Pea Roots Research Articles

Synergy between bio-control agents to trigger the defensive responses against Rhizoctonia root rot and enhance the growth, yield, and physiological and anatomical traits of pea plants

AbstractRhizoctonia solani (Rs) is the fungus that causes the primary and deadly disease that attacks pea plants throughout the cool growing season. It causes seed rot, damping off, and pea root rot diseases. The current study used arbuscular mycorrhizal fungi; Rhizoglomus clarum, Gigaspora margarita, Rhizophagus irregularis and Funneliformis mosseae (AMF), Pseudomonas fluorescens HE21 (Pf), and Trichoderma harzianum HL9 (TH) singly or in combination to suppress Rhizoctonia root rot of pea in a greenhouse. Using the in vitro dual culture assay, TH and Pf inhibited the radial growth of the Rs by 73.3 and 60.0%, respectively. The results of greenhouse experiments showed that all treatments significantly decreased the percentages of pre- and post-emergence damping while significantly increasing the number of surviving plants, particularly in the dual and triple combination treatments. Furthermore, all treatments improved yield and seed quality in addition to plant growth, total phenol content and antioxidant enzyme activity. There were also noted modifications to the treated plants’ anatomical, physiological, and distinctive features. The synergistic triple treatment consisting of M, TH, and Pf achieved the maximum reduction of disease severity (78.5%) compared to the untreated control treatment. As a result of the synergistic triple treatment due to their effectiveness and eco-safety, we recommend using the synergistic triple by M + Pf + TH to manage the root rot disease in peas caused by Rs and to enhance the crop’s growth, yield, and seed quality.

Factors governing attachment of Rhizobium leguminosarum to legume roots at acid, neutral, and alkaline pHs.

The first step by which bacteria interact with plant roots is by attachment. In this study, we use a combination of insertion sequencing and biochemical analysis to determine how bacteria attach to pea roots and how this is influenced by pH. We identify several key adhesins, which are molecules that enable bacteria to stick to roots. This includes a novel filamentous hemagglutinin which is needed at all pHs for attachment. Overall, 115 proteins are required for attachment at one or more pHs.

The effectiveness of using the laboratory samples based on bacteria of the genus Streptomyces on peas in the conditions of the Volga-Vyatka region

Data on productivity, fungal diseases and the quality of seed peas grown on sod-podzolic medium-clay soil in 2021–2023 using pre-sowing seed treatment separately and in combination with plant vegetation treatment with experimental preparations based on local strains of the genus Streptomyces (A4 and 8A1-3) are presented. The comparison drugs were the chemical fungicide Pioneer, KS and the biological drug Pseudobacterin-2, J. The assessment of the biological effectiveness (BE) of the drugs was carried out on cultivars of peas of various morphotypes bred by the FARC North-East: ‘Falensky yubileiny’, ‘Falensky usaty’, ‘Falensky kormovoy’. The biological effectiveness of all tested preparations in protecting peas from root rot and ascochitosis was determined by the weather conditions of the year of research. In 2021, a significant decrease in the development of root rot compared with the control (38.4 %) was facilitated by seed treatment with a preparation based on S. antimycoticus 8A1-3 strain (29.0 %). A significant reduction in the development of pea root rot in 2022 was achieved by seed treatment with the chemical fungicide Pioneer (by 9.1 %), the reference bio-drug Pseudobacterin-2 (by 9.9 %) and the test strain S. antimycoticus 8Al-3 (by 7.1 %). In protecting peas from ascochitosis in 2022, the strain Streptomyces A4 (BE 72.7 %) proved itself as a Pioneer chemical fungicide (BE 72.7 %), and the strain Streptomyces 8A1-3 (BE 84.1 %) significantly surpassed them in effectiveness. The effect of drugs on the yield of peas in the years of research (HTC = 0.77–0.83 with an average long-term HTC = 1.4) was estimated as insignificant. Treatment with both experimental and commercial preparations of seeds and vegetative plants did not adversely affect the grain size and the content of crude protein in it. The ‘Falensky usaty’ was distinguished among the studied cultivars by large seeds: the mass of 1000 grains was 258.8±18.5 g. The ‘Falensky kormovoy’ and the ‘Falensky jubileiny’ cultivars proved to be medium-seeded ones (174.7±23.1 and 147.9±37.1 g, respectively). The content of crude protein in grain was negatively affected by the development of root rot on peas (correlation coefficient r =-0.77). The maximum crude protein content was recorded during the joint treatment of seeds and plants with a preparation based on S. castalarensis A4 (24.0±2.6 %) in the ‘Falensky jubileiny’ cultivar, with Pseudobacterin-2 (23.1±2.0 %) in the ‘Falensky kormovoy’ cultivar, with a preparation based on S. antimycoticus 8A1-3 (21.1±1.7 %) in the ‘Falensky usaty’ cultivar.

