Exogenous salicylic acid induces defense responses in tea plants against Toxoptera aurantii (Hemiptera: Aphididae).

Toxoptera aurantii is one of the most destructive pests, threatening the yield and quality of tea plantations. The salicylic acid (SA)-mediated signaling pathway is vital for the induction of plant defense responses; however, its role in tea plant resistance to T. aurantii remains unclear. Thus, this study used and electrical penetration graph and monitoring of population dynamics to evaluate the effects of exogenous SA application on T. aurantii feeding behavior and population growth in tea seedlings. Moreover, the effects of SA treatment on the activities of defense-related enzymes were analyzed. Probe counts and the duration of xylem sap ingestion were significantly higher in SA-treated plants than those in the control group. The total duration of passive phloem ingestion was significantly decreased in 0.5 mmol/l SA-treated plants, and the application of 0.5, 1, and 4 mmol/l SA significantly inhibited T. aurantii population growth. In addition, the activities of polyphenol oxidase, peroxidase, and superoxide dismutase were significantly increased in the 0.5 mmol/l SA-treated plants. Overall, this study demonstrates the capacity of exogenous SA to activate defense responses against T. aurantii. These results have crucial implications for understanding the mechanisms of enhanced resistance, thereby providing a sustainable approach for managing T. aurantii.

Different Tea Germplasms Distinctly Influence the Adaptability of Toxoptera aurantii (Hemiptera: Aphididae).

Aphids are typical phloem-sucking insect pests. A good understanding regarding their feeding behavior and population dynamics are critical for evaluating host adaptation and screening of aphid-resistant resources. Herein, the adaptability of Toxoptera aurantii (Boyer) (Hemiptera: Aphididae) to different hosts was evaluated via electropenetrography and an age-stage, two-sex life table on six tea germplasms: Zikui (ZK), Zhongcha108 (ZC108), Zhongcha111 (ZC111), Qianmei419 (QM419), Meitan5 (MT5), and Fudingdabaicha (FD). Our findings revealed that the feeding activities of T. aurantii differed considerably among the host plants. T. aurantii exhibited significantly more pathway activities on ZK and FD than on the other hosts. However, the duration of feeding of T. aurantii on ZK phloem considerably decreased compared with those of the other germplasms. Life parameters indicated that T. aurantii exhibited the highest intrinsic rate of increase (r), net reproductive rate (R0), and finite rate of increase (λ) on MT5, and the maximum values of total longevity and oviposition period were recorded on FD; these variables were reduced significantly on ZK. The results of our study demonstrate that T. aurantii can successfully survive on the six tea germplasms; however, ZK was less suitable for T. aurantii and should be considered as a potential source of resistance in breeding and Integrated Pest Management.

Genome-wide association study of leaf-related traits in tea plant in Guizhou based on genotyping-by-sequencing.

BACKGROUND: Studying the genetic characteristics of tea plant (Camellia spp.) leaf traits is essential for improving yield and quality through breeding and selection. Guizhou Plateau, an important part of the original center of tea plants, has rich genetic resources. However, few studies have explored the associations between tea plant leaf traits and single nucleotide polymorphism (SNP) markers in Guizhou. RESULTS: In this study, we used the genotyping-by-sequencing (GBS) method to identify 100,829 SNP markers from 338 accessions of tea germplasm in Guizhou Plateau, a region with rich genetic resources. We assessed population structure based on high-quality SNPs, constructed phylogenetic relationships, and performed genome-wide association studies (GWASs). Four inferred pure groups (G-I, G-II, G-III, and G-IV) and one inferred admixture group (G-V), were identified by a population structure analysis, and verified by principal component analyses and phylogenetic analyses. Through GWAS, we identified six candidate genes associated with four leaf traits, including mature leaf size, texture, color and shape. Specifically, two candidate genes, located on chromosomes 1 and 9, were significantly associated with mature leaf size, while two genes, located on chromosomes 8 and 11, were significantly associated with mature leaf texture. Additionally, two candidate genes, located on chromosomes 1 and 2 were identified as being associated with mature leaf color and mature leaf shape, respectively. We verified the expression level of two candidate genes was verified using reverse transcription quantitative polymerase chain reaction (RT-qPCR) and designed a derived cleaved amplified polymorphism (dCAPS) marker that co-segregated with mature leaf size, which could be used for marker-assisted selection (MAS) breeding in Camellia sinensis. CONCLUSIONS: In the present study, by using GWAS approaches with the 338 tea accessions population in Guizhou, we revealed a list of SNPs markers and candidate genes that were significantly associated with four leaf traits. This work provides theoretical and practical basis for the genetic breeding of related traits in tea plant leaves.

