Presence of hydroxamic acids in the honeydew of aphids feeding on wheat seedlings, and its significance for plant resistance and virus transmission

Author(s):  
Arturo Givovich ◽  
Hermann M. Niemeyer
2019 ◽  
Vol 20 (19) ◽  
pp. 4923 ◽  
Author(s):  
Jolanta Jaroszuk-Ściseł ◽  
Renata Tyśkiewicz ◽  
Artur Nowak ◽  
Ewa Ozimek ◽  
Małgorzata Majewska ◽  
...  

Both hormonal balance and plant growth may be shaped by microorganisms synthesizing phytohormones, regulating its synthesis in the plant and inducing plant resistance by releasing elicitors from cell walls (CW) by degrading enzymes (CWDE). It was shown that the Trichoderma DEMTkZ3A0 strain, isolated from a healthy rye rhizosphere, colonized the rhizoplane of wheat seedlings and root border cells (RBC) and caused approximately 40% increase of stem weight. The strain inhibited (in over 90%) the growth of polyphagous Fusarium spp. (F. culmorum, F. oxysporum, F. graminearum) phytopathogens through a mechanism of mycoparasitism. Chitinolytic and glucanolytic activity, strongly stimulated by CW of F. culmorum in the DEMTkZ3A0 liquid culture, is most likely responsible for the lysis of hyphae and macroconidia of phytopathogenic Fusarium spp. as well as the release of plant resistance elicitors. In DEMTkZ3A0 inoculated plants, an increase in the activity of the six tested plant resistance markers and a decrease in the concentration of indoleacetic acid (IAA) auxin were noted. IAA and gibberellic acid (GA) but also the 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase (ACCD) enzyme regulating ethylene production by plant were synthesized by DEMTkZ3A0 in the liquid culture. IAA synthesis was dependent on tryptophan and negatively correlated with temperature, whereas GA synthesis was positively correlated with the biomass and temperature.


Agriculture ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 193
Author(s):  
Lin Li ◽  
Shuangchao Wang ◽  
Xiufen Yang ◽  
Frederic Francis ◽  
Dewen Qiu

Barley yellow dwarf virus (BYDV), transmitted by the wheat aphid, generates serious wheat yellow dwarf disease and causes great losses in agriculture. Induced resistance has attracted great attention over recent years as a biological method to control plant pathogens and herbivores. Protein elicitor PeaT1 induces defense response in plants against fungi, viruses, and aphids. In this study, wheat seeds and seedlings were soaked and sprayed with 30 μg/mL PeaT1, respectively. Then seedlings were inoculated with BYDV by viruliferous Schizaphis graminum to detect the control efficiency of PeaT1-induced resistance against BYDV. The control efficiency was over 30% on the 14th and 21st days after the inoculation access period. Quantitative real time polymerase chain reaction (Q-RT-PCR) tests showed that there was less mRNA from the BYDV coat protein in PeaT1-treated wheat seedlings than in the control group. Electrical penetration graph (EPG) tests showed that virus transmission vector S.graminum took a longer time to find probe and feeding sites on PeaT1-treated wheat seedlings. Additionally, PeaT1-treated wheat seedlings gained higher plant height and more chlorophyll a&b. These results showed that PeaT1 efficiently controlled BYDV by inhibiting BYDV proliferation, reducing the virus transmission ability of S. graminum and alleviating the symptoms of dwarfism and yellow colouring caused by BYDV. This study provided a new integrated way to control BYDV biologically.


2013 ◽  
Author(s):  
He-He Cao ◽  
Meng Zhang ◽  
Hui Zhao ◽  
Yi Zhang ◽  
Xing-Xing Wang ◽  
...  

The non-protein amino acid β-aminobutyric acid (BABA) could induce plant resistance to a broad spectrum of biotic and abiotic stresses. However, BABA-induced plant resistance to insects is less well-studied, especially its underlying mechanism. In this research, we applied BABA to wheat seedlings and tested its effects on Sitobion avenae. When applied as a soil drench, BABA significantly reduced weight of S. avenae, whereas foliar spray and seed treatment had no such effects. BABA-mediated suppression of S. avenae growth is dose dependent and could last at least for 7 days. The aminobutyric acid concentration in phloem sap of BABA-treated plants accumulated to high levels and increased with BABA concentrations applied. Moreover, after 10 days of treatment, the aminobutyric acid content in BABA-treated plants was still higher than that in control treatment. S. avenae could not discriminate artificial diet containing BABA from standard diet, indicating that BABA itself is not a deterrent to this aphid. Also S. avenae did not show preference for control plants or BABA-treated plants. Consistent with choice test results, S. avenae had similar feeding activities on control and BABA-treated plants, suggesting that BABA did not induce antifeedants in wheat seedlings. In addition, aminobutyric acid concentration in S. avenae feeding on BABA-treated plants was significantly higher than those feeding on control palnts. S. avenae growth rate was reduced on artificial diet containing BABA, indicating direct toxic effects of BABA to this aphid. These results suggest that BABA application could enhance wheat plant resistance to S. avenae and the mechanism is possibly due to direct toxicity of high BABA contents in plant phloem.