Untargeted metabolomic analysis reveals a potential role of saponins in the partial resistance of pea (Pisum sativum) against a root rot pathogen, Aphanomyces euteiches.

In soil-borne diseases, the plant-pathogen interaction begins as soon as the seed germinates and develops into a seedling. Aphanomyces euteiches, an oomycete, stays dormant in soil and gets activated by sensing the host through chemical signals present in the root exudates. The composition of plant exudates may, thus, play an important role during the early phase of infection. To better understand the role of root exudates in plant resistance, we investigated the interaction between partially resistant lines (PI660736 and PI557500) and susceptible pea cultivars (CDC Meadow and AAC Chrome) against Aphanomyces euteiches during the pre-invasion phase. The root exudates of two sets of cultivars clearly distinguished from each other in inducing oospore germination. PI557500 root exudate not only had diminished induction but also inhibited the oospore germination. The contrast between the root exudates of resistance and susceptible cultivars was reflected in their metabolic profiles. Data from fractionation and oospore germination inhibitory experiments identified a group of saponins that accumulated differentially in susceptible and resistant cultivars. We detected 56 saponins and quantified 44 of them in pea root and 30 from root exudate; the majority of them, especially Soyasaponin I and dehydrosoyasaponin I with potent in vitro inhibitory activities, were present in significantly higher amounts in both roots and root exudates of PI660736 and PI557500 as compared to Meadow and Chrome. Our results provide evidence for saponins as deterrents against Aphanomyces euteiches, which might have contributed to the resistance against root rot in the studied pea cultivars.

Role of Silicon in Counteracting Cadmium Stress in Pea Plants (Pisum sativum L.): Insights Into Cadmium Binding Mechanisms and Pectin Methylesterase Activity

Purpose: The aim of this study was to investigate the role of silicon (Si) in counteracting a cadmium (Cd) stress to pea plants (Pisum sativum L.) and to identify the mechanism by which Cd is bound within pea roots. Methods: These goals were achieved through (i) a histochemical study of Cd localization in pea roots, (ii) spectrophotometric determination of pectin content and the activity of pectin methylesterase (PME), (iii) speciation of Cd extracted from pea roots conducted through size exclusion chromatography (SEC) and inductively coupled plasma mass spectrometry (ICP/MS). Results: Cd was found mainly in the root stele of the Cd-stressed plants. The pectin content and PME activity were lower in the Cd-stressed plants, but Si supplementation reversed these effects. Selectivity was noticed in Cd extraction efficiency with water being the least effective and enzymatic-assisted extraction proving to be the most effective. Speciation analysis revealed significant heterogeneity in molar mass, ranging from approximately 295 to 95 kDa. Galacturonic acid was identified the dominant species responsible for Cd binding. The choice of solvent for extraction markedly influenced the Cd binding profile, indicating shifts in the distribution of species’ molar mass and their relative concentrations in extracts. Conclusions: Si alleviates Cd toxicity in pea plants, and one of the mechanisms through which it operates involves increasing pectin levels and PME activity. Pectin plays an active role in Cd detoxification in the root cell walls, forming electrostatic bonds with Cd cations through its carboxyl groups.

