Nematode Meloidogyne Javanica Research Articles

Chlorella vulgaris improves growth of Abrometiella scapigera, Abrometiella brevifolia and Abrometiella chloranta and reduces root attack by nematodes

Research objective: The aim of this study is to investigate the effects of Chlorella extract as a biofertiliser on the growth of Abrometiella spp. seedlings and to assess whether it has a repellent effect against nematodes Materials and Methods: The experiments, which began in November 2024, were conducted in the CREA-OF greenhouses in Pescia (PT), Tuscany, Italy (43°54′N 10°41′E) on Abrometiella scapigera, Abrometiella brevifolia and Abrometiella chloranta. The plants were placed in ø12 cm pots; 30 plants per thesis, divided into 3 replicates of 10 plants each. The experimental groups were: i) group without algae, irrigated with water and previously fertilised substrate; ii) group with Chlorella vulgaris, previously fertilised substrate. On 2 April 2024, plant height, leaves number, vegetative weight, root weight, root lenght, number of new plantlets, chlorophyll content, leaf area, control of the nematodes Meloidogyne javanica and Meloidogyne incognita were measured. Results and Discussion: The experiment showed that the use of Chlorella vulgaris extracts can improve the vegetative and root growth of Abrometiella scapigera, Abrometiella brevifolia and Abrometiella chloranta plants grown in pots. The treatment also led to an increase in plant height, number of leaves, length of root hairs, leaf area and number of new seedlings. The trial also showed that the use of Chlorella in plant growing media can also increase the photosynthesis rate (SPAD index) and significantly reduce the presence of nematodes, in particular Meloidogyne javanica and Meloidogyne incognita. According to some researchers, the influence of Chlorella extract on cell metabolisms is mainly due to the physiological effect of major and minor nutrients, amino acids, vitamins, and plant growth regulators on cellular metabolisms in treated plants, which increase crop yields and growth. Chlorella plants have very high photosynthesis rates, dozens of times higher than other plants. The main reason why Chlorella can grow rapidly is because it contains Chlorella Growth Factor (CGF), which is quite rich in nucleoproteins, nucleic acids, ribonucleic acids (RNA), deoxyribonucleic acids (DNA), vitamins, amino acids, polysaccharides, complex protein bodies, enzymes, glycoproteins, plant hormones, etc. Its ability to promote plant growth may be due to this factor. Conclusions: Chlorella extract significantly increased Abrometiella seedling height, leaf number and leaf area. In particular, Abrometiella seedlings treated with chlorella extract developed better root system, chlorophyll a increased significantly and the root length and number of new seedlings also improved significantly. Based on the above results that Chlorella extracts contribute to the growth and development of Abrometiella plants, we can conclude that with the treatment of Chlorella extracts, the application of chemical fertilisers in the production of succulents such as Abrometiella can be reduced.

The other side of the coin: systemic effects of Serendipita indica root colonization on development of sedentary plant–parasitic nematodes in Arabidopsis thaliana

Main conclusionUpon systemic S. indica colonization in split-root system cyst and root-knot nematodes benefit from endophyte-triggered carbon allocation and altered defense responses what significantly facilitates their development in A. thaliana.Serendipita indica is an endophytic fungus that establishes mutualistic relationships with different plants including Arabidopsis thaliana. It enhances host’s growth and resistance to different abiotic and biotic stresses such as infestation by the cyst nematode Heterodera schachtii (CN). In this work, we show that S. indica also triggers similar direct reduction in development of the root-knot nematode Meloidogyne javanica (RKN) in A. thaliana. Further, to mimick the natural situation occurring frequently in soil where roots are unequally colonized by endophytes we used an in vitro split-root system with one half of A. thaliana root inoculated with S. indica and the other half infected with CN or RKN, respectively. Interestingly, in contrast to direct effects, systemic effects led to an increase in number of both nematodes. To elucidate this phenomenon, we focused on sugar metabolism and defense responses in systemic non-colonized roots of plants colonized by S. indica. We analyzed the expression of several SUSs and INVs as well as defense-related genes and measured sugar pools. The results show a significant downregulation of PDF1.2 as well as slightly increased sucrose levels in the non-colonized half of the root in three-chamber dish. Thus, we speculate that, in contrast to direct effects, both nematode species benefit from endophyte-triggered carbon allocation and altered defense responses in the systemic part of the root, which promotes their development. With this work, we highlight the complexity of this multilayered tripartite relationship and deliver new insights into sugar metabolism and plant defense responses during S. indica–nematode–plant interaction.

