Biotic Inducers Research Articles

Unveiling mechanisms for induced systemic resistance, resistance breeding and molecular marker‐assisted breeding against Phomopsis blight of Solanum melongena

AbstractPhomopsis vexans is one of the most destructive fungal pathogens associated with eggplant and currently poses a significant threat to eggplant production worldwide. The detrimental impact of P. vexans on eggplant yield has been extensively explored by various mycologists who have conducted thorough studies on the diversity, pathology and biological aspects of the pathogen. However, achieving enduring resistance or effective management has proven to be a challenge thus far. PCR‐based detection and molecular association of Phomopsis resistance use molecular markers to examine the potential for heterosis in various crosses, aiming for premium hybrids with genetic resistance and high‐yielding capabilities. The latest genome sequencing methods and availability of a wider range of genetic diversity has enabled the breeding of resistant varieties of eggplant. This review provides a detailed description on P. vexans including its epidemiology, dispersal methods, symptomology, colony characteristics, taxonomy and evolution of its strains. Different resistance breeding techniques including heterosis breeding, host plant resistance, identification of resistant sources, inheritance pattern for Phomopsis resistance, importance of grafting to impart resistance, significance of induced resistance, PCR‐based detection and molecular association of Phomopsis resistance are explained. Future approaches include molecular marker techniques such as genome‐wide association studies, sequence‐characterized amplified regions (SCAR), role of biotic inducers, pathogenesis‐related proteins and plant growth‐promoting rhizobacteria against Phomopsis blight of eggplant.

Efficiency of Some Abiotic and Biotic Agents on Vicia faba L. Rust and Chocolate Spot Diseases

A variety of soil- and air-borne pathogens can attack faba bean plants, leading to rust and chocolate spot diseases that seriously affect plant yield. This study aims to evaluate the efficacy of certain essential oils as abiotic agents and biotic agents as safe alternatives to fungicides for both diseases. Double foliar applications of these essential oils and biotic agents significantly reduced the development of faba bean rust and chocolate spot incidence. The highest reduction in faba bean rust (92.7%) was achieved after spraying with jojoba oil, followed by 88.9% and 85.3% for grape and bitter orange oils, respectively. Furthermore, biotic inducers such as Bacillus subtilis, Trichoderma harzianum, and Saccharomyces cerevisiae reduced chocolate spot incidence by 100.0%, followed by a 72.3% reduction with bitter orange, thyme, black seed, and jojoba oils. The second foliar treatment with B. subtilis, T. harzianum, black seed oil, jojoba oil, and chitosan increased faba bean protein contents more than the first treatment. Individual foliar sprays with chitosan and grape oils enhanced catalase (CAT) specific activity, with the highest levels achieved after the first and second foliar applications, respectively. S. cerevisiae and lemongrass oil induced the highest peroxidase (POD) specific activity after both spray applications. Black seed oil induced the highest chitinase (CHIA) specific activity after the first foliar application, while lemongrass oil achieved the highest level after the second spray. The second foliar application of moringa oil, black seed oil, jojoba oil, chitosan, B. subtilis, and S. cerevisiae stimulated the formation of new protein bands in treated faba bean plants, which were not found after the first application. Therefore, the abiotic and biotic agents used in this study could be considered good and safe alternatives for resistance against these foliar diseases, reducing the harmful effects of synthetic fungicides.

Exploration of biotic inducers through seed infiltration technique for the management of phyllody in sesame caused by Candidatus Phytoplasma

This study aimed to evaluate the efficacy of biotic inducers for the management of phyllody disease in sesame, as well as in analyzing the defense enzyme activity. The field trial experiments were conducted with the biotic inducers [salicylic acid (SA), methyl jasmonate (MeJA), and beta amino butyric acid (BABA)] in individually (50 ppm, 100 ppm and 150 ppm) and in combination. Concerning biotic inducers, SA 50 / 100 ppm pre-seed treatment and exogenous application at 30th, 45th and 60th DAS resulted in no/less phyllody disease incidence and added significant value by increasing defense enzyme activity (PO, PPO, PAL and SOD).