Effects of PVY-Infected Tobacco Plants on the Adaptation of Myzus persicae (Hemiptera: Aphididae).

The indirect interaction between viruses and their insect vectors via the host plants can mediate viral transmission. Thus, elucidating these tripartite interactions is crucial for controlling the occurrence of viral diseases. This study examined the feeding behavior and life table parameters of the green peach aphid, Myzus persicae, using electropenetrography and an age-stage, two-sex life table on PVY-infected and uninfected tobacco plants. Furthermore, the amino acid and soluble sugar contents in tobacco tissue at different stages of PVY infection were determined. The results showed that PVY-infected plants exerted remarkable effects on the feeding activities of M. persicae. Aphids exhibited a reduced non-probing duration and increased phloem sap ingestion on infected plants. Although the nymph development time on the PVY-infected plants was significantly shorter than that of uninfected plants, M. persicae reared on infected plants had reduced fecundity and significantly shortened adult longevity. On day 12, the sugar: amino acid ratio of the PVY-infected plants was significantly higher than that of uninfected plants, whereas the opposite was observed on day 24. Our results demonstrated that PVY could alter the adaptability of M. persicae by modifying the nutritional quality of tobacco plants. In addition, divergent effects on aphids were observed at different infection stages, which are crucial to consider while exploring the interactions between viruses, insect vectors, and host plants. These results provided significant information for comprehending PVY spread and outbreaks.

Population structure analysis to explore genetic diversity and geographical distribution characteristics of cultivated-type tea plant in Guizhou Plateau.

BACKGROUND: Tea plants originated in southwestern China. Guizhou Plateau is an original center of tea plants, and is rich in germplasm resources. However, the genetic diversity, population structure and distribution characteristics of cultivated-type tea plants in the region are unknown. In this study, we explored the genetic diversity and geographical distribution of cultivated-type tea accessions in Guizhou Plateau. RESULTS: We used 112,072 high-quality genotyping-by-sequencing to analyze the genetic diversity, principal components, phylogeny, population structure, and linkage disequilibrium, and develop a core collection of 253 cultivated-type tea plant accessions from Guizhou Plateau. The results showed Genetic diversity of the cultivated-type tea accessions of the Pearl River Basin was significantly higher than that of the cultivated-type tea accessions of the Yangtze River Basin. Three inferred pure groups (CG-1, CG-2 and CG-3) and one inferred admixture group (CG-4), were identified by a population structure analysis, and verified by principal component and phylogenetic analyses. The highest genetic distance and differentiation coefficients were determined for CG-2 vs CG-3. The lower genetic distance and differentiation coefficients were determined for CG-4 vs CG-2 and CG-4 vs CG-3, respectively. We developed a core set and a primary set. The primary and core sets contained 77.0 and 33.6% of all individuals in the initial set, respectively. The primary set may serve as the primary population in genome-wide association studies, while the core collection may serve as the core population in multiple treatment setting studies. CONCLUSIONS: The present study demonstrated the genetic diversity and geographical distribution characteristics of cultivated-type tea plants in Guizhou Plateau. Significant differences in genetic diversity and evolutionary direction were detected between the ancient landraces of the Pearl River Basin and the those of the Yangtze River Basin. Major rivers and ancient hubs were largely responsible for the genetic exchange between the Pearl River Basin and the Yangtze River Basin ancient landraces as well as the formation of the ancient hubs evolutionary group. Genetic diversity, population structure and core collection elucidated by this study will facilitate further genetic studies, germplasm protection, and breeding of tea plants.

Different Host Plants Distinctly Influence the Feeding Ability of the Brown Citrus Aphid Toxoptera citricida.