Potential of 2-Hydroxyacetophenone Derivatives and Simple Phenol's for the control of Meloidogyne javanica

Objective: In this study, a series of synthetic hydroxylated (5-10) and prenylated (10-17) acetophenones, chalcones (18-20) and a flavone (21) have been synthesized and evaluated on the nematode Meloidogyne javanica. Additional phenolic compounds, including salicylic acid, isopropyl salicylate, thymol, carvacrol, cumic acid, eugenol, vanillin, and vanillic acid (22-29), were also tested. Methods: Compounds 5-21 have been synthesized by a sequence of reactions and were isolated and identified by 1H-NMR, 13C-NMR, and HRMS. The in vitro nematicidal effects of the compounds were tested on J2 juveniles. The nematicidal activity was confirmed by their egg hatching inhibition effects, tested at the minimum lethal concentration (minimum dose to give 100% J2 mortality). Results: Compounds 5-18 have been previously reported and 19-21 are described here for the first time. The 2´-hydroxylated acetophenones (5-9) showed strong nematicidal effects, being 7-9 the most active. Salicylic (22) and cumic (26) acids were effective compounds. Compounds 7, 12, 22-26, active on M. javanica J2 juveniles, were also egg hatching inhibitors. Conclusions: A C-2/C-4 dihydroxylation or C-2/C-4/C-3 trihydroxylation of the acetophenone moiety improved the activity, while introducing a hydrophilic isoprene chain (10-17) eliminated the effect, with only one prenylated acetophenone (12) being active. Among the additional phenolic compounds (22-29), these with a carboxyl group instead of the acyl side were better nematicides. These results generate molecular leads for developing new nematicidal phenolic compounds.

Transcriptome-based analysis of candidate gene markers associated with resistance mechanism to Phytophthora melonis that causes root and crown rot in pumpkin.

Root and crown rot incited by an oomycete, Phytophthora melonis, causes significant yield losses in commercial pumpkin (Cucurbita pepo) production worldwide. Currently, resistant cultivars and knowledge of molecular mechanism of C. pepo against P. melonis are scarce. Here, we analysed the quantitative gene expression changes of 10 candidate gene markers (bHLH87, ERF014, HSF, MYB, PR-1, WRKY21, CPI, POD, PSK, SGT) in pumpkin roots and leaves at three time points (h post-inoculation, hpi) following inoculation with P. melonis in two resistant (Ghelyani and Tanbal), and two susceptible (Marmari and Khoreshti) varieties of pumpkin. Gene expression using quantitative real time PCR along a time course revealed the strongest transcriptomic response at 48 and 72hpi in resistant genotypes, 1.1-2.7-fold in roots and leaves, respectively, with a high significant correlation (r=0.857**-0.974**). We also found that CPI, PSK, SGT1 and POD act as a dual regulator that similarly modulate immunity not only against P. melonis, but also against other diseases such as early blight (Alternaria cucumerina), powdery mildew (Podosphaera xanthii), downy mildews (Pseudoperonospora cubensis), and pathogenic plant nematodes (Meloidogyne javanica). Furthermore, significantly higher activities of the ROS scavenging defence enzymes, catalase (1.6-fold increase) and peroxidase (6-fold increase) were observed in the roots of resistant cultivars at different hpi compared with non-inoculated controls. In addition, the biomass growth parameters including leaf and root length, stem and root diameter, root fresh weight and volume were significantly different among studied genotypes. Cumulatively, the transcriptome data provide novel insights into the response of pumpkins for improving pumpkin breeding to P. melonis.