1992 ◽  
Vol 67 (01) ◽  
pp. 019-027 ◽  
Author(s):  
Joseph E Addiego ◽  
Edward Gomperts ◽  
Liu Shu-Len ◽  
Patricia Bailey ◽  
Suzanne G Courter ◽  
...  

SummaryTo reduce the risk of pathogenic virus transmission associated with the therapeutic administration of plasma-derived antihemophilic factor (FVIIIc), a process utilizing anti-FVIIIc immunoaffinity chromatography to isolate FVIIIc has been developed. In addition, the starting cryoprecipitate solution has been treated with an organic solvent/detergent mixture to inactivate lipid-enveloped viruses. A final ion exchange chromatography step is used to further remove contaminants, e.g., anti-FVIIIc antibody, potentially leached with FVIIIc during the immunoaffinity step. The purified FVTII is stabilized for lyophili-zation and storage by the addition of human albumin. The monoclonal anti-FVIIIc antibody used in the immunoaffinity step of the process is not detectable in the final preparation. Viral reduction studies performed at specific steps of the process demonstrate that 11 logs of human immunodeficiency virus (HIV) and greater than 4-5 logs of other lipid-enveloped viruses are inactivated within the first 30 s of exposure to the solvent/ detergent mixture and 4-5 logs of various model viruses, e. g. Endomyocarditis virus (EMC), are physically removed during washing of the immunoaffinity column. The lyophilized product is reconstituted using sterile water in a matter of seconds.The pharmacokinetics of Hemofil® M were compared to those obtained using a standard heat-treated concentrate (Hemofil® CT) in five severe factor VIII deficient hemophiliacs in a randomized, cross-over study. No statistically significant differences were observed in mean half life (p >0.6) or median recovery (p = 0.4) between the two preparations. No clinically significant adverse effects were observed in patients receiving either FVIII preparation.In addition, 43 patients at 18 different centers underwent pharmacokinetic studies, with a nominal dose of 50 u/kg FVIIIc Hemofil® M. The mean recovery was 103.6%, and the t 1/2 was 14.6 h. The recovery of FVIII in this group was as expected, providing an increase of assayed FVIII of approximately 2% per unit of FVTII/kg infused.Clinical trials using Hemofil® M have been initiated in 124 hemophilia A patients. The safety and efficacy of Hemofil® M has been established. To date, 0 of 60 patients tested have seroconverted to HIV. None of the previously untreated patients show clinical or laboratory evidence of Non-A, Non-B hepatitis (NANB), with 21 patients remaining negative as far as presence of antibodies to the Hepatitis C virus (a-HCV negative) at least 6 months after the initial infusion. There is no evidence of neoantigenicity, evidenced by seroconversion to murine antibody. An 8.7% (2 of 23) prevalence of anti-FVIIIc inhibitor development has been observed in previously untreated patients with FVIIIc⩽3%, receiving only the monoclonally purified solvent/ detergent treated FVIII concentrate while on study and on poststudy surveillance. All patients demonstrated clinical hemostasis following product use for either on demand bleeding or surgical prophylaxis.


Author(s):  
Wanderson Kleber de Oliveira ◽  
Juan Cortez-Escalante ◽  
Wanessa Tenório Gonçalves Holanda De Oliveira ◽  
Greice Madeleine Ikeda do Carmo ◽  
Cláudio Maierovitch Pessanha Henriques ◽  
...  

2016 ◽  
Vol 65 (9) ◽  
pp. 242-247 ◽  
Author(s):  
Wanderson Kleber de Oliveira ◽  
Juan Cortez-Escalante ◽  
Wanessa Tenório Gonçalves Holanda De Oliveira ◽  
Greice Madeleine Ikeda do Carmo ◽  
Cláudio Maierovitch Pessanha Henriques ◽  
...  

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