Tomato Seedlings Research Articles

Biopriming of Tomato Seeds with Native Trichoderma Species for Enhanced Seedlings Vigour

The present research was carried out to investigate the effect of tomato seed biopriming using six native Trichoderma isolates under laboratory conditions. The seeds of tomato were primed in Trichoderma isolates and as a control treatment seeds were treated in sterile distilled water. It was observed that all the six native Trichoderma isolates showed good performance with respect to growth, germination percentage and vigour index of tomato seedlings as compared to control. Among the different Trichoderma isolates tested, T5 isolate showed highest shoot growth (5.44 cm), root growth (3.74 cm), germination percentage (90.0%) and seedling vigour index (826.37) followed by T4 isolate. The lowest shoot growth (4.22 cm), root growth (3.07 cm), germination percentage (56.7%) and seedling vigour index (412.70) were recorded in untreated control.

Drought stress amelioration in tomato (Solanum lycopersicum L.) seedlings by biostimulant as regenerative agent.

Drought adversely affects many physiological and biochemical events of crops. This research was conducted to investigate the possible effects of biostimulants containing plant growth-promoting rhizobacteria (PGPR) on plant growth parameters, chlorophyll content, membrane permeability (MP), leaf relative water content (LRWC), hydrogen peroxide (H2O2), proline, malondialdehyde (MDA), hormone content, and antioxidant enzymes (catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD)) activity of tomato (Solanum lycopersicum L.) seedlings under different irrigation levels. This study was carried out under controlled greenhouse conditions with two irrigation levels (D0: 100% of field capacity and D1: 50% of field capacity) and three biostimulant doses (B0: 0, B1: 4 L ha-1, and B2: 6 L ha-1). The results of the study show that drought stress negatively influenced the growth and physiological characteristics of tomato seedlings while biostimulant applications ameliorated these parameters. Water deficit conditions (50% of field capacity) caused decrease in indole acetic acid (IAA), gibberellic acid (GA), salicylic acid (SA), cytokine, zeatin, and jasmonic acid content of tomato seedlings by ratios of 83%, 93%, 82%, 89%, 50%, and 57%, respectively, and shoot fresh weight, root fresh weight, shoot dry weight, root dry weight, plant height, stem diameter, and leaf area decreased by 43%, 19%, 39%, 29%, 20%, 18%, and 50%, respectively, compared to the control (B0D0). In addition, 21%, 16%, 21%, and 17% reductions occurred in LRWC, chlorophyll a, chlorophyll b, and total chlorophyll contents with drought compared to the control, respectively. Biostimulant applications restored the plant growth, and the most effective dose was 4 L ha-1 under drought condition. Amendment of biostimulant into the soil also enhanced organic matter and the total N, P, Ca, and Cu content of the experiment soil. In conclusion, 4 L ha-1 biostimulant amendment might be a promising approach to mitigate the adverse effects of drought stress on tomato.

Activity of volatiles induced by microbes and natural plants stifled the growth of Pythium aphanidermatum - the damping off in Tomato

BackgroundVolatilomes from natural plants and microbes imparts diverse antifungal properties to suppress the growth of plant pathogens and therefore can be a suitable alternative of chemical fungicides. The present experiment was to study effect of volatiles produced by natural plants and microbes on the fungal growth of Pythium aphanidermatum, which is a tomato seedling pathogen.ResultsIsolate of P. aphanidermatum, causing damping off in tomato were isolated and incubated at 25 ± 2 °C. The isolate was tested for the anti-oomycetes activities of volatiles in vitro. The volatiles produced by the leaves of Mentha spicata and Cymbopogon citratus showed the maximum inhibitory effect of 45.56 and 24.70 percent, respectively on the mycelial growth of P. aphanidermatum, whereas, the pathogen was not inhibited on exposure to the volatiles of macro-basidiomycetes fungi. The volatiles of T. asperellum showed the maximum inhibitory effect of 69.26 percent against P. aphanidermatum. The study also included the identification of Volatile Organic Compounds (VOCs) involved in the suppression of pathogens by Headspace Gas Chromatography Mass Spectrometry (HS GCMS). The results revealed the production of carvone by the leaves of M. spicata; citronellol and geraniol by C. citratus; isopentyl alcohol and limonene by T. asperellum with increased peak area percentage and these compounds possessed antifungal properties. The vaporous action of isopentyl alcohol completely suppressed the mycelial growth of P. aphanidermatum, which is highly correlated to the T. asperellum extract on pathogenic growth. While the compounds, carvone, and citronellol showed the maximum inhibitory effect of 89.02 and 85.49 percent, respectively when used at 500 ppm and also altered the sporulation behavior of P. aphanidermatum.ConclusionResults showed that volatiles of M. spicata and T. asperellum have anti-oomycetes action on pathogenic growth leading to a distortion of sporulation of P. aphanidermatum. High antifungal properties make VOCs suitable for incorporation as a new integrated plant disease management programs.

