The rise of baobab trees in Madagascar.

The baobab trees (genus Adansonia) have attracted tremendous attention because of their striking shape and distinctive relationships with fauna1. These spectacular trees have also influenced human culture, inspiring innumerable arts, folklore and traditions. Here we sequenced genomes of all eight extant baobab species and argue that Madagascar should be considered the centre of origin for the extant lineages, a key issue in their evolutionary history2,3. Integrated genomic and ecological analyses revealed the reticulate evolution of baobabs, which eventually led to the species diversity seen today. Past population dynamics of Malagasy baobabs may have been influenced by both interspecific competition and the geological history of the island, especially changes in local sea levels. We propose that further attention should be paid to the conservation status of Malagasy baobabs, especially of Adansonia suarezensis and Adansonia grandidieri, and that intensive monitoring of populations of Adansonia za is required, given its propensity for negatively impacting the critically endangered Adansonia perrieri.

Arabidopsis TETRASPANIN8 mediates exosome secretion and glycosyl inositol phosphoceramide sorting and trafficking.

Sphingolipids are components of plant membranes, and their heterogeneous distribution gives different membrane systems distinct properties. For example, glycosyl inositol phosphoceramides (GIPCs), 1 major type of sphingolipids, aggregate in the outer layer of the plasma membrane (PM), as well as in extracellular vesicles (EVs), including the small (30 to 100 nm) EVs termed exosomes. How these sphingolipids are sorted and trafficked is not clear. In this work, we report that Arabidopsis thaliana TETRASPANIN8 (TET8) acts as a sphingolipid carrier and thus regulates the export of GIPCs from the Golgi apparatus. TET8 recognized the coat protein complex I (COPI) subunit γ2-COPI and moved to its proper location in the PM; this recognition required the TET8 C-terminal tail. Deleting the C-terminal tail of TET8 largely restricted its roles in GIPC transport and endosomal trafficking. Further, we show that TET8 affects EV secretion in association with GIPCs. Thus, our findings shed light on GIPC transport and the molecular machinery involved in EV biogenesis.

The kiwifruit amyloplast proteome (kfALP): a resource to better understand the mechanisms underlying amyloplast biogenesis and differentiation.

The biogenesis and differentiation (B&D) of amyloplasts contributes to fruit flavor and color. Here, remodeling of starch granules, thylakoids and plastoglobules was observed during development and ripening in two kiwifruit (Actinidia spp.) cultivars - yellow-fleshed 'Hort16A' and green-fleshed 'Hayward'. A protocol was developed to purify starch-containing plastids with a high degree of intactness, and amyloplast B&D was studied using label-free-based quantitative proteomic analyses in both cultivars. Over 3000 amyloplast-localized proteins were identified, of which >98% were quantified and defined as the kfALP (kiwifruit amyloplast proteome). The kfALP data were validated by Tandem-Mass-Tag (TMT) labeled proteomics in 'Hort16A'. Analysis of the proteomic data across development and ripening revealed: 1) a conserved increase in the abundance of proteins participating in starch synthesis/degradation during both amyloplast B&D; 2) up-regulation of proteins for chlorophyll degradation and of plastoglobule-localized proteins associated with chloroplast breakdown and plastoglobule formation during amyloplast differentiation; 3) constitutive expression of proteins involved in ATP supply and protein import during amyloplast B&D. Interestingly, two different pathways of amyloplast B&D were observed in the two cultivars. In 'Hayward', significant increases in abundance of photosynthetic- and tetrapyrrole metabolism-related proteins were observed, but the opposite trend was observed in 'Hort16A'. In conclusion, analysis of the kfALP provides new insights into the potential mechanisms underlying amyloplast B&D with relevance to key fruit quality traits in contrasting kiwifruit cultivars.

Role of MST2/YAP1 signaling pathway in retinal cells apoptosis and diabetic retinopathy.