Genetic Characterization of Rhizobium spp. Strains in an Organic Field Pea (Pisum sativum L.) Field in Lithuania.

Biological nitrogen fixation in legume plants depends on the diversity of rhizobia present in the soil. Rhizobial strains exhibit specificity towards host plants and vary in their capacity to fix nitrogen. The increasing interest in rhizobia diversity has prompted studies of their phylogenetic relations. Molecular identification of Rhizobium is quite complex, requiring multiple gene markers to be analysed to distinguish strains at the species level or to predict their host plant. In this research, 50 rhizobia isolates were obtained from the root nodules of five different Pisum sativum L. genotypes ("Bagoo", "Respect", "Astronaute", "Lina DS", and "Egle DS"). All genotypes were growing in the same field, where ecological farming practices were applied, and no commercial rhizobia inoculants were used. The influence of rhizobial isolates on pea root nodulation and dry biomass accumulation was determined. 16S rRNA gene, two housekeeping genes recA and atpD, and symbiotic gene nodC were analysed to characterize rhizobia population. The phylogenetic analysis of 16S rRNA gene sequences showed that 46 isolates were linked to Rhizobium leguminosarum; species complex 1 isolate was identified as Rhizobium nepotum, and the remaining 3 isolates belonged to Rahnella spp., Paenarthrobacter spp., and Peribacillus spp. genera. RecA and atpD gene analysis showed that the 46 isolates identified as R. leguminosarum clustered into three genospecies groups (B), (E) and (K). Isolates that had the highest influence on plant dry biomass accumulation clustered into the (B) group. NodC gene phylogenetic analysis clustered 46 R. leguminosarum isolates into 10 groups, and all isolates were assigned to the R. leguminosarum sv. viciae.

Hairy roots biochemical characteristics of vegetable pea’s morphotype with modified leaf

BACKGROUND: In the literature, data on the successful production of high-protein pea root cultures with mutant alleles tl and af tl and their biochemical characteristics are not presented. AIM: The aim of this study is the biochemical characteristic of the obtained transformed cultures of mutant pea lines with a modified leaf morphotype was. Rol genes clarification of transformed pea mutant lines by wild strains of Agrobacterium rhizogenes and amino acid analysis of the total protein of the obtained roots cultures were objectives of the research. MATERIALS AND METHODS: Total DNA has been isolated from pea mutant root cultures. The studies were carried out on the equipment of the thermal cycler Tertsik of the company DNA-Technology (Russia). Amplicons were detected by electrophoresis in a 2% agarose gel. The gel was visualized and photographed under ultraviolet light (λ = 312 nm). The quantitative and qualitative amino acid composition of root cultures was determined by ion exchange chromatography on the amino acid analyzer AAA-339 (Microtechna, Czech Republic). RESULTS: PCR analysis revealed the absence of agrobacterial contamination in the transformed cultures and their stable growth on liquid and agar hormone-free media for 5 years. PCR assay showed the presence of rol C and D genes in culture with the tltl genotype and four rol genes A, B, C, and D in culture with the afaftltl genotype. A differentiated content of a number of amino acids in the biomass of transformed cultures was found depending on the genotype of the culture and the insertion of rol genes. Seven essential amino acids were identified in both cultures. CONCLUSIONS: Tryptophan turned out to be the limiting essential amino acid for both cultures. In terms of the sum of essential, ketogenic and sulfur-containing amino acids, the culture with the rol genes A, B, C, and D turned out to be the richest and most balanced.