Uncovering the synergistic interplay of melatonin and spermidine in the alleviation of nematode stress in Solanum lycopersicum

Worldwide, biotic stress severely degrades agricultural output and increases the risk of starvation. Root-knot nematodes (Meloidogyne incognita) are one of the important endoparasites that adversely affect the growth and development in plants, thus affecting their productivity. Contrarily, humans employ a number of unfriendly techniques, such as chemical applications, to manage biotic stressors. Use of Plant Growth Regulators is an environmentally safe alternative method against chemical pesticides that can be used to defend plants from biotic stressors. Melatonin and polyamines have been broadly found in multiple physiological processes and in diverse biotic and abiotic stresses faced by plants. In the contemporaneous study, we conducted an in vitro experiment which disclosed that pretreated seeds with melatonin and spermidine (a polyamine), decreased root galls in afflicted plants and uplifted the growth of Solanum lycopersicum seedlings. According to our findings, tomato plants' photosynthetic efficiency dropped and reactive oxygen species levels dramatically rose after nematode inoculation. On the other hand, melatonin and spermidine decreased oxidative stress by scavenging hydrogen peroxide and decreased malonaldehyde. The present work investigated improvement in growth characteristics, photosynthetic pigments, antioxidative enzymes and non-antioxidative enzymes in PGR treated tomato seedlings even during the nematode stress. Confocal studies evaluated nuclear damage within root apices and intensity of blue colour was directly proportional to nuclear damage. The findings of the present investigation support the use of plant growth regulators, melatonin and spermidine as seed priming agent to manage nematode stress in plants.

Ethylene inhibitors improve crop productivity by modulating gene expression, antioxidant defense machinery and photosynthetic efficiency of Solanum lycopersicum L. cv. Pusa Ruby grown in controlled salinity stress conditions

Tomato is an important horticultural crop of global importance but its susceptibility to salinity stress significantly retards growth and thereby its yield. The impact of gaseous hormone, ethylene, accentuates the effect of salinity stress by negatively regulating various growth and developmental processes. Ethylene overproduction and ionic imbalance triggered by salinity stress exhibit upregulation of 1-aminocyclopropane-1-carboxylic acid synthase (ACS) and downregulation of NHX1, SOS1 and HKT1;2 under salinity stress conditions that negatively affect proline content, ROS scavenging machinery, morphometric and physiological attributes. Variation in the proline content, activation of ROS scavenging machinery, affected morphometric and physiological attributes are some discernible points in response to salinity stress induced ethylene production. Therefore, the experiment was designed to study the role of ethylene inhibitors silver nitrate (AgNO3) and cobalt chloride (CoCl2) in mitigating the negative effects of ethylene over production under salinity stress. Tomato seedlings were treated with 0 mM NaCl, 250 mM NaCl and 250 mM NaCl + 100 µM AgNO3, 250 mM NaCl + 100 µM CoCl2 for three days. The gene expression of ACS2, NHX1, SOS1 and HKT1;2, and ACS activity, endogenous ethylene level, Na+ and K+ ions concentration, proline content, antioxidant enzymes activity, photosynthetic efficiency and different morphological and yield parameters were assessed in tomato plants treated with salinity stress, and ethylene inhibitors at 45 DAS and 90 DAS. Results revealed that ethylene inhibitors might be playing the role in minimizing the ethylene and ACC load. The ACS enzyme activity and ethylene content were considerably decreased due to application of AgNO3and CoCl2. Further, the endogenous proline and K+ content, and K+/Na+ ratio were considerably increased in response to ethylene inhibitors treatment. Also, antioxidant enzymesviz., SOD, CAT, APX and GR, growth matrices, photosynthetic efficiency and yield attributes were significantly improved in treated tomato plants (salinity with ethylene inhibitors).

