A new method based on melatonin-mediated seed germination to quickly remove pesticide residues and improve the nutritional quality of contaminated grains.

In the present study, we attempted to use melatonin combined with germination treatment to remove pesticide residues from contaminated grains. High levels of pesticide residues were detected in soybean seeds after soaking with chlorothalonil (10 mM) and malathion (1 mM) for 2 hours. Treatment with 50 µM melatonin for 5 days completely removed the pesticide residues, while in the control group, only 61-71% of pesticide residues were removed from soybean sprouts. Compared with the control, melatonin treatment for 7 days further increased the content of ascorbic acid (by 48-66%), total phenolics (by 52-68%), isoflavones (by 22-34%), the total antioxidant capacity (by 37-40%), and the accumulated levels of unsaturated fatty acids (C18:1, C18:2, and C18:3) (by 17-30%) in soybean sprouts. Moreover, melatonin treatment further increased the accumulation of ten components of phenols and isoflavones in soybean sprouts relative to those in the control. The ability of melatonin to accelerate the degradation of pesticide residues and promote the accumulation of antioxidant metabolites might be related to its ability to trigger the glutathione detoxification system in soybean sprouts. Melatonin promoted glutathione synthesis (by 49-139%) and elevated the activities of glutathione-S-transferase (by 24-78%) and glutathione reductase (by 38-61%). In summary, we report a new method in which combined treatment by melatonin and germination rapidly degrades pesticide residues in contaminated grains and improves the nutritional quality of food.

Excellent Anode Performance of N-, P-, and As-Doped Graphdiynes for Lithium-Ion Batteries.

Recently, graphdiyne (GDY) as a two-dimensional planar carbon allotrope has received significant research attention in the fields of rechargeable batteries, catalysis, biomedicine, and so forth. However, the theoretical capacity of a perfect GDY anode is only 744 mA h/g in the configuration of LiC3, encouraging further efforts to increase the capacity. In this study, we explore the anode performance of N-, P-, and As-doped GDYs by using first-principles calculations. Ab initio molecular dynamics simulations show that the doped GDYs can remain stable at 1000 K, indicating good thermal stability. With the loss of part acetylenic linkages, the rhomboid-like pores produce more Li sites, and the theoretical capacities reach 2209, 2031, and 1681 mA h/g for the N-, P-, and As-doped GDYs, respectively. In addition, the transition-state calculations indicate that the Li diffusion barriers of the three doped GDYs are similar to the perfect GDY. This study demonstrates that doping is an effective strategy to improve the anode performance of GDY.

Phosphorylation of a wheat aquaporin at two sites enhances both plant growth and defense.

Eukaryotic aquaporins share the characteristic of functional multiplicity in transporting distinct substrates and regulating various processes, but the underlying molecular basis for this is largely unknown. Here, we report that the wheat (Triticum aestivum) aquaporin TaPIP2;10 undergoes phosphorylation to promote photosynthesis and productivity and to confer innate immunity against pathogens and a generalist aphid pest. In response to elevated atmospheric CO2 concentrations, TaPIP2;10 is phosphorylated at the serine residue S280 and thereafter transports CO2 into wheat cells, resulting in enhanced photosynthesis and increased grain yield. In response to apoplastic H2O2 induced by pathogen or insect attacks, TaPIP2;10 is phosphorylated at S121 and this phosphorylated form transports H2O2 into the cytoplasm, where H2O2 intensifies host defenses, restricting further attacks. Wheat resistance and grain yield could be simultaneously increased by TaPIP2;10 overexpression or by expressing a TaPIP2;10 phosphomimic with aspartic acid substitutions at S121 and S280, thereby improving both crop productivity and immunity.

Endophytic Bacillus amyloliquefaciens YTB1407 elicits resistance against two fungal pathogens in sweet potato (Ipomoea batatas (L.) Lam.).

