Pigeonpea Wilt Research Articles

Efficacy of fungicides against Fusarium oxysporum f. sp. udum associated with wilt of pigeonpea

Efficacy of fungicides against Fusarium oxysporum f. sp. udum associated with wilt of pigeonpea

Metabolite profiling and molecular characterization of NBAIR BSWG1: A potential strain of Bacillus subtilis against Fusarium oxysporium f. sp. udum

To address the fungal wilt of pigeon pea caused by Fusarium oxysporium f. sp. udum, farmers currently rely on chemical fungicides, despite their harmful effects. However, there is a growing need for safer alternatives like green pesticides. Bacterial biocontrol agents and their derivatives serve as potential green pesticides in the management of plant pathogens. In the present study, we aimed to identify indigenous Bacillus subtilis strains effective against F. oxysporium f. sp. udum. We used PCR and MALDI-TOF analysis to identify the active components responsible for the efficiency of efficient strain. Biochemical studies of cell-free extracts extracted from B. subtilis strains demonstrated the highest biosurfactant activity in NBAIR BSWG1, with an oil displacement of 2 cm and an emulsification index of 60 %. Molecular characterization confirmed the presence of surfactin, fengycin, and iturin coding genes in the B. subtilis strains, among them, NBAIR BSWG1 showed the highest number of lipopeptide-producing genes. Meanwhile, NBAIR BSWG1 showed inhibition of 79.84 % against F. oxysporium f. sp. udum using cell-free extract. Further metabolite profiling of NBAIR BSWG1 using MALDI-TOF analysis further confirmed surfactin, fengycin, and iturin in the purified cell-free extract of NBAIR BSWG1. Two peaks with m/z of 923.77 and 1149.92 were identified as novel lipopeptide compounds which need further characterization. The present study identified NBAIR BSWG1 as an efficient bacterial strain for the inhibition of F. oxysporium f. sp. udum and its antifungal properties are mainly due to the production of cyclic lipopeptides.

Harnessing the power of native biocontrol agents against wilt disease of Pigeonpea incited by Fusarium udum

Fusarium wilt, caused by (Fusarium udum Butler), is a significant threat to pigeonpea crops worldwide, leading to substantial yield losses. Traditional approaches like fungicides and resistant cultivars are not practical due to the persistent and evolving nature of the pathogen. Therefore, native biocontrol agents are considered to be more sustainable solution, as they adapt well to local soil and climatic conditions. In this study, five isolates of F. udum infecting pigeonpea were isolated from various cultivars and characterized morphologically and molecularly. The isolate from the ICP 8858 cultivar displayed the highest virulence of 90%. Besides, 100 endophytic bacteria, 100 rhizosphere bacteria and three Trichoderma spp. were isolated and tested against F. udum isolated from ICP 8858 under in vitro conditions. Out of the 200 bacteria tested, nine showed highest inhibition, including Rb-4 (Bacillus sp.), Rb-11 (B. subtilis), Rb-14 (B. megaterium), Rb-18 (B. subtilis), Rb-19 (B. velezensis), Eb-8 (Bacillus sp.), Eb-11 (B. subtilis), Eb-13 (P. aeruginosa), and Eb-21 (P. aeruginosa). Similarly, Trichoderma spp. were identified as T. harzianum, T. asperellum and Trichoderma sp. Notably, Rb-18 (B. subtilis) and Eb-21 (P. aeruginosa) exhibited promising characteristics such as the production of hydrogen cyanide (HCN), cellulase, siderophores, ammonia and nutrient solubilization. Furthermore, treating pigeonpea seedlings with these beneficial microorganisms led to increased levels of key enzymes (POD, PPO, and PAL) associated with resistance to Fusarium wilt, compared to untreated controls. In field trials conducted for four seasons, the application of these potential biocontrol agents as seed treatments on the susceptible ICP2376 cultivar led to the lowest disease incidence. Specifically, treatments T2 (33.33) (P. aeruginosa) and T3 (35.41) (T. harzianium) exhibited the lowest disease incidence, followed by T6 (36.5) (Carbendizim), T1 (36.66) (B. subtilis), T4 (52.91) (T. asperellum) and T5 (53.33) (Trichoderma sp.). Results of this study revealed that, P. aeruginosa (Eb-21), B. subtilis (Rb-18) and T. harzianum can be used for plant growth promotion and management of Fusarium wilt of pigeonpea.