Priming effect of chitosan on induces protection against tomato root wilt disease mediated through upregulation of defense enzymes

The antifungal activity of chitosan against Sclerotinia sclerotiorum, the causal agent of tomato wilt was investigated. Chitosan was used at 0.2%, 0.4%, and 0.6% concentration in a potato dextrose agar and potato dextrose broth media inhibited S. sclerotiorum growth after ten days (p < 0.05). In vitro antifungal analysis confirmed membrane damage and increased lipid peroxidation reaction in chitosan-treated fungal mycelia than control (p < 0.05). The tomato seeds treated with chitosan registered a significant improvement in seed germination, growth profile and biosynthesis of defense enzymes, chitinase and b-glucanase in tomato seedlings. Tomato seeds treated with 0.3%, and 0.4% chitosan exhibited a significant increase in tomato seed germination rates at 87.4 ± 2.4%, 97.8 ± 4.7%, respectively (p < 0.05). In addition, chitosan-treated tomato seedlings registered upregulation of peroxidase, polyphenol oxidase, phenylalanine ammonia-lyase activity, catalase and β-1, 3 glucanase activity (p < 0.05). Tomato seeds treated with chitosan improved disease protection against wilt disease and maximum protection (85.7 ± 3.2%) was achieved at 0.5% treatment (p < 0.05). Chitosan (0.5%) treated tomato seeds improved shoot length (4.9 ± 0.1), root length (3.5 ± 0.2), and plant biomass (0.428 ± 0.24 g). Chitosan exhibited antifungal activity and defense response on wilt disease and improved plant growth-promoting activities.

First report of Fusarium equiseti causing root and crown rot in tomato in Mexico.

Tomato (Solanum lycopersicum L.) is one of the most important crops in Mexico due to its economic and nutritional value. Among the main diseases in tomato production is Fusarium wilt, which can cause 60% production losses (Ascencio et al, 2008). Mixed infections of Fusarium species or other fungi genera, would increase disease severity. During April to May of 2021, tomato plants with more than 60 days old, were collected from the main production areas of Aguascalientes (22°03'46.5"N 102°05'17.4"W and 22°04'53.64"N 101°58'55.81"W) and Zacatecas (23°05'59.2"N 102°41'07.3"W and 22°16'52.1"N 102°00'11.8"W) Mexico states. Plants showed main root rot, vascular bundles necrosis with corky appearance, stem crown rot, and ascending yellowing. The main root and stem crown were cut in 0.25 cm2 pieces and disinfested in 2% NaClO for one minute, rinsed with distilled water two times, placed on acidified potato dextrose agar (PDA) medium, and incubated at 25 ± 2°C for 7 days. Characteristic Fusarium growths were purified by hyphal tip on PDA, subsequently pure strains were obtained by single-spore isolation method. Several fungi colonies were obtained, but we focused on the colonies that showed abundant aerial mycelium of white color and irregular growth, which turned yellowish to golden and brown color as it ages. Carnation leaf agar (CLA) medium were used for conidia and sporodochium development. Chains of terminal, intercalary and agglomerated chlamydospores with thick, rough brown walls of 18.9 (7.46) µm in diameter (n=120) were observed in the mycelium. Macroconidia with 5 to 7 septa were 30 to 75 (28.32) µm in long and 1.2 to 4.8 (3.2) µm in wide (n=72). Basal cell developed in foot-shape, apical cell was elongated and slightly curved, and some macroconidia had swollen midd-cell. Sporodochium was orange to brown in color and microconidia were absent (Figure 1). Two representative strains from each state, LCA-3.1 and EMA-1 from Aguascalientes and ECZ-4 and LRZ-6 from Zacatecas, were selected for DNA amplification of ITS, TEF-1α and RPB2 regions, with universal primers ITS1/ITS4, EF1/EF2 and 2-5F2/7cR (White et al.1990; O'Donnell et al. 1998, 2013). PCR products were sequenced by Psomagen, Inc. (USA). The sequences obtained showed 100% of similarity among themselves and within species of the Fusarium incarnatum-equiseti species complex (FIESC) with nucleotide NCBI accessions NR_121457 (Type material) for ITS and MW362069 for TEF-1α; and 99.28% with MN170399 for RPB2 in FUSARIOID-ID database. According to morphological (Leslie and Summerell, 2006) and molecular characteristics, isolates were identified as Fusarium equiseti (FIESC 14). The LCA-3.1 sequences were selected to be deposited in GenBank with accession numbers OM812801 (ITS), OM937108 (TEF-1α) and ON653596 (RPB2). Pathogenicity tests were performed twice, under greenhouse conditions in tomato seedlings of cv. Rio Grande. Five tomato seedlings were inoculated by root immersion method (Lopez et al, 2018) in a 1x106 spores/mL solution for 8 min, and transplanted to 1L pots with sterile peat. Five controls plants were immersed in sterile water. At 14 days after inoculation, a general plant decline and slower growth compared to the control plants were observed. Subsequently, plants showed root rot, vascular necrosis, and a brown ring in stem crown. Controls were symptomless. The fungi were re-isolated from symptomatic plants and were morphologically similar to the inoculated strains. Patel et al. (2017) described the pathogenic and toxic effects of F. equiseti on tomato, causing low seed germination, and low root and shoot growth. This is the first report of F. equiseti causing root and stem rot in tomato plants in Mexico.