Characterization of Rhizobia Isolated from Tigray Soil and Assessment of Their Effect on Germination and Seedling Vigor of Wheat and Field Pea

Nowadays, the inoculation of plant growth-promoting rhizobia in leguminous and nonleguminous crops is given great emphasis as it improves germination and seedling vigor, resulting in increased yields. In this study, 32 rhizobia isolates were obtained from five different sampling sites in Tigray, Ethiopia. Based on morphological, biochemical, and confirmatory tests, including sugar fermentation, the isolates were identified as belonging to the rhizobia genera. In vitro assessment of plant growth-promoting properties revealed that all isolates produced indole-acetic-acid, ammonia, and solubilized phosphate, except TA8, which did not solubilize phosphate. Only 3 isolates (TA1, TA2, and TA8) produced hydrogen cyanide, so they can be used as biocontrol agents. Nineteen isolates showed a growth reduction activity against Fusarium oxysporum, with a percent inhibition range of 34.2%–65.8%. All isolates tolerated a pH range of 4.0–9.0. The isolates showed growth variations in various temperatures and salt concentrations. A few isolates were tolerant up to 45°C temperature and 6% (w/v) CaCl2 and NaCl concentrations. Inoculation of the isolates to wheat seeds increased seed germination, seedling shoot/root length, and seedling vigor index compared to the positive and negative controls. Isolates KO3, KO4, ME3, and TA5 increased seed germination by 4%. KO1 (11.60 cm) and TA7 (11.70 cm) showed a significantly enhanced shoot length, and ME3 showed a maximum root length (13.90 cm). SH1, KO2, and the positive control showed a significant (P≤0.05) increase in pea seed germination (by 20%) compared to the negative control. The positive control had the longest field pea shoot (5.70 cm), and isolate TA9 had the longest field pea root (5.32 cm) compared to the negative control. Generally, the wheat and field pea seedlings responded differently to the inoculation of different isolates. This study shows that Tigray soils harbor a variety of rhizobia species, which can be used as plant growth-promoting and biocontrol agents.

Root uptake of umbelliferone enhances pea's resistance against root-knot nematodes

Coumarins are secondary plant metabolites which play a key role in plant–plant and plant–microbe interactions. In particular, they are highly involved in environmental stress responses. Coumarins can transfer from plants producing coumarins to non-coumarin-producing neighbouring plants. As in vitro studies have shown that coumarins are nematicidal, we hypothesized that this transfer may also result in enhanced resistance against plant parasitic nematodes in coumarin-receiving plants. To test if the uptake of coumarins in a non-coumarin- producing plant protects the plant against nematode attack, we incubated non-coumarin- producing pea seedlings in growth media with the coumarin umbelliferone for three weeks, after which the plants were transplanted into soil and inoculated with root-knot nematodes (Meloidogyne incognita). We quantified the coumarin content in pea organs and nematode root invasion 2, 4, and 6 weeks after transplantation. Umbelliferone was taken up by the pea roots and translocated to the shoots. As a result of metabolization, umbelliferone and its derived metabolites coumarin, scopoletin, and scopolin were detected in the plants. The root uptake of umbelliferone reduced root-knot nematode invasion significantly up to 4 weeks after the root exposure. Our results suggest that the root uptake and the transfer of bioactive compounds between plants can expand the understanding of plant–plant interactions.

Deciphering Aphanomyces euteiches-pea-biocontrol bacterium interactions through untargeted metabolomics

Aphanomyces euteiches causes root rot in pea, leading to significant yield losses. However, the metabolites involved in this pathosystem have not been thoroughly studied. This study aimed to fill this gap and explore mechanisms of bacterial suppression of A. euteiches via untargeted metabolomics using pea grown in a controlled environment. Chemical isotope labeling (CIL), followed by liquid chromatography-mass spectrometry (LC–MS), was used for metabolite separation and detection. Univariate and multivariate analyses showed clear separation of metabolites from pathogen-treated pea roots and roots from other treatments. A three-tier approach positively or putatively identified 5249 peak pairs or metabolites. Of these, 403 were positively identified in tier 1; 940 were putatively identified with high confidence in tier 2. There were substantial changes in amino acid pool, and fatty acid and phenylpropanoid pathway products. More metabolites, including salicylic and jasmonic acids, were upregulated than downregulated in A. euteiches-infected roots. 1-aminocyclopropane-1-carboxylic acid and 12-oxophytodienoic acid were upregulated in A. euteiches + bacterium-treated roots compared to A. euteiches-infected roots. A great number of metabolites were up- or down-regulated in response to A. euteiches infection compared with the control and A. euteiches + bacterium-treated plants. The results of this study could facilitate improved disease management.