Diabetic retinopathy (DR) is a main factor affecting vision of patients, and its pathogenesis is not completely clear. The purpose of our study was to investigate correlations between MST2 and DR progression, and to study the possible mechanism of MST2 and its down pathway in high glucose (HG)-mediated RGC-5 apoptosis. The diabetic rat model was established by intraperitoneal injection of streptozotocin (STZ) 60 mg/kg. HE and TUNEL staining were used to evaluate the pathological changes and apoptosis of retinal cells in rats. Western blot, qRT-PCR and immunohistochemistry showed that levels of MST2 were increased in diabetic group (DM) than control. In addition, the differential expression of MST2 is related to HG-induced apoptosis of RGC-5 cells. CCK-8 and Hoechst 33,342 apoptosis experiments showed that MST2 was required in HG-induced apoptosis of RGC-5 cells. Further research revealed that MST2 regulated the protein expression of YAP1 at the level of phosphorylation in HG-induced apoptosis. Simultaneously, we found that Xmu-mp-1 acts as a MST2 inhibitor to alleviate HG-induced apoptosis. In summary, our study indicates that the MST2/YAP1 signaling pathway plays an important role in DR pathogenesis and RGC-5 apoptosis. This discovery provides new opportunities for future drug development targeting this pathway to prevent DR.

U-fiber diffusion kurtosis and susceptibility characteristics in relapsing-remitting multiple sclerosis may be related to cognitive deficits and neurodegeneration.

OBJECTIVES: To evaluate the diffusion kurtosis and susceptibility change in the U-fiber region of patients with relapsing-remitting multiple sclerosis (pwRRMS) and their correlations with cognitive status and degeneration. MATERIALS AND METHODS: Mean kurtosis (MK), axial kurtosis (AK), radial kurtosis (RK), kurtosis fractional anisotropy (KFA), and the mean relative quantitative susceptibility mapping (mrQSM) values in the U-fiber region were compared between 49 pwRRMS and 48 healthy controls (HCs). The U-fiber were divided into upper and deeper groups based on the location. The whole brain volume, gray and white matter volume, and cortical thickness were obtained. The correlations between the mrQSM values, DKI-derived metrics in the U-fiber region and clinical scale scores, brain morphologic parameters were further investigated. RESULTS: The decreased MK, AK, RK, KFA, and increased mrQSM values in U-fiber lesions (p < 0.001, FDR corrected), decreased RK, KFA, and increased mrQSM values in U-fiber non-lesions (p = 0.034, p < 0.001, p < 0.001, FDR corrected) were found in pwRRMS. There were differences in DKI-derived metrics and susceptibility values between the upper U-fiber region and the deeper one for U-fiber non-lesion areas of pwRRMS and HCs (p < 0.05), but not for U-fiber lesions in DKI-derived metrics. The DKI-derived metrics and susceptibility values were widely related with cognitive tests and brain atrophy. CONCLUSION: RRMS patients show abnormal diffusion kurtosis and susceptibility characteristics in the U-fiber region, and these underlying tissue abnormalities are correlated with cognitive deficits and degeneration. CLINICAL RELEVANCE STATEMENT: The macroscopic and microscopic tissue damages of U-fiber help to identify cognitive impairment and brain atrophy in multiple sclerosis and provide underlying pathophysiological mechanism. KEY POINTS: • Diffusion kurtosis and susceptibility changes are present in the U-fiber region of multiple sclerosis. • There are gradients in diffusion kurtosis and susceptibility characteristics in the U-fiber region. • Tissue damages in the U-fiber region are correlated with cognitive impairment and brain atrophy.

Comparison of diffusion tensor imaging (DTI) tissue characterization parameters in white matter tracts of patients with multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD).