The effects of double-stemmed grafted tomato plants on yield and quality of tomato cultivation

In this study, the effect of the production of double-stemmed grafted and non-grafted tomato plants on yield and quality was investigated. Android F1 and Torry F1 tomato (S. lycopersicum L.) cultivars were grafted on “Classmate” tomato rootstock, and grafting was doneaccording to one or two stems for treatments. There were 12 plants in each treatment over 4 grafting and 2 varieties and the plants were provided seedling nursery. The number of stems left in tomato seedlings as grafted and non-grafted was taken as the basis. The plants which are consisting of two stems are formed from the cotyledon axillary buds. The grafting in the experiment were created as follows;.1- grafted-double stem: Shoots were formed with the development of cotyledon axillary buds, 2- Non-grafted-double stem: Shoots were formed with the development of cotyledon axillary buds on cultivars, 3- Grafted-single stem and 4- non-grafted-single stem (control) were formed. In the experiment conducted, the highest plant height (167.25 cm) was obtained from the control treatment and the highest stem diameter (16.58 mm) was obtained from the grafted double stem treatment. L and Hue angel values measured in fruit color of treatments were not statistically significant. The highest total soluble solids (4.46%) was obtained from the non-grafted double stem treatment. In terms of total yield, the highest value (12.27 kg m-2) was obtained in the control plants. The effect of double stem in cotyledon axillary buds on grafted tomato cultivation was found statistically significant on yield, and grafting with double stem decreased the yield, as compare to the control treatment.

Relationship between different physiological processes of Tomato seedlings exposed to acid mine water Uncovered using correlation analysis

This study was conducted to assess the correlation between growth response, phytoaccumulation factor of different tissues, and elemental composition in tomato seedlings exposed to acid mine water (AMW). In pairwise correlation determinations values of plant height, stem diameter, seed germination indices (radicle length, final germination percentage (FGP), emergency rate index (ERI), vigour index (VI), germination percentage (G%) and germination rate index (GRI)) and the elemental compositions (Cd, Cr, Cu, Ni and Zn) in the different plant tissues, root (root accumulation factor = RAF), stem (stem translocation factor = STF) and leaves (leaf translocation factor = LTF) were selected for the relationship determinations. Pearson correlation coefficients were calculated and revealed the relationships between the paired parameters. The study concluded that the strongly correlated physiological parameters were jointly co-ordinated in tomato seedlings exposed to AMW.