Exploitation of biotic inducers and hyperparasites as potential biological control against foliar diseases in peanut

Field experiments were conducted to study the efficacy of biotic inducers namely salicylic acid (SA), methyl jasmonate (MeJA) and Beta amino barbutric acid (BABA) and Plant growth promoting microbes viz., Trichoderma asperllum and Bacillus subtilis, hyperparasite (Spharellopsis filum) along with fungicide (carbendazim) against foliar diseases of groundnut. In the study, vacuum seed infiltration application along with foliar spray of biotic inducers @ 30, 45 and 60 days after planting significantly reduced the late leaf spot (23.8) while S. filum recorded least rust incidence (11.21) and also increased the pod yield compared to fungicide and untreated control. The induced defense enzymes namely phenol (46 μg of catechol / g of fresh tissue) and Phenyl alanine ammonia lyase (1.754nmol/min/g) was also high in biotic inducers and S. filum treated plants followed by B. subtilis treatedpeanut plants.

Exploitation of biotic inducers for the management of important foliar diseases of sunflower (Helianthus annuus L.)

Sunflower (Helianthus annuus L.) is a unique crop grown for human consumption as edible oil and also for ornamental use. It has become a popular cut flower, easy to grow under varied climatic conditions requires 672.4 mm water requirement during growing season. Sunflower crop is native to North America and as of now we have the varieties, hybrids developed from the huge germplasm collections maintained at ICAR-Indian Institute of Oilseeds Research and also at co-ordinating centres under AICRP on sunflower situated at different agro-climatic regions of India. During the crop growing period, many fungal and viral diseases start affecting the crop from early stage up to flowering and milky stage leads to drastic losses in seed yield. In particular, necrosis, leaf spot and powdery mildew diseases are causing drastic yield losses in the cultivation. In this study, we have attempted the biotic inducers as seed treatment and foliar spray against this disease as an alternative to fungicide.

Microbial Filtrates Improved Growth Parameters of In vitro PVX Infected Potato Plantlets

This study focuses on utilizing the phenomenon of systemic acquired resistance (SAR) to control plant viruses and increased growth in vitro. The study demonstrated the induction of SAR in potato plantlets against Potato Virus X by using bacterial culture filtrates invitro. These biotic inducers included Pseudomonas spp. and Bacillus spp. The study observed the occurrence of induced resistance and enhanced growth in potato plantlets treated with culture filtrates containing these microorganisms. This was evident through a reduction in PVX infection, disease severity and associated biochemical changes (such as elevated levels of endogenous salicylic acid, protein content, chlorophyll content, peroxidase and polyphenol oxidase activities), as well as improvements in growth parameters.

Induction of Systemic Resistance in Hibiscus sabdariffa Linn. to Control Root Rot and Wilt Diseases Using Biotic and Abiotic Inducers.

The possibility of inducing systemic resistance in roselle against root rot and wilt diseases was investigated using biotic and abiotic inducers. The biotic inducers included three biocontrol agents (i.e., Bacillus subtilis, Gliocladium catenulatum, and Trichoderma asperellum) and two biofertilizers (i.e., microbein and mycorrhizeen), while the abiotic inducers included three chemical materials (i.e., ascorbic acid, potassium silicate, and salicylic acid). In addition, preliminary in vitro studies were conducted to evaluate the inhibitory activity of the tested inducers on the growth of pathogenic fungi. The results show that G. catenulatum was the most efficient biocontrol agent. It reduced the linear growth of Fusarium solani, F. oxysporum, and Macrophomina phaseolina by 76.1, 73.4, and 73.2%, respectively, followed by B. subtilis by 71.4, 69, and 68.3%, respectively. Similarly, potassium silicate was the most effective chemical inducer followed by salicylic acid, each at 2000 ppm. They reduced the linear growth of F. solani by 62.3 and 55.7%; M. phaseolina by 60.7 and 53.1%; and F. oxysporum by 60.3 and 53%, respectively. In the greenhouse, all inducers applied as a seed treatment and/or foliar spray strongly limited the development of root rot and wilt diseases. In this regard, G. catenulatum, at 1 × 109 CFU mL-1, achieved the highest values of disease control, followed by B. subtilis; while T. asperellum, at 1 × 105 CFU mL-1, recorded the lowest values. In addition, the plants treated with potassium silicate followed by salicylic acid, each at 4 g/L, recorded the highest disease control compared to ascorbic acid at 1 g/L, which had the lowest values. The mixture of mycorrhizeen + microbein (at 10 g/kg seeds) was the most effective compared to either of them alone. All treatments, applied alone or in combination in the field, significantly reduced the incidence of diseases. The most effective treatments were a mixture of G. catenulatum (Gc) + Bacillus subtilis (Bs) + Trichoderma asperellum (Ta); a mixture of ascorbic acid (AA) + potassium silicate (PS) + and salicylic (SA); G. catenulatum; potassium silicate; and a mixture of mycorrhizeen + microbein. Rhizolix T had the highest disease-reducing efficacy. In response to the treatments, significant improvements in growth and yield, changes in biochemicals, and increased activities of defense enzymes were achieved. This research points to the activity of some biotic and abiotic inducers that can play a vital role in managing the root rot and wilt of roselle through the induction of systemic plant resistance.

