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Abstract Wheat leaf rust, caused by Puccinia triticina (Pt), remains a constant threat to wheat production worldwide. Deployment of race-specific leaf rust (Lr) resistance genes in wheat provides effective protection against leaf rust, but often leads to selective pressures that drive the rapid emergence of new virulent Pt isolates in nature. However, the molecular mechanisms underlying the evasion of Lr-delivered resistance by leaf rust remain largely unknown. Here, we identify an avirulence gene AvrLr21 in Pt that triggers Lr21-dependent immune responses. BSMV (Barley stripe mosaic virus)-mediated host-induced gene silencing assay shows that silencing AvrLr21 compromises Lr21-mediated immunity. AvrLr21 interacts directly with Lr21 protein to induce a hypersensitive response in tobacco leaves. The evolved Lr21-breaking Pt isolates can suppress Lr21-mediated immunity. Our data provide a basis for studying the molecular determinants in Pt-wheat incompatible interaction and monitoring natural Pt populations to prioritize the deployment of Lr resistance genes in the field.

BackgroundRadish seed is a functional food with many beneficial health effects. Glucosinolates are characteristic components in radish seed that can be transformed into bioactive isothiocyanates by gut microbiota.ObjectiveThe present study aims to assess anti-obesity efficacy of radish seed glucosinolates (RSGs) and explored the underlying mechanisms with a focus on gut microbiota and fecal metabolome.MethodsHigh-fat diet-induced obese mice were supplemented with different doses of RSGs extract for 8 weeks. Changes in body weight, serum lipid, alanine aminotransferase (ALT), and aspartate aminotransferase (AST) levels; and pathological changes in the liver and adipose tissue were examined. Fecal metabolome and 16S rRNA gene sequencing were used to analyze alterations in fecal metabolite abundance and the gut microbiota, respectively.Results and conclusionResults showed that RSG extract prevented weight gain and decreased serum lipid, ALT, AST levels and lipid deposition in liver and epididymal adipocytes in obese mice. Treatment with RSG extract also increased gut microbiota diversity and altered the dominant bacteria genera in the gut microbiota, decreasing the abundance of Faecalibaculum and increasing the abundance of Allobaculum, Romboutsia, Turicibacter, and Akkermansia. Fecal metabolome results identified 570 differentially abundant metabolites, of which glucosinolate degradation products, such as sulforaphene and 7-methylsulfinylheptyl isothiocyanate, were significantly upregulated after RSG extract intervention. Furthermore, enrichment analysis of metabolic pathways showed that the anti-obesity effects of RSG extract may be mediated by alterations in bile secretion, fat digestion and absorption, and biosynthesis of plant secondary metabolites. Overall, RSG extract can inhibit the development of obesity, and the obesity-alleviating effects of RSG are related to alternative regulation of the gut microbiota and glucosinolate metabolites.

Puccinia triticina (Pt), as the causal agent of wheat leaf rust, employs a plethora of effector proteins to modulate wheat immunity for successful colonization. Understanding the molecular mechanisms underlying Pt effector-mediated wheat susceptibility remains largely unexplored. In this study, an effector Pt_21 was identified to interact with the apoplast-localized wheat thaumatin-like protein TaTLP1 using a yeast two-hybrid assay and the Pt_21-TaTLP1 interaction was characterized. The interaction between Pt_21 and TaTLP1 was validated by in vivo co-immunoprecipitation assay. A TaTLP1 variant, TaTLP1C71A, that was identified by the site-directed mutagenesis failed to interact with Pt_21. Pt_21 was able to suppress Bax-mediated cell death in leaves of Nicotiana benthamiana and inhibit TaTLP1-mediated antifungal activity. Furthermore, infiltration of recombinant protein Pt_21 into leaves of transgenic wheat line overexpressing TaTLP1 enhanced the disease development of leaf rust compared to that in wild-type leaves. These findings demonstrate that Pt_21 suppresses host defense response by directly targeting wheat TaTLP1 and inhibiting its antifungal activity, which broadens our understanding of the molecular mechanisms underlying Pt effector-mediated susceptibility in wheat.