The endophytic Bacillus amyloliquefaciens YTB1407 was previously reported to promote the growth of sweet potato (Ipomoea batatas cv. Yanshu 25). Here, we demonstrate in both in vitro and pot trial assays that pre-treatment with YTB1407 suspension could enhance resistance against root rot disease and black rot disease, caused by Fusarium solani Mart. Sacc. f. sp. batatas McClure and Ceratocystis fimbriata Ell. & Halst on sweet potato, respectively. When seedlings were infected with fungal pathogens at 10 days post irrigation, pre-treatment with YTB1407 suspension decreased these pathogens and YTB1407 bacterial biomass in sweet potato roots. The pre-treatment activated the expression of salicylic acid (SA)-responsive PR-1 gene, raised SA content, and reduced hydrogen peroxide (H2O2) in the host to resist F. solani, while it enhanced the expression levels of SA-responsive NPR1 and PR1 genes and increased SA content to resist C. fimbriata. The disease resistance control effect initiated by pre-treatment with YTB1407 for root rot pathogen (F. solani) was better than for black rot pathogen (C. fimbriata). The results indicated that Bacillus amyloliquefaciens YTB1407 played a pivotal role in enhancing resistance to two fungi pathogens in sweet potato, through production of some antifungal metabolites to decrease infection in the early stage as well as induction of SA-dependent systemic resistance.

The type II phosphoinositide 4-kinase FgLsb6 is important for the development and virulence of Fusarium graminearum.

Fusarium graminearum is the main pathogenic fungus causing Fusarium head blight (FHB), which is a wheat disease with a worldwide prevalence. In eukaryotes, phosphatidylinositol 4-phosphate (PI4P), which participates in many physiological processes, is located primarily in different organelles, including the trans-Golgi network (TGN), plasma membrane and endosomes. Type II phosphatidylinositol 4-kinases (PI4Ks) are involved in regulating the production of PI4P in yeast, plants and mammalian cells. However, the role of these proteins in phytopathogenic fungi is not well understood. In this study, we characterized the type II PI4K protein FgLsb6 in F. graminearum, a homolog of Lsb6 in Saccharomyces cerevisiae. Unlike Lsb6, FgLsb6 localizes to the vacuoles and endosomes. The ΔFglsb6 mutant displayed defects in vegetative growth, deoxynivalenol (DON) production and pathogenicity. Furthermore, the ΔFglsb6 deletion mutant also exhibited increased resistance to osmotic, oxidative and cell wall stresses. Further analyses of the ΔFglsb6 mutant showed that it was defective in the generation of PI4P on endosomes and endocytosis. Collectively, our data suggest that the decreased vegetative growth and pathogenicity of ΔFglsb6 was due to the conservative roles of FgLsb6 in the generation of PI4P on endosomes and endocytosis.

N2O and CO2 emissions from a dryland wheat cropping system with long-term N fertilization and their relationships with soil C, N, and bacterial community.

In dryland cropping ecosystems, nitrogen (N) fertilization causes changes in soil biochemical cycling and influences the crop biomass and grain yield. Based on a long-term field experiment involving three N rates (0 (N0), 160 (N160), and 320 (N320) kg N ha-1 year-1), we measured nitrous oxide (N2O) and carbon dioxide (CO2) emissions from wheat fields and determined the soil organic carbon (SOC), total N, microbial biomass C (MBC), and N (MBN), mineralized C (Cmin) and N (Nmin) concentrations and the bacterial community composition. The results showed that N fertilization significantly (P < 0.05) increased N2O and CO2 emissions. N fertilization also significantly (P < 0.05) increased SOC by 13.2%, total N by 7.4%, MBN by 34.3%, Cmin by 15.5%, and Nmin by 27.8%, as well as the soil bacterial diversity and abundances of N cycling functional groups (by 149%). Additionally, N2O and CO2 emissions were positively and linearly correlated with NH4-N and NO3-N concentrations and positively correlated with SOC, total N, MBN, and the number of bacterial species, as well as most of the bacterial phyla and functional groups. These results suggest that N fertilizer applied to the dryland soils improved soil fertility and changed the soil bacterial community composition and function, thus increased N2O and CO2 emissions. Therefore, to mitigate greenhouse gas emissions and maintain soil fertility for wheat production, an optimized N fertilizer rate should be applied in the southern region of the Loess Plateau in China.