Genetic diversity and population structure of Fusarium udum in India and its correlation with pigeonpea wilt incidence.

In a study conducted in India, 50 Fusarium isolates were collected from pigeonpea growing regions and extensively examined for their cultural and morphological characteristics. These isolates exhibited significant variations in traits including growth rate, mycelial growth patterns, color, zonation, pigmentation, spore size, and septation. Subsequently, 30 isolates were chosen for pathogenicity testing on eight pigeonpea genotypes. Results showed distinct reactions, with four genotypes displaying differential responses (ICP8858, ICP8859, ICP8862, and BDN-2), while ICP9174 and ICP8863 consistently exhibited resistance and ICP2376 and BAHAR remained susceptible to wilt disease. To study the interaction between Fusarium isolates and pigeonpea host differentials (HDs), an additive main effects and multiplicative interactionanalysis was conducted. The majority of disease incidence variation (75.54%) was attributed to HD effects, while Fusarium isolate effects accounted for only 1.99%. The interaction between Isolates and HDs (I × HD) contributed 21.95% to the total variation, being smaller than HD but larger than I. Based on HD reactions, isolates were classified into nine variants, showing varying distributions across pigeonpea growing states, with variants 2 and 3 being prevalent in several regions. This diversity underscores the need for location-specific wilt-resistant pigeonpea cultivars. Furthermore, genetic analysis of 23 representative isolates, through internal transcribed spacer region of ribosomal DNA and translation elongation factor 1-αgene sequencing, revealed three major clusters: Fusarium udum, Fusarium solani, and Fusarium equiseti. These findings hold potential for developing location-specific wilt-resistant pigeonpea cultivars and enhancing disease management strategies.

Effect of meteorological parameters on the dynamics of wilt and pod borer severity in pigeonpea of Bundelkhand region of Uttar Pradesh

The weather parameters play a predominant role in determining the course and severity of insect pests and pathogens in different crops. Wilt and pod borer are the most devastating biotic stresses, causes huge losses from the vegetative stage until harvest. The present study was aimed to analyze the seasonal dynamics of wilt and pod borer incidence in relation to critical weather parameters in pigeonpea from the Bundelkhand region, a pulses basket of Uttar Pradesh. The fusarium wilt (Fusarium udum) and pod borer (Helicoverpa armigera) incidence were found to be major biotic stresses in pigeonpea from 2017-18 to 2020-21. The wilt disease commenced at 48 MSW and the mean incidence ranged from 0.0 to 25.5 percent. The pod borer incidence started at 01 MSW, and the larval population ranged from 0.5 to 1.40 larvae/plant. Though the correlation between pest incidence and weather parameters was found to be non-significant. The wilt and pod borer incidence were positively correlated with Tmax (r= 0.35 and 0.33), Tmin (r= 0.39 and 0.37), rainfall (r= 0.43 and 0.41) and negatively correlated with relative humidity (r= -0.32 and -0.26). The regression analysis indicated variability in wilt and pod borer incidence due to temperature, humidity and rainfall. The information generated on the pest dynamics of wilt and pod borer in pigeonpea under the influence of weather parameters may be helpful in devising the forecasting models as well as the management practices well in advance so as to avoid yield losses.

Unveiling Oil Seed Cakes Ability to Suppress Fusarium Wilt (Fusarium udum Butler) in Pigeonpea (Cajanus cajan L. Millsp.)

Pigeonpea (Cajanus cajan) holds significant economic importance as a versatile crop due to its various uses. It is a valuable source of nutrition for human consumption, rich in protein, dietary fiber, vitamins and minerals. Additionally, pigeonpea plays a crucial role in sustainable agriculture by fixing atmospheric nitrogen and enhancing soil fertility. Fusarium wilt caused by Fusarium udum is an important economic threat to the growers of pigeonpea in India and across the globe. The study was therefore conducted during the years 2017–2019 to determine the impact of the various oil seed cakes on the fusarium wilt of pigeonpea. Seven treatments including different types of oil seed cakes viz., mustard cake, neem cake, linseed cake, mahua cake, sunflower cake, groundnut cake and carbendazim (treated check) were employed by adopting the soil inoculation method. All of the treatments employed notably diminished the incidence of fusarium wilt. Among the treatments, neem cake (T2) was most effective in suppressing disease incidence (73.78% and 76.89%), registering the least plant fatalities (19.05 and 18.02), respectively. Furthermore, treatment (T2) also showed maximum plant height at 120 DAS (151.86 cm and 153.34 cm) and the highest root-nodules count of pigeon pea (5.71, 5.66) respectively in both the cropping years compared to other treatments and untreated control (T0).