Enhancing Pisum sativum growth and symbiosis under heat stress: the synergistic impact of co-inoculated bacterial consortia and ACC deaminase-lacking Rhizobium

The 1-aminocyclopropane-1-carboxylate (ACC) deaminase is a crucial bacterial trait, yet it is not widely distributed among rhizobia. Hence, employing a co-inoculation approach that combines selected plant growth-promoting bacteria with compatible rhizobial strains, especially those lacking ACC deaminase, presents a practical solution to alleviate the negative effects of diverse abiotic stresses on legume nodulation. Our objective was to explore the efficacy of three non-rhizobial endophytes, Phyllobacterium salinisoli (PH), Starkeya sp. (ST) and Pseudomonas turukhanskensis (PS), isolated from native legumes grown in Tunisian arid regions, in improving the growth of cool-season legume and fostering symbiosis with an ACC deaminase-lacking rhizobial strain under heat stress. Various combinations of these endophytes (ST + PS, ST + PH, PS + PH, and ST + PS + PH) were co-inoculated with Rhizobium leguminosarum 128C53 or its ΔacdS mutant derivative on Pisum sativum plants exposed to a two-week heat stress period.Our findings revealed that the absence of ACC deaminase activity negatively impacted both pea growth and symbiosis under heat stress. Nevertheless, these detrimental effects were successfully mitigated in plants co-inoculated with ΔacdS mutant strain and specific non-rhizobial endophytes consortia. Our results indicated that heat stress significantly altered the phenolic content of pea root exudates. Despite this, there was no impact on IAA production. Interestingly, these changes positively influenced biofilm formation in consortia containing the mutant strain, indicating synergistic bacteria-bacteria interactions. Additionally, no positive effects were observed when these endophytic consortia were combined with the wild-type strain. This study highlights the potential of non-rhizobial endophytes to improve symbiotic performance of rhizobial strains lacking genetic mechanisms to mitigate stress effects on their legume host, holding promising potential to enhance the growth and yield of targeted legumes by boosting symbiosis.

Bio-efficacy of Alcoholic Extracts of Botanicals to Mitigate Pea Root Rot Caused by Fusarium solani f.sp. pisi

Pea root rot caused by Fusarium solani f. sp. pisi has been observed as an alarming problem in pea growing regions of Himachal Pradesh and poses major constraints in pea cultivations. The alcoholic leaf extracts of four plants viz., Eupatorium adenophorum, Eucalyptus sp., Vitex negundo and Ageratum conyzoides were evaluated at different concentrations for their efficacy against F. solani f. sp. pisi under in vitro conditions. Among all extracts, E. adenophorum yielded maximum mycelial inhibition of 77.4 per cent followed by Eucalyptus sp. 74.9 per cent at 25 per cent test concentration. Thus, among all test botanicals, E. adenophorum was found the most efficient against F. solani f. sp. pisi. These findings suggest that E. adenophorum extracts could be used as eco-friendly alternatives to control Fusarium solani f. sp. pisi.

Occurrence of Pea Root Rot in Different Regions of Himachal Pradesh and Identification of Pathogen Associated with Disease

Pea root rot has emerged as a significant concern in select cultivation regions of Himachal Pradesh, with varying levels of disease incidence recorded across districts. In this study, disease incidence was quantified, with notable rates documented in Bir, Chougan, and Kukumseri. The widespread presence of pea root rot, underscores the severity of the issue. Previous research has identified Fusarium solani F. sp. pisi as a primary pathogen. The morphological, cultural, and pathogenic evaluations, confirm the involvement of Fusarium solani F. sp. pisi in pea root rot. Economic implications of this disease complex are significant, necessitating comprehensive understanding and management strategies. The methodological approach, including pathogenicity tests using Hoagland's solution, offers insights into disease progression and symptomatology. These findings contribute valuable insights into the biology and management of pea root rot, essential for developing effective disease control strategies in pea cultivation.