Changes in Shoot and Root Growth of Tomato Seedlings Stimulated by Brushing

Changes in Shoot and Root Growth of Tomato Seedlings Stimulated by Brushing

Biomolecules from Chaetomium globosum Possessing Antimicrobial Compounds Potentially Inhibits Fusarium Wilt of Tomato.

Wilt disease caused by Fusarium solani, a soil-borne plant pathogenic fungus, is a serious disease in tomato causing economic losses. In the present study, among the nine isolates of Chaetomium globosum Kunze (Chg1-Chg9), screened against F. solani No. Fs-1, Chg2 exhibited the maximum inhibition (49.2 %), followed by the isolates Chg6 (47.4%) and Chg1 (46.3%) in dual culture. Further, the crude secondary metabolites from these three isolates showed maximum reduction of the mycelial growth of Fs-1 compared to control. Gas Chromatography-Mass Spectrometry (GC-MS) analysis of the metabolites from Chg2 revealed the presence of major compounds, viz., benzothiazole, 2-(2-hydroxyethylthio) (7.51%); 9,12,15- octadecatrienoic acid, 2,3-bis[(trimethylsilyl)oxy] propyl ester (3.13%); and hexadecanoic acid, 1- (hydroxymethyl)-1,2-ethanediyl ester (2.69%). Fourier transform infrared (FTIR) spectroscopy revealed the presence of alcohol, secondary amine, aliphatic primary amine, carboxylic acid, allene, conjugated ketone, imine/oxime, sulphate, and halo compound groups with a weak to strong range of intensity. Pure compound of benzothiazole @ 5000 ppm exhibited higher antagonistic activity of Fs-1which decreased at lower concentration. In pot culture experiment, dipping tomato seedlings cv. PKM1 in 2% ethyl acetate-fractionated biomolecules of Chg2 recorded a minimum disease incidence of 20.0%, whereas seedlings dipped in the culture filtrate of Chg2 showed a disease incidence of 26.6% compared to control (86.6%). Besides, these seedlings treated with the culture filtrate showed the highest plant height of 37.68 cm and the maximum number of leaves and flowers (39.6 and 5.48, respectively), followed by those treated with the biomolecules of Chg2 (C. globosum) and the culture filtrate of T. asperellum. The results revealed that the antifungal efficacy of C. globosum Chg2 is due to the presence of antimicrobial metabolites including benzothiazole. Exploring the use of this novel antifungal compound in the management of plant diseases is highly warranted.

Induction of tomato plant biochemical immune responses by the synthesized zinc oxide nanoparticles against wilt-induced Fusarium oxysporum.

Thecurrent study used zinc oxide nanoparticles (ZnO-NPs) to protect the tomato plant against Fusarium wilt. Gamma rays were used to synthesize ZnO-NPs, and the designed ZnO-NPs were characterized using high-resolution transmission electron microscopy (HRTEM), scanning electron microscope (SEM), dynamic light scattering (DLS), energy-dispersive X-ray spectroscopy (EDX), and ultraviolet-visible (UV-Vis.) spectroscopy. We found that the 20 kGy dose is the most effective for ZnO-NPs synthesis, with the highest O.D. = 1.65 (diluted 3 times) at 400 nm. The scale of ZnO-NPs ranged from 10.45 to 75.25 nm with an average diameter of 40.20 nm. The results showed that the designed ZnO-NPs showed promising activity as a potent inducer of plant physiological immunity against Fusarium wilt disease. Likewise, ZnO-NPs significantly reduced the wilt disease symptoms incidence by 28.57% and high protection by 67.99% against F. oxysporum. Additionally, infected tomato plants treated with ZnO-NPs show improved shoot length (44.71%), root length (40.0%), number of leaves (60.0 %), chlorophyll a (36.93%), chlorophyll b (16.46%), and carotenoids (21.87%) versus infected plants. Notably, in the treatment of tomato seedlings, the beneficial effects of ZnO-NPs extended to increase not only in osmolyte contents but also total phenol contents in comparison with control plants. In conclusion, the designed ZnO-NPs can control Fusarium wilt disease and improve and develop biochemical compounds responsible for defense against fusarial infection.

