查找使用阿拉丁产品的科研文献

‘The Three Sisters’ (maize/bean/squash) polyculture promotes the direct and indirect defences of maize against herbivores

Huimin Liao,Zifang Zhou,Yangbeijia Liu,Yuyan Luo,Chenning Zhang,Yuanjiao Feng,Yinghua Shu,Jianwu Wang

It is well-known that increasing crop biodiversity plays an essential role in achieving ecologically based pest management (EBPM); however, the mechanism is poorly understood. The Three Sisters (Maize/Bean/Squash polyculture [MBS]) is a traditional mixed cropping strategy that has been practiced for thousands of years in Mesoamerica; however, mechanistic evidence for its resistance to herbivores is still lacking. In the present study, using both greenhouse and field experiments, we investigated the effects of MBS on the direct and indirect defences of maize ( Zea mays ) against Asian corn borer ( Ostrinia furnacalis ) and fall armyworm ( Spodoptera frugiperda ) caterpillars. MBS significantly improved the direct chemical defences of maize, especially against O. furnacalis , by increasing the content of primary metabolites, secondary metabolites (Benzoxazinoids), and phytohormones ((±)-Jasmonic acid-isoleucine, Jasmonic acid) in maize leaves, thus significantly reducing their survival and relative growth rates. MBS significantly improved the indirect chemical defences of maize by varying the species and content of volatile organic compounds (such as a mixture of nonanal, 1-dodecanol and 2-butyl-1-octanol), seemingly resulting in the avoidance of MBS plants by both herbivores in the Y-tube olfactometer tests. Field experiments further demonstrated that MBS significantly reduced damage to maize leaves by herbivores, enhanced maize yields, and increased the abundance of natural enemies. Therefore, we concluded that MBS improves the resistance of maize to major pests, and can be used as an effective and eco-friendly crop protection strategy in agroecosystems.

Non-canonical role of UCKL1 on ferroptosis defence in colorectal cancer

Weili Wu,Yingying Zhao,Baifu Qin,Xin Jiang,Chuyue Wang,Rong Hu,Rui Ma,Mong-Hong Lee,Huanliang Liu,Kai Li,Ping Yuan

Nonenzymatic Sequestering of Formaldehyde into the Antibiotic Methylene-Bridged Dimer Phaeochromycin F by Streptomyces sp. OUCMDZ-4982 as a Possible Multipronged Chemical Defense Mechanism

Weihong Wang,Jiaxu Shang,Shupeng Yin,Kunyu Xia,Rui Ma,Weiming Zhu,Peng Fu

Metabolites with high chemical reactivity serve important roles in chemical defenses of organisms. Formaldehyde, as a simple and highly reactive small molecule, can be produced by microorganisms, plants, and animals. Its toxicity is well known, but information about its other biological functions remains scarce. Here, we report that the natural product SEK34b produced by Streptomyces species can react nonenzymatically with formaldehyde in water to yield the methylene-bridged dimer phaeochromycin F. This process can eliminate the toxic substance formaldehyde produced by Staphylococcus aureus. Furthermore, there is a substantial inhibitory impact of phaeochromycin F on S. aureus. We hypothesize that these constitute an integrated system of defense and attack of Streptomyces species against competitors. Our study indicates that formaldehyde can react with vancomycin and tigecycline under mild conditions to generate the derivatives bearing an imidazolidin-4-one moiety, thereby reducing the antibacterial activity of these antibiotics. These data provide a possible chemical interaction mechanism of bacteria involving the nonenzymatic reactions of formaldehyde with highly reactive natural products.

Herbicides interfere with antigrazer defenses in Scenedesmus obliquus

Xuexia Zhu,Yunfei Sun,Xingxing Zhang,Hailu Heng,Haihong Nan,Lu Zhang,Yuan Huang,Zhou Yang