Piercing-sucking insects are important crop pests, and an understanding of their feeding behavior and population development plays a crucial role in studying insect population dynamics and crop resistance. In our study, we examined the probing behavior of the brown citrus aphid, Toxoptera citricida, using electropenetrography and assessed its population development after 8 days on seven host plants: Yuzu, Citrus junos Sieb. ex Tanaka; Rough Lemon, C. jambhiri Lush.; 'Luofu' kumquat, Fortunella margarita Swingle; 'Olinda' valencia orange, C. sinensis (L.) Osbeck; 'Yanxiwanlu' Ponkan, C. reticulata Blanco; 'Rohde Red' valencia orange, C. sinensis; and 'Eureka' lemon, C. limon (L.) Osbeck. The results demonstrated that probing by the brown citrus aphid differed significantly according to the target hosts. Toxoptera citricida produced significantly more pathway activities on Eureka than on Rough Lemon and Yuzu. Toxoptera citricida spent more time from the first probe to first salivation into phloem sieve elements on Eureka compared to Yuzu. In addition, the total duration of ingestion from sieve cells of each aphid in the phloem-feeding phase was shortest on Eureka, and this was significantly shorter than that on Yuzu, Rough Lemon, Luofu, and Olinda. The population number of T. citricida on Eureka after 8 days was significantly lower than that on the other hosts. Overall, Eureka was found to have obvious resistance to T. citricida, whereas Yuzu and Rough Lemon were susceptible host plants. These results provide a theoretical basis for exploring aphid-resistant fruit tree resources using resistant varieties.

Outcomes of primary membranous nephropathy based on serum anti-phospholipase A2 receptor antibodies and glomerular phospholipase A2 receptor antigen status: a retrospective cohort study.

INTRODUCTION: Primary membranous nephropathy (PMN) is associated with the anti-phospholipase A2 receptor (anti-PLA2R) antibody in 70% of cases. Some anti-PLA2R-negative patients have the PLA2R antigen in renal tissue. This study examined the prognosis of patients with PMN according to their serum anti-PLA2R antibody (SAb) and glomerular PLA2R antigen (GAg) status. METHODS: Patients diagnosed with PMN were included retrospectively. Patients were grouped according to their PLA2R status into the SAb-/GAg-, SAb-/GAg+, and SAb+/GAg + groups. Baseline data, renal biopsy results, treatment, and clinical data were compared among the groups. Cox univariable and multivariable analyses examined the factors related to complete remission (CR). RESULTS: A total of 114 patients were enrolled; 10 (9%) in the SAb-/GAg-, 23 (20%) in the SAb-/GAg+, and 81 (71%) in the SAb+/GAg+ groups. Cumulative CR rate showed a significant difference between the SAb-/GAg - and SAb+/GAg+ groups (log-rank p = 0.003). The multivariable Cox proportional hazard analysis showed that age (HR = 0.968; 95%CI = 0.946-0.990; p = 0.005), SAb+/GAg+ versus SAb-/GAg- (HR = 0.387; 95%CI = 0.190-0.788; p = 0.009), SAb-/GAg+ versus SAb-/GAg- (HR = 0.398; 95%CI = 0.169, 0.939; p = 0.035), total renal chronicity score ≥2 (HR = 0.461, 95%CI: 0.277-0.766, p = 0.003), and IgA deposition (HR = 2.596; 95%CI = 1.227-5.492; p = 0.013) were all independently related (p < 0.05) to CR. CONCLUSIONS: The SAb and GAg status was an indicator of PMN prognosis. The patients with SAb-/GAg - had an increased likelihood of achieving CR than those with SAb-/GAg+ and SAb+/GAg+.

Behavioral Intention to Initiate Antiretroviral Therapy (ART) Among Chinese HIV-Infected Men Who Have Sex With Men Having High CD4 Count in the Era of "Treatment for All".

China has updated its national guideline recommending antiretroviral therapy (ART) to all people living with HIV (PLWH) since 2016. This study was to investigate the prevalence of behavioral intention to initiate ART among HIV-infected men who have sex with men (MSM) with CD4 levels >350 cells/mm3, who had just become eligible to receive free ART in China. A cross-sectional survey was conducted among 262 eligible HIV-infected MSM who had never received ART. The theory of planned behavior (TPB) was used to guide the variable selection. The prevalence of behavioral intention to initiate ART was 69.9%. After adjusting for significant background variables, all five constructs of TPB were significantly associated with behavioral intention to initiate ART. These significant constructs were: positive attitudes (adjusted odds ratios, AOR: 1.14; 95% CI [1.06, 1.24]) and negative attitudes (AOR: 0.89; 95% CI [0.82, 0.97]) toward immediate ART initiation; perceived their significant others would support them to initiate ART immediately (perceived subjective norm; AOR: 1.14; 95% CI [1.03, 1.25]); perceived high proportion of PLWH having similar CD4 cell levels were on ART (perceived descriptive norm; AOR: 2.22, 95% CI [1.16, 4.24]); and being confident in initiating ART immediately (perceived behavioral control; AOR: 1.21; 95% CI [1.04, 1.39]). Prevalence of behavioral intention to initiate ART was high among this group of MSM. Effective health promotion is needed to translate behavioral intention into related action. TPB may be a useful framework for developing future health promotion increasing ART coverage in this group.