Wheat leaf rust, caused by Puccinia triticina, is one of the most common fungal diseases of wheat in China and occurs widely in various wheat-growing regions. To clarify the epidemic, spread rules, and population structure of P. triticina among different regions, 217 isolates of P. triticina collected from Hebei, Shandong, Sichuan, and Xinjiang in China were tested by 34 Thatcher near-isogenic lines and 21 pairs of EST-SSR primers. A total of 83 races were identified, and THTT, PHTT, THTS, and PHJT were the most predominant races in the four provinces in 2009. We found enriched virulence and genetic diversity in the four P. triticina populations and a significant correlation between genetic polymorphism and geographic regions. However, no significant correlation was found between virulence phenotypes and molecular genotypes. Moreover, a notable high level of gene flow (Nm = 2.82 > 1) among four P. triticina populations was detected. The genetic relationship among Hebei, Shandong, and Sichuan populations was close, possibly due to the spread of P. triticina from Sichuan to Shandong and then to Hebei. In contrast, the Xinjiang population was relatively independent. Genetic differentiation analysis showed some level of differentiation among or within populations of P. triticina in the four provinces, and the genetic variation within populations (74.97%) was higher than across populations (25.03%). Our study provides a basis for a better understanding of the regional migration, epidemic, and population structure of P. triticina in China.

The binding capacity of 10 flavonoids with okra seed protein (OSP) was studied by fluorescence spectroscopy. The structure of flavonoids had an obvious impact on binding performance. The binding ability of flavanone was lower than that of flavone, isoflavone and dihydrochalcone. The binding capacity of flavonoid glycoside was superior to that of the corresponding flavonoid aglycone. The binding ability was positively correlated with the number of phenolic hydroxyl groups on the B ring. The steric field and electrostatic field model constructed by 3D-QSAR method could well explain the above interaction behavior. Thermodynamic analysis suggested that the quenching mechanism of OSP caused by flavonoids was static quenching, and the binding-site number was 1. In addition, hydrogen bonding and van der Waals force dominated this interaction. The 3D and synchronous fluorescence spectra showed that there was no significant change in the polarity of the environment around tryptophan and tyrosine residues during binding.

Wheat leaf rust, caused by Puccinia triticina, is one of the most important fungal diseases of wheat in China. However, little is known about the dynamic changes of population structure and genetic diversity of P. triticina during a period of time. In this study, 247 isolates of P. triticina collected from Hebei Province from 2001 to 2010 were tested on 36 Thatcher near-isogenic lines for virulence diversity and detected by 21 pairs of Expressed Sequence Tag derived Simple Sequence Repeat (EST-SSR) primers for genetic diversity. A total of 204 isolates were successfully identified as 164 races, and THTT, THST, PHRT, THTS, and PHTT were the most common races in Hebei Province from 2001 to 2010. The cluster analysis based on virulence showed that P. triticina has a rich virulence polymorphism, which had a certain correlation with the years, while the cluster analysis based on EST-SSR showed that the genetic diversity of the P. triticina population was significantly different between years in Hebei Province from 2001 to 2010. In addition, the population structure of P. triticina may have changed greatly in 2007 and 2009, which was significantly different from that of 2001–2006 on either virulence or genetic characteristics. The variation frequency of the population structure had an increasing trend during this period. From 2001 to 2010, there was a certain degree of gene flow among the P. triticina populations. No significant correlation was found between virulence and molecular polymorphism. The genetic differentiation analysis of the 10 tested populations (each year as a population) showed that the coefficient of genetic differentiation (Gst) was 0.27, indicating that there was a certain genetic differentiation among or within populations of P. triticina in Hebei Province. The genetic variation within populations (73.08%) was higher than that among populations (26.92%), which indicated that the genetic variations were mainly found within populations. Our study provides the foundation for a better understanding of the population structure change and genetic diversity of P. triticina over a period in Hebei Province of China.