The extensive application of herbicides has led to a serious threat of herbicide contamination to aquatic ecosystem . Herbicide exposure affects aquatic communities not only by exerting toxicity on single species but also by changing interspecific interactions . This study investigated the antigrazer defenses of the common green alga Scenedesmus obliquus against different herbicides [glyphosate, 2,4-dichlorophenoxyacetic acid (2,4-D), and atrazine] at various concentrations (0–2.0 mg L −1 ). In the presence of grazer ( Daphnia )-derived cues, S. obliquus populations without herbicides formed high proportions of multicelled (e.g., four- and eight-celled) colonies. This result confirms that S. obliquus exhibits a morphological defense against grazing risk. At the low concentration range of 0.002–0.02 mg L −1 , the three herbicides exerted no influence on the growth and photosynthetic efficiency of S. obliquus , and multicelled colonies showed constant proportions. At the high concentration range of 0.20–2.0 mg L −1 , atrazine significantly inhibited the algal growth and photosynthesis whereas glyphosate or 2,4-D did not. Nonetheless, these levels of glyphosate or 2,4-D remarkably decreased the proportion of multicelled colonies, with reduced numbers of cells per particle in Daphnia filtrate-treated population. No eight-celled colony was formed after treatment with atrazine at 0.20–2.0 mg L −1 despite the addition of Daphnia filtrate. These results suggest that herbicide exposure impairs antigrazer colonial morphs in phytoplankton although it is not sufficient to hamper algal growth. This phenomenon can increase the risk of predation by herbivores, thereby disrupting the inducible phytoplankton community. Furthermore, the predator-prey interactions between herbivores and phytoplankton can be potentially changed more seriously than previously considered.

Viruses hijack FPN1 to disrupt iron withholding and suppress host defense

Tong Li,Wang Jie,Ma Yunjin,Wang Chunying,Fu Yue,Li Qi,Gao Chengjiang,Song Hui,Qin Ying,Zhao Chunyuan,Zhao Wei

Viruses rely on intracellular materials, including iron, to complete their life cycles and iron withholding may limit viral infections. However, the mechanisms through which viruses disrupt host iron homeostasis and the impact of intracellular iron on the host’s antiviral defense aren’t well studied. Here we show that viral infections facilitate the polyubiquitination and degradation of ferroportin (FPN1, the only cellular iron exporter) by upregulating the host E3 ubiquitin ligase DTX3L, leading to an elevation in cellular iron levels. Excessive ferrous iron suppresses type I IFN responses and autophagy by promoting TBK1 hydroxylation and STING carbonylation in macrophages. FPN1 deficiency suppresses host antiviral defense and facilitates viral replication in vitro and in vivo, while DTX3L deficiency has the opposite effect. These results reveal that viruses hijack host FPN1 to disrupt iron withholding and achieve immune escape, and suggest that iron homeostasis maintained by FPN1 is required for the optimal activation of TBK1- and STING-dependent antiviral responses.

Leaf defense system of Robinia pseudoacacia L. seedlings exposed to 3 years of elevated atmospheric CO2 and Cd-contaminated soils

X. Jia,Y.H. Zhao,T. Liu,Y.H. He

Short-term exposure to elevated CO 2 increases cadmium (Cd) uptake in some plant species (wheat, poplars, and willows), which triggers an increase in antioxidative system activity to deal with additional reactive oxygen species that are generated. Here, we examined leaf defenses in Robinia pseudoacacia L. seedlings exposed to elevated CO 2   +   Cd for 3   years. Three years of elevated CO 2 decreased Cd uptake into leaves and the Cd content in soils and increased the pH of rhizosphere soil relative to ambient CO 2 . In plants exposed to Cd stress , leaf chlorophyll content was greater under elevated CO 2 than under ambient CO 2 . Superoxide dismutase, peroxidase, and catalase activity increased, glutathione content increased, and malondialdehyde and phytochelatins contents decreased under elevated CO 2   +   Cd relative to Cd alone. Proline, soluble sugars, flavonoids, saponins, and phenolic acids contents were greater under elevated CO 2   +   Cd than under Cd alone, and condensed tannin content was lower. Overall, long-term elevation of CO 2 enhanced the leaf defense system of R. pseudoacacia exposed to Cd by stimulating antioxidant enzyme activity , osmotic adjustment, and the production of glutathione, flavonoids and phenolic acids. Future research should focus on understanding the mechanisms involved in the decrease in Cd uptake into leaves and Cd content in soils and the increase in rhizosphere soil pH under long-term exposure to elevated CO 2 .

Calcium and L-glutamate present the opposite role in managing arsenic in barley

Fanrong Zeng,Muhammad Mudassir Nazir,Temoor Ahmed,Muhammad Noman,Shafaqat Ali,Muhammad Rizwan,Mohammad Shah Alam,Jonas Lwalaba Wa Lwalaba,Guoping Zhang