OBJECTIVE: To investigate the microstructural properties of T2 lesion and normal-appearing white matter (NAWM) in 20 white matter tracts between multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) and correlations between the tissue damage and clinical variables. METHODS: The white matter (WM) compartment of the brain was segmented for 56 healthy controls (HC), 48 patients with MS, and 38 patients with NMOSD, and for the patients further subdivided into T2 lesion and NAWM. Subsequently, the diffusion tensor imaging (DTI) tissue characterization parameters of fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) were compared for 20 principal white matter tracts. The correlation between tissue damage and clinical variables was also investigated. RESULTS: The higher T2 lesion volumes of 14 fibers were shown in MS compared to NMOSD. MS showed more microstructure damage in 13 fibers of T2 lesion, but similar microstructure in seven fibers compared to NMOSD. MS and NMOSD had microstructure damage of NAWM in 20 fibers compared to WM in HC, with more damage in 20 fibers in MS compared to NMOSD. MS patients showed higher correlation between the microstructure of T2 lesion areas and NAWM. The T2 lesion microstructure damage was correlated with duration and impaired cognition in MS. CONCLUSIONS: Patients with MS and NMOSD show different patterns of microstructural damage in T2 lesion and NAWM areas. The prolonged disease course of MS may aggravate the microstructural damage, and the degree of microstructural damage is further related to cognitive impairment. CLINICAL RELEVANCE STATEMENT: Microstructure differences between T2 lesion areas and normal-appearing white matter help distinguish multiple sclerosis and neuromyelitis optica spectrum disorder. In multiple sclerosis, lesions rather than normal-appearing white matter should be a concern, because the degree of lesion severity correlated both with normal-appearing white matter damage and cognitive impairment. KEY POINTS: • Multiple sclerosis and neuromyelitis optica spectrum disorder have different damage patterns in T2 lesion and normal-appearing white matter areas. • The microstructure damage of normal-appearing white matter is correlated with the microstructure of T2 lesion in multiple sclerosis and neuromyelitis optica spectrum disorder. • The microstructure damage of T2 lesion in multiple sclerosis is correlated with duration and cognitive impairment.

Increased cortical lesion load contributed to pathological changes beyond focal lesion in cortical gray matter of multiple sclerosis: a diffusion kurtosis imaging analysis.

Biomarkers specific to cortical gray matter (cGM) pathological changes of multiple sclerosis (MS) are desperately needed to better understand the disease progression. The cGM damage occurs in cortical lesion (CL) and normal-appearing cGM (NAcGM) areas. While the association between CL load and cGM damage has been reported, little is known about how different CL types, i.e. intracortical lesion (ICL) and leukocortical lesion (LCL) would be associated with cGM damage. In our study, relapsing-remitting MS patients and healthy controls were divided into 4 groups according to CL load level. NAcGM diffusion kurtosis imaging (DKI)/diffusion tensor imaging (DTI) values and cGM volume (cGMV) were used to characterize the pathological changes in cGM. Univariate general linear model was used for group comparisons and stepwise regression analysis was used to assess the effects of ICL volume and LCL volume on NAcGM damage. We found peak values in DKI/DTI values, cGMV and neuropsychological scores in high CL load group. Kurtosis fractional anisotropy (KFA) was the most sensitive in characterizing NAcGM damage, and LCL volume related more to NAcGM damage. Our findings suggested KFA could become a surrogate biomarker to cGM damage, and LCL might be the main factor in whole brain NAcGM damage.

Comparative Long Non-Coding Transcriptome Analysis of Three Contrasting Barley Varieties in Response to Aluminum Stress.

Aluminum toxicity is a major abiotic stress on acidic soils, leading to restricted root growth and reduced plant yield. Long non-coding RNAs are crucial signaling molecules regulating the expression of downstream genes, particularly under abiotic stress conditions. However, the extent to which lncRNAs participate in the response to aluminum (Al) stress in barley remains largely unknown. Here, we conducted RNA sequencing of root samples under aluminum stress and compared the lncRNA transcriptomes of two Tibetan wild barley genotypes, XZ16 (Al-tolerant) and XZ61 (Al-sensitive), as well as the aluminum-tolerant cultivar Dayton. In total, 268 lncRNAs were identified as aluminum-responsive genes on the basis of their differential expression profiles under aluminum treatment. Through target gene prediction analysis, we identified 938 candidate lncRNA-messenger RNA (mRNA) pairs that function in a cis-acting manner. Subsequently, enrichment analysis showed that the genes targeted by aluminum-responsive lncRNAs were involved in diterpenoid biosynthesis, peroxisome function, and starch/sucrose metabolism. Further analysis of genotype differences in the transcriptome led to the identification of 15 aluminum-responsive lncRNAs specifically altered by aluminum stress in XZ16. The RNA sequencing data were further validated by RT-qPCR. The functional roles of lncRNA-mRNA interactions demonstrated that these lncRNAs are involved in the signal transduction of secondary messengers, and a disease resistance protein, such as RPP13-like protein 4, is probably involved in aluminum tolerance in XZ16. The current findings significantly contribute to our understanding of the regulatory roles of lncRNAs in aluminum tolerance and extend our knowledge of their importance in plant responses to aluminum stress.