Biocontrol efficacy and induced defense mechanisms of indigenous Trichoderma strains against Fusarium wilt [F. udum (Butler)] in pigeonpea

This study aimed to identify efficient Trichoderma isolate(s) for the management of Fusarium wilt in pigeonpea. In vitro and in vivo (greenhouse) experiments were conducted to evaluate 17 Trichoderma isolate(s) for their anti-pathogenic activity, induction of plant biochemical functions, disease suppression, and plant growth traits comparing with standard Trichoderma strains. Among the indigenous isolates, IIPRTh-31 (T. asperellum) and IIPRTh-33 (T. afroharzianum) had a higher mycelia growth inhibition in vitro [membrane assay (>74%), binary assay (>65%)]. Seed treatment with IIPRTh-31 and IIPRTh-33 isolates led to an increase in peroxidase (173–244%), polyphenol oxidase (48–80%), phenylalanine ammonia–lyase (147–178%) activities in pigeonpea plants over control and reduced disease incidence by 78–85%. Hence, IIPRTh-31, and IIPRTh-33 strains demonstrate excellent bio-control of Fusarium wilt in pigeonpea via induction of defense-related enzymes. These isolates have been registered (Registration No. NAIMCC-R-5, NAIMCC-R-6) and used for talc-based bio-formulations for field application.

Identification of sources of resistance to Fusarium wilt and sterility mosaic diseases in pigeonpea [Cajanus cajan (L.) Millsp.

The experiment was conducted to screen a set of 100 genotypes of pigeonpea (Cajanus cajan L.) for resistance to Fusarium wilt andsterility mosaic disease during 2021-2022 using root dip technique and the leaf stapling method, respectively. Based on percent diseaseincidence of Fusarium, seven genotypes were classified as resistant. Seventeen genotypes showed resistant reaction against sterilitymosaic disease. Combined resistance for both diseases was recorded in six genotypes namely, ICPL 15023, ICPL 15063, ICPL 19467,ICPL 19482, ICPL 19489, and ICPL 19499. These resistant lines can be utilized directly as useful donor source in pigeonpea hybridizationprograms to improve resistance

Evaluation of organics, antagonists and carbendazim against Fusarium wilt of pigeonpea (Cajanus cajan L.)

In India, pigeonpea [Cajanus Cajan (L.) Millsp.] wilt caused by Fusarium udum is prevalent in all areas it cultivated. Among the major soil borne diseases pigeonpea, the Fusarium wilt caused by Fusarium udum is one of the most important diseases and can cause 30-100% loss in grain yield. A pot experiment was conducted to assess the efficacy of Trichoderma harzianum, Pseudomonas fluorescens, farm yard manure, spent mushroom substrate of oyster mushroom and the fungicide Carbendazim 50% WP against Fusarium wilt of pigeonpea in terms ofseed germination and disease incidence under artificial inoculation conditions during Kharif 2021. Among the treatments assessed, maximum seed germination (95.83%) was recorded in treatments in which seed were treated with Carbendazim 50% WP or soil amended with the combination of spent mushroom substrate+Trichoderma harzianum or spent mushroom substrate+(Trichoderma harzianum+ Pseudomonas fluorescens) prior to sowing. Maximum reduction in disease incidence (73.81%) of Fusarium wilt over the control was recorded in treatment in which soil was amended with combination of spent mushroom substrate+(Trichoderma harzianum+ Pseudomonas fluorescens). The results revealed that all the treatments applied as prophylactic measure, reduced the Fusarium wilt and increased the seed germination significantly over the unprotected crop.

Virulence and pathogenicity determinants in whole genome sequence of Fusarium udum causing wilt of pigeon pea.