Field evaluation of single and interaction effects of nematode, fungus and bacterium on nodulation and pathological parameters of Bambara groundnut (Vigna subterrenea (l.) Verdc.) in field condition

The aim of the present study was to determine the effects of single and mixed infections of nematode (Meloidogyne javanica), fungus (Fusarium oxysporum) and bacterium (Xanthomonas axonopodis) on nodulation and pathological parameters of Bambara groundnut (Vigna subterrenea (L.) Verdc.) in field condition. Nematode infested field was used while other pathogens were obtained from diseased plants. The Randomized Complete Block Design (RCBD) was adopted in a 5 × 9 × 5 factorial design (5 blocks, 9 treatments and 5 replicates per treatments) resulting in 225 experimental units. In each experimental unit, three seeds were sown to a depth of 5cm and thinned to one plant per planting hole after germination at day 7. Treatments were inoculated into test plant following standard methods. As a result, the control treatment recorded the highest number of nodules (64.0 ± 6.91), followed by bacterium (45.2 ± 5.11) while N + F + B had the lowest number of root nodules (23.4 ± 2.42). Simultaneous treatment (N + F + B) gave the highest percentage reduction in nodulation (63.44%), followed by treatment N + F7 (56.25%). Fungus treatment recorded the highest mean wilted plants (3.8 + 0.20) followed by N + F7 treatment (3.40 + 0.40). Gall formation in the nematode treatment increased proportionately by 56.33% as the highest recorded, followed by treatment N + F7 with 50.0%. Treatment N + F7 had the highest reproduction factor (Rf) value of 9.30 followed by nematode (8.30), N + B7 (7.40), N + F + B (6.80) and N + F14 (6.50). Zero (0) Rf value was recorded in fungus, bacterium and control treatments. The observed differences in nodulation and pathological parameters among the treatments are significant (P < 0.05). The data provided in this work is important in the control of the three pathogens affecting the productivity of Bambara nut. Formulation of a single protectant should be designed to have potent effects on the three pathogens to achieve effective protection and good production of Bambara nut.

Valorization of the essential oil from Drypetes gossweileri S. Moore (Putranjivaceae): in vitro, in vivo, and in silico nematicidal activity

The chemical composition, insect antifeedant, in vtro/in vivo nematicidal activity, phytotoxicity, and in silico nematicidal activity of the essential oil (EO) of the African medicinal plant Drypetes gossweileri were studied. Chemical analysis using GC/MS indicated that benzyl isothiocyanate (96.23%) was the major compound, followed by benzyl cyanide (1.38%). The biocidal effects of this oil were tested against insect pests and root-knot nematodes. All the insect species tested were significantly affected by the oil according to their feeding adaptations (Spodoptera littoralis and Myzus persicae were less affected than Rhopalosiphum padi) with efficient doses (EC50) of 29.4 8.3 μg/cm2, 14.744 8.3 μg/cm2, and 8.3 μg/cm2, respectively. The oil was highly effective against juveniles J2 of the nematode Meloidogyne javanica, with LC50–LC90 values of 0.007 mg/mL–0.0113 mg/mL. D. gossweileri EO at minimum lethal concentrations (MLC) and below strongly inhibited egg hatching in vitro, whereas soil treatment caused a strong suppression of nematode population, infection frequency, and multiplication rate. The EO inhibited ryegrass (Lolium perenne) germination at 0.4 mg/mL, while at 0.1 mg/mL, its effects on germination, root and leaf growth were moderate (32.4%, 8.4%, and 18.3%, respectively). The tomato (Solanum lycopersicum) germination was not affected by the EO, but the root growth was reduced (56% at 0.1 mg/mL) at a dose 10 times higher than the LD50 calculated for M. javanica J2 mortality. Molecular docking of the nematicidal effects of the oil using PyRx revealed a strong interaction between potassium chloride transporting KCC3 (PDB ID: 7D90) and benzyl cyanide at a distance of 2.20 A° with GLN C:350, followed by benzyl isothiocyanate at a distance of 2.78 A° with ARG B:294. The in vivo nematicidal effects of D. gossweileri EO on M. javanica penetration and reproduction in tomato roots further support the potential of this EO as a nematicidal agent with insect antifeedant effects, which could be used by local farmers for crop protection.

