis was attenuated by P27 overexpression.  These findings suggest that miR-24-3p regulates the physiological functions of GCs.

Insects depend on sophisticated olfactory systems for essential behaviors, with odorant receptors (ORs) lying at the core of odor detection. Spodoptera frugiperda is a major global agricultural pest, but the response profiles of its ORs remain largely unresolved. Here we focused on the functional characterization of SfruOR37 in S. frugiperda, an ortholog of Helicoverpa armigera HarmOR50 – which responds to (±)-camphor, an important plant volatile. Tissue expression analysis showed that SfruOR37 is specific expressed in the antennae of both sexes. Using Xenopus laevis oocytes, we functionally screened candidate ligands and identified linalyl acetate as the most potent activator of SfruOR37. To elucidate the binding mechanism between this receptor and its ligand, we performed molecular docking and dynamics simulations, which highlighted several non-conserved residues (notably S151, Y155, and Y325) likely shaping the SfruOR37 binding pocket and mediating the binding affinity to linalyl acetate. Electroantennogram (EAG) recordings demonstrated that linalyl acetate effectively elicits significant electrophysiological responses in adult antennae. In behavioral assays, linalyl acetate elicited a pronounced repellent effect on adult S. frugiperda. Together, our results illuminate how conserved ORs can diverge functionally within Lepidoptera and how such divergence contributes to ecologically relevant olfactory coding. Finally, by establishing linalyl acetate as a behaviorally active repellent for S. frugiperda, this study provides a theoretical basis for developing odorant-based, eco-friendly pest control strategies.

Water-driven crop simulation models are commonly employed to evaluate crop yields and irrigation management strategies to improve agricultural water productivity.  Well-tested models can serve as powerful tools for guiding agricultural practices.  The objective of this study was to assess the capability of the AquaCrop model for simulation of cotton transpiration and water use under drip irrigation conditions comparing with field sap flow measurements.  A two-year field experiment (2020-2021) in cotton was conducted in Xinjiang China including two row spacing and two topping methods.  The model adequately estimated canopy cover with a normalized root mean square error (nRMSE) of less than 5% and a model efficiency (EF) close to 1.  The model estimation of transpiration obtained a good agreement with sap flow measurements (nRMSE=22.4%) across all years and treatments.  The model simulated water use efficiency (WUE, 4.42 g m^-2 mm^-1) of cotton were lower than those calculated from actual measurements with WUE of 4.79 g m^-2 mm^-1.  The estimated transpiration was slightly higher than that measured using sap flow meter due to an 11.5% of overestimation for crop coefficient in the model when cotton grew in short and dense canopy structure under drip irrigation and plastic film cover conditions.  Air temperature, vapor pressure difference and radiation had positive effects on cotton transpiration while humidity had negative effects.  The model could capture the trends of transpiration with climate factors, but the climatic effects were stronger than that of sap flow.  In conclusion, AquaCrop model is useful tool in optimizing cotton irrigation strategies.

The bean bug, Riptortus pedestris, is a major pest of soybeans in East Asian countries. Male-released aggregation pheromones attract both adults and nymphs, offering potential for eco-friendly pest control. However, the molecular mechanisms underlying the detection of the aggregation pheromones remain unclear. In the present study, functional analysis using the Xenopus oocyte expression system demonstrated that two ORs (OR23h and OR109d) were responsible for sensing aggregation pheromones, with the primary component (E)-2-hexenyl (E)-2-hexenoate (E2HE2H) being shared by the two ORs. Further quantitative PCR (qPCR) profiling indicated that OR109d was expressed only in male antennae, while OR23h was expressed in both sexes at similar levels. RNA interference assays demonstrated that dsOR23h-treatment significantly reduced the Electroantennographic (EAG) response of (E)-2-hexenyl (Z)-3-hexenoate (E2HZ3H) in both sexes. Furthermore, simultaneous RNAi knockdown of the two ORs significantly reduced the male EAG response to E2HE2H and abolished male attraction to this compound. These results were consistent with the sex expression profile, demonstrating the sex and functional differentiation between the two ORs. Taken together, this study characterizes the ORs responsible for chemical perception and the associated aggregation behaviors driven by these pheromones. Thus, this study enhances our understanding of olfactory signaling in a hemipteran insect and contributes to the knowledge required for improved pest management.