Research of Soil Biome of a Young Apple Orchard of Intensive Type

Fungi are one of the main sources of biotic inducers of plant immunity, but among this group of microorganisms, the largest number of phytopathogens is also noted. A two-year study was carried out on the dynamics of the composition and structure of the fungal community in the soil and the agrochemical characteristics of the soil of a young apple orchard of intensive type. The study of the fungi pool in the control (background, without plants) showed that the content of soil saprotrophs and cellulolytics was two times higher than the abundance of these groups in the root zone of a young apple tree. The importance of the role of plant exudates for the formation of the root zone mycobiota, its participation in the differentiation of the soil microbial community and the formation of the “phytogenic region” where root exudates affect the activity and distribution of ecological-trophic groups of fungi, is demonstrated. In the zone of intensive root growth in the 10–20 cm layer, a sharp decrease in the content of macroelements (nitrogen, phosphorus, potassium) was noted.

Fungi That Promote Plant Growth in the Rhizosphere Boost Crop Growth.

The fungi species dwelling in the rhizosphere of crop plants, revealing functions that endeavor sustainability of the plants, are commonly referred to as 'plant-growth-promoting fungi' (PGPF). They are biotic inducers that provide benefits and carry out important functions in agricultural sustainability. The problem encountered in the agricultural system nowadays is how to meet population demand based on crop yield and protection without putting the environment and human and animal health at risk based on crop production. PGPF including Trichoderma spp., Gliocladium virens, Penicillium digitatum, Aspergillus flavus, Actinomucor elegans, Podospora bulbillosa, Arbuscular mycorrhizal fungi, etc., have proven their ecofriendly nature to ameliorate the production of crops by improving the growth of the shoots and roots of crop plants, the germination of seeds, the production of chlorophyll for photosynthesis, and the abundant production of crops. PGPF's potential mode of action is as follows: the mineralization of the major and minor elements required to support plants' growth and productivity. In addition, PGPF produce phytohormones, induced resistance, and defense-related enzymes to inhibit or eradicate the invasion of pathogenic microbes, in other words, to help the plants while encountering stress. This review portrays the potential of PGPF as an effective bioagent to facilitate and promote crop production, plant growth, resistance to disease invasion, and various abiotic stresses.

Systemic Resistance in Chickpea (Cicer arietinum L.) Elicited by Some Biotic Inducers Against Root Diseases

Systemic Resistance in Chickpea (Cicer arietinum L.) Elicited by Some Biotic Inducers Against Root Diseases

Phenylalanine ammonia lyase (PAL) activity in genotypes of Opuntia spp. against artificial infestation of Dactylopius opuntiae submitted to biotic and abiotic resistance inducers

Products of biotic and abiotic origin are being investigated for use in pest management, many of these substances can act as resistance inducers, which induces the metabolism of enzymes involved in defense mechanisms. There is a search for efficient and alternative ways of controlling carmine cochineal (Dactylopius opuntiae Cockerell), the main pest of forage palm (Opuntia spp) in Northeast Brazil. The aim of the study was to evaluate the application of biotic and abiotic inducers on the palms to induce resistance through the activity of the antioxidant enzyme phenylalanine ammonia lyase. The experiment was carried out in a greenhouse at the Federal University of Agreste of Pernambuco, using an Completely Randomized Design (CRD), distributed in a factorial scheme (3x8x3) with three Opuntia genotypes, eight treatments: Trichoderma viride URM 6824, Trichoderma viride URM 6823, Aureobasidium pullulans URM 6874, salicylic acid, chitosan, amino butyric acid, distilled water with the insect (positive control), distilled water without the insect (negative control), with three collection periods and four repetitions. The results were subjected to analysis of variance (ANOVA), the means being compared by the Scott-Knott test at the level of 5% probability (p <0.05) and by orthogonal contrasts. The biological inducers T. viride URM 6824 and T. viride URM 6823 as well amino butyric acid influenced the increase in the enzymatic activity of phenylalanine ammonia lyase. This result demonstrates the potential for use in alternative management, and future studies are needed to deepen the applicability in field conditions.