Arsenic contamination in agricultural soils has posed tremendous threat to sustainable crop production and human health via food chain. Calcium and Glutamate have been well-documented in metal(loid)s detoxification, but it is poorly understood how they regulate arsenic-induced toxicity to plants. In this study, the effect of glutamate and calcium at high concentration on arsenic toxicity and accumulation in barley seedling was accessed in terms of plant growth, photosynthetic efficacy, arsenic uptake, translocation and accumulation, antioxidant defense, nutrient uptake and the expression of As transporters. Our results have demonstrated that calcium could effectively ameliorate arsenic toxicity to barley seedlings, which is mainly attributed to its beneficial effect on increasing nutrient uptake, reducing the aboveground arsenic accumulation and enhancing antioxidative defense capacity. However, it is unexpected that glutamate considerably exacerbated the arsenic toxicity to barley seedlings. More importantly, for the first time, glutamate was observed to tremendously facilitate the root-to-shoot translocation of arsenic by 41.8- to 60.8-fold, leading to 90% of the total amount of As accumulating in barley shoots. The reason of this phenomenon can be well explained by the glutamate-triggered enormous upregulation of genes involved in arsenic uptake ( HvPHT1;1 , HvPHR2 and HvNIP3;2 ), reduction ( HvHAC1;1 ), translocation ( HvABCC7 , HvNIP1;1 and HvNIP3;3 ) and intracellular sequestration ( HvABCC1 ). These findings suggest that calcium and glutamate function as the opposite player in managing arsenic, with calcium being an effective alleviator of arsenic stress to ensure the safe production of crops; while glutamate being a highly efficient phytoextraction agent for phytoremediation of arsenate-contaminated soils.

Effects of Zn Exposure on Populus simonii Seedling Growth and Its Resistance to Leaf Rust

Lulu Gao,Aoying Zhang,Shanchun Yan

Heavy metals are serious pollutants that affect the growth and disease resistance of woody plants. Herein, the enrichment characteristics of an essential element (Zn) inPopulus simoniiseedlings, as well as the effects of Zn stress on seedling growth and resistance to leaf rust, were investigated. Zn contents in roots, stems, and leaves of treatment groups were significantly increased. Zn stress at all concentrations significantly inhibited the biomass of seedlings. Under the low, middle, and high Zn treatments, compared with the control group, CAT activity significantly decreased by 36%, 21%, and 14%; SOD activity significantly decreased by 13%, 8%, and 5%; PPO activity significantly decreased by 27%, 31%, and 47%; TI activity significantly decreased by 48%, 55%, and 61%, and CI activity significantly decreased by 10%, 20%, and 14%, respectively. In the natural environment, we accidentally discovered thatP. simoniiwas infected with leaf rust, and Zn stress significantly increased the rust disease index. The disease index correlated positively with Zn content in leaves and negatively with the chemical defense indexes. Taken together, Zn stress causes a strong growth toxicity inP. simoniiseedlings, and the reduced chemical defense under Zn stress increases the susceptibility of seedlings to leaf rust.Keywords:essential element;Populus simonii;growth;chemical defense;leaf rust

Preparation of pH-Responsive Kas@ZnO Quantum Dots for Synergistic Control of Rice Blast and Enhanced Disease Resistance in Rice

Jie Hu,Changwei Gong,Yan Jia,Hui Feng,Jinfeng Chen,Ge Qin,Ao Liang,Anchun Peng,Yanyan Huang,Mengmeng Sun,Hanbing Rao,Xuegui Wang

The construction of controlled-release formulations improves the sustained-release performance and utilization efficiency of pesticides, which are important aspects in plant protection and environmental chemistry. The current study employs kasugamycin (Kas), which is widely used to control Magnaporthe oryzae, conjugated with carboxyl-functionalized ZnO quantum dots via amide linkages to yield a pH-responsive pesticide delivery system (Kas@ZnO). Physicochemical characterizations indicated the successful preparation of the Kas@ZnO nanoparticles. In vitro drug release assessments indicated that Kas@ZnO exhibited a loading capacity of 21.05% and could effect the controlled release of Kas in an acidic environment, which is beneficial given the unique acidic microenvironment of M. oryzae. Bioactivity assays demonstrated that Kas@ZnO could simultaneously inhibit mycelial growth and spore germination. Additionally, bioactivity tests showed that the control efficacy of Kas@ZnO against rice blast reached 67.43% after 14 days of in vivo spray inoculation, which was higher than that obtained with Kas (55.50%), suggesting improved beneficial effects of Kas@ZnO application over a prolonged duration. Moreover, Kas@ZnO enhanced the activity of defense-related enzymes in rice and upregulated the expression of defense-related genes, such as OsPR2, OsPR3, OsPR5, OsWRKY45, OsLYP6, and OsNAC4. Ultimately, the biosafety assessments revealed that Kas@ZnO did not exert any harmful effects on rice and demonstrated slight toxicity toward zebrafish. These findings indicate that Kas@ZnO can function as a pH-sensitive pesticide delivery system, allowing for targeted release of the pesticide within plant tissues. This technology demonstrates significant potential for eco-friendly plant disease management.

