Volatile-mediated tritrophic defense and priming in neighboring maize against Ostrinia furnacalis and Mythimna separata.

BACKGROUND: Plants respond to attackers by triggering phytohormones signaling associated metabolites, including herbivore-induced plant volatiles (HIPVs). HIPVs can indirectly act against herbivory by recruitment of natural enemies and priming of neighboring plants. Ostrinia furnacalis and Mythimna separata are important insect herbivores of maize plants that have a devastating influence on yield. However, little is known about how maize temporally reconfigures its defense systems against these herbivores and variation of neighboring plant resistance. RESULTS: This study investigated the effects of HIPVs on the behavior of the dominant predatory beetle Harmonia axyridis and priming in neighboring maize defense against O. furnacalis and M. separata over time. The results showed that maize damaged by either O. furnacalis or M. separata enhanced the release of volatiles including terpenes, aldehydes, alkanes and an ester, which elicited an increased attractive response to H. axyridis after 3 and 12 h, respectively. O. furnacalis damage resulted in accumulations of leaf jasmonic acid (JA) and salicylic acid in maize after 6 and 3 h, respectively, while M. separata damage only raised the JA level after 3 h. Furthermore, HIPVs were able to prime neighboring plants through the accumulation of JA after 24 h. Both larvae showed a significant decrease in weight accumulation after 48 h of feeding on the third leaves of the primed plant. CONCLUSION: Taken together, the findings provide a dynamic overview of how attacked maize reconfigures its volatiles and phytohormones to defend against herbivores, as well as priming of neighboring plants against oncoming attacks. © 2022 Society of Chemical Industry.

Volatiles and hormones mediated root-knot nematode induced wheat defense response to foliar herbivore aphid.

Plant root-leaf communication signals are critical for plant defense. Numerous studies show that belowground organisms can alter systemically resistance traits in aboveground parts against herbivores. However, there are limited studies on root-knot nematode-aphid interaction. Moreover, the impact of nematode's initial density and infection time on plant defense is poorly understood. Here we aim to examine the induced defense responses by root-knot nematode Meloidogyne incognita against aboveground feeding aphid Sitobion avenae in wheat. Further, we investigated the influence of the nematode infection density as well as the length of infection in these interactions. We tested the direct and indirect defense responses triggered by M. incognita against S. avenae as well as how the responses affect the preference of Harmonia axyridis. Plant volatiles and hormones were determined to explore plant defense mechanisms that mediate aboveground-belowground defense. The photosynthetic rate was tested to examine plant tolerance strategy. We found that, both low and high densities M. incognita root infection at 7 days post inoculation (dpi) reduced the feeding of the aphid S. avenae. Behavioral assay showed that H. axyridis preferred plants co-damaged by both M. incognita and S. avenae at 7 dpi. M. incognita infection induced the changes of jasmonic acid, salicylic acid and volatile content, which mediated plant response to S. avenae. Furthermore, photosynthetic rate in wheat increased at 5 dpi under 300 M. incognita or 1000 M. incognita infection. These results suggest that plant roots induced multiple defense strategies against foliar herbivores as damages increased. Our study provides evidence of a complex dynamic response of wheat aboveground defense against aphids in response to belowground nematode damage on a temporal scale.

A Salivary Odorant-Binding Protein Mediates Nilaparvata lugens Feeding and Host Plant Phytohormone Suppression.

Odorant-binding proteins (OBPs) typically act as transporters of odor molecules and play an important role in insect host location. Here, we identified an OBP in brown planthopper (BPH) Nilaparvata lugens salivary glands via transcriptome sequencing. Real-time quantitative PCR and Western blotting analysis results showed that NlugOBP11 was highly expressed in salivary glands and secreted into rice plant during feeding, suggesting that it assists in BPH feeding on rice. Functional analysis in N. lugens saliva revealed that silencing this gene by RNA interference decreased the BPH stylet performance in the phloem of rice plants, reduced sap sucking, and ultimately led to insect death. Moreover, overexpression of NlugOBP11 in rice protoplasts or Nicotiana benthamiana leaves inhibited the production of defense-related signaling molecule salicylic acid in rice plant. The results demonstrate that NlugOBP11 is not only essential for BPH feeding, but also acts as an effector that inhibits plant defense.

Phytopathogenic infection alters rice-pest-parasitoid tri-trophic interactions.