ZmASR3 from the Maize ASR Gene Family Positively Regulates Drought Tolerance in Transgenic Arabidopsis.

Abscisic acid (ABA)-, stress-, and ripening-induced (ASR) proteins are reported to be involved in drought stress responses. However, the function of maize ASR genes in enhancing drought tolerance is not known. Here, nine maize ASR members were cloned, and the molecular features of these genes were analyzed. Phenotype results of overexpression of maize ZmASR3 gene in Arabidopsis showed lower malondialdehyde (MDA) levels and higher relative water content (RWC) and proline content than the wild type under drought conditions, demonstrating that ZmASR3 can improve drought tolerance. Further experiments showed that ZmASR3-overexpressing transgenic lines displayed increased stomatal closure and reduced reactive oxygen species (ROS) accumulation by increasing the enzyme activities of superoxide dismutase (SOD) and catalase (CAT) under drought conditions. Moreover, overexpression of ZmASR3 in Arabidopsis increased ABA content and reduced sensitivity to exogenous ABA in both the germination and post-germination stages. In addition, the ROS-related, stress-responsive, and ABA-dependent pathway genes were activated in transgenic lines under drought stress. Taken together, these results suggest that ZmASR3 acts as a positive regulator of drought tolerance in plants.

Tobacco TTG2 regulates vegetative growth and seed production via the predominant role of ARF8 in cooperation with ARF17 and ARF19.

BACKGROUND: Plant TRANSPARENT TESTA GLABRA (TTG) proteins regulate various developmental activities via the auxin signaling pathway. Recently, we elucidated the developmental role of tobacco (Nicotiana tabacum L.) NtTTG2 in association with 12 genes that putatively encode AUXIN RESPONSIVE FACTOR (ARF) proteins, including NtARF8, NtARF17, and NtARF19. Here we show that NtTTG2 regulates tobacco growth and development by involving the NtARF8, NtARF17, and NtARF19 genes, with the NtARF8 gene playing a predominant contribution. RESULTS: Independent silencing of the NtARF8 gene more strongly repressed tobacco growth than silencing the NtARF17 or NtARF19 gene and more effectively eradicated the growth enhancement effect of NtTTG2 overexpression. In contrast, plant growth was not affected by silencing additional nine NtTTG2-regulated NtARF genes. In double and triple gene silencing combinations, silencing the NtARF8 gene was more effective than silencing the NtARF17 or NtARF19 gene to repress growth as well as nullify growth enhancement. Therefore, the NtARF8 predominantly cooperated with the NtARF17 and NtAFR19 of the NtTTG2 functional pathway. NtARF8 also contributed to NtTTG2-regulated seed production as concurrent NtTTG2 and NtARF8 overexpression played a synergistic role in seed production quantity, whereas concurrent silencing of both genes caused more severe seed abortion than single gene silencing. In plant cells, the NtTTG2 protein facilitated the nuclear import of NtARF8 as well as increased its function as a transcription activator. CONCLUSIONS: NtARF8 is an integral component of the NtTTG2 functional pathway, which regulates tobacco growth and development.

The clinical application of laparoscope-assisted peritoneal vaginoplasty for the treatment of congenital absence of vagina.