IntroductionWheat leaf rust caused by Puccinia triticina (Pt) remains one of the most destructive diseases of common wheat worldwide. Understanding the pathogenicity mechanisms of Pt is important to control wheat leaf rust.MethodsThe urediniospores of Pt race PHNT (wheat leaf rust resistance gene Lr19-avirulent isolate) were mutagenized with ethyl methanesulfonate (EMS), and two Lr19-virulent mutants named M1 and M2 were isolated. RNA sequencing was performed on samples collected from wheat cultivars Chinese Spring and TcLr19 infected with wild-type (WT) PHNT, M1, and M2 isolates at 14 days post-inoculation (dpi), respectively. Screening AvrLr19 candidates by quantitative reverse transcription PCR (qPCR) and Agrobacterium-mediated transient assays in Nicotiana benthamiana.Results560 genes with single nucleotide polymorphisms (SNPs) and insertions or deletions (Indels) from non-differentially expressed genes were identified. Among them, 10 secreted proteins were screened based on their fragments per kilobase of exon model per million mapped reads (FPKM) values in the database. qPCR results showed that the expression profiles of 7 secreted proteins including PTTG_27471, PTTG_12441, PTTG_28324, PTTG_26499, PTTG_06910, PTTG_26516, and PTTG_03570 among 10 secreted proteins in mutants were significantly different with that in wild-type isolate after infection wheat TcLr19 and might be related to the recognition between Lr19 and AvrLr19. In addition, a total of 216 differentially expressed genes (DEGs) were obtained from three different sample comparisons including M1-vs-WT, M2-vs-WT, and M1-vs-M2. Among 216 DEGs, 15 were predicted to be secreted proteins. One secreted protein named PTTG_04779 could inhibit programmed progress of cell death (PCD) induced by apoptosis-controlling genes B-cell lymphoma-2 associated X protein (BAX) on Nicotiana benthamiana, indicating that it might play a virulence function in plant. Taken together, total 8 secreted proteins, PTTG_04779, PTTG_27471, PTTG_12441, PTTG_28324, PTTG_26499, PTTG_06910, PTTG_26516, PTTG_03570 are identified as AvrLr19 candidates.DiscussionOur results showed that a large number of genes participate in the interaction between Pt and TcLr19, which will provide valuable resources for the identification of AvrLr19 candidates and pathogenesis-related genes.

Wheat leaf rust, caused by Puccinia triticina Eriks. (Pt), is a global wheat disease threatening wheat production. Dissecting how Pt effector proteins interact with wheat has great significance in understanding the pathogenicity mechanisms of Pt. In the study, the cDNA of Pt 13-5-72 interacting with susceptible cultivar Thatcher was used as template to amplify Pt13024 gene. The expression pattern and structure of Pt13024 were analyzed by qRT-PCR and online softwares. The secretion function of Pt13024 signal peptide was verified by the yeast system. Subcellular localization of Pt13024 was analyzed using transient expression on Nicotiana benthamiana. The verification that Pt13024 inhibited programmed cell death (PCD) was conducted on N. benthamiana and wheat. The deletion mutation of Pt13024 was used to identify the virulence function motif. The transient transformation of wheat mediated by the type III secretion system (TTSS) was used to analyze the activity of regulating the host defense response of Pt13024. Pt13024 gene silencing was performed by host-induced gene silencing (HIGS). The results showed that Pt13024 was identified as an effector and localized in the cytoplasm and nucleus on the N. benthamiana. It can inhibit PCD induced by the Bcl-2-associated X protein (BAX) from mice and infestans 1 (INF1) from Phytophthora infestans on N. benthamiana, and it can also inhibit PCD induced by DC3000 on wheat. The amino acids 22 to 41 at N-terminal of the Pt13024 are essential for the inhibition of programmed cell death (PCD) induced by BAX. The accumulation of reactive oxygen species and deposition of callose in near-isogenic line TcLr30, which is in Thatcher background with Lr30, induced by Pt13024 was higher than that in 41 wheat leaf rust-resistant near-isogenic lines (monogenic lines) with different resistance genes and Thatcher. Silencing of Pt13024 reduced the leaf rust resistance of Lr30 during the interaction between Pt and TcLr30. We can conclude that Pt13024 is avirulent to TcLr30 when Pt interacts with TcLr30. These findings lay the foundation for further investigations into the role of Pt effector proteins in pathogenesis and their regulatory mechanisms.

