Both conventionally and organically fertilized tomatoes maintain fruit quality through uncontrolled green peach aphid infestation, with a transcriptional shift towards catabolism

Simple SummaryThe green peach aphid (Myzus persicae (Sulzer)) is considered one of the main pests of economically valuable crops. In the last decades, it has developed resistance to several chemical pesticides. More effective and environmentally friendly solutions for green peach aphid management, including plant essential oils, are being tested as alternatives to chemical pesticides. Repellents have gained interest because lower doses can be used against agricultural pests, with a reduced risk of developing insect resistance. In this study, three different types of caraway (Carum carvi L.) seed essential oils against green peach aphids were tested. Repellent activity testing was carried out using a bridge method and host plants of white cabbage. The aphids were placed on the bridge, and their choice was recorded depending on whether they went to the treatment side (containing the selected essential oil) or the control side (no essential oil). All the selected caraway essential oils showed that they repel aphids to various degrees. The optimal essential oil dose was determined in the same way. In addition, the essential oil was mixed with different surfactants to create a formulation basis for ready-to-use products, but the testing showed decreased repellent activity of such mixtures.An in vivo dual choice bioassay with white cabbage as a host plant was used to determine the repellent effect of three different accessions of caraway (Carum carvi L.) essential oils (EOs) against the green peach aphid Myzus persicae (Sulzer). The dominant components of the EO were D-Carvone (47.3–74.4%) and D-limonene (25.2–51.9%), which accounted for 99.2–99.5% of the EOs determined by GC/MS. The EO with the highest D-limonene content (51.9%) showed the highest repellence (Repellency Index (RI) = +41%), which was stable up to 330 min. The incorporation of several surfactants with different hydrophilic-lipophilic balance values (from 12.4 to 16.7) with caraway EO caused a general inhibition of the repellent effect during the testing period (RI from +41% to −19%). Overall, the findings indicate that caraway EO could be used as a green peach aphid repellent, but more work is needed to formulate the EO into a ready-to-use product.

The tomato crop is affected by a number of pests in the world as well as in China and Pakistan. The whitefly (Bemisia tabaci) is considered a very serious and damaging pest of tomato crop along with many other vegetables and field crops. Population buildup of whitefly is affected by many factors, including biotic and a biotic. One of the factors affecting the whitefly population in the tomato crop is green peach aphid (Myzus persicae) infestation before the whitefly attack. This project designed to note the direct and indirect effect of Myzus persicae infestation on the population setup of whitefly in tomato crops. The results revealed that whitefly prefers tomato plants without having aphids on them (choice) and can be settled on the tomato plants also when there are aphids present (no choice). The period after aphid infestation have a negative effect on the whitefly population, and the density of aphids/leaf has also influenced the whitefly population.

Aggregate-scale mechanisms driving carbon and nitrogen stocks under organic and conventional vineyard systems in semiarid regions.