OBJECTIVE: To evaluate the outcomes of laparoscope-assisted peritoneal vaginoplasty for the treatment of congenital vaginal atresia. METHODS: A retrospective study enrolled patients diagnosed with congenital vaginal atresia who were treated with one of two different laparoscope-assisted peritoneal vaginoplasty techniques (named Luohu-one and Luohu-two) between October 31, 2001 and December 31, 2014. Operative time, intraoperative bleeding volume, surgical difficulty, complications, and post-procedure sexual satisfaction were reported. RESULTS: Data were collected for 620 patients. The Luohu-one procedure was used in the treatment of 145 patients, while 475 patients were treated with the Luohu-two procedure. In 5 (0.8%) patients, it was necessary to perform a sigmoid colon vaginoplasty. During surgery, 16 patients experienced a rectal injury, among whom, 9 patients experienced a rectal-vaginal fistula. Follow-up data extending to 7years were available for 285 patients. Of these 285 patients, 231 agreed to report details of their sexual experiences. In total, 222 (96.1%) patients reported being very satisfied with their vaginal conditions and sex life. The Luohu-two procedure demonstrated shorter operative and recovery time, and reduced intraoperative bleeding. However, both procedures demonstrated satisfactory results. CONCLUSION: Laparoscope-assisted peritoneal vaginoplasty demonstrated good safety and effectiveness in the treatment of patients with congenital vaginal atresia.

[Effects of electroacupuncture at "Neiguan" (PC 6) on sodium channel-related proteins in rats with ischemic myocardial injury].

OBJECTIVE: To explore the protective mechanism of electroacupuncture (EA) at "Neiguan" (PC 6) on ischemic myocardial injury, and to explain the response patterns and characteristics of the specific effect of acupoints along meridians in sodium channel in the level of cardiac organ. METHODS: A total of 60 SPF male rats were randomly divided into a blank group, a model group, a non-acupoint group, a Neiguan group and a Lieque group, 12 cases in each one. Except the blank group, rats in the remaining group were treated with subcutaneous injection of isoprenaline to establish the model of myocardial ischemia. Rats in the Neiguan group, Lieque group and non- acupoint group were treated with EA, dilatational wave, with a frequency of 2 Hz/20 Hz. The intensity was 2-3 mA. The needles were retained for 20 min per time, once a day for consecutive 7 days. In the blank group and control group, the rats were grasped and fixed at the treating time each day. The western-blot method was used to test the expression of voltage-gated sodium channel alpha subunit (Nav 1.5), protein tyrosine kinase (PTKs) and protein tyrosine phosphatase (PTPs). RESULTS: The expression of Nav 1.5 and PTKs in the model group was lower than that in the blank group (both P<0. 01); the expression in the Neiguan group and Lieque group was higher than that in the model group (all P < 0.01); the expression of Nav 1.5 and PTKs in the Neiguan group was higher than that in the Lieque group (both P < 0.01). The expression of PTPs in the model group and non-acupoint group was higher than that in the blank group (both P < 0.01); the expression of PTPs in the Neiguan group and Lieque group was significantly down-regulated, which was lower than the model group (both P < 0.01); the down-regulation in the Neiguan group was significantly different from that in the Lieque group (P < 0.05). CONCLUSION: EA at "Neiguan" (PC 6), by down-regulating the expression of PTPs, up-regulating the expression of Nav 1.5 and PTKs, is likely to achieve the aim of regulation on sodium channel activity and calcium overload, further to improve myocardial ischemia, which provides experimental basis for the theory of the specific effect of acupoints along meridians.

[Effect of electroacupuncture stimulation of "Neiguan" (PC 6) on expression of alpha- and beta-subunit proteins of voltage-gated sodium channels in rats with myocardial ischemia].