Effect on Hatching and Mortality of Root-knot Nematode (Meloidogyne javanica) by Bio-agents

Investigations were carried out in vitro condition to evaluate the antagonistic effect of fungal and bacterial bio-agents. For effective management of root-knot nematode experiment was conducted in laboratory condition using the culture filtrate (5, 10 and 20 percent concentrate) of bio-agents (viz., Trichoderma viride, Trichoderma harzianum, Purpureocillium lilacinum, Pochonia chlamydosporia and Pseudomonas fluorescens). Experimental results showed that all the tested bio-agents significantly reduced the percent hatched juveniles and increased the percent mortality of juveniles. Among the tested bio-agents T. viride was found most effective treatment with minimum percent hatched juveniles and maximum percent mortality on eggs and juveniles of Meloidogyne javanica.

SlWRKY16 and SlWRKY31 of tomato, negative regulators of plant defense, involved in susceptibility activation following root-knot nematode Meloidogyne javanica infection

The involvement of WRKY transcription factors in plant-nematode interactions, and in particular, how these WRKYs participate in regulating the complex morphological and physiological changes occurring after nematode infection, are the topic of active research. We characterized the functional role of the unstudied tomato WRKY genes SlWRKY16 and SlWRKY31 in regulating tomato roots’ response to infection by the root-knot nematode Meloidogyne javanica. Using promoter–GUS reporter gene fusions and qRT-PCR, we show that both SlWRKYs are predominantly expressed during the first half of the parasitic life stages, when feeding-site induction and construction occur. Expression of SlWRKY16 increased sharply 15 days after inoculation, whereas SlWRKY31 was already induced earlier, but reached its maximum expression at this time. Both genes were downregulated at the mature female stage. To determine biological function, we produced transgenic lines overexpressing SlWRKY16 and SlWRKY31 in tomato hairy roots. Overexpression of both genes resulted in enhanced M. javanica infection, reflected by increased galling occurrence and reproduction. Expression profiling of marker genes responsive to defense-associated phytohormones indicated reductions in salicylic acid defense-related PR-1 and jasmonic acid defense-related PI in inoculated roots overexpressing SlWRK16 and SlWRKY31, respectively. Our results suggest that SlWRKY16 and SlWRKY31 function as negative regulators of plant immunity induced upon nematode infection.

Effective combination of arugula vermicompost, chitin and inhibitory bacteria for suppression of the root-knot nematode Meloidogyne javanica and explanation of their beneficial properties based on microbial analysis.

Root-knot nematodes (Meloidogyne spp.) are dangerous parasites of many crops worldwide. The threat of chemical nematicides has led to increasing interest in studying the inhibitory effects of organic amendments and bacteria on plant-parasitic nematodes, but their combination has been less studied. One laboratory and four glasshouse experiments were conducted to study the effect on M. javanica of animal manure, common vermicompost, shrimp shells, chitosan, compost and vermicompost from castor bean, chinaberry and arugula, and the combination of arugula vermicompost with some bacteria, isolated from vermicompost or earthworms. The extract of arugula compost and vermicompost, common vermicompost and composts from castor bean and chinaberry reduced nematode egg hatch by 12-32% and caused 13-40% mortality of second-stage juveniles in vitro. Soil amendments with the combination vermicompost of arugula + Pseudomonas. resinovorans + Sphingobacterium daejeonense + chitosan significantly increased the yield of infected tomato plants and reduced nematode reproduction factor by 63.1-76.6%. Comparison of chemical properties showed that arugula vermicompost had lower pH, EC, and C/N ratio than arugula compost. Metagenomics analysis showed that Bacillus, Geodermatophilus, Thermomonas, Lewinella, Pseudolabrys and Erythrobacter were the major bacterial genera in the vermicompost of arugula. Metagenomics analysis confirmed the presence of chitinolytic, detoxifying and PGPR bacteria in the vermicompost of arugula. The combination of arugula vermicompost + chitosan + P. resinovorans + S. daejeonense could be an environmentally friendly approach to control M. javanica.