Bioactivity of the defensive chemicals of six millipede species in the superorder Juliformia against Solenopsis invicta Buren (Hymenoptera: Formicidae)

Delong Kong,Siquan Ling,Wanru Guo,Eduardo G.P. Fox,Jinzhu Xu,Jiamei Zhong,Desen Wang,Hualong Qiu,Weixin Liu

Millipedes are known to produce a diverse array of chemical defenses against natural predators, notably ants, positioning them as a promising source of natural products useful for pest ant control. A top invasive ant species of international scale is the red imported fire ant, Solenopsis invicta , for which there are numerous studies surveying alternative chemicals, as traditional insecticides have not been able to stop their spread. In this study, we characterized the composition of the defensive secretions from six quinone millipedes and evaluated the fumigant, contact, and repellent activities of some main components against S. invicta workers. In total, 27 components were detected in the defensive secretions of the six millipede species, with 2-methoxy-3-methyl-1,4-benzoquinone being the predominant compound overall. Nine compounds (1,4-benzoquinone, α -pinene, dimethyl trisulfide, β -pinene, 2-methyl-1,4-benzoquinone, 2-methoxy-3-methyl-1,4-benzoquinone, orcinol, 3,4-dimethoxyphenol, and 1-hydroxycyclohexyl phenyl ketone) were selected for bioassays. Among them, the three benzoquinones displayed significant fumigant and contact toxicity, as well as repellent effects against S. invicta . Dimethyl trisulfide exhibited fumigant and repellent activity, while 1-hydroxycyclohexyl phenyl ketone demonstrated just contact toxicity. These findings highlight the potential of millipede-derived compounds as natural agents for S. invicta control, possibly to direct a mixture of chemicals for use against fire ants' infestation in transported goods.

Defense systems of soil microorganisms in response to compound contamination by arsenic and polycyclic aromatic hydrocarbons

Meng Zhou,Zishu Liu,Baofeng Zhang,Baolan Hu

Arsenic and PAHs impose environmental stress on soil microorganisms, yet their compound effects remain poorly understood. While soil microorganisms possess the ability to metabolize As and PAHs, the mechanisms of microbial response are not fully elucidated. In our study, we established two simulated soil systems using soil collected from Xixi Wetland Park grassland, Hangzhou, China. The As-600 Group was contaminated with 600 mg/kg sodium arsenite, while the As-600-PAHs-30 Group received both 600 mg/kg sodium arsenite and 30 mg/kg PAHs (phenanthrene:fluoranthene:benzo[ a ]pyrene = 1:1:1). These systems were operated continuously for 270 days, and microbial responses were assessed using high-throughput sequencing and metagenomic analysis. Our findings revealed that compound contamination significantly promoted the abundance of microbial defense-related genes, with general defense genes increasing by 11.07 % ∼ 74.23 % and specific defense genes increasing by 44.13 % ∼ 55.74 %. The dominate species Rhodococcus adopts these general and specific defense mechanisms to resist compound pollution stress and gain ecological niche advantages, making it a candidate strain for soil remediation. Our study contributes to the assessment of ecological damage caused by As and PAHs from a microbial perspective and provides valuable insights for soil remediation.

Three years of exposure to lead and elevated CO2 affects lead accumulation and leaf defenses in Robinia pseudoacacia L. seedlings

Xia Jia,Chunyan Zhang,Yonghua Zhao,Tuo Liu,Yunhua He

Few studies have explored the long-term effects of elevated atmospheric CO 2 combined with lead (Pb) contamination on plants. The objective of this study was to examine the effects of 3 years of elevated CO 2 (700 ± 23 μmol mol –1 ) on Pb accumulation and plant defenses in leaves of Robinia pseudoacacia L. seedlings in exposed to Pb (500 mg kg −1 soil). Elevated CO 2 increased Pb accumulation in leaves and Pb removal rate in soils. In plants exposed to Pb stress, total chlorophyll and carotenoid contents in leaves were lower under elevated CO 2 than under ambient CO 2 , but seedling height and width increased under elevated CO 2 relative to ambient CO 2 . Elevated CO 2 significantly ( p  < .01) stimulated malondialdehyde content in leaves under Pb exposure. Superoxide dismutase and catalase activity increased significantly ( p  < .01), peroxidase activity decreased significantly ( p  < .01), and glutathione , cystine, and phytochelatin contents increased under elevated CO 2  + Pb relative to Pb alone. Elevated CO 2 stimulated the production of soluble sugars, proline, flavonoids , saponins, and phenolics in plants exposed to Pb stress. Ove rall, long-term elevation of CO 2 increased Pb-induced oxidative damage in seedlings, but enhanced the phytoextraction of Pb from contaminated soils.