Oxidation-Resistant Silicon Nanosystem for Intelligent Controlled Ferrous Foliar Delivery to Crops.

Since ferrous (Fe(II)) is the main form of plant absorption, traditional ferrous foliar fertilizers (TFFF) are widely used in modern agriculture. However, TFFF suffer from the shortcomings of weak antioxidant capacity (AC), low foliar adhesion efficiency (FAE), poor fertilizer utilization efficiency (FUE), and noncontrollable slow-release behavior. To overcome these limitations, an oxidation-resistant silicon nanosystem for intelligent controlled ferrous foliar delivery to crops was first developed by using environmentally friendly micro/nano structured hollow silicon as carrier, and combining with vitamin C (in situ antioxidant) to synthesize an oxidation-resistant ferrous foliar fertilizer (ORFFF) for ameliorating Fe-deficiency in crops and increasing crop yield. Compared with TFFF, the ORFFF has excellent ferrous AC (only 11.5% of Fe(II) was oxidized in ORFFF within 72 h), ultrahigh FAE (∼84% of adhesion percentage (%) after two-times simulated rain rinsing), nutrient slow-release ability (720 h gradually release 100.6 mg·g-1), pH-controlled release ability (pH 3-8), and verified high biological safety (100% survival rate for zebrafish and earthworm). The pot experiments showed that ORFFF can correct the Fe-deficiency symptoms of tomato seedlings promptly compared with TFFF, and the FUE of ORFFF is 4.2 times that of TFFF. The specific pH responsiveness of ORFFF can control the slow-release rate of Fe(II) to satisfy the needs of Fe in varying crops and different growing periods of crops. This work provides a feasible way to achieve green and safe Fe supplementation for crops, reduce Fe fertilizer waste, avoid soil pollution caused by Fe fertilizer abuse, and promote the sustainable development of modern nanoagriculture.

The effect of silicon on the antioxidant system of tomato seedlings exposed to individual and combined nitrogen and water deficit

AbstractExploring sustainable strategies for improving crop water and nitrogen use efficiency is essential. Silicon (Si) has been reported as a beneficial metalloid for plants since it alleviates several abiotic stresses (including drought) by triggering the plants' antioxidant system. However, its role in mitigating the negative impact of nitrogen (N) deficit alone or when combined with water (W) deficit is not well studied. This study applied 0 or 2 mM of Na₂SiO3 to 3‐week‐old tomato cv. Micro‐Tom seedlings that were grown under the following conditions: control (CTR; 100%N + 100% Field Capacity), N deficit (N; 50% N + 100% Field Capacity), water deficit (W; 100% N + 50% Field Capacity) or combined stress (N + W; 50% N + 50% Field Capacity). The Si effect on tomato plant growth depended on the type of stress. Si could only alleviate stress caused by N + W deficit resulting in a higher root dry weight (by 28%), total dry weight (by 23%) and root length (by 37%). Alongside this, there was an increase in the antioxidant (AOX) system activity with the root activity of ascorbate peroxidase and catalase enzymes being enhanced by 48% and by 263%, respectively. Si application also enhanced AOX enzyme activity when tomato plants were subjected to individual deficits but to a lesser extent. In conclusion, Si‐treated tomato plants could efficiently modulate their AOX networks in a situation of combined N and water limitation, thus mitigating some of the adverse effects of this combined stress.