Impact of the Interaction between Meloidogyne javanica and Fusarium oxysporum on the Okra Plantation

The development of diseases in cultivated crops depends on the complex interrelationship between the host, pathogen, and prevailing environmental conditions. The interaction between the root knot nematode Meloidogyne javanica and the fungus Fusarium oxysporum was studied for the okra cultivar Pusa Sawani. Sequential and simultaneous inoculation of the nematode and fungus was performed to observe the disease severity in the plants due to the individual and interactive effects of the tested nematode and fungus. The results indicated that plant growth was adversely affected in all cases where the plant was inoculated with M. javanica and F. oxysporum, compared to the uninoculated control. The study clearly showed that nematodes act as predisposing factors in the spread of secondary fungal pathogens.

Reproduction factor of Meloidogyne javanica, M. incognita and Pratylenchus brachyurus in sorghum, millet and sunflower varieties

The use of agricultural species resistant to root-knotting and root-wounding nematodes, in crop rotation systems, keeps the nematode population at low levels, reducing losses and enabling the planting of more susceptible species. In this study, the resistance of sorghum, millet and sunflower genotypes to root-knot nematodes Meloidogyne javanica, M. incognita and Pratylenchus brachyurus was evaluated. The tests were conducted in a greenhouse and the genotypes sown in plastic pots containing 2 L of sterilized substrate and inoculated with 1,600 nematode eggs and juveniles per pot, arranged in a completely randomized design with nine replications. The evaluation of nematode reproduction was performed by counting the number of juveniles/adults per root system and soil, calculating the Reproduction Factor (FR = Pf/Pi). According to the results, all sorghum, millet and sunflower genotypes behaved as resistant to the reproduction of M. javanica, M. incognita and P. brachyurus. Commercial resistant genotypes are indicated for use in rotation of areas infested by these nematodes.

Plant disease management with amelioration of systemic resistance in soybean by endophytic fungi associated with GC-MS metabolic profiling of Chaetomium sp.,

Plants exhibit beneficial associations between fungal endophytes and roots for better growth, disease suppression, and stress tolerance. Considerable information is now available about the beneficial role of fungal endophytes. In this study, endophytic fungi Chaetomium sp., Curvularia chonburiensis, C. specifera, C. hawaiiensis, Rhizoctonia solani, Fusarium solani, Talaromyces assiutensis and T. trachyspermus isolated and evaluated for nematocidal activity against a root-knot nematode Meloidogyne javanica. The culture filtrates of endophytic fungi were prepared and used to check their efficacy against root knot nematodes. The culture filtrates of endophytic fungi were applied to pot and field experiments using soybean as host plants. In vitro study of these endophytic fungal culture filtrates showed strong nematocidal activity by killing juveniles of M. javanica to a certain degree, while Chaetomium sp., and Talaromyces assiutensis showed 100% mortality rate after 48 h. The application of Cephalosporium sp., Chaetomium sp., Talaromyces trachyspermus and T. assiutensis suppressed root rotting fungi of soybean in both screen house and field plots experiments. Significance of fungal isolates was further confirmed by repeated experiments. Endophytic fungi also showed positive impacts on the host plants by increasing the rate of their growth and improving their tolerance level to biotic stress which was evident by the production of increased amounts of resistance markers like salicylic acid and polyphenol contents with subsequent improvement of the antioxidant status. The n-hexane fraction of the culture filtrate of Chaetomium sp., were subjected to GC-MS analysis for the identification of compounds and some new compounds have been reported for the first time from this fungus. The results will facilitate a better understanding of host plant and fungal interaction and are likely to assist in the screening and utilization of beneficial microbes.