Bioprospecting of Rhizosphere-Resident Fungi: Their Role and Importance in Sustainable Agriculture.

Rhizosphere-resident fungi that are helpful to plants are generally termed as ‘plant growth promoting fungi’ (PGPF). These fungi are one of the chief sources of the biotic inducers known to give their host plants numerous advantages, and they play a vital role in sustainable agriculture. Today’s biggest challenge is to satisfy the rising demand for crop protection and crop yield without harming the natural ecosystem. Nowadays, PGPF has become an eco-friendly way to improve crop yield by enhancing seed germination, shoot and root growth, chlorophyll production, and fruit yield, etc., either directly or indirectly. The mode of action of these PGPF includes the solubilization and mineralization of the essential micro- and macronutrients needed by plants to regulate the balance for various plant processes. PGPF produce defense-related enzymes, defensive/volatile compounds, and phytohormones that control pathogenic microbes’ growth, thereby assisting the plants in facing various biotic and abiotic stresses. Therefore, this review presents a holistic view of PGPF as efficient natural biofertilizers to improve crop plants’ growth and resistance.

Systemic Resistance in Chickpea (Cicer arietinum L.) Elicited by Some Biotic Inducers Against Root Diseases

Systemic Resistance in Chickpea (Cicer arietinum L.) Elicited by Some Biotic Inducers Against Root Diseases

Efficiency of biological and chemical inducers for controlling Septoria tritici leaf blotch (STB) on wheat (Triticum aestivum L.)

The hemibiotrophic fungus Zymoseptoria tritici is the causative agent of Septoria tritici leaf blotch (STB) disease of wheat (Triticum aestivum L.), the economically most damaging disease of wheat in Europe. Today, ecofriendly plant protection methods compatible with sustainable agriculture are strongly desirable. Here, we tested two chemical inducers β-aminobutyric acid (BABA) and benzo-(1,2,3)-thiadiazole-7-carbothioic acid S-methyl ester (BTH) and the two biotic inducers Pseudomonas protegens CHA0 (CHA0) and P. chlororaphis PCL1391 (PCL) for their ability to induce resistance against STB in wheat seedlings. At 21 days after inoculation, only plants treated with BABA showed a smaller area covered by lesions and less pycnidia compared to the untreated control plants. We evaluated spore germination and fungal development on inoculated wheat leaves at early infection stages using calcofluor white staining. Overall, spores of Z. tritici germinated less on plants soil-drenched with BABA and BTH and their hyphal growth was significantly delayed. On the contrary, CHA0 and PCL seed treatments did not affect fungal growth in wheat leaves. In conclusion, BABA efficiently enhanced plant resistance to Z. tritici, BTH delayed fungal development at early stages while the two biotic inducers did not influence the resistance against STB disease.

Tagitinin A from Tithonia diversifolia provides resistance to tomato spotted wilt orthotospovirus by inducing systemic resistance

Tomato spotted wilt orthotospovirus (TSWV) causes devastating losses to agronomic and ornamental crops worldwide. Currently, there is no effective strategy to control this disease. Use of biotic inducers to enhance plant resistance to viruses maybe an effective approach. Our previous study indicated that Tagitinin A (Tag A) has a high curative and protective effect against TSWV. However, the underlying molecular mechanism of Tag A-mediated antiviral activity remains unknown. In this study, Tag A reduced the expression of the NSs, NSm genes was very low in untreated leaves following TSWV infection. In addition, the expression of all TSWV genes in the inoculated and systemic leaves was inhibited in the protective assay, and with an inhibition rate of more than 85% in systemic leaves. Tag A increased phenylalanine ammonia-lyase (PAL) activity in the curative and protective assays. The concentrations of jasmonic acid (JA) and jasmonic acid -isoleucine (JA-Ile) and the expression of its key gene NtCOI1 in Tag A-treated and systemic leaves of treated plants were significantly higher than those of the control plant. Furthermore, Tag A-induced resistance to TSWV could be eliminated by VIGS-mediated silencing of the NtCOI1 gene. These indicated that Tag A acts against TSWV by activating the JA defense signaling pathway.