Physiological and transcriptomic analyses reveal that phytohormone pathways and glutathione metabolism are involved in the arsenite toxicity response in tomatoes

The main forms of inorganic arsenic (As) in soil are arsenate [As(V)] and arsenite [As(III)]. Both forms inhibit plant growth. Here, we investigate the effects of As(III) toxicity on the growth of tomatoes by integrating physiological and transcriptomic analyses. As(III) toxicity induces oxidative damage, inhibits photosynthetic efficiency, and reduces soluble sugar levels. As(III) toxicity leads to reductions in auxin, cytokinin and jasmonic acid contents by 29 %, 39 % and 55 %, respectively, but leads to increases in the ethylene precursor 1-amino-cyclopropane carboxylic acid, abscisic acid and salicylic acid contents in roots, by 116 %, 79 % and 39 %, respectively, thereby altering phytohormone signalling pathways. The total glutathione, reduced glutathione (GSH) and oxidized glutathione (GSSG) contents are reduced by 59 %, 49 % and 94 % in roots; moreover, a high GSH/GSSG ratio is maintained through increased glutathione reductase activity (increased by 214 %) and decreased glutathione peroxidase activity (decreased by 40 %) in the roots of As(III)-treated tomato seedlings. In addition, As(III) toxicity affects the expression of genes related to the endoplasmic reticulum stress response. The altered expression of aquaporins and ABCC transporters changes the level of As(III) accumulation in plants. A set of hub genes involved in modulating As(III) toxicity responses in tomatoes was identified via a weighted gene coexpression network analysis. Taken together, these results elucidate the physiological and molecular regulatory mechanism underlying As(III) toxicity and provide a theoretical basis for selecting and breeding tomato varieties with low As(III) accumulation. Therefore, these findings are expected to be helpful in improving food safety and to developing sustainable agricultural.

Parallel genetic adaptation of Bacillus subtilis to different plant species.

Plant growth-promoting rhizobacteria benefit plants by stimulating their growth or protecting them against phytopathogens. Rhizobacteria must colonize and persist on plant roots to exert their benefits. However, little is known regarding the processes by which rhizobacteria adapt to different plant species, or behave under alternating host plant regimes. Here, we used experimental evolution and whole-population whole-genome sequencing to analyse how Bacillus subtilis evolves on Arabidopsis thaliana and tomato seedlings, and under an alternating host plant regime, in a static hydroponic setup. We observed parallel evolution across multiple levels of biological organization in all conditions, which was greatest for the two heterogeneous, multi-resource, spatially structured environments at the genetic level. Species-specific adaptation at the genetic level was also observed, possibly caused by the selection stress imposed by different host plants. Furthermore, a trade-off between motility and biofilm development was supported by mutational changes in motility- and biofilm-related genes. Finally, we identified several condition-specific and common targeted genes in different environments by comparing three different B. subtilis biofilm adaptation settings. The results demonstrate a common evolutionary pattern when B. subtilis is adapting to the plant rhizosphere in similar conditions, and reveal differences in genetic mechanisms between different host plants. These findings will likely support strain improvements for sustainable agriculture.

Bacillus methylotrophicus Could Improve the Tolerance and Recovery Ability of the Tomato to Low-Temperature Stress and Improve Fruit Quality

Low-temperature stress seriously affects the growth, development, yield, and quality of tomato production. Bacillus methylotrophicus is an important plant growth promoting rhizobacteria (PGPR). However, the role of B. methylotrophicus under low-temperature stress is poorly understood. Accordingly, the effects of B. methylotrophicus (‘VL-10′) on tomato cold stress (15 °C/8 °C, 12 h/12 h, and day/night) were studied. B. methyltrophicus ‘VL-10′ was added into the substrate at the time of sowing, and the plants were treated at a low temperature for 2 weeks after 40 days of growth. We found that the low temperature reduced the spatial distribution of the aboveground and underground sections of tomatoes and the leaf SPAD and photochemical efficiency of PS II (Fv/Fm). After low-temperature stress, the tomato flowering was delayed, the vitamin C and lycopene content in fruit decreased, and the nitrate content increased. However, inoculated with B. methyltrophicus ‘VL-10′ during sowing promoted the growth of tomato seedlings, enhanced the native defense ability of the tomatoes, and effectively reduced the cold shock response of the roots to cold damage and the adverse effects of low temperature on leaf SPAD and Fv/Fm. After the cultivation at normal temperature, the inoculat B. methyltrophicus ‘VL-10′ could rapidly regain plant growth levers, and eliminate the delay of low temperature on flowering. TOPSIS analysis showed that the nutritional quality of tomatoes could be effectively improved by inoculation with B. methyltrophicus ‘VL-10′ regardless of normal cultivation or low-temperature stress.