Generation and characterization of a P2rx2 V60L mouse model for DFNA41.

P2RX2 encodes the P2X2 receptor, which is an adenosine triphosphate (ATP) gated (purinoreceptor) ion channel. P2RX2 c. 178G > T (p.V60L) mutation was previously identified in two unrelated Chinese families, as the cause of human DFNA41, a form of dominant, early-onset and progressive sensorineural hearing loss. We generated and characterized a knock-in mouse model based on human p.V60L mutation that recapitulates the human phenotype. Heterozygous KI mice started to exhibit hearing loss at 21-day-old and progressed to deafness by 6-month-old. Vestibular dysfunction was also observed in mutant mice. Abnormal morphology of the inner hair cells and ribbon synapses was progressively observed in KI animals suggesting that P2rx2 plays a role in the membrane spatial location of the ribbon synapses. These results suggest that P2rx2 is essential for acoustic information transfer, which can be the molecular mechanism related to hearing loss.

A highly accumulated secretory protein from cotton bollworm interacts with basic helix-loop-helix transcription factors to dampen plant defense.

Caterpillar oral secretion (OS) contains active molecules that modulate plant defense signaling. We isolated an effector-like protein (Highly Accumulated Secretory Protein 1, HAS1) from cotton bollworm (Helicoverpa armigera) that is the most highly accumulated secretory protein of the nondigestive components in OS and belongs to venom R-like protein. Elimination of HAS1 by plant-mediated RNA interference reduced the suppression of OS on the defense response in plants. Plants expressing HAS1 are more susceptible to insect herbivory accompanied by the reduced expressions of multiple defense genes. HAS1 binds to the basic helix-loop-helix (bHLH) transcription factors, including GoPGF involved in pigmented gland formation and defense compounds biosynthesis in cotton and MYC3/MYC4 the main regulators in jasmonate (JA) signaling in Arabidopsis. The binding activity is required for HAS1 to inhibit the activation of bHLHs on plant defense gene expressions. Together with our previous study that another venom R-like protein HARP1 in cotton bollworm OS blocks JA signaling by interacting with JASMONATE-ZIM-domain repressors, we conclude that the venom R-like proteins in OS interfere with plant defense in a dual suppression manner. Considering the venom proteins in parasitic wasp assault the immune system of its host animal, our investigation reveals their conserved function in carnivorous and herbivorous insects.

A 2-oxoglutarate-dependent dioxygenase converts dihydrofuran to furan in Salvia diterpenoids.

Tanshinone ⅡA (TⅡA), a diterpene quinone with a furan ring, is a bioactive compound found in the medicinal herb redroot sage (Salvia miltiorrhiza Bunge), in which both furan and dihydrofuran analogs are present in abundance. Progress has been made recently in elucidating the tanshinone biosynthetic pathway, including heterocyclization of the dihydrofuran D-ring by cytochrome P450s; however, dehydrogenation of dihydrofuran to furan, a key step of furan ring formation, remains uncharacterized. Here, by differential transcriptome mining, we identified six 2-oxoglutarate-dependent dioxygenase (2-ODD) genes whose expressions corresponded to tanshinone biosynthesis. We showed that Sm2-ODD14 acts as a dehydrogenase catalyzing the furan ring aromatization. In vitro Sm2-ODD14 converted cryptotanshinone to TⅡA and thus was designated TⅡA synthase (SmTⅡAS). Furthermore, SmTⅡAS showed a strict substrate specificity, and repression of SmTⅡAS expression in hairy root by RNAi led to increased accumulation of total dihydrofuran-tanshinones and decreased production of furan-tanshinones. We conclude that SmTⅡAS controls the metabolite flux from dihydrofuran- to furan-tanshinones, which influences medicinal properties of S. miltiorrhiza.