The present study deals with whole genome analysis of Fusarium udum, a wilt causing pathogen of pigeon pea. The de novo assembly identified a total of 16,179 protein-coding genes, of which 11,892 genes (73.50%) were annotated using BlastP and 8,928 genes (55.18%) from KOG annotation. In addition, 5,134 unique InterPro domains were detected in the annotated genes. Apart from this, we also analyzed genome sequence for key pathogenic genes involved in virulence, and identified 1,060 genes (6.55%) as virulence genes as per the PHI-BASE database. The secretome profiling of these virulence genes indicated the presence of 1,439 secretory proteins. Of those, an annotation of 506 predicted secretory proteins through CAZyme database indicated maximum abundance of Glycosyl hydrolase (GH, 45%) family proteins followed by auxiliary activity (AA) family proteins. Interestingly, the presence of effectors for cell wall degradation, pectin degradation, and host cell death was found. The genome comprised approximately 895,132 bp of repetitive elements, which includes 128 long terminal repeats (LTRs), and 4,921 simple sequence repeats (SSRs) of 80,875 bp length. The comparative mining of effector genes among different Fusarium species revealed five common and two specific effectors in F. udum that are related to host cell death. Furthermore, wet lab experiment validated the presence of effector genes like SIX (for Secreted in Xylem). We conclude that deciphering the whole genome of F. udum would be instrumental in understanding evolution, virulence determinants, host-pathogen interaction, possible control strategies, ecological behavior, and many other complexities of the pathogen.

Assessment of Weather Parameters on Per Cent Disease Incidence and Forewarning Models of Fusarium Wilt in Pigeonpea as Influenced by Different Sowing Windows

Background: Fusarium wilt caused by Fusarium udum (Butler) var. cajani is one of the most important soil-borne diseases of pigeonpea capable of causing 30-100% loss in grain yield. So it is essential to establish the relationship with weather parameters and prediction of per cent disease incidence. Methods: An experiment was laid out in split plot design with three replications and sixteen treatment combinations considering different varieties and sowing windows. Correlation and multiple linear regression equations were elucidated between weather parameters and per cent disease incidence (PDI) of Fusarium wilt on different pigeonpea varieties under different sowing windows during 2017-18 and 2018-19. Result: The correlation of weather parameters with PDI of Fusarium wilt indicated that significant and positively correlation with maximum and minimum temperature and negative correlation with evening relative humidity. Among all sowing windows 30th meteorological week (MW) sowing window with the variety ICPH 2740 PDI for two weeks prior was significantly positively correlated with maximum temperature (0.871** and 0.919**) and morning relative humidity (0.727* and 0.056). The prediction of PDI of Fusarium wilt with multiple linear regression equations were recorded the highest R2 valueas 95.5% in case of treatment combination of 30th MW and the variety Vipula.

Major diseases of field and horticultural crops in Northern Bihar region of India

A survey was conducted to determine the status of major diseases of field and horticultural crops grown in Saharsa, Supaul, Madhepura and Khagaria districts of northern Bihar, India. Three blocks in each district and three villages in each block were surveyed through a random field survey method. Per cent disease incidence was recorded on randomly selected plants in a particular field of selected location. The incidence of diseases was observed on the basis of typical field symptoms and later the association was confirmed through microscopic examinations in the laboratory. In view of maximum diseases incidence; foliar blight of wheat, sheath blight of rice, turcicum leaf blight of maize, mungbean yellow mosaic virus, Alternaria blight of mustard were recorded with >50% incidence in these districts. However, dry root rot and wilt of chickpea and lentil, wilt of pigeonpea, powdery mildew of pea, Alternaria leaf spot of linseed, Fusarium wilt and red rot of sugarcane and root rot of jute were noticed with 10 to 50% incidence. In fruit crops; sigatoka disease of banana was noticed with >50% incidence, while, anthracnose/ die back and floral malformation of mango, wilt of banana, foot rot of papaya and anthracnose of guava and citrus canker were observed with 10-50% incidence. Diseases viz., late blight, bacterial wilt, black leaf spot/ rot, leaf curl, yellow vein mosaic virus, die back and late blight were recorded with >50% incidence in tomato, brinjal, cauliflower, cucurbits, okra, chilli and potato, respectively. The purple blotch of onion, black leaf rot of cabbage and collar rot of elephant foot yam were noticed with 10-50% incidences.