In order to clarify the effect of different fertilizers on foxtail millet quality under low nitrogen conditions, we used JGNo.21 and LZGNo.2 as experimental materials and set up five treatments, including non-fertilization, nitrogen, phosphorus, compound, and organic fertilizers, to study the regulation of different fertilizer types on agronomic traits, nutrient fractions, and pasting characteristics of foxtail millet under low nitrogen conditions. Compared with the control, all of the fertilizers improved the agronomic traits of JGNo.21 to a certain extent. Nitrogen and compound fertilizer treatments reduced the starch content of JGNo.21; the starch content was reduced by 0.55% and 0.07% under nitrogen and compound fertilizers treatments. Phosphorus and organic fertilizers increased starch content, and starch content increased by 0.50% and 0.56% under phosphorus and organic fertilizer treatments. The effect of each fertilizer treatment on protein content was completely opposite to that of starch; different fertilizer treatments reduced the fat content of JGNo.21 and increased the fiber content. Among them, nitrogen and phosphorus fertilizers increased the yellow pigment content; the yellow pigment content increased by 1.21% and 2.64% under nitrogen and phosphorus fertilizer treatments. Organic and compound fertilizers reduced the content of yellow pigment; the yellow pigment content was reduced by 3.36% and 2.79% under organic and compound fertilizer treatments. Nitrogen and organic fertilizers increased the fat content of LZGNo.2; the fat content increased by 2.62% and 1.98% under nitrogen, organic fertilizer treatment. Compound and phosphorus fertilizer decreased the fat content; the fat content decreased by 2.16% and 2.90% under compound and phosphorus fertilizer treatment. Different fertilizer treatments reduced the cellulose and yellow pigment content of LZGNo.2. The content of essential, non-essential, and total amino acids of JGNo.21 was increased under compound and nitrogen fertilizer treatments and decreased under organic and phosphorus fertilizer treatments. The content of essential, non-essential, and total amino acids of LZGNo.2 was significantly higher under compound, nitrogen, and organic fertilizer treatments compared with control and significantly decreased under phosphorus fertilizer treatments. Nitrogen and compound fertilizer treatments significantly reduced the values of peak viscosity, trough viscosity, breakdown viscosity, final viscosity, setback viscosity, and pasting time of each index of JGNo.21; phosphorus and organic fertilizer treatments improved the values of each index. In contrast, the pasting viscosity of LZGNo.2 increased under phosphorus fertilizer treatment and decreased under nitrogen fertilizer treatment. Reasonable fertilization can improve the quality of foxtail millet, which provides a scientific theoretical basis for improving the quality of foxtail millet.

Potato virus Y (PVY) is a destructive and widespread virus in a number of important crops, including potato. Aphid vectors spread this viral infection between plants in a non-persistent manner, and the green peach aphid (Myzus persicae) is the most efficient known vector. In this research, we investigated five cuticle proteins (CuPs) which are expected to be involved in virus transmission at the stylet of aphids. In an RNA interference (RNAi) gene-silencing assay with the green peach aphids (M. persicae), we evaluated the impact of these CuPs on the transmission of PVY with potato and tobacco plants. Using an oral RNAi bioassay where the aphids pierce-suck in an artificial diet that was supplemented with gene-specific dsRNA, the expression of only two CuPs, mpcp2 (DQ108935) and mpcp1 (AF435075.1), could be decreased by 63 and 75%, respectively. Expression of the other three CuPs could not be affected. Subsequently, we investigated what the effect is of the RNAi-mediated gene silencing on the transmission of PVY from potato to tobacco plants. These results showed with a high certainty of 99.5%, for the first time in vivo, a significant involvement of MPCP2 with a reduction of 47% (compared to the dsGFP control) in the transmission of PVY. For MPCP1, the effect was smaller with a reduction of 19% and lower certainty of 86%.

Efficient usage of fertilizers in organic or inorganic forms show conflicting results in terms of net fish production under various climatic conditions. Manures applied to polyculture ponds as organic fertilizer, require a process of decomposition before the nutritional contents are released, assimilated, and utilized by plankton. On the other hand, inorganic (chemical) fertilizers are granular and concentrated with primary nutrients. Major nutrients such as nitrogen (N) and phosphorus (P) readily dissolve in water in ionic forms of nitrate, ammonium and orthophosphate. The differences in fertilizer solubility (nutrient release rate) and decomposition processes (organic fertilization) make the water quality and biological response distinctively different in inorganic fertilizer applied ponds. Previous research has indicated that one grass carp, Ctenopharyngodon idella, can support the growth of three silver carp. This means the excreta of herbivorous fish can be utilized to fertilize the water and produce plankton for filter-feeding fish to consume. Due to an inconsistent supply of grass foliage, farmers in North Vietnam found it difficult to include an adequate percentage of grass carp to support polyculture operation without supplementary fertilization to maintain adequate levels of natural foods in the pond. This supplementary fertilization, in particular manure application, often impacted water quality, which negatively affected health of grass carp. In the present study, an attempt was made to evaluate the production of grass carp polyculture when N:P were maintained through supplementary organic fertilization. An assessment of organic and inorganic fertilizer application on fish production was also undertaken and compared with grass carp polyculture performance. Fish biomass change and fertilizer treatments had significant interaction (P= 0.001). The fish production was found to be significantly different for organic fertilizer, grass carp + organic fertilizer and inorganic fertilizer treatments. The net fish production was highest (5.6±0.03 tonnes/ hectare) in grass carp + organic fertilizer treatment followed by organic fertilizer (4.0±0.06 tonnes/hectare). The inorganic fertilizer treatment yielded the least with 3.0±0.05 tonnes/hectare. The control ponds with no fertilizer was applied produced only 0.29±0.01 tonnes/hectare.