ВЛИЯНИЕ ПРИМЕНЕНИЯ СРЕДСТВ ИНТЕНСИФИКАЦИИ НА БИОЛОГИЧЕСКУЮ АКТИВНОСТЬ И ФИТОСАНИТАРНОЕ СОСТОЯНИЕ ПОЧВЫ ПОД ПОСЕВОМ ГОРОХА

The aim of research is to determine the parameters of biological activity of meadow-chernozem soil and its phytoimmunity in grain-fallow crop rotation at different levels of cultivation intensification and the use of chemicals. The studies were carried out in a long-term (launched in 1973) stationary experiment in grain-fallow crop rotation (fallow – wheat – peas – wheat – barley) under pea crop in the Federal State Budgetary Scientific Institution Omsk Agrarian Scientific Center. In certain periods of 2022 and 2023, with favorable soil moisture, the presence of a significant amount of plant residues in the variant with minimum-zero tillage and the use of complex chemicals, the number of soil micromycetes and nodule bacteria increased to 93.0 thousand and 13.9 million CFU/g, respectively. The total number of soil microflora in the arable layer under different soil cultivation systems for peas without the use of complex chemicals was 51.4–61.2 million CFU/g with a difference of 19.0 % in the ascending series: No-till < moldboard < combined. The use of mineral fertilizers in combination with plant protection products in moldboard and combined tillage did not have a significant effect on the amount of soil microflora, a slight decrease to 17.0 % within the experimental error was noted. In the variants with No-till tillage in combination with intensification products, stimulation of the growth of the number of microorganisms to 22.0 % in relation to the control was noted. On average, according to the soil tillage factor, the greatest development of pea root rot was observed in the No-till variant (3.8 %), a slight decrease (3.2–3.6 %) – in moldboard and combined tillage. The use of plant protection products during the growing season of peas made it possible to reduce the development of root rot by 47.0 % relative to the control, depending on the soil tillage method. With combined treatment, the greatest prevalence of pea root system disease was noted (37.8 %), the least – with No-till treatment (30.8 %). In laboratory conditions, using the wet chamber method, a complex of root rot pathogens was determined, among which fungi of the genus Fusarium spp. prevailed.

Plant seedlings of peas, tomatoes, and cucumbers exude compounds that are needed for growth and chemoattraction of Rhizobium leguminosarum bv. viciae 3841 and Azospirillum brasilense Sp7.

This study characterizes seedling exudates of peas, tomatoes, and cucumbers at the level of chemical composition and functionality. A plant experiment confirmed that Rhizobium leguminosarum bv. viciae 3841 enhanced growth of pea shoots, while Azospirillum brasilense Sp7 supported growth of pea, tomato, and cucumber roots. Chemical analysis of exudates after 1 day of seedling incubation in water yielded differences between the exudates of the three plants. Most remarkably, cucumber seedling exudate did not contain detectable sugars. All exudates contained amino acids, nucleobases/nucleosides, and organic acids, among other compounds. Cucumber seedling exudate contained reduced glutathione. Migration on semi solid agar plates containing individual exudate compounds as putative chemoattractants revealed that R. leguminosarum bv. viciae was more selective than A. brasilense, which migrated towards any of the compounds tested. Migration on semi solid agar plates containing 1:1 dilutions of seedling exudate was observed for each of the combinations of bacteria and exudates tested. Likewise, R. leguminosarum bv. viciae and A. brasilense grew on each of the three seedling exudates, though at varying growth rates. We conclude that the seedling exudates of peas, tomatoes, and cucumbers contain everything that is needed for their symbiotic bacteria to migrate and grow on.

