RESUMO
BACKGROUND: Normalization with respect to stable housekeeping genes is important to facilitate gene transcription regulation research and acquire more accurate quantitative polymerase chain reaction (qPCR) data. In the current study, five candidates housekeeping genes of the cotton leafworm, Spodoptera littoralis encoding for Actin (Actin), elongation factor 1-alpha (EF1α), ribosomal protein S3 (RPS3), ribosomal protein 49 (RP49), and Ubiquitin (Ubi), were evaluated as normalization housekeeping genes under Spodoptera littoralis nucleopolyhedrovirus (SpliNPV) viral infection. METHODS AND RESULTS: The qPCR results confirmed the expression of all five housekeeping genes in S. littoralis viral infected larvae. The expression profiles of the housekeeping genes showed that the EF1α, Actin, and RP49 had the minimum average Ct values of 18.41 ± 0.66, 18.84 ± 0.90 and 19.01 ± 0.87 in all infected samples, respectively. While RPS3 and Ubi showed the maximum average Ct of 21.61 ± 0.51 and 21.11 ± 0.82, respectively. According to the results of ΔCt and geNorm analysis, EF1α was ranked as the most stable housekeeping gene during infection time-course. While by using BestKeeper, geNorm and NormFinder, the Ubi, RP49, and RPS3 showed the most genes transcription stability. The obtained results were also validated using the Cytochrome c oxidase (COX) gene transcripts in response to SpliNPV infection. CONCLUSIONS: The results revealed that EF1α and Ubi were the most stable housekeeping genes to be used for normalizing S. littoralis gene transcription regulation under SpliNPV infection. These findings, provide a significant addition for gene transcription regulation studies of S. littoralis upon infection using SpliNPV as a bio-agent.
Assuntos
Genes Essenciais , Nucleopoliedrovírus , Spodoptera , Animais , Spodoptera/genética , Spodoptera/virologia , Genes Essenciais/genética , Nucleopoliedrovírus/genética , Regulação da Expressão Gênica , Larva/genética , Larva/virologia , Transcrição Gênica/genética , Perfilação da Expressão Gênica/métodos , Proteínas de Insetos/genéticaRESUMO
Reducing nematicide dose rates could be a useful strategy for mitigating their negative effects on health and the environment. In this study, enzymatic activities and the parasitic ability of Meloidogyne incognita after exposure to sub-lethal concentrations (0.25, 1, 2, and 5 ppm) of ethoprophos, fenamiphos, and oxamyl were investigated. Although the tested concentrations did not show nematicidal properties in vitro, they reduced root galls by at least 30% at 0.25 ppm and up to 67% at 5 ppm in pots, besides disrupting nematode fertility. For all three nematicides at 2 ppm, a chemotaxis assay showed that ≤ 11% of the nematode population was successfully oriented to the host roots, compared to 44% in the control. Ethoprophos and fenamiphos at 5 ppm showed poor inhibitory effects on acetylcholinesterase (AChE) activity (5.6% and 12.5%, respectively). In contrast, the same nematicides were shown to be strong ATPase inhibitors, causing 82.4% and 82.8% inhibition, respectively. At the same concentration, oxamyl moderately inhibited AChE and ATPase-specific activities, the inhibition being 22.5% and 35.2%, respectively. This study suggests that the use of very low nematicide concentrations could be a promising strategy for nematode management. Furthermore, it has also highlighted the role of ATPases as a possible target site for suppressing nematode activity in the development of future nematicides.
Assuntos
Tylenchoidea , Animais , Tylenchoidea/fisiologia , Acetilcolinesterase , Antinematódeos/farmacologiaRESUMO
OBJECTIVE: To investigate the effect of humic acid on nematode infected, resistant and susceptible grapes in relation to lipid peroxidation and antioxidant mechanisms on selected biochemical parameters known as proactive substances. METHODS: The grape rootstocks, superior, superior/freedom and freedom were reacted differently to Meloidogyne incognita and Rotylenchulus reniformis according to rootstock progenitor. Two weeks after inoculation, two commercial products of humic acid were applied at the rate of (2, 4 mL or grams/plant) as soil drench. After 4 months, nematode soil populations were extracted and counted. A subsample of roots from each plant was stained and gall numbers, embedded stages per root were calculated, final population, nematode build up (Pf/Pi), average of eggs/eggmass were estimated. Subsamples of fresh root of each treatment were chemically analyzed. RESULTS: Freedom reduced significantly the nematode criteria and build up. Humic acid granules appeared to be more suppressive to nematode build up on superior and the higher dose on superior/freedom than liquid treatments. On freedom, all treatments reduced significantly the nematode build up regardless to the material nature. The higher dose was more effective than the lower one. As a result of humic acid applications, the malondialdehyde (MDA) and H2O2 contents were significantly reduced after humic acid treatments while the antioxidant compounds glutathione (GSH), ascorbic acid (ASA) and total phenol contents were significantly increased when compared with check. Antioxidant defense enzymes ascorbate peroxidase (APX), superoxide dismutase (SOD), catalase (CAT) and polyphenol oxidase (PPO)showed significant increase in their specific activities in treated plants compared with nematode treated check. CONCLUSIONS: Humic acid treatments improve the yield of grape by increasing the contents of antioxidant compounds and the specific activities of antioxidant enzymes.