Glucosinolate-extracts from residues of conventional and organic cultivated broccoli leaves (Brassica oleracea var. italica) as potential industrially-scalable efficient biopesticides against fungi, oomycetes and plant parasitic nematodes

This study aimed to standarize a protocol for obtaining a bioactive extract from broccoli (Brassica oleracea var. italica) crop residues, that is suitable for application on an industrial scale and effective in reducing plant disease incidence. For this purpose, the influence of several extraction factors in the glucosinolate (GSL) content was studied with leaves collected from two conventional broccoli fields and two organic broccoli fields. The analysis showed that lyophilization had no influence on the GSL content. Storage of plant material under two different temperatures (− 20ºC and − 80ºC) had no influence on the GSLs content of the extracts. Phytotoxicity of the extracts was studied with six different plant seeds, and also cytotoxicity was determined with human liver cells in vitro. The extracts were phytotoxic at dilutions above 10%, while cell toxicity was low. Extracts concentrations of 0.1%, 1% and 2% were tested in vitro against eight plant pathogenic fungi and two oomycetes in solid and in liquid media. The extracts reduced the growth of several plant pathogenic fungi at 2% dilution by up to 38.37% against Alternaria alternata and up to 46.55% against Sclerotinia sclerotiorum. When combined with myrosinase enzyme the effect of the extracts was enhanced, reaching inhibition values of 67.06% against A. alternata in solid medium and 68.52% against Rhizoctonia solani in liquid medium. In contrast, the same extracts increased the growth of the plant pathogenic oomycetes Pythium ultimum and Phytophthora cactorum. The effect of the same extracts in the free leaving larvae, J2s, of the plant-parasitic nematode (PPN) Meloidogyne javanica was not obvious. Minor significant differences were obtained but with no clear dose-response in nematode mortality, and no inhibition of eggs hatching was observed. These results show the industrial potential of using broccoli residues to obtain extracts with biopesticide activity against plant pathogenic fungi.

Nematicidal Potential of Thymol against Meloidogyne javanica (Treub) Chitwood.

Root-knot nematodes (RKN; Meloidogyne spp.) are obligatory endoparasites with worldwide distribution which cause severe damage to agricultural crops. The present study aimed to define the nematicidal activity of thymol on different life stages of the root-knot nematode Meloidogyne javanica (Treub) Chitwood, at concentrations of 37.5-1000 μL/L. This study is the first to report the effect of thymol on egg differentiation and also its vapor and sublethal concentration activities. A mortality of greater than 90% of M. javanica second-stage juveniles (J2s) occurred after 96 h of exposure at a concentration of 500 μL/L. At this concentration, thymol inhibited 59.7% of nematode hatching. In addition, the use of thymol at sublethal concentrations reduced the number of females per gram in tomato roots in a pot test, as well as inhibiting egg differentiation. On the contrary, no nematostatic effects were observed in paralysis bioassays. The results presented here indicate that the use of thymol may show its potential as a source of a new sustainable nematicidal product.

Discerning host plant resistance sources in common bean (Phaseolus vulgaris) against root-knot nematode (Meloidogyne javanica) infection

From this study we could conclude that, resistant cultivars are the single effective solution to the management of root-knot nematode population to avoid crop losses. Also, it is essential to use resistant cultivars in situations where nematodes are present and when control is advantageous to yields. However, the reported moderately resistant cultivars, viz. Gujarat Rajmash, Amber (IPR 96-4) and HUR15 belong to secondary gene pool with cross-compatibility to cultivated common bean. Therefore, it may be further used in the pre- breeding programme for developing resistant common bean cultivars against root knot nematodes.