Enlarged choroid plexus related to cortical atrophy in multiple sclerosis.

OBJECTIVES: To investigate the correlation between choroid plexus volume and whole brain morphology in patients with multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD). METHODS: Fifty-one patients with MS, 42 patients with NMOSD, and 56 healthy controls (HC) were recruited. The morphological changes in choroid plexus and whole brain tissue were compared between three groups and the correlations between choroid plexus volume and brain atrophy were further investigated. The longitudinal alterations of brain morphology in 25 MS and 20 NMOSD patients were compared. RESULTS: Compared to the HC group, the choroid plexus volumes were increased in the MS group (p < 0.001) but not in the NMOSD group (p > 0.05). Compared to the HC group, the MS group showed reduced cortex thickness, deep gray matter volume, and increased ventricle system volume, and the NMOSD group showed increased third ventricle volume (all p < 0.05, false discovery rate corrected). In the MS group, there were widespread correlations between enlarged choroid plexus volume and reduced cerebral cortex thickness (p < 0.05, r = -0.292~-0.538, false discovery rate corrected). The interval time was not significantly different between the MS (median: 1.37 years) and NMOSD group (median: 1.25 years) (p > 0.05). In MS, compared with the baseline, the right hippocampus and nucleus accumbens volumes were decreased in long follow-up, and bilateral lateral ventricle volumes were increased both in short and long follow-up (all p < 0.05, false discovery rate corrected). CONCLUSIONS: The enlarged choroid plexus related to reduced cortical thickness and progressive local brain atrophy are shown in MS patients, but not obvious in NMOSD patients. KEY POINTS: • MS and NMOSD have different altered patterns in choroid plexus volume and brain atrophy. • The enlarged choroid plexus related to brain atrophy is shown in MS patients, but not obvious in NMOSD patients. • Progressive local brain atrophy is shown in MS patients, but not obvious in NMOSD patients.

Hexafluorobutanol primary alcohol ethoxylate-based supramolecular solvent formation and their application in direct microextraction of malachite green and crystal violet from lake sediments.

A new type of hexafluorobutanol (HFB) primary alcohol ethoxylate (AEO)-based supramolecular solvent (SUPRAS) with density higher than water was prepared for the first time. HFB acted as AEO micelle-forming agent and density-regulating agent for SUPRAS formation. The prepared SUPARS was applied as extraction solvent for vortex-assisted direct microextraction of malachite green (MG) and crystal violet (CV) from lake sediment followed by high-performance liquid chromatographic determination. In the present work, SUPRASs prepared from AEO with different carbon chains as the amphiphiles and various coacervation agents were investigated. SUPARS formed from MOA-3 and HFB provided better extraction efficiency in comparison with other SUPRASs. Parameters influencing the extraction recovery of target analytes including the type and volume of AEO, volume of HFB, and vortex time were investigated and optimized. Under optimized conditions, linearity in the range of 2.0-400 µg g-1 for MG and 2.0-500 µg g-1 for CV with a correlation coefficient higher than 0.9947 was obtained. Limits of detection of 0.5 µg g-1 and relative standard deviations in the range of 0.9-5.8% were obtained. Compared to conventional extraction techniques for analysis of analytes in solid samples, the proposed method reduced sample usage and eliminated a primary extraction process by using a toxic organic solvent. The proposed method is simple, fast, and green and can be used for the analysis of target analytes in solid samples.

Two types of O-methyltransferase are involved in biosynthesis of anticancer methoxylated 4'-deoxyflavones in Scutellaria baicalensis Georgi.