OBJECTIVE: To observe the effect of electroacupuncture (EA) stimulation of "Neiguan" (PC 6) on expression of sodium (Nav) channel α-subunit 1.5 and Nav ß-subunits ß 1-ß 4 (the known myocardial sodium channel proteins) in acute myocardial ischemia (AMI) rats so as to explore its mechanisms underlying protection of ischemic myocardium. METHODS: Sixty SD male rats were randomly divided into normal control, AMI model, Neiguan (PC 6), Lieque (LU 7) and non-acupoint groups. The AMI model was established by intravenous injection of Isoprenaline (85 mg/kg) once daily for 2 days. Myocardial Nav 1.5 and Nav ß 1, ß 2, ß 3, ß 4 protein expression levels were detected by Western blot. RESULTS: In comparison with the control group, myocardial Nav 1.5, ß 1, ß 2, ß 3 and ß 4 protein expression levels were significantly down-regulated in the AMI model group (P<0.01). After EA stimulation, compared with the model group, the expression levels of Nav 1.5, Nav ß 1, ß 2, ß 3 and ß 4 protein expression levels were significantly up-regulated in the Neiguang (PC 6) and Lieque (LU 7) groups (P<0.01) rather than in the non-acupoint group (P>0.05). There was no statistical significance between the Neiguan (PC 6) and Lieque (LU 7) groups in ß 4 protein expression level (P>0.05). CONCLUSION: EA stimulation of both PC 6 and LU 7 can significantly reverse AMI-induced down-regulation of myocardial Nav 1.5, ß 1, ß 2, ß 3 and ß 4 protein expression levels in AMI rats, which might contribute to its function in improving AMI by reducing calcium overload.

Chinese water-pipe smoking and the risk of COPD.

BACKGROUND: Studies show that the incidence of COPD has remained high in southwest China despite the 1976 National Stove Improvement Program for indoor air quality. Chinese water-pipe tobacco smoking (commonly referred to as water-pipe smoking), which is thought to be less harmful under the assumption that no charcoal is used and water filters tobacco smoke, is popular in China. We investigated whether Chinese water-pipe use and exposure are associated with the risk of COPD. METHODS: This multicenter, cross-sectional study enrolled 1,238 individuals from 10 towns in the Fuyuan area, Yunnan Province, China. A matched design was used to estimate the impact of active and passive exposure to Chinese water-pipe smoking on COPD risk; multivariate analyses adjusted for other risk factors. We also collected the water from Chinese water pipes to assess the mutagenicity of its major components and simulated Chinese water-pipe smoke exposure fine particulate 2.5 (PM2.5) by using the High Volume Air Sampler and individuals' sera to search for the potential protein biomarkers of COPD. RESULTS: The increased risk of COPD was profound for Chinese water-pipe smokers (adjusted OR, 10.61; 95% CI, 6.89-16.34), Chinese water-pipe passive smokers (adjusted OR, 5.50; 95% CI, 3.61-8.38), cigarette smokers (adjusted OR, 3.18; 95% CI, 2.06-4.91), and cigarette passive smokers (adjusted OR, 2.52; 95% CI, 1.62-3.91) compared with never-smoking control subjects. Chinese water-pipe use aggravates lungs with more PM2.5 compared with cigarettes. ChemR23 and tissue inhibitor of metalloproteinase-1 may be potential protein biomarkers of COPD. CONCLUSIONS: Chinese water-pipe smoking significantly increases the risk of COPD, including the risk to women who are exposed to the water-pipe smoke. TRIAL REGISTRY: Chinese Clinical Trial Registry; No.: ChiCTR-CCH-12002235; URL: www.chictr.org/cn/

TTG2-regulated development is related to expression of putative AUXIN RESPONSE FACTOR genes in tobacco.