A comparative study between some biocontrol agents and the nematicide furfural on growth of tomato plants and pathogenesis of meloidogyne javanica under green-house condition

An experiment was conducted to study the effect of three fungal biocontrol agents along with G.mosseae and nematicide furfural against root knot nematode Meloidogyne javanica infecting tomato plants(Lycopersicon esculentum) under greenhouse condition. Bioagents are Paecilomyces lilacinus, Trichoderma harzianum , T. viride and mycorrhizal fungus Glomus mosseae which were compared with the nematicide furfural . The furfural compound was the best treatment in promoting plant growth and reduction the number of root galls/plant . The result showed that the T. harzianum was the best biocontrol agent in increasing shoot length and root length 16.2 % , 26.1% respectively .The P. lilacinus was the best biocontrol agent in reduction root galling (57.53%). Combination of biocotrol agents with G. mosseae and furfural was the least effective treatment in promoting plant growth and the reduction of root galling was 31.43%.

Improvement the activities of plant growth-promoting rhizobacteria in root-knot nematode Meloidogyne javanica and tomato plant growth in Wasit Province

This study had been conducted to detect the existence and dispersal of bacteria in the agricultural area in Wasit province and the role of them in controlling root knote nematode .Two genera of bacteria Azotobacter and Pseudomonas were isolated from six locations in Wasit province which were Alsiwarah , Alnuamania , Alahrar , Alhay , Alkut and Algardhia with five isolates of Azotobacter and eight isolates of Pseudomonas . The infectivity study of five Azotobacter isolates revealed that there is a significant differences between the isolates comparing with the control in reduction eggs hatching and the more effective isolates was Azotobacter sp1 ( Az1) with inhibition percentage 95.05% followed by the isolate Azotobacter sp2 (Az2 ) 84.32%. while the study of eight Pseudomonas isolates revealed that the more effective isolates was Ps eudomonas fluorescens2 ( Ps2) ) with inhibition percentage 90.16% and the lowest percentage recorded in the case of the isolate P. fluorescens6 ( Ps6) which was 55.76% . The infectivity study of four selective bacterial isolates (Az1, Az2, Ps1 , Ps2 ) with the fungus Glomus against nematode revealed the highest percentage of reduction in root galling recorded when the tomato plants inoculated with the fungus and the two bacterial isolates( Az1) , ( Ps2) and the number of galls were 3 galls/gm roots comparing with the control 10.6 galls/gm roots and the percentage of reduction 71.69 follwed by the treatment with the fungus and the two bacterial isolates( Az1) , ( Ps1) 68.86 %. The result also revealed that the combination between Glomus and bacterial isolates induced plant growth and increased the criteria of growth parameters. The result also revealed G lomus alone achieved percentage of reduction in root galling recorded when47.16% and the number of galls were 5.6 galls/gm roots comparing with the control 10.6 galls/gm roots.

Bioactivity of plants eaten by wild birds against laboratory models of parasites and pathogens

Plants are not only used as energy and nutrient resources for herbivores. Plants can be ingested because of their activity against host parasites and other pathogens. This so-called medicinal role of plants is well reported in ethnopharmacology and under-reported in wild animals. More studies on wild animals are needed because any plant in the world contains bioactive compounds, and probably all plants, no matter how toxic they are, experience herbivory. For example, we tested the activity of extracts and essential oils from Papaver rhoeas and Echium plantagineum against a selection of laboratory pathogens because Great bustards Otis tarda preferred these plants during the mating season, with male fecal droppings showing a higher frequency of P. rhoeas particles than the fecal droppings of females. We hypothesized that P. rhoeas could be helpful for males in the mating season if any part of this plant harbors bioactivity against parasites and other pathogens. Males’ immune system is weakened during the mating season because of their investment in secondary sexual characters and sexual display. As a first exploration of the bioactivity of these plants, we evaluated extracts of both plants against a sample of laboratory models, including a flagellated protozoon (Trichomonas gallinae), a nematode (Meloidogyne javanica) and a fungus (Aspergillus niger). Non-polar and polar extracts of the aerial parts of P. rhoeas, especially the extracts of flowers and capsules, and the extracts of leaves and flowers of E. plantagineum showed activity against nematodes and trichomonads. The bioactivity of plants against parasites could explain the foraging behavior of stressed animals. The chemical communication underpinning the capacity of fauna to recognize those plants is far less known.