The medicinal plant Scutellaria baicalensis Georgi is rich in specialized 4'-deoxyflavones, which are reported to have many health-promoting properties. We assayed Scutellaria flavones with different methoxyl groups on human cancer cell lines and found that polymethoxylated 4'-deoxyflavones, like skullcapflavone I and tenaxin I have stronger ability to induce apoptosis compared to unmethylated baicalein, showing that methoxylation enhances bioactivity as well as the physical properties of specialized flavones, while having no side-effects on healthy cells. We investigated the formation of methoxylated flavones and found that two O-methyltransferase (OMT) families are active in the roots of S. baicalensis. The Type II OMTs, SbPFOMT2 and SbPFOMT5, decorate one of two adjacent hydroxyl groups on flavones and are responsible for methylation on the C6, 8 and 3'-hydroxyl positions, to form oroxylin A, tenaxin II and chrysoeriol respectively. The Type I OMTs, SbFOMT3, SbFOMT5 and SbFOMT6 account mainly for C7-methoxylation of flavones, but SbFOMT5 can also methylate baicalein on its C5 and C6-hydroxyl positions. The dimethoxylated flavone, skullcapflavone I (found naturally in roots of S. baicalensis) can be produced in yeast by co-expressing SbPFOMT5 plus SbFOMT6 when the appropriately hydroxylated 4'-deoxyflavone substrates are supplied in the medium. Co-expression of SbPFOMT5 plus SbFOMT5 in yeast produced tenaxin I, also found in Scutellaria roots. This work showed that both type I and type II OMT enzymes are involved in biosynthesis of methoxylated flavones in S. baicalensis.

A Promiscuous CYP706A3 Reduces Terpene Volatile Emission from Arabidopsis Flowers, Affecting Florivores and the Floral Microbiome.

Flowers are essential but vulnerable plant organs, exposed to pollinators and florivores; however, flower chemical defenses are rarely investigated. We show here that two clustered terpene synthase and cytochrome P450 encoding genes (TPS11 and CYP706A3) on chromosome 5 of Arabidopsis (Arabidopsis thaliana) are tightly coexpressed in floral tissues, upon anthesis and during floral bud development. TPS11 was previously reported to generate a blend of sesquiterpenes. By heterologous coexpression of TPS11 and CYP706A3 in yeast (Saccharomyces cerevisiae) and Nicotiana benthamiana, we demonstrate that CYP706A3 is active on TPS11 products and also further oxidizes its own primary oxidation products. Analysis of headspace and soluble metabolites in cyp706a3 and 35S:CYP706A3 mutants indicate that CYP706A3-mediated metabolism largely suppresses sesquiterpene and most monoterpene emissions from opening flowers, and generates terpene oxides that are retained in floral tissues. In flower buds, the combined expression of TPS11 and CYP706A3 also suppresses volatile emissions and generates soluble sesquiterpene oxides. Florivory assays with the Brassicaceae specialist Plutella xylostella demonstrate that insect larvae avoid feeding on buds expressing CYP706A3 and accumulating terpene oxides. Composition of the floral microbiome appears also to be modulated by CYP706A3 expression. TPS11 and CYP706A3 simultaneously evolved within Brassicaceae and form the most versatile functional gene cluster described in higher plants so far.plantcell;31/12/2947/FX1F1fx1.

Aromatization of natural products by a specialized detoxification enzyme.

In plants, lineage-specific metabolites can be created by activities derived from the catalytic promiscuity of ancestral proteins, although examples of recruiting detoxification systems to biosynthetic pathways are scarce. The ubiquitous glyoxalase (GLX) system scavenges the cytotoxic methylglyoxal, in which GLXI isomerizes the α-hydroxy carbonyl in the methylglyoxal-glutathione adduct for subsequent hydrolysis. We show that GLXIs across kingdoms are more promiscuous than recognized previously and can act as aromatases without cofactors. In cotton, a specialized GLXI variant, SPG, has lost its GSH-binding sites and organelle-targeting signal, and evolved to aromatize cyclic sesquiterpenes bearing α-hydroxyketones to synthesize defense compounds in the cytosol. Notably, SPG is able to transform acetylated deoxynivalenol, the prevalent mycotoxin contaminating cereals and foods. We propose that detoxification enzymes are a valuable source of new catalytic functions and SPG, a standalone enzyme catalyzing complex reactions, has potential for toxin degradation, crop engineering and design of novel aromatics.

Mitochondrial small heat shock protein mediates seed germination via thermal sensing.