Vegetables from the Brassica species are excellent sources of glucosinolates (GLSs), the precursors of health-promoting isothiocyanates (ITCs). Fermentation enhances the biotransformation of GLSs into potential bioactive ITCs. To explore the biotransformation of GLSs during Brassica fermentation, the changes in GLSs during the fermentation of two Brassica species (i.e., cauliflower and broccoli); the formation of corresponding breakdown products; and the shifts in physicochemical parameters, bacterial communities, and myrosinase activities involved in GLSs degradation were systematically investigated. Nine aliphatic, three indolic, and two benzenic GLSs were identified in fermented cauliflower (FC) and fermented broccoli (FB). Aliphatic glucoiberin and glucoraphanin were the major forms of GLS in FC and FB, respectively; indolic glucobrassicin was also abundant in both FC and FB. The total GLS content decreased by 85.29% and 65.48% after 3 d of fermentation in FC and FB, respectively. After 2 d of fermentation, a significant increase in bioactive GLS degradation products (P

Olive leaves are rich in phenolic compounds. This study explored the chemical profiles and contents of free phenolics (FPs) and bound phenolics (BPs) in olive leaves, and further investigated and compared the antioxidant properties of FPs and BPs using chemical assays, cellular antioxidant evaluation systems, and in vivo mouse models. The results showed that FPs and BPs have different phenolic profiles; 24 free and 14 bound phenolics were identified in FPs and BPs, respectively. Higher levels of phenolic acid (i.e., sinapinic acid, 4-coumaric acid, ferulic acid, and caffeic acid) and hydroxytyrosol were detected in the BPs, while flavonoids, triterpenoid acids, and iridoids were more concentrated in the free form. FPs showed a significantly higher total flavonoid content (TFC), total phenolic content (TPC), and chemical antioxidant properties than those of BPs (p < 0.05). Within the range of doses (20–250 μg/mL), both FPs and BPs protected HepG2 cells from H2O2-induced oxidative stress injury, and there was no significant difference in cellular antioxidant activity between FPs and BPs. The in vivo experiments suggested that FP and BP treatment inhibited malondialdehyde (MDA) levels in a D-galactose-induced oxidation model in mice, and significantly increased antioxidant enzyme activity of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT), and the total antioxidant capacity (T-AOC). Mechanistically, FPs and BPs exert their antioxidant activity in distinct ways; FPs ameliorated D-galactose-induced oxidative stress injury partly via the activation of nuclear factor erythroid-2-related factor 2 (Nrf2) signaling pathway, while the BP mechanisms need further study.

The impact of fermentation by Levilactobacillus brevis YSJ3 on sleep-promoting components (SPCs) of carrot juice was evaluated. The contents of acetic acid, isovaleric acid, butyric acid, and γ-aminobutyric acid (GABA) significantly increased after fermentation. The beneficial effects of fermented carrot juice (FCJ) on sleep were evaluated in animal experiments. Behavioral test reveal SPCs-enriched FCJ could effectively relieve anxiety. The sleep duration in the FCJ group were extended compared to the control (NC) group and the unfermented carrot juice (UCJ) group. Moreover, the relative abundances of Ruminiclostridium and Akkermansia in the FCJ group and PC group, respectively, increased significantly, compared to the NC group the UCJ group. The contents of gut short-chain fatty acids in the FCJ group were significantly higher than that in the NC group and the UCJ group. The levels of GABA and 5-hydroxytryptamine in the brain for the FCJ group also increased significantly, compared to the NC group and the UCJ group. It indicated that SPCs-enriched FCJ effectively improved sleep in mice, which might be related to the fermentation of carrot juice and the compounds produced during the fermentation.