Biotic and abiotic resistance inducers for controlling white rust in rocket (Eruca sativa)

ABSTRACT: Induced resistance emerges as an alternative method for controlling plant diseases. This study aimed to evaluate the efficacy of biotic and abiotic resistance inducers for controlling white rust in rocket (Eruca sativa), as well as biochemical changes (peroxidase) and fitness costs. The experiments were developed with the abiotic inducers acibenzolar-S-methyl (ASM) (12.5, 25, and 50 mg ai L-1) and citrus biomass (CB) (0.1, 0.25, and 0.5%), as well as with the biotic ones Saccharomyces cerevisiae (25 mg mL-1), Bacillus thuringiensis (25 mg p.c. mL-1), Saccharomyces boulardii (25 mg mL-1), and phosphorylated mannan oligosaccharide (PMO) (0.25%), in preventive and curative interventions. Fungicide mancozeb (1.6 g ai L-1), Bordeaux mixture (1%), and water were the control treatments. Leaf samples were collected 3, 7, 11, 15, and 19 days after the treatments to determine peroxidases and assess the severity and production. Concerning abiotic inducers, all doses of ASM and CB 0.5% (preventive) and CB 0.25% (curative) reduced the severity of white rust, whereas, among biotic inducers, only PMO applied preventively controlled the disease. Peroxidase activity was higher for CB 0.25% and ASM 50 mg L-1. Bordeaux mixture induced higher peroxidase activity.

Nanoapplication of a Resistance Inducer to Reduce Phytophthora Disease in Pineapple (Ananas comosus L.).

Treatment of plants with a variety of abiotic and biotic inducers causes induced resistance to pathogen attack. In this study, the effect of four resistance inducers on plant diseases caused by Phytophthora cinnamomi was screened in vivo initially by using lupin, a susceptible model plant. Lupin pretreated with 0.5 mM salicylic acid (SA) showed effective resistance against P. cinnamomi with restricted lesions. Then, mesoporous silica nanoparticles (MSNs) with particle size around 20 nm and approximate pore size of 3.0 nm were synthesized and functionalized for loading and importing SA to pineapple plantlets. Decanethiol gatekeepers were introduced to the surface of MSNs via glutathione (GSH)–cleavable disulfide linkages to cover the pore entrance, which was confirmed through using Raman spectroscopy. Through free diffusion, the loading efficiency of SA in MSNs gated with gatekeepers was 11.7%, but was lower in MSNs without gatekeepers (8.0%). In addition, in vitro release profile of SA from gatekeeper-capped MSNs indicated that higher concentrations of GSH resulted in more cargo release. Moreover, the experiments in planta showed that the application of MSNs as a resistance inducer delivery system significantly improved pineapple resistance to P. cinnamomi in terms of inhibiting lesion development and improving root growth of infected plants, compared to the use of free SA and MSNs without gatekeepers. The analysis of SA, GSH, and defense-related genes, of PR1 and PR5, further confirmed that the slow and prolonged release of SA from MSNs inside the roots of pineapple plants was achieved through a redox-stimuli release mechanism. Therefore, the application of MSNs with redox-responsive gatekeepers has shown great potential as an efficient tool for delivering chemicals into plants in a controllable way.

EFFECT OF DIFFERENT INDUCERS ON CONTROLLING DAMPING-OFF AND WILT DISEASES OF LUPINE

The present investigation was carried out to study the effect of seed treatments of lupine plants (cv.Giza 2) with chemical inducers Bion (5mM) , salicylic acid (5mM) and saccharin (3mM) as well as as well as Paenibacillus polymyxa and Trichoderma harzianum as biotic inducers on the infection with Rhizoctonia solani and Fusarium oxysporum f. sp. lupine under greenhouse and field conditions. Under greenhouse condition (Agricultural Research Centre, Giza) all treatments significantly reduced the percentages of pre- and post-emergence damping-off compared with the untreated control, the highest percentage of survived plants was achieved 92% by Bion and T. harzianum as well as fungicide Rizolex-T followed by salicylic acid and P. polymyxa as 88%. On the other hand, all treatments decrease significantly the incidence and severity of wilt, also increased the percentage of survived plants compared with untreated control. Under field conditions at Giza and Ismailia Agricultural Research Stations (Giza and Ismailia governorates) during winter season 2016-2017, all the treatments decreased the percentage of pre- and post-emergence damping-off as well as the percentage of wilted plants and increased the percentage of survived plants compared with untreated control in two locations. At Giza research station, the highest percentages of survived plants were recorded with Rizolex-T followed by Bion, P. polymyxa, and salicylic acid. While at Ismailia, the highest percentage of survived plants were recorded with Rizolex-T followed by Bion, P. polymyxa, T. harzianum, and salicylic acid. Meantime, these treatments improved growth parameters i.e. plant height, number of pods/plant, the weight of seeds /plant and the weight of one hundred seed. The higher increase in seed yield (ton /feddan) was obtained with Rizolex-T and Bion treatments followed by Salicylic acid, P. polymyxa, and T. harzianum at two locations. Activities of peroxidase (PO), polyphenol oxidase (PPO) enzymes and phenol content were determined. Bion treatment showed the highest increase in PO and PPO activity, and total phenols followed by salicylic acid and P. polymyxa treatments in the presence of R. solani or F. oxysporum. f. sp. lupine.