Phytophagous Entomofauna of Tomato, Paprika and Eggplant Occurring on Plantations in Poland in 1919-2010 In Poland, in the years 1919-2010, in field crops of tomato (Lycopersicon esculentum Mill.), paprika (Capsicum annuum L.) and eggplant (Solanum melongena L.) there were found 52 phytophagous species belonging to 6 orders of insects: Orthoptera, Thysanoptera, Hemiptera, Coleoptera, Lepidoptera and Diptera. The number of pest species occurring on the different crops was: tomato - 39, paprika - 41, eggplant - 27. The presented phytophagous entomofauna proved to be stable in terms of species composition over the years of observations. However, there was a significant variation in population size, which was subject to considerable fluctuations in successive growing seasons. The dominant species posing a threat to plantations every year included: for tomato: Colorado potato beetle (Leptinotarsa decemlineata), green peach aphid (Myzus persicae), soil pests: cutworm (Agrotis sp), wireworms (Agriotes sp) and white grubs (Melolontha sp); for paprika: onion thrips (Thrips tabaci), green peach aphid (Myzus persicae), bugs (Lygus sp.); for eggplant: green peach aphid (Myzus persicae), Colorado beetle (Leptinotarsa decemlineatas), onion thrips (Thrips tabaci).

Piercing/sucking insects such as green peach aphid (GPA) (Myzus persicae) cause direct damage by obtaining phloem nutrients and indirect damage by spreading plant viruses. To investigate the response of peach trees (Prunus persica) to aphids, the leaf transcriptome and metabolome of two genotypes with different sensitivities to GPA were studied. The gene expression of aphid-susceptible plants infested with aphids was similar to that of control plants, whereas the gene expression of aphid-resistant plants infested with aphids showed strong induced changes in gene expression compared with control plants. Furthermore, gene transcripts in defense-related pathways, including plant-pathogen interaction, MAPK signaling, and several metabolic pathways, were strongly enriched upon aphid infestation. Untargeted secondary metabolite profiling confirmed that aphid infestation induced larger changes in aphid-resistant than in aphid-susceptible peaches. Consistent with transcriptomic alterations, nine triterpenoids showed highly significant GPA-induced accumulation in aphid-resistant peaches, whereas triterpenoid abundance remained predominantly unchanged or undetected in aphid-susceptible peaches. Furthermore, some types of transcription factors (including WRKYs, ERFs, and NACs) were strongly induced upon GPA infestation in aphid-resistant, but not in aphid-susceptible peaches. These results suggested that the accumulation of specialized triterpenoids and the corresponding pathway transcripts may play a key role in peach GPA resistance.

Implications of dietary phenolic compounds for human health and disease prevention have been indicated by a body of literature. A greenhouse pot study was performed to investigate the impacts of fertilizer source and preventive insecticide application on phenolic compound levels in pac choi [Brassica rapa (L.) cv. Mei Qing]. A two-way randomized complete-block design with five replications was used in this experiment. Fertilizer source consisted of two levels: conventional fertilizer (pre-plant application of Osmocote slow-release fertilizer), and organic fertilizer (pre-plant application of vermicompost and fertigation with compost tea and fish emulsion). Insecticide application consisted of three levels: organic (pyrethrin) vs. conventional (permethrin), and a plain water control. At harvest, total phenolics and individual phenolic compounds in pac choi leaves (blades) were analyzed by Folin assay and HPLC, respectively. Head weight of pac choi was significantly higher under conventional fertilizer treatment, while it was not affected by insecticides. Total phenolic content of pac choi was significantly increased by organic fertilizer treatment. HPLC results indicated that organic fertilizer treatment resulted in significantly higher levels of individual phenolic compounds, including chlorogenic acid and ferulic acid. In contrast, preventive insecticide application showed little effect on the phenolics in pac choi. Correlation analysis excluded the influence of plant size (head weight) on phenolic content in pac choi. Differential N-forms, rates of nutrient release, and/or variable nutrient content in organic and conventional fertilizer treatments may contribute to elevated phenolic content in organically fertilized pac choi.