Biological control of Root-knot nematode (Meloidogyne javanica) by potential antagonism of endophytic fungi isolated from Taify roses

ObjectivesPlant-parasitic nematodes are a serious threat to global agricultural production worldwide. To avoid synthetic chemistries toxicity there is a dire need of the hour to develop innovative nematode control strategies. Biological control using the antagonistic fungi of the plants is considered very economical and environment friendly. MethodsEfficacy of different fungal filtrate concentrations was estimated towards the mortality and clutching of Meloidogyne javanica. To determine the antagonistic potential of Penicillium citrinum (MN518391), time of disclosure was assessed in the laboratory with the result “exposure to 8% filtrate for a clock (24 hrs.), expressively reduced the viable juveniles and hatched eggs. ResultsExposition to aforementioned filtrate of P. citrinum for a clock (24 hrs.) revealed that juvenile body turned into straight stature leading to reduction in viability of nematodes. Contrary to it most of nematodes exhibited bent body when exposed to Aspergillusniger (MK713445), or (MN513383) its filtrates. Among the various isolated antagonistic fungi, GC–MS analysis revealed 22 unique compounds e.g., quinazoline and its derivatives as the most prevalent and squalene as least occurring possess significant nematicidal properties against the rootknot nematodes. ConclusionHence, using antagonistic fungus from the described plans as BCAs in agriculture against plant-parasitic nematodes is a viable long-term biocontrol technique and provide future avenues in this area of research.

Activation of indolic glucosinolate pathway by extracellular ATP in Arabidopsis.

Dear Editor, Extracellular ATP (eATP) is a purinergic signal recognized by plasma membrane-localized transmembrane receptors, such as P2X or P2Y receptors found in mammals (Verkhratsky and Burnstock, 2014), and the P2K receptors found in plants (Choi et al., 2014; Pham et al., 2020). In mammals, eATP and purinoceptors are the basis of intercellular signaling used to regulate diverse processes including neuronal signaling, apoptosis, and inflammation (Verkhratsky and Burnstock, 2014). In plants, eATP and P2K1 appear to influence root growth (Weerasinghe et al., 2009; Zhu et al., 2017), but are currently best characterized as a damage associated molecular pattern signal and recognition system contributing to plant defense (Tanaka et al., 2014). In this study, we found that the indolic glucosinolate pathway is induced by eATP in Arabidopsis (Arabidopsis thaliana) and may play a role as a biochemical defense when plants are damaged by pathogens and herbivores. Accumulating evidence from our group and others suggests that eATP is released to trigger plant responses to various biotic stresses and touch/wounding (Dark et al., 2011; Ramachandran et al., 2019). Recently, the P2K1 overexpression line OxP2K1 was reported to enhance plant resistance against various foliar pathogens, such as Phytophthora brassicae (biotrophic oomycete), Pseudomonas syringae (hemibiotrophic bacterium), Botrytis cinerea (necrotrophic fungus), and Rhizoctonia solani (necrotrophic root fungus), whereas a knockout mutant line of P2K1, dorn1-3, showed increased susceptibility (Bouwmeester et al., 2011; Wang et al., 2014, 2016; Balagué et al., 2017; Chen et al., 2017; Tripathi et al., 2018; Kumar et al., 2020). As shown in Table 1 and Supplemental Figures S1–S4, a similar trend was observed with Sclerotinia sclerotiorum (necrotrophic fungus) and Phytophthora capsici (hemi-biotrophic oomycete), overexpression of P2K1 made the plants more resistant to the parasitic nematode Meloidogyne javanica, and, interestingly, pre-treatment of Arabidopsis with eATP made the plants more resistant to the turnip mosaic virus (TuMV). These data suggest that eATP plays an important role in plant defense against a broad range of pathogens. Furthermore, OxP2K1 showed enhanced resistance against Pieris rapae (specialist) and Spodoptera exigua (generalist) (Supplemental Figure S5), suggesting that eATP also plays an important role in the plant defense response against wounding caused by herbivorous insects. How eATP signaling contributes to defense against varied pests is not well understood.