Puccinia triticina, which is the causative agent of wheat leaf rust, is widely spread in China and most other wheat-planting countries around the globe. Cultivating resistant wheat cultivars is the most economical, effective, and environmentally friendly method for controlling leaf rust-caused yield damage. Exploring the source of resistance is very important in wheat resistance breeding programs. In order to explore more effective resistance sources for wheat leaf rust, the resistance of 112 wheat accessions introduced from the U.S. National Plant Germplasm System were identified using a mixture of pathogenic isolates of THTT, THTS, PHTT, THJT and THJS which are the most predominant races in China. As a result, all of these accessions showed high resistance at seedling stage, of which, ninety-nine accessions exhibited resistance at adult plant stage. Eleven molecular markers of eight effective leaf rust resistance genes in China were used to screen the 112 accessions. Seven effective leaf rust resistance genes Lr9, Lr19, Lr24, Lr28, Lr29, Lr38 and Lr45 were detected, except Lr47. Twenty-three accessions had only one of those seven effective leaf rust resistance gene. Eleven accessions carried Lr24+Lr38, and 7 accessions carried Lr9+Lr24+Lr38, Lr24+Lr38+Lr45, Lr24+Lr29+Lr38 and Lr19+Lr38+Lr45 respectively. The remaining seventy-one accessions had none of those eight effective leaf rust resistance genes. This study will provide theoretical guidance for rational utilization of these introduted wheat accessions directly or for breeding the resistant wheat cultivars.

Pathogenesis-related (PR) proteins play important roles in plant defense response and systemic acquired resistance (SAR). PR1 has antifungal activity against many plant pathogens. In our previous study, RNA sequencing (RNA-seq) was conducted on resistant wheat line TcLr19 and sensitive wheat cultivar Chinese Spring inoculated with Puccinia triticina (Pt) race PHNT. In this study, seven salicylic acid (SA)-induced TaPR1 genes involved in plant disease resistance were found in the RNA-seq library. Quantitative PCR (qPCR) results showed that TaPR1-4 was most induced by Pt among these seven TaPR1 genes in the incompatible interaction. Yeast two-hybrid (Y2H) results showed that TaPR1-4 interacted with TaTLP1 via the αIV helix. Protein-mediated phenotyping assays in vivo and antifungal activity in vitro demonstrated that wheat leaves infiltrated with pure TaPR1-4 protein developed significantly less disease compared to control leaves. This effect was correlated with a strong increase in defense gene expression, and resistance activity was dependent on the CAPE1 motif located in the C-terminal region of TaPR1-4. These findings increase current knowledge regarding the interaction of TaPR1 and TaTLP1 and provide new insights on the role of TaPR1 protein in the resistance of wheat to Pt.

Olive leaves, which are the most abundant byproducts of the olive industry, offer multiple health benefits. The investigation of the phytochemical profiles and relevant biological activities is an essential step toward transforming these low-value byproducts into value-added ones. This study systematically investigated the phytochemical profiles, antioxidant capacity, and inhibition rates of olive leaves from four cultivars on the α-glucosidase, α-amylase, and angiotensin-converting enzyme (ACE). The leaves were prepared using two common drying methods, namely, hot air-drying and freeze-drying. A total of 33 bioactive compounds were identified in the olive leaves, namely, 19 flavonoids, 2 phenylethanoids, 2 coumarins, 2 hydroxycinnamic acids, 2 iridoids, and 6 triterpenic acids. Quantification of the bioactive compounds revealed high amounts of polyphenols, especially flavonoids [2,027–8,055 mg/kg dry weight (DW)], iridoids (566–22,096 mg/kg DW), and triterpenic acids (13,824–19,056 mg/kg DW) in the olive leaves. The hot air-dried leaves showed significantly (P < 0.05) higher iridoid (oleuropein and secoxyloganin) content than the fresh leaves, while freeze-drying resulted in significantly (P < 0.05) higher flavonoid aglycone and hydroxytyrosol content. Additionally, freeze-drying led to samples with the highest radical scavenging, α-amylase, α-glucosidase, and ACE inhibition abilities. The flavonoid (e.g., quercetin, luteolin, eriodictyol, kaempferol-7-O-glucoside, and luteolin-7-O-glucoside), hydroxytyrosol, and oleanolic acid contents in the olive leaves were positively correlated (P < 0.05) with their bioactive potentials.