به منظور بررسی اثرات کود‌‌های آلی و شیمیایی بر برخی ویژگی‌های کمی و کیفی چای ترش آزمایشی در قالب طرح بلوک‌های کامل تصادفی با 10 تیمار و 4 تکرار در مزرعه تحقیقاتی دانشکده کشاورزی دانشگاه زابل انجام شد. تیمار‌ها شامل: (T1) عدم مصرف کود (شاهد)، (T2) 300 کیلوگرم کود نیتروژن، فسفر و پتاسیم در هکتار به نسبت 2:1:1، (T3) 20 تن کود گاوی در هکتار، (T4) 10 تن کمپوست در هکتار، (T5) 5 تن ورمی‌کمپوست در هکتار، (T6) محلول پاشی اسید هیومیک به نسبت 5/1 در هزار، (T7) 50 درصد T2 + T6، (T8) 50 درصد T3 + T6، (T9) 50 درصد T4 +T6 و (T10) 50 درصد T5 + T6 بودند. نتایج نشان داد در اکثر صفات مورد بررسی اختلاف معنی‌داری بین تیمارهای اعمال شده و شاهد وجود داشت، به طوری که بیشترین مقدار ارتفاع و تعداد شاخه‌های جانبی و قطر ساقه در نتیجه کاربرد تیمار کودهای آلی توأم با اسید هیومیک (T8، T9 و T10) حاصل شد. تأثیر کود‌ کمپوست توأم با اسید هیومیک (T9) بر وزن‌تر و خشک کاسبرگ (31/157، 69/22 گرم در بوته)، تعداد میوه در بوته، وزن میوه، تعداد دانه در بوته، و در مورد میزان آنتوسیانین، تأثیر کود گاوی توأم با اسید هیومیک (T8) نسبت به سایر تیمارها بیشتر بود. نتایج این تحقیق نشان داد که کاربرد کودهای آلی در بهبود عملکرد کمی و کیفی گیاه دارویی چای ترش و همچنین در جهت پایداری تولید و حفظ محیط زیست تأثیر مثبتی داشته و به نظر می‌رسد کودهای آلی جایگزین مناسبی برای کودهای شیمیایی باشند.

The introduction of alternative crops, including wild edible and medicinal plants, in organic cultivation systems presents an attractive approach to producing healthy and high-quality products due to their content in beneficial compounds and increased nutritional value. The current study evaluated the impact of organic and conventional fertilization on the growth, quality, nutrient status and stress response of the two wild edible species, e.g., purslane (Portulaca oleracea L.) and common sowthistle (Sonchus oleraceus L.), under field conditions. The fertilization treatments included the following: a control (NoFert) treatment with no fertilizers added, base dressing with conventional fertilization (CoFert), base dressing with organic fertilization (OrFert), base dressing and side dressing with conventional fertilization (OrFert + SCoFert) and base dressing and side dressing with organic fertilization (CoFert + SCoFert). Organic fertilization was carried out using a commercial vinasse-based organic fertilizer. In both purslane and common sowthistle, the application of organic fertilizers provided comparable or even enhanced plant growth traits, macronutrient content (i.e., P and K for purslane, and N for sowthistle) and quality (i.e., total soluble solids) compared to the application of conventional fertilizers. On the other hand, conventional fertilization with supplementary fertilization positively influenced the plant growth of purslane (i.e., plant height and stems biomass), as well as its physiological parameters (i.e., chlorophylls content), total phenolics content and antioxidant capacity (i.e., DPPH and FRAP). Similarly, conventional fertilization led to increased total phenolics and antioxidants in common sowthistle, while variable effects were observed regarding plant physiology, stress response and antioxidant capacity indices. In conclusion, the use of organic fertilization in both purslane and common sowthistle exhibited a performance similar to that of conventional fertilization, although further optimization of fertilization regimes is needed to improve the quality of the edible products.