BACKGROUND: The phytohormone auxin mediates a stunning array of plant development through the functions of AUXIN RESPONSE FACTORs (ARFs), which belong to transcription factors and are present as a protein family comprising 10-43 members so far identified in different plant species. Plant development is also subject to regulation by TRANSPARENT TESTA GLABRA (TTG) proteins, such as NtTTG2 that we recently characterized in tobacco Nicotiana tabacum. To find the functional linkage between TTG and auxin in the regulation of plant development, we performed de novo assembly of the tobacco transcriptome to identify candidates of NtTTG2-regulated ARF genes. RESULTS: The role of NtTTG2 in tobacco growth and development was studied by analyzing the biological effects of gene silencing and overexpression. The NtTTG2 gene silencing causes repressive effects on vegetative growth, floral anthocyanin synthesis, flower colorization, and seed production. By contrast, the plant growth and development processes are promoted by NtTTG2 overexpression. The growth/developmental function of NtTTG2 associates with differential expression of putative ARF genes identified by de novo assembly of the tobacco transcriptome. The transcriptome contains a total of 54,906 unigenes, including 30,124 unigenes (54.86%) with annotated functions and at least 8,024 unigenes (14.61%) assigned to plant growth and development. The transcriptome also contains 455 unigenes (0.83%) related to auxin responses, including 40 putative ARF genes. Based on quantitative analyses, the expression of the putative genes is either promoted or inhibited by NtTTG2. CONCLUSIONS: The biological effects of the NtTTG2 gene silencing and overexpression suggest that NtTTG2 is an essential regulator of growth and development in tobacco. The effects of the altered NtTTG2 expression on expression levels of putative ARF genes identified in the transcriptome suggest that NtTTG2 functions in relation to ARF transcription factors.

Tobacco TTG2 suppresses resistance to pathogens by sequestering NPR1 from the nucleus.

TRANSPARENT TESTA GLABRA (TTG) proteins that contain the WD40 protein interaction domain are implicated in many signalling pathways in plants. The salicylic acid (SA) signalling pathway regulates the resistance of plants to pathogens through defence responses involving pathogenesis-related (PR) gene transcription, activated by the NPR1 (nonexpresser of PR genes 1) protein, which contains WD40-binding domains. We report that tobacco (Nicotiana tabacum) NtTTG2 suppresses the resistance to viral and bacterial pathogens by repressing the nuclear localisation of NPR1 and SA/NPR1-regulated defence in plants. Prevention of NtTTG2 protein production by silencing of the NtTTG2 gene resulted in the enhancement of resistance and PR gene expression, but NtTTG2 overexpression or NtTTG2 protein overproduction caused the opposite effects. Concurrent NtTTG2 and NPR1 gene silencing or NtTTG2 silencing in the absence of SA accumulation compensated for the compromised defence as a result of the NPR1 single-gene silencing or the absence of SA. However, NtTTG2 did not interact with NPR1 but was able to modulate the subcellular localisation of the NPR1 protein. In the absence of NtTTG2 production NPR1 was found predominantly in the nucleus and the PR genes were expressed. By contrast, when NtTTG2 accumulated in transgenic plants, a large proportion of NPR1 was retained in the cytoplasm and the PR genes were not expressed. These results suggest that NtTTG2 represses SA/NPR1-regulated defence by sequestering NPR1 from the nucleus and the transcriptional activation of the defence-response genes.

[Teaching experience in Science of Acupuncture and Moxibustion : the advantage of "training the techniques of acupuncture and moxibustion before introducing meridians and acupoints"].

In term of four aspects, named "getting the familiarity", "turning to the positive action", "conquering the fear emotion" and "bringing the practice into play", the authors state that the teaching pattern, "training the techniques of acupuncture and moxibustion before introducing meridians and acupoints" can vividly introduce the classical content of meridians and acupoints in the Part One of Science of Acupuncture and Moxibustion, exclude the repeatability of the content and improve the teaching quality. This teaching pattern enables the students mastering the techniques of acupuncture and moxibustion before the practice and laying a good foundation for learning meridians and acupoints. The authors put forward the good suggestion of the teaching course arrangement of Science of Acupuncture and Moxibustion to benefit the teaching reform.

[Laparoscopy-insisted vaginoplasty with peritoneum in patients with androgen insensitivity syndrome].