Effects of Aphidius gifuensis on the feeding behavior and potato virus Y transmission ability of Myzus persicae.

The stylet penetration behavior of aphids when feeding on plants is associated with virus acquisition and inoculation. Aphidius gifuensis (Ashmead) is a primary endoparasitoid of Myzus persicae (Sulzer) which is the most efficient vector of plant viruses. Information about the effects of parasitoid on aphid and virus transmission can provide an essential foundation for designing effective biological control strategies. This study aimed to investigate the effects of A. gifuensis on the feeding behavior and potato virus Y (PVY) transmission ability of M. persicae. The results showed that after M. persicae was parasitized by A. gifuensis, the duration of the first probe significantly decreased. Additionally, A. gifuensis exerted remarkable effects on aphid feeding in phloem ingestion. The contribution of the E1 waveform to the phloem phase was significantly higher in all parasitized aphids than in the control group. Although the time of infestation increased for parasitized aphids, the total duration of phloem sap ingestion decreased. Interestingly, the percentage of time M. persicae spent in the xylem and phloem phases only changed significantly on day 5. The percent transmission of PVY by the aphids parasitized on day 5 was lower than that in the control, but no significant differences were detected. The significance of this work is the demonstration that A. gifuensis can impede the feeding behavior of M. persicae, which sheds light on the biological basis of A. gifuensis as a natural enemy, but unfortunately does not provide an immediate solution for disrupting the transmission of PVY.

Sublethal Effects of Cyantraniliprole and Imidacloprid on Feeding Behavior and Life Table Parameters of Myzus persicae (Hemiptera: Aphididae).

The green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae), is an agricultural pest that seriously infests many crops worldwide. This study used electrical penetration graphs (EPGs) and life table parameters to estimate the sublethal effects of cyantraniliprole and imidacloprid on the feeding behavior and hormesis of M. persicae The sublethal concentrations (LC30) of cyantraniliprole and imidacloprid against adult M. persicae were 4.933 and 0.541 mg L(-1), respectively. The feeding data obtained from EPG analysis indicated that the count probes and number of short probes (<3 min) were significantly increased when aphids were exposed to LC30 of imidacloprid-treated plants. In addition, the phloem-feeding behavior of M persicae was significantly impaired on fed tobacco plants treated with cyantraniliprole and imidacloprid at LC30 Analysis of life table parameters indicated that the growth and reproduction of F1 generation aphids were significantly affected when initial adults were exposed to LC30 of cyantraniliprole and imidacloprid. The nymphal period, female longevity, total preoviposition period, and mean generation time were significantly prolonged when initial adults were exposed to LC30 of imidacloprid. By comparison, these parameters were prolonged but not significantly in the cyantraniliprole treatment. The fecundity and gross reproductive rate were significantly increased in the treated groups. Similarly, the net reproductive rate was greater in the treated group than the control group. Our results indicate that treatment with LC30 of imidacloprid and cyantraniliprole would lead to a hormetic response of M. persicae, with higher likelihood of occurrence when initial adults were exposed to LC30 of cyantraniliprole.

A comparative study of female sterilization via modified Uchida and silver clip techniques in rural China.

OBJECTIVE: To compare the specific effects of 2 female sterilization methods: the modified Uchida technique and the application of silver clips. METHODS: A total of 2198 women living in rural areas who were still of reproductive age but opting for sterilization were enrolled. The participants were randomly divided into 2 groups, and underwent sterilization by either modified Uchida technique or silver clips. Information on acceptability, operation conditions, effectiveness, adverse effects, and complaints was collected 3, 6, and 12 months after the procedure. RESULTS: No significant difference in effectiveness, adverse effects or chief complaints between the 2 procedures was found. Differences in operative outcome, bleeding volume during the procedure, and operation time were found. CONCLUSION: A shorter operation time and less bleeding for the silver clip method indicated that female sterilization by this technique was as safe as that by modified Uchida technique.