BACKGROUND: Plant pathogens and pests often occur together, causing damage while interfering with plant growth. The effects of phytopathogenic infections on plant-herbivore-natural enemy tri-trophic interactions (TTIs) have been extensively investigated, but little is known about how the interval of infection influences such relationships. Here, the effect of rice plants infected by the phytopathogen Rhizoctonia solani on the herbivorous rice brown planthopper (BPH) and associated egg parasitoid Anagrus nilaparvatae over a temporal scale was examined. RESULTS: Our results showed that rice plants infected by R. solani showed increased volatile profiles and significantly attracted BPH and A. nilaparvatae at 5-15 days post infection (DPI) and 5-10 DPI, respectively, when compared with healthy plants. Jasmonic acid and salicylic acid content decreased significantly in BPH-damaged plants after 15 DPI, whereas oxalic acid accumulated soon after 5 DPI when compared with healthy plants. To adapt to adverse environment, BPH laid more eggs and developed into macropterous adults. Under field conditions, R. solani infection had no substantial effect on the arthropod community when compared with healthy plants. CONCLUSION: Taken together, R. solani infection altered rice-pest-parasitoid TTIs over a temporal scale. This result will shed more light on our understanding of plant pathogen-insect cross-talk essential for developing novel pest management strategies. © 2021 Society of Chemical Industry.

The control of the brown planthopper by the rice Bph14 gene is affected by nitrogen.

BACKGROUND: Brown rice planthopper (BPH) is a devastating rice pest in Asia. Bph14 is the first cloned BPH-resistance gene in rice, inducing callose deposition while impeding BPH feeding. Nitrogen application affects plant growth and resistance. However, there is little evidence on the influence of nitrogen on the callose content or regulation of rice BPH resistance. In this study, Luoyou9348 (containing Bph14 and highly resistant to BPH) and Yangliangyou6 (without Bph14 and susceptible to BPH) were planted under varying nitrogen regimes (0 , 90, 180 kg ha-1 ) to determine their effects on the resistance levels of rice to BPH feeding. The experiments involved BPH performance, plant volatile profiling and BPH preferences in laboratory and field experiments. RESULTS: We found that BPH egg hatching rate, total number of eggs laid and BPH preference increased with increasing nitrogen application in both rice varieties. However, the expression of Bph14, callose content and BPH feeding significantly declined with an increase in nitrogen fertilization in Luoyou9348, compared with Yangliangyou6. Also, the emission of volatile terpene compounds increased with increasing nitrogen application, which resulted in an increase in BPH numbers on both varieties. Two-way analysis of variance indicated a significant interaction between rice variety and nitrogen in BPH feeding behavior. CONCLUSION: Our findings provide an insight for addressing problems involved in the incorporation of insecticidal genes into crop plants. The effects of nitrogen on insecticidal gene expression in rice plant defense are discussed. © 2020 Society of Chemical Industry.

Rice defense responses are induced upon leaf rolling by an insect herbivore.

BACKGROUND: Plant defense against herbivores begins with perception. The earlier plant detects the harm, the greater plant will benefit in its arm race with the herbivore. Before feeding, the larvae of the rice pest Cnaphalocrocis medinalis, initially spin silk and fold up a leaf. Rice can detect and protect itself against C. medinalis feeding. However, whether rice could perceive C. medinalis leaf rolling behavior is currently unknown. Here, we evaluated the role of leaf rolling by C. medinalis and artificial leaf rolling in rice plant defense and its indirect effect on two important C. medinalis parasitoids (Itoplectis naranyae and Apanteles sp.) through a combination of volatile profiling, gene-transcriptional and phytohormonal profiling. RESULTS: Natural leaf rolling by C. medinalis resulted in an increased attraction of I. naranyae when compared to the undamaged plant after 12 h. Volatile analysis revealed that six out of a total 22 components significantly increased in the headspace of C. medinalis rolled plant when compared to undamaged plant. Principal component analysis of these components revealed similarities in the headspace of undamaged plant and artificially rolled plant while the headspace volatiles of C. medinalis rolled plant deferred significantly. Leaf rolling and feeding by C. medinalis up-regulated the plant transcriptome and a series of jasmonic acid (JA) and salicylic acid (SA) related genes. While feeding significantly increased JA level after 12 to 36 h, rolling significantly increased SA level after 2 to 12 h. Compared to artificial rolling, natural rolling significantly increased JA level after 36 h and SA level after 2 and 12 h. CONCLUSIONS: Our findings suggest that natural leaf rolling by C. medinalis can be perceived by rice plant. The detection of this behavior may serve as an early warning signal in favor of the rice plant defenses against C. medinalis.

Recycled ancient ghost carbonate in the Pitcairn mantle plume.