Evaluation of Pseudomonas and Bacillus Strains as Potential Biocontrol Agents against Fusarium Wilt of Chickpea

Evaluation of Pseudomonas and Bacillus Strains as Potential Biocontrol Agents against Fusarium Wilt of Chickpea

Distribution and pathogenic diversity in Fusarium udum Butler isolates: the causal agent of pigeonpea Fusarium wilt

BackgroundFusarium wilt (Fusarium udum Butler), an important soil-borne disease of pigeonpea [Cajanus cajan (L.)], causes significant yield losses across the major pigeonpea production regions. Widespread and high diversity in F. udum hampers the breeding for pigeonpea wilt resistance. The study aimed to elucidate the pathogenic diversity and distribution of F. udum variants in major pigeonpea growing regions of India.ResultsThe roving survey was conducted in major pigeonpea-growing states of India to collect the F. udum isolates. Pathogenic variability of 60 F. udum isolates which are selected from diverse geographical locations and pathogenicity test were performed against 11 pigeonpea host differentials cultivars [ICP 8858, ICP 8859, ICP 8862, ICP 8863, ICP 9174, C 11, BDN 1, BDN 2, LRG 30, ICP 2376 and Bahar (ICP 7197)]. The current study indicated distribution of F. udum isolates into nine variants (0, 1, 2, 3, 4, 5, 6, 7 and 8). Variant-2 and 3 were found to be widespread and predominant in most pigeonpea producing regions. Variant-7 (Karnataka) and Variant-8 (Madhya Pradesh and Maharashtra) were found highly virulent, as most of the host differentials were susceptible to these variants. Three host differential cultivars namely ICP 9174, BDN-2 and Bahar (ICP 7197) were found resistant to most of the F. udum isolates.ConclusionThe present study generated significant information in terms of variants of F. udum which could be used further for the deployment of location-specific wilt resistant cultivars for optimized disease-management strategies. Study is also useful for development of broad-based wilt resistant cultivars to curtail the possible epidemics.

Gibberella indica (wilt of pigeon pea)

Gibberella indica (wilt of pigeon pea)

Pathogenic and morphological variability among the isolates of Fusarium udum (Butler) causing wilt of pigeonpea (Cajanus cajan)

Wilt is the most serious disease causing irreversible losses and lethal damage to the crop in Bihar, Jharkhand, Orissa and the West Bengal states of Eastern India. Because of the existence of high pathogen variability, management of the disease using resistant cultivars will be a challenging task. For breeding resistant varieties, knowledge of pathogen variability in the particular crop area is essential. In present study, fifteen isolates viz., Fu-9, Fu-10, Fu-27,Fu-32, Fu-42, Fu-49, Fu-63, Fu-72, Fu-73, Fu-74,Fu-75,Fu-84, Fu-86, Fu-87, Fu-97of Fusarium udum obtained from wilt infected pigeonpea plants of Bihar, Jharkhand, Orissa and West Bengal of Eastern India were assessed for the phenotypic variation. The isolates exhibited considerable variations in cultural and morphological characters viz., radial growth, mycelial color, sporulation, size and shape of macroconidia. Pathogenic variability on soil inoculated pot grown plants of pigeonpea resulted in 12.0 to 57.1 percent wilt incidence. The isolates also exhibited significant variations in symptoms like drooping of shoots, latent period, timing of fungal invasion, vascular clogging, drooping of shoots, and wilt establishment etc. Based on the wilt incidence, the fifteen isolates were distinguished into pathogenic groups. Fu- 10, Fu-27, Fu-32 and Fu-49 were found highly pathogenic and predominantly causing the typical wilt symptoms of more than one 31% wilt incidence. The present study indicates the existence of variability among isolates of vascular wilt pathogen collected from Eastern region of India.

Evaluation of Some New Generation Fungicides against Pigeonpea (Cajanus cajan (L.) Millsp.) Wilt Causal agent Fusarium udum under in vitro Conditions

Pigeonpea wilt disease caused by Fusarium udum is one of the most devastating soil borne disease. The objective of this investigation was to determine the antifungal activities of fungicides which can be used to control wilt disease of pigeonpea. Among all the fungicides Azoxystrobin+Tebuconazole, Carbendazim, Tebuconazole+Trifloxystrobin, Hexaconazole, Tebuconazole exhibited 100% inhibition at all the concentrations, followed by Azoxystrobin+ Difenconazole which exhibited 92.22%, 94.4%, 94.4% and 100% inhibition at 250 ppm, 500 ppm, 750 ppm and 1000 ppm respectively.