Seed germination is an energy demanding process that requires functional mitochondria upon imbibition. However, how mitochondria fine tune seed germination, especially in response to the dynamics of environmental temperature, remains largely unknown at the molecular level. Here, we report a mitochondrial matrix-localized heat shock protein GhHSP24.7, that regulates seed germination in a temperature-dependent manner. Suppression of GhHSP24.7 renders the seed insensitive to temperature changes and delays germination. We show that GhHSP24.7 competes with GhCCMH to bind to the maturation subunit protein GhCcmFc to form cytochrome C/C1 (CytC/C1) in the mitochondrial electron transport chain. GhHSP24.7 modulates CytC/C1 production to induce reactive oxygen species (ROS) generation, which consequently accelerates endosperm rupture and promotes seed germination. Overexpression of GhHSP24.7's homologous genes can accelerate seed germination in Arabidopsis and tomato, indicating its conserved function across plant species. Therefore, HSP24.7 is a critical factor that positively controls seed germination via temperature-dependent ROS generation.

An effector from cotton bollworm oral secretion impairs host plant defense signaling.

Insects have evolved effectors to conquer plant defense. Most known insect effectors are isolated from sucking insects, and examples from chewing insects are limited. Moreover, the targets of insect effectors in host plants remain unknown. Here, we address a chewing insect effector and its working mechanism. Cotton bollworm (Helicoverpa armigera) is a lepidopteran insect widely existing in nature and severely affecting crop productivity. We isolated an effector named HARP1 from H. armigera oral secretion (OS). HARP1 was released from larvae to plant leaves during feeding and entered into the plant cells through wounding sites. Expression of HARP1 in Arabidopsis mitigated the global expression of wounding and jasmonate (JA) responsive genes and rendered the plants more susceptible to insect feeding. HARP1 directly interacted with JASMONATE-ZIM-domain (JAZ) repressors to prevent the COI1-mediated JAZ degradation, thus blocking JA signaling transduction. HARP1-like proteins have conserved function as effectors in noctuidae, and these types of effectors might contribute to insect adaptation to host plants during coevolution.

Highly Efficient Ionic Gating of Solid-State Nanosensors by the Reversible Interaction between Pillar[6]arene-AuNPs and Azobenzene.

By mimicking nature, various artificial nanofluidic platforms have been widely applied in a range of scientific fields. However, their low performance in terms of gating efficiency (<25) still hinders their practical applications. Herein, we present a highly efficient ionic gating nanosensor by fusing the merits of host-guest chemistry and Au nanoparticles (AuNPs). Based on this strategy, the pillar[6]arene (WP6)-functionalized AuNPs facilely regulated an azobenzene (AZO)-modified nanosensor with an excellent ion rectification ratio (∼22.2) and gating efficiency (∼89.5). More importantly, this gating nanosensor system also demonstrated promising stability and recyclability under conditions of alternative irradiation of visible and ultraviolet light. These excellent results would significantly help in expanding the utilization of artificial nanosensors for controllable drug delivery and biosensors.

Mediation of JA signalling in glandular trichomes by the woolly/SlMYC1 regulatory module improves pest resistance in tomato.

Almost all plants form trichomes, which protect them against insect herbivores by forming a physical barrier and releasing chemical repellents. Glandular trichomes produce a variety of specialized defensive metabolites, including volatile terpenes. Previous studies have shown that the defence hormone jasmonic acid (JA) affects trichome development and induces terpene synthases (TPSs) but the underlying molecular mechanisms remain unclear. Here, we characterized a loss-of-function allele of the HD-ZIP IV transcription factor woolly (wo) and analysed its role in mediating JA signalling in tomato. We showed that knockout of wo led to extensive trichome defects, including structural and functional changes in type VI glandular trichomes, and a dramatic reduction in terpene levels. We further found that wo directly binds to TPS gene promoters to recruit SlMYC1, a JA signalling modulator, and that together these transcription factors promote terpene biosynthesis in tomato trichomes. The wo/SlMYC1 regulatory module is inhibited by SlJAZ2 through a competitive binding mechanism, resulting in a fine-tuned JA response in tomato trichomes. Enhanced expression of SlMYC1 substantially increased terpene levels and improved tomato resistance to spider mites. Interestingly, we also found that SlMYC1 plays an additional role in glandular cell division and expansion in type VI trichomes, independent of JA. Together, our results reveal a novel, JA-mediated regulatory mechanism that promotes insect resistance in tomato.