The extreme Sr, Nd, Hf, and Pb isotopic compositions found in Pitcairn Island basalts have been labeled enriched mantle 1 (EM1), characterizing them as one of the isotopic mantle end members. The EM1 origin has been vigorously debated for over 25 years, with interpretations ranging from delaminated subcontinental lithosphere, to recycled lower continental crust, to recycled oceanic crust carrying ancient pelagic sediments, all of which may potentially generate the requisite radiogenic isotopic composition. Here we find that δ26Mg ratios in Pitcairn EM1 basalts are significantly lower than in normal mantle and are the lowest values so far recorded in oceanic basalts. A global survey of Mg isotopic compositions of potentially recycled components shows that marine carbonates constitute the most common and typical reservoir invariably characterized by extremely low δ26Mg values. We therefore infer that the subnormal δ26Mg of the Pitcairn EM1 component originates from subducted marine carbonates. This, combined with previously published evidence showing exceptionally unradiogenic Pb as well as sulfur isotopes affected by mass-independent fractionation, suggests that the Pitcairn EM1 component is most likely derived from late Archean subducted carbonate-bearing sediments. However, the low Ca/Al ratios of Pitcairn lavas are inconsistent with experimental evidence showing high Ca/Al ratios in melts derived from carbonate-bearing mantle sources. We suggest that carbonate-silicate reactions in the late Archean subducted sediments exhausted the carbonates, but the isotopically light magnesium of the carbonate was incorporated in the silicates, which then entered the lower mantle and ultimately became the Pitcairn plume source.

[Clinical Trials for Thyroidectomy Under Acupuncture-aided Anesthesia by Using Electroacupuncture or Transcutaneous Acupoint Electrical Stimulation of Different Acupoints].

OBJECTIVE: To observe the effectiveness of transcutaneous acupoint electrical stimulation (TAES) or electroacupuncture (EA) stimulation of different acupoints in combination with anesthetics in the management of thyroidectomy patients, so as to choose a better stimulating method and most effective acupoints for thyroidectomy. METHODS: A total of 216 thyroidectomy patients (ASA Ⅰ-Ⅱ grades) with thyroid gland adenoma, thyroid cyst or thyroid nodules from 3 hospitals (3 research centers) were randomized into 6 groups, i.e., local anesthesia (LA, n=34), Futu (LI 18)-EA (n=36), Hegu (LI 4)-Neiguan (PC 6)-TAES (n=34), LI 4-PC 6-EA (n=36), Yanglingquan (GB 34)-EA (n=36) and non-acupoint (NA, about 1.5 cm latero-posterior to KI 9)-EA (n=34) groups according to the hospitalizition sequence. For patients of the LI 18-EA, LI 4-PC 6-TAES/EA, GB 34 and non-acupoint-EA groups, EA or TAES (2 Hz/100 Hz) was applied to the abovementioned bilateral acupoints or non-acupoint till the termination of the surgical operation. The surgery was conducted under anesthesia by local injection of 0.5% lidocaine and midazolam, and intravenous injection of fentanyl (for severe pain cases) 20 min after beginning of TAES or EA. The patients' scores of visual analogue scale (VAS),mean arterial pressure (MAP) and heart rate (HR) at the time-points of pre-anesthesia (T 0), skin-incision (T 1), skin flap-freeing (T 2), anterior cervical muscle traction (T 3), thyroid upper/lower-pole-sectioning (T 4/T 5), and thyroidectomy (T 6), and the dosages of the administered fentanyl and lidocaine were recorded. RESULTS: Compared with the corresponding time-points of the non-acupoint group, the VAS scores at T 1 and T 4 time-points in the LI 18-EA group and LI 4-PC 6-EA group, at T 1, T 5 and T 6 time-points in the LI 4-PC 6-TAES group were significantly lower (P<0.05). Compared with the corresponding time-points of the LA group, the VAS scores at T 2, T 3, T 5 and T 6 time-points in the LI 18-EA group and LI 4-PC 6-EA group, at T 3, T 5 and T 6 in the LI 4-PC 6-TAES group, and the MAP levels at T 2, T 3, T 4 and T 6 time-points in the LI 18-EA group, at T 3, T 4 in the LI 4-PC 6-EA group, at T 3, T 4, T 6 in the LI 4-PC 6 TAES group, as well as the HR levels at T 4, T 5 and T 6 in the LI 18-EA group, and at T 5, T 6 in the LI 4-PC 6-TAES group were significantly lower (P<0.05). The dosages of fentanyl in the LI 18-EA and LI 4-PC 6-TAES groups, and those of lidocaine in the LI 18-EA, LI 4-PC 6-EA and TAES groups were significantly lower relevant to the LA group and non-acupoint group (P<0.05). No significant differences were found between the LA and GB 34-EA groups, and between the LA and non-acupoint groups, as well as between the LI 4-PC 6-EA and LI 4-PC 6-TAES groups in the VAS scores, the MAP and HR levels, the dosages of lidocaine and fentanyl consumption (P>0.05). CONCLUSIONS: EA stimulation of both LI 18 and LI 4-PC 6 and TAES of LI 4-PC 6 combined with anesthetics have a better effect in inducing analgesia and controlling MAP and HR, and need lower dosages of anesthetics for patients undergoing thyroidectomy, for which LI 18 and LI 4-PC 6 are evidently superior to GB 34 and non-acupoint. Hence, combined EA or TAES and anesthetics is highly recommended for thyroidectomy.