The infestation of two aphid species, the green peach aphid (Myzus persicae) and black bean aphid (Aphis fabae), along with the viruses they transmit, causes significant yield losses in sugar beet (Beta vulgaris). With increasingly strict regulations on pesticide use, especially the recent EU ban on neonicotinoids, and a lack of effective alternative methods, protecting sugar beet during the early growth stage has become more challenging. Therefore, there is an urgent need to explore novel resistance mechanisms and identify potential resistant sugar beet genotypes to integrate into sugar beet breeding programs. In the first part, 25 genotypes were screened by assessing the intrinsic rate of increase (rm) of both aphid species, respectively. Susceptible and resistant candidates were selected based on the lowest or highest intrinsic rate of increase. Both aphid species showed high rm on susceptible candidates G17 and G19. In contrast, G3 and G11 were defined as resistant candidates for both aphid species because the rm values of M. persicae were negative and were among the lowest in A. fabae. Electrical penetration graph (EPG) analysis of pre-selected candidates showed tissue-specific resistance to the two aphid species. M. persicae encountered difficulties in the stylet movement before reaching the sieve element, and A. fabae faced resistance at the sieve element. Furthermore, a high incidence of black deposits was observed in more than 85% of M. persicae’s stomachs regardless of sugar beet genotypes, indicating a general and strong incompatibility between sugar beet and M. persicae in an initial phase of interaction. The resistance was further validated in a whole plant assay in the greenhouse and under semi-field conditions by the introduction of Zero-inflated count model. An assumption of temporal adaptation by M. persicae during sugar beet colonization was introduced. The second part of the research investigated the formation of stomach deposits when M. persicae was transferred from other hosts to sugar beets. Two types of stomach deposits, black and white, were examined. As hypothesized based on literature, both types were identified to have a protein nature. Based upon mass spectrometry analysis, an 18.2 kDa sugar beet-specific lectin was detected as a part of the stomach deposits from M. persicae feed on sugar beets, and its presence was confirmed in sugar beet phloem sap. Additionally, a 72-hour EPG analysis showed that the black deposit formation led to enhanced xylem ingestion activities in unadapted aphids. Transcriptome analysis of unadapted and adapted M. persicae samples revealed an elevated expression of a Cath B gene encoding a cysteine protease, and its presence in the stomach was described. All the findings support the hypothesis that sugar beet lectin, which is highly conserved in B. vulgaris, is a protein strongly correlated with the formation of black and white deposits. The adaptation of subsequent M. persicae generations to sugar beet diet appears to be driven by Cath B overexpression-mediated effects. However, the mechanism of black deposit formation remains unknown due to its strong insolubility. Possible mechanisms have been discussed, but further investigation is needed. In the third part, the nature of black deposit formation was investigated with regard to genetic variability between M. persicae and beet yellow virus (BYV) infection. Analysis of different M. persicae biotypes showed that the occurrence of black deposit formation is biotype-specific, with variations among 3 M. persicae biotypes collected from Germany, Hungary, and France. The French biotype has the lowest occurrence of formation within the first 4 days of infestation. An BYV adaptability bioassay was performed by transferring either BYV-infested sugar beet-adapted or healthy sugar beet-adapted M. persicae to healthy sugar beet leaf. Results showed that M. persicae adapted to BYV-infected plants had a higher incidence of black deposit formation compared to those adapted to virus-free sugar beet. Transcriptome analysis revealed only minor differences in gene expression between these two M. persicae populations. The impact of BYV, a semi-persistently transmitted virus located in the phloem, is primarily discussed in the area of plant physiology, probably affecting the expression, folding, or transport of the previously described plant lectin, which is known to be involved in the formation of deposits. This change likely contributes to the observed reduction of black deposits on BYV-infected sugar beet plants. The work is of practical importance as it identified sugar beet genotypes with strong aphid resistant potential that can be integrated into breeding programs. Additionally, a novel sugar beet resistance mechanism for deposit formation was described, as the identified sugar beet lectin is a highly potential elicitor for black deposit formation and subsequent aphid death. The findings of Cath B deployed by M. persicae are regarded as an adaptation strategy in response to ingested sugar beet lectin and could be manipulated to intervene in the adaptation process. Taken together, these findings can be integrated into breeding programs as a crucial component of integrated pest management (IPM) strategies. Furthermore, the results obtained provide an insight into the complex interaction between sugar beet, aphid vectors, and viruses.