The Evaluation of Trichoderma consortia against Fusarium udum causing wilt of Pigeonpea

Pigeonpea is one of the important pulse crop of Madhya Pradesh, a State of India. The plant gets infected by the pathogen Fusarium udum causing wilt disease, which is one of the major constraints in the production and productivity of pigeonpea. The present study aimed to carry out in vitro condition to assess the possible use of biocontrol consortia in field conditions. Six Trichoderma consortia viz., T1- T. viride + T. harzianum (JC-I), T2- T. viride + T. virens (JC-2), T3:- T. harzianum +T. virens (JC-3), T4- T. hamatum +T. viride (JC-4), T5- T. hamatum + T. harzianum (JC-5), T6- T. hamatum + T. virens (JC-6) and T0- Control were evaluated for their antagonistic activity against F. udumunder in vitro conditions. The consortia of T4- T. hamatum +T. viride (JC-4) was found most effective(58.82 %) in inhibiting the radial growth of Fusarium udum. The volatile compound from consortium of T5-T. hamatum + T. harzianum (JC-5) exhibited maximum growth inhibition (81.84%) and sporulation of Fusarium udum followed by T1-T. viride + T. harzianum (JC-I) (55.49% inhibition) . The culture filtrate of consortia of T4- T. hamatum +T. viride (JC-4) showed 100% inhibition of test pathogen followed by T5-T. hamatum + T. harzianum (JC-5) (82.89%) at 5 % concentration. It was also observed that with an increase in the concentration of culture filtrates of all the Trichoderma species, the radial mycelial growth of the test pathogen was proportionally decreased. The Trichodema consortium viz., T4- T. hamatum +T. viride (JC-4) may be tried in the field to manage wilt of pigeonpea because they worked synergistically and gave the high impact of their use.

Ascertaining sources of resistance against fusarium wilt and sterility mosaic disease of pigeonpea

Ascertaining sources of resistance against fusarium wilt and sterility mosaic disease of pigeonpea

Biological control of Fusarium wilt and growth promotion in pigeon pea (Cajanus cajan) by antagonistic rhizobacteria, displaying multiple modes of pathogen inhibition

Fusarium udum is one of the most important pathogens impacting the production of pigeon pea (Cajanus cajan) legume. Legume growers depend heavily on pesticides; however, toxicity danger to farmers, consumers, non-target organisms as well as environmental health cause huge concern. Besides, the rise of fungicide resistance is problematic. The objectives of this study were to decipher the multiple mechanisms of biological control in previously identified two promising rhizobacteria (Pseudomonas sp. NS 1 and Bacillus sp. NS 22) in vitro and evaluate their disease suppression and plant growth promotion ability in pigeon pea in vivo. These rhizobacteria inhibited F. udum mycelia growth and biomass in vitro and reduced wilt disease severity in plants grown in Fusarium-infested soil in controlled environmental conditions. Fungicidal action of these rhizobacteria was due to the production of numerous biocidal compounds including different antifungal metabolites, chitinolytic (endochitinase, exochitinase, chitobiase) and other cell wall degrading lytic enzymes (proteinase, cellulose, amylase, pectinase, lipase), siderophores, and antifungal volatile compounds such as ammonia and cyanide. In planta assay, these rhizobacteria made the plant more resistant to fungal attacks through the induction of systemic defense in host tissue by improving the status of different defense enzymes (phenylalanine ammonia lyase, polyphenol oxidase, and peroxidase) and phenolics. Furthermore, these two bacteria significantly reduced disease severity, root mortality, and at the same time, promoted shoot and root elongation in pigeon pea seedlings as compared to the absolute, pathogen, and chemical control. In nutshell, Pseudomonas sp. NS 1 and Bacillus sp. NS 22 displayed the potential as biofungicides and biofertilizers to prevent F. udum induced disease incidence and promote plant growth in an integrative disease and nutrient management approach of sustainable agriculture practices.