Effect of weeds on pea (Pisum sativum) seed germination

Segetal vegetation should be controlled both during crop growing season and after harvesting. The reason is that undesirable vegetation accumulates a significant mass, one that will later become a threat to the following crop in crop rotation. Mixtures of substances of biogenic origin, called allopathic, are constantly changing subject to abiotic factors and environmental conditions. Therefore, their effects on organisms are characterized by significant variability. According to the biotesting results, we found that allopathically active substances of all experimental weed species had a negative effect on pea seed germination. In the control variant, all seeds germinated in 4 days, but in some experimental variants 2–3% of the seeds were in the phase of swelling. Water extracts from different species and parts of weeds had significant inhibitory effect on the germination of pea seeds and further growth. The water-soluble extracts from the underground organs of perennial weeds such as Elytrigia repens L. and Cirsium arvense L. were particularly strong, leading to 58.2% and 53.1% reduction in the length of the embryonic root. Water-soluble extracts from the leaves of these weeds had slightly lower effects on pea germination, and the lags in root growth were 33.5% and 31.4%, respectively. Extracts from weed stems also inhibited pea germination and had an intermediate effect between the effect of water-soluble extracts from the underground part and leaf blades. The effect of extracts from roots of annual weeds on the length of the germinal root ranged 36.6% in common stork’s-bill (Erodium cicutarium L.) to 13.9% in chickweed (Stellaria media L.). The allopathic effect of the substances from the leaves of chickweed (Stellaria media L.) and potato weed (Galinsoga parviflora Cav.) had the lowest effect on the growth of pea root. The lag of the indicator in the control was 7.2% and 12.9% for the variants.

Global Scenario of Vegetable Fungal Diseases

Plant diseases threaten crop production and are responsible for considerable losses in vegetables worldwide. Every year diseases cause losses up to 40 to 60% in vegetable crops. Vegetable crops are comparatively more susceptible to various types of diseases inflicted by fungi, bacteria, virus, viroid, phytoplasma and nematodes. Genera of fungal pathogens viz. Alternaria, Aschochyta, Colletotrichum, Didymella, Phoma, Phytophthora, Pythium, Rhizoctonia, Sclerotinia and Sclerotium on vegetable crops increased tremendously. Emerging seed-borne and seed-transmitted fungal plant diseases became a major threat for the vegetable seed production system. Emerging diseases in vegetable crops like tomato (early and late blight, Fusarium wilt), chili and peppers (anthracnose, Phytophthora blight), brinjal (phomopsis blight, Alternaria leaf spot), cucurbits (Downey mildew, gummy stem blight, Fusarium wilt, fruit rot, anthracnose and Cercospora leaf spot), okra (Cercospora leaf spot), pea (powdery mildew, fusarium wilt, rust and root rot), French bean (Sclerotinia stem rot), cowpea/dolichos bean (anthracnose, Sclerotinia stem rot), cole crop (black rot, Alternaria blight, downy mildew) etc. The vegetable produce is spoiled by post-harvest pathogens and makes them unfit for human consumption and market due to the production of mycotoxins. Profiling, detection and diagnosis of vegetable pathogens (diseases) are essential for better understanding of pathogens and formulation of safe disease management strategy of vegetable crops. Therefore, there is an urgent need to wide array of diagnoses of pathogens of vegetables and their in-vitro testing towards chemo-sensitivity for formulation of safe management of vegetable diseases

Characterization of Fusarium oxysporum f. sp. pisi Associated with Root Rot of Field Pea in North Dakota and the Effects of Temperature on Aggressiveness.