Wheat bran supplementation in cereal food processing improves the nutritional value and quality of the final products. However, whether wheat bran has the potential as a biofortifier to enhance nutritional and flavor of fermented vegetables remains unknown. The study aimed to evaluate the potential of wheat bran supplementation for nutrition and flavor fortification during radish fermentation, and to explore the role of microorganisms in nutritional and flavor development. Using high-throughput sequencing coupled with high-performance liquid chromatography and headspace solid-phase microextraction-gas chromatography-mass spectrometry, the microbial community profiles and nutritional and flavor changes of wheat bran-treated samples were analyzed and compared with control samples. Correlation analysis between bacteria taxa with metabolites were also performed. The results showed that wheat bran treatment increased the content of most free amino acids (FAAs), α-linolenate, thiamine, and riboflavin in the samples (p < 0.05). In addition, the increased consumption of reducing sugar and glutamate in the wheat bran-treated samples was due to the production of secondary metabolites such as lactic acid, ethanol, acetic acid, and GABA (p < 0.05). Moreover, compared with control samples, the flavor of the wheat bran-treated pickled radish was preferable. Wheat bran increased the amount of alcohol, ester, acid, and ketones compounds but reduced the number of sulfides, which increased the aroma but decreased the pungent flavor. Additionally, the correlation analysis suggested that Lactobacillus, the most dominant genus, was boosted by wheat bran and was positively associated with most of FAAs, GABA, and lactate, while negatively associated with most sulfides. Therefore, compared with the control, wheat bran treatment could improve the nutritional values and sensorial properties of radish pickles. New areas of research should explore the co-fermentation of other vegetables with wheat bran, and the potential of this processing technique to provide consumers with products of high nutritional quality.

Cyst nematodes are one of the most important pathogens worldwide. Most cyst nematode species have been reported recently in China. From 2016 to 2020, an extensive survey of cyst nematodes was conducted in the Bashang region of Hebei Province. A total of 158 soil samples were collected, and cyst-forming nematodes were isolated from five soil samples. Morphological and molecular characterization showed that four of the cyst-forming nematode populations were Heterodera glycines (SCN), named populations of ZM, KM, CB and FN, respectively. These SCN populations were collected from Zhangbei County, Kangbao County, Chabei Management Area of Zhangjiakou and Fengning Manchu Autonomous County of Chengde, respectively, where the corresponding cyst densities were 57, 41, 103 and 31 cysts/200 cc soil. Furthermore, the populations of ZM, KM and CB were identified as race 4, whereas the FN population was identified as race 3. The cyst-forming nematode population was collected from Zhangbei County of Zhangjiakou, which was confirmed to be Heterodera schachtii (SBCN), named population ZZ, and the cyst density was 94 cysts/200 cc soil. It is a new disease of Chinese cabbage caused by SBCN based on Koch’s postulates. Fourteen cultivars from five plant families were evaluated as hosts for SBCN. Chinese cabbage (cv. Linglonghuang012) and cabbage (cv. Chunwang) were suitable hosts, while celery (cv. Yuhuang), potato (cv. Helan 15) and eggplant (cv. Junlang) were nonhosts. The obtained results regarding the occurrence, distribution, races of SCN and hosts of SBCN in the Bashang region in this study provide a reference for SCN and SBCN management.