OBJECTIVE: To investigate the technique and therapeutic effect of laparoscopy-insisted vaginoplasty with peritoneum in patients with androgen insensitivity syndrome. METHODS: From May. in the Fifth People' s Hospital of Shenzhen. The therapeutic effect was retrospectively analyzed. RESULTS: Laparoscopy-insisted vaginoplasty was successfully completely with peritoneum in patients with androgen in 4 cases. Ileumtivity segyndroment was used instead of peritoneum in one case. Open operation was not adopted in any cases. The ectopic testicles were removed during operation in 4 cases. The average operation time and bleeding volume was 60 min and 20 ml, respectively. Rectum, bladder and urethra were not injured in any case. The average vaginal length was 9 cm (range 8-10 cm) 21-28 days after operation. 6 months after operation, the surface of reconstructed vagina was smooth, ruddy and flexible, with satisfactory anatomical and functional results. Normal sexual activity was achieved in 2 cases. CONCLUSIONS: Laparoscopy-insisted vaginoplasty with peritoneum could be used for female patients with androgen insensitivity syndrome. The ectopic testicles should be removed. Estrogen supplement and psychological guide after operation are also important.

An h-type thioredoxin functions in tobacco defense responses to two species of viruses and an abiotic oxidative stress.

Various thioredoxin (Trx) proteins have been identified in plants. However, many of the physiological roles played by these proteins remain to be elucidated. We cloned a TRXh-like gene predicted to encode an h-type Trx in tobacco (Nicotiana tabacum) and designated it NtTRXh3, based on the biochemical activity of the NtTRXh3 protein. Overexpression of NtTRXh3 conferred resistance to Tobacco mosaic virus and Cucumber mosaic virus, both of which showed reduced multiplication and pathogenicity in NtTRXh3-overexpressing plants compared with controls. NtTRXh3 overexpression also enhanced tobacco resistance to oxidative stress induced by paraquat, an herbicide that inhibits the production of reducing equivalents by chloroplasts. The NtTRXh3 protein localized exclusively to chloroplasts in coordination with the maintenance of cellular reducing conditions, which accompanied an elevation in the glutathione/glutathione disulfide couple ratio. NtTRXh3 gene expression and NtTRXh3 protein production were necessary for these defensive responses, because they were all arrested when NtTRXh3 was silenced and the production of NtTRXh3 protein was abrogated. These results suggest that NtTRXh3 is involved in the resistance of tobacco to virus infection and abiotic oxidative stress.

Nicotiana tabacum TTG1 contributes to ParA1-induced signalling and cell death in leaf trichomes.

Leaf trichomes serve as a physical barrier and can also secrete antimicrobial compounds to protect plants from attacks by insects and pathogens. Besides the use of the physical and chemical mechanisms, leaf trichomes might also support plant responses by communicating the extrinsic cues to plant intrinsic signalling pathways. Here we report a role of leaf trichomes in tobacco (Nicotiana tabacum) hypersensitive cell death (HCD) induced by ParA1, an elicitin protein from a plant-pathogenic oomycete. After localized treatment with ParA1, reactive oxygen species were produced first in the leaf trichomes and then in mesophylls. Reactive oxygen species are a group of intracellular signals that are crucial for HCD to develop and for cells to undergo cell death subsequent to chromatin condensation, a hallmark of HCD. These events were impaired when the production of hydrogen peroxide (H(2)O(2)) was inhibited by catalase or a NADPH-oxidase inhibitor applied to trichomes, suggesting the importance of H(2)O(2) in the pathway of HCD signal transduction from the trichomes to mesophylls. This pathway was no longer activated when leaf trichomes were treated with C51S, a ParA1 mutant protein defective in its interaction with N. tabacum TTG1 (NtTTG1), which is a trichome protein that binds ParA1, rather than C51S, in vitro and in trichome cells. The ParA1-NtTTG1 interaction and the HCD pathway were also abrogated when NtTTG1 was silenced in the trichomes. These observations suggest that NtTTG1 plays an essential role in HCD signal transduction from leaf trichomes to mesophylls.