Fusarium root rot is an important disease of field pea (Pisum sativum var. sativum L.) that occurs everywhere pea is grown, causing yield loss of up to 75%. Fusarium root rot is caused by a complex of Fusarium species, most notably Fusarium solani in the Pacific Northwest of the United States and F. avenaceum in the northern Great Plains of the United States and Canada. F. oxysporum f. sp. pisi (Fop) was frequently isolated from peas exhibiting root rot symptoms in North Dakota during recent surveys. Fop causes wilt (races 1, 5, and 6) and near wilt (race 2) on pea. However, its contribution to pea root rot remains unclear. Fop race was determined for isolates from North Dakota pea root rot surveys. ND Fop isolates were evaluated for root rot pathogenicity and aggressiveness at standard and elevated temperatures. Results from greenhouse wilt assays indicated that all Fop races exist in North Dakota, with race 2 most prevalent among the 25 North Dakota isolates evaluated. Root rot evaluations conducted at 21/18°C and 25/19°C day/night temperatures demonstrated that most Fop isolates were as aggressive or more aggressive than F. solani and F. avenaceum under both temperature regimes. Aggressiveness of Fop isolates tended to increase at elevated assay temperatures. Results from these experiments indicate that Fop may be an important contributor to the root rot complex of field pea in North Dakota and should be considered in integrated pest management strategies, including pea breeding efforts to improve resistance to Fusarium root rot.[Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Impact of two Erwinia sp. on the response of diverse Pisum sativum genotypes under salt stress

Currently, salinization is impacting more than 50% of arable land, posing a significant challenge to agriculture globally. Salt causes osmotic and ionic stress, determining cell dehydration, ion homeostasis, and metabolic process alteration, thus negatively influencing plant development. A promising sustainable approach to improve plant tolerance to salinity is the use of plant growth-promoting bacteria (PGPB). This work aimed to characterize two bacterial strains, that have been isolated from pea root nodules, initially called PG1 and PG2, and assess their impact on growth, physiological, biochemical, and molecular parameters in three pea genotypes (Merveille de Kelvedon, Lincoln, Meraviglia d’Italia) under salinity. Bacterial strains were molecularly identified, and characterized by in vitro assays to evaluate the plant growth promoting abilities. Both strains were identified as Erwinia sp., demonstrating in vitro biosynthesis of IAA, ACC deaminase activity, as well as the capacity to grow in presence of NaCl and PEG. Considering the inoculation of plants, pea biometric parameters were unaffected by the presence of the bacteria, independently by the considered genotype. Conversely, the three pea genotypes differed in the regulation of antioxidant genes coding for catalase (PsCAT) and superoxide dismutase (PsSOD). The highest proline levels (212.88 μmol g−1) were detected in salt-stressed Lincoln plants inoculated with PG1, along with the up-regulation of PsSOD and PsCAT. Conversely, PG2 inoculation resulted in the lowest proline levels that were observed in Lincoln and Meraviglia d’Italia (35.39 and 23.67 μmol g−1, respectively). Overall, this study highlights the potential of these two strains as beneficial plant growth-promoting bacteria in saline environments, showing that their inoculation modulates responses in pea plants, affecting antioxidant gene expression and proline accumulation.

Role of organic and inorganic amendments on physiological attributes of germinating pea seedlings under arsenic stress

There are scarce data regarding the effects of soil amendments on biophysicochemical responses of plants at the early stages of growth/germination. This study critically compares the effects of ethylene-diamine-tetra-acetic-acid (EDTA) and calcium (Ca) on biophysicochemical responses of germinating pea seedlings under varied arsenic levels (As, 25, 125, 250 µM). Arsenic alone enhanced hydrogen peroxide (H2O2) level in pea roots (176%) and shoot (89%), which significantly reduced seed germination percentage, pigment contents, and growth parameters. Presence of EDTA and Ca in growth culture minimized the toxic effects of As on pea seedlings, EDTA being more pertinent than Ca. Both the amendments decreased H2O2 levels in pea tissues (16% in shoot and 13% in roots by EDTA, and 7% by Ca in shoot), and maintained seed germination, pigment contents, and growth parameters of peas close to those of the control treatment. The effects of all As-treatments were more pronounced in the pea roots than in the shoot. The presence of organic and inorganic amendments can play a useful role in alleviating As toxicity at the early stages of pea growth. The scarcity of data demands comparing plant biophysicochemical responses at different stages of plant growth (germinating vs mature) in future studies.