Olive (Olea europaea L.) is a world-famous woody oil tree and popular for redundant unsaturated fatty acids. Fatty acid desaturase (FAD) genes are responsible for fatty acid desaturation and stress regulation but have not yet been identified in olive at the whole genome level. This study identified 40 and 27 FAD genes in the cultivated olive O. europaea cv. Farga and the wild olive O. europaea var. Sylvestris, respectively. Phylogenetic analysis showed that all the FAD genes could be classified into the soluble FAB2/SAD clade and membrane-bound clade, including ADS/FAD5, DES, FAD4, SLD, ω-6 and ω-3, with the high consistency of subcellular localization, motif composition and exon-intron organization in each group. FAD genes in olive showed the diverse functional differentiation in morphology of different tissues, fruit development and stress responses. Among them, OeFAB2.8 and OeFAD2.3 were up-regulated and OeADS.1, OeFAD4.1 and OeFAD8.2 were down-regulated under the wound, Verticillium dahliae and cold stresses. This study presents a comprehensive analysis of the FAD genes at the whole-genome level in olives and will provide guidance for the improvement of oil quality or stress tolerance of olive trees.

Olives (Olea europaea L.) are a significant part of the agroindustry in China. Olive leaves, the most abundant by-products of the olive and olive oil industry, contain bioactive compounds that are beneficial to human health. The purpose of this study was to evaluate the phytochemical profiles and antioxidant capacities of olive leaves from 32 cultivars grown in China. A total of 32 phytochemical compounds were identified using high-performance liquid chromatography–electrospray ionization–tandem mass spectrometry, including 17 flavonoids, five iridoids, two hydroxycinnamic acids, six triterpenic acids, one simple phenol, and one coumarin. Specifically, olive leaves were found to be excellent sources of flavonoids (4.92–18.29 mg/g dw), iridoids (5.75–33.73 mg/g dw), and triterpenic acids (15.72–35.75 mg/g dw), and considerable variations in phytochemical content were detected among the different cultivars. All tested cultivars were classified into three categories according to their oil contents for further comparative phytochemicals assessment. Principal component analysis indicated that the investigated olive cultivars could be distinguished based upon their phytochemical profiles and antioxidant capacities. The olive leaves obtained from the low-oil-content (20%) cultivars contained mainly triterpenic acids in their compositions. Correspondingly, the low-oil-content cultivars (OL3, Frantoio selection and OL14, Huaou 5) exhibited the highest ABTS antioxidant activities (758.01 ± 16.54 and 710.64 ± 14.58 mg TE/g dw, respectively), and OL9 (Olea europaea subsp. Cuspidata isolate Yunnan) and OL3 exhibited the highest ferric reducing/antioxidant power assay values (1228.29 ± 23.95 mg TE/g dw and 1099.99 ± 14.30 mg TE/g dw, respectively). The results from this study may be beneficial to the comprehensive evaluation and utilization of bioactive compounds in olive leaves.

Puccinia triticina (Pt), as the causal agent of wheat leaf rust, employs a plethora of effector proteins to modulate wheat immunity for successful colonization. Understanding the molecular mechanisms underlying Pt effector-mediated wheat susceptibility remains largely unexplored. In this study, an effector Pt_21 was identified to interact with the apoplast-localized wheat thaumatin-like protein TaTLP1 using a yeast two-hybrid assay and the Pt_21-TaTLP1 interaction was characterized. The interaction between Pt_21 and TaTLP1 was validated by in vivo co-immunoprecipitation assay. A TaTLP1 variant, TaTLP1C71A, that was identified by the site-directed mutagenesis failed to interact with Pt_21. Pt_21 was able to suppress Bax-mediated cell death in leaves of Nicotiana benthamiana and inhibit TaTLP1-mediated antifungal activity. Furthermore, infiltration of recombinant protein Pt_21 into leaves of transgenic wheat line overexpressing TaTLP1 enhanced the disease development of leaf rust compared to that in wild-type leaves. These findings demonstrate that Pt_21 suppresses host defense response by directly targeting wheat TaTLP1 and inhibiting its antifungal activity, which broadens our understanding of the molecular mechanisms underlying Pt effector-mediated susceptibility in wheat. [ABSTRACT FROM AUTHOR]