[Contrast study of acupuncture anesthesia and local anesthesia: their effects on the blood pressure and the heart rate in chronic rhinitis patients accompanied inferior turbinate hypertrophy in low temperature radiofrequency ablation].

OBJECTIVE: To compare the effects of acupuncture anesthesia (AA) and local anesthesia (LA) on the blood pressure (BP) and the heart rate (HR) in chronic rhinitis patients accompanied inferior turbinate hypertrophy in low temperature radiofrequency ablation (RFA). METHODS: Totally 61 chronic rhinitis patients accompanied inferior turbinate hypertrophy were randomly assigned to the AA group (31 cases) and the control group (30 cases). All patients received RFA respectively under AA and RA. Their heart rate (HR), systolic pressure (SP), diastolic pressure (DP), and mean pressure (MP) were recorded and compared at 10 minutes after their entry into the operating room, immediately before surgery, intraoperation, and 5 min after operation. RESULTS: When compared with the control group at the same time points, the SP, DP, MP, and HR all decreased at intraoperation and 5 min after operation in the AA group. There was statistical difference in the SP on the right side at the 2nd melting point and the HR on the left side at the 2nd melting point between the two groups (P < 0.05). Compared with the same group at 10 min after entry into the operating room, the SP on the right side at the 1st melting point, the SP, DP, and MP on the right side at the 2nd melting point, the SP, DP, and MP on the left side at the 1st melting point, and the SP on the left side at the 2nd melting point all obviously increased with statistical difference (P < 0.05, P < 0.01). When compared with the same group at 10 min after entry into the operating room and immediately before surgery, there was no statistical difference in the SP, DP, MP, or HR of the AA group at intraoperation and 5 min after operation (P > 0.05). When compared with the same group at 10 min after entry into the operating room and immediately before surgery, there was no statistical difference in HR of the control group at intraoperation and 5 min after operation (P > 0.05). CONCLUSION: Patients undergoing AA had less fluctuation of the BP and the HR, indicating AA had better analgesic effects.

[Randomized controlled study on electroacupuncture compound anesthesia in radiofrequency ablation for hypertrophic inferior turbinate].

OBJECTIVE: To explore the feasibility of electroacupuncture compound anesthesia in radiofrequency ablation for hypertrophic inferior turbinate. METHODS: The patients confirmed to the enrolled criteria were randomly divided into an observation group (n = 31) and a control group (n = 30). The observation group was treated with electroacupuncture at Sibai (ST 2), Xiaguan (ST 7), Hegu (LI 4) and Zhigou (TE 6) on the left side and routine local anesthesia on the right side. The control group was treated with routine local anesthesia on the both side. The feelings of pain, circulatory index and operation effect were observed and compared. RESULTS: During radiofrequency ablation, the pain grade of two measurements on the left side and the 2nd measurement on the right in the observation group were all lower than those in the control group (all P<0.05). In the observation group, the pain grades on the left side were lower than that on the right side (P<0.05), and the systolic blood pressure and the heart rate were lower than that in the control group when undergoing the 2nd radiofrequency ablation on the right side and on the left side, respectively (both P<0.05). There was no significant difference in operation effect between the two groups. CONCLUSION: Electroacupuncture compound anesthesia can meet the analgesia requirement of radiofrequency ablation for treatment of hypertrophic inferior turbinate, and would be helpful to prevent cyclic fluctuation during the operation at the same time.

[Analysis on the superiority of compound acupuncture anesthesia for thyroid ablation].

In the present paper, the authors compare the fits and unfit of different anesthetic methods for thyroid ablation and try to find a better one for it according to their own clinical practice and other scholars' experience. Results indicate that any anesthetic method has its own advantages and disadvantages, while compound acupuncture anesthesia for thyroid surgery is of prominent preponderance not only in the analgesic effect but also in fewer side-effects and less physiological interference. Thus, compound acupuncture anesthesia is a reliable and better anesthetic method for thyroid operation in clinic.