Local and systemic hormonal responses in pepper (Capsicum annuum L.) leaves under green peach aphid (Myzus persicae Sulzer) infestation

Because they suck phloem sap and act as vectors for phytopathogenic viruses, aphids pose a threat to crop yields worldwide. Pectic homogalacturonan (HG) has been described as a defensive element for plants during infections with phytopathogens. However, its role during aphid infestation remains unexplored. Using immunofluorescence assays and biochemical approaches, the HG methylesterification status and associated modifying enzymes during the early stage of Arabidopsis (Arabidopsis thaliana) infestation with the green peach aphid (Myzus persicae) were analyzed. Additionally, the influence of pectin methylesterase (PME) activity on aphid settling and feeding behavior was evaluated by free choice assays and the Electrical Penetration Graph technique, respectively. Our results revealed that HG status and HG-modifying enzymes are significantly altered during the early stage of the plant-aphid interaction. Aphid infestation induced a significant increase in total PME activity and methanol emissions, concomitant with a decrease in the degree of HG methylesterification. Conversely, inhibition of PME activity led to a significant decrease in the settling and feeding preference of aphids. Furthermore, we demonstrate that the PME inhibitor AtPMEI13 has a defensive role during aphid infestation, since pmei13 mutants are significantly more susceptible to M. persicae in terms of settling preference, phloem access, and phloem sap drainage.

Simple SummaryPotato (Solanum tuberosum L.) is a vegetable crop that plays a major role in global food security. However, its production and sustainability are adversely affected due to aphid infestation. The green peach aphid, Myzus persicae (Sulzer), poses a significant threat to potato plants globally due to its high production of honeydew and transmission of viruses. Other researchers reported that drought severity could result in an outbreak of insect pests such as aphids. Accordingly, understanding the mechanism of host plant defense against aphids under drought stress is a major concern for insect pest management. This study was conducted to examine the cross-talk of phytohormones in potato glycoalkaloids’ defense against green peach aphids under greenhouse conditions. The results showed that under drought conditions, the cross-talks of phytohormones do not only function as signal hormones, but also modify host plant secondary metabolites to defend against sap-sucking insects. Many potato cultivars may activate phytohormones under drought stress; however, only host plants with a greater level of secondary metabolites may be able to defend against aphid attack. This research will provide a scientific basis for the development of potato varieties with high yield, improved quality, and drought and pest resistance.Potato production is adversely affected by aphid infestation across the globe. Understanding the mechanism of host plant defense against aphids under drought stress is paramount for insect pest management. This study was conducted to examine the cross-talk of phytohormones in potato glycoalkaloids’ defense against green peach aphids under greenhouse conditions. A 3 × 2 × 2 factorial experiment comprising three potato cultivars (Qingshu 9, Longshu 3, and Atlantic) and two levels each of water availability and aphid infestation was conducted. The results show that under drought stress, green peach aphids thrive well on host plants, which contain a relatively high water content. The resistant cultivar DXY, which exhibited a higher level of phytohormones, also demonstrated higher α-chaconine and α-solanine contents in both leaf and root, under drought and aphid stress. Conversely, the susceptible cultivar QS9, which exhibited a lower level of phytohormones, also demonstrated low α-chaconine and α-solanine contents in both leaf and root, under drought and aphid stress. The DXY cultivar, which possessed high resistant traits such as α-chaconine and α-solanine, can be used in areas where green peach aphid infestation is a major setback.