Diterpenoid compounds from Wedelia trilobata induce resistance to Tomato spotted wilt virus via the JA signal pathway in tobacco plants

Tomato spotted wilt virus (TSWV) causes major losses of many crops worldwide. Several strategies have been attempted to control disease caused by TSWV. However, many challenges for the effective control of this disease remain. A promising approach is the use of abiotic or biotic inducers to enhance plant resistance to pathogens. We screened a diterpenoid compound from Wedelia trilobata, 3α-Angeloyloxy-9β-hydroxy-ent-kaur-16-en-19-oic acid (AHK), which had higher curative and protective effects against TSWV than the ningnanmycin control. The rapid initiation of the expression of all the TSWV genes was delayed by more than 1d in the curative assay, and the expression of the NSs, NSm and RdRp genes was inhibited. In addition, the replication of all TSWV genes in systemic leaves was inhibited in the protective assay, with an inhibition rate of more than 90%. The concentrations of jasmonic acid (JA) and jasmonic acid isoleucine (JA-ILE) in the AHK-treated and systemic leaves of the treated plants were significantly higher than those observed in the control. The results suggested that AHK can induce systemic resistance in treated plants. The transcription of the NtCOI1 gene, a key gene in the JA pathway, was significantly higher in both the inoculated and systemic leaves of the AHK-treated plants compared to the control. The AHK-induced resistance to TSWV in Nicotiana benthamiana could be eliminated by VIGS-mediated silencing of the NtCOI1 gene. These results indicated that AHK can activate the JA pathway and induce systemic resistance to TSWV infection.

Systemic Resistance in Snap Bean (Phaseolus vulgaris L.) Elicited by Some Chemicals and Biotic Inducers Against White Mold Disease Caused by Sclerotinia sclerotiorum

The effect of chemicals and biotic inducers i.e., Bion [benzothiadiazole (BTH)], Salicylic acid (SA), Bacillus subtilis and Trichoderma harzianum as seed treatments of snap bean (Phaseolus vulgaris L. cv. Paulista.) compared to the fungicide Topsin M-70, were evaluated in the greenhouse and under field conditions during the two successive growing seasons 2016/2017 and 2017/2018 at Ashmoun, Menoufia Governorate, Egypt to control the white mold disease caused by Sclerotinia sclerotiorum (Lib.) de Bary. All the tested chemicals and biotic inducers treatments significantly reduced the percentages of pre- and post-emergence damping-off compared with the untreated control under greenhouse conditions. The highest percentage of survived plants was achieved by Topsin M-70 and Bion, followed by B. subtilis, Salicylic acid, and T. harzianum. Activities of defense-related enzymes peroxidase (PO), polyphenoloxidase (PPO) enzymes, and phenol content were determined. Bion treatment showed the highest increase in PO and PPO activity and total phenols followed by B. subtilis, Salicylic acid, and T. harzianum treatments in the presence of S. sclerotiorum. In the two successive growing seasons under field conditions, all the tested chemicals and biotic inducers treatments reduced the percentage of white mold incidence and severity of the treated snap bean plants compared with the untreated control. The highest reduction of disease incidence and severity was recorded by Topsin M-70 followed by Bion, B. subtilis, Salicylic acid,and T. harzianum, respectively. As well as, all treatments significantly increased vegetative characteristics i.e., plant height, No. of branches/plant, plant fresh and dry weight, and yield parameters i.e., average pod weight (g) and yield (ton/fed). Furthermore, chemical composition of green pods showed a significant increase in protein and carbohydrates content (%) beside all minerals Nitrogen (N), Phosphorus (P) and Potassium (K) content as compared with the untreated control in the two growing seasons.