Interactions between plant-beneficial microorganisms in a consortium: Streptomyces microflavus and Trichoderma harzianum.

The construction of microbial consortia is challenging due to many variables to be controlled, including the cross-compatibility of the selected strains and their additive or synergistic effects on plants. In this work, we investigated the interactions in vitro, in planta, and at the molecular level of two elite biological control agents (BCAs), that is Streptomyces microflavus strain AtB-42 and Trichoderma harzianum strain M10, to understand their attitude to cooperate in a consortium. In vitro, we observed a strong cross-antagonism between AtB-42 and M10 in agar plates due to diffusible metabolites and volatile organic compounds. In liquid co-cultures, M10 hindered the growth of AtB-42 very likely because of secondary metabolites and strong competition for the nutrients. The interaction in the co-culture induced extensive transcriptional reprogramming in both strains, especially in the pathways related to ribosomes, protein synthesis, and oxidoreductase activity, suggesting that each strain recognized the counterpart and activated its defence responses. The metabolome of both strains was also significantly affected. In contrast, in the soil, M10 growth was partially contrasted by AtB-42. The roots of tomato seedlings inoculated with the consortium appeared smaller than the control and single-strain-inoculated plants, indicating that plants diverted some energy from the development to defence activation, as evidenced by the leaf transcriptome. The consortium induced a stronger transcriptional change compared to the single inoculants, as demonstrated by a higher number of differentially expressed genes. Although the cross-antagonism observed in vitro, the two strains exerted a synergistic effect on tomato seedlings by inducing resistance responses stronger than the single inoculants. Our observations pose a question on the usefulness of the sole in vitro assays for selecting BCAs to construct a consortium. In vivo experiments should be preferred, and transcriptomics may greatly help to elucidate the activity of the BCAs beyond the phenotypic effects on the plant.

Study of Morphological Qualitative and Quantitative Characterization of Different Traits in Tomato (Solanum lycopersicum L.) Genotypes

Tomato is classified as a warm-season crop and is characterized by two distinct plant growth habits: determinate and indeterminate. The flowers of tomatoes are typically bisexual and possess both male and female reproductive structures, making them perfect flowers. The stigma of the flower is surrounded by a protective anther cone, which promotes self-pollination. This self-pollination trait in tomato plants facilitates their maintenance breeding, and simple selection methods can be employed to effectively improve the crop. The current investigation involved the characterization of twenty-five tomato germplasm genotypes. The experimental was carried out during rabi season 2021-2022 and 2022-2023 at Horticulture Research Centre, College of Horticulture, Sardar Vallabhbhai Patel University of Agriculture and Technology, Meerut. Seedlings of tomato were transplanted at spacing of 60 x 45 cm in randomized block design with three replications. Data was collected based on eight qualitative traits, namely, plant growth habit, leaf colour, flower colour, fruit size, fruit shape, fruit colour, fruit surface, and stem end fruit shape. The tomato genotypes demonstrated significant variability in all qualitative traits, with the exception of the fruit surface trait. This highlights the importance of focusing on these traits in future crop improvement programs for tomato.

Study on Some Species of Trichoderma for the Management of Root Knot Nematode (Meloidogyne spp.) in Tomato

Pot experiment was conducted to find out the competence of some commercial product of Trichoderma spp. on the management of root knot nematode in tomato crop. The experiment was conducted in RCBD having seven treatments of six different Trichoderma spp. including one control in three replications. Each treatment had five pots. Twenty five days old seedling of Shrijana hybrid tomato was transplanted and inoculated with 1500 eggs of Meloidogyne spp. in soil after five days of transplanting of tomato seedlings. The spore suspensions of different Trichoderma spp. adjusted to 1 × 106 spores/ml and also inoculated per pot with 30 ml after one week of nematode inoculation. The same concentration and amount of Trichoderma spores solution was again inoculated after one month from the date of first application. Sixty five days after transplanting, all tomato plants were uprooted and the number of galls in root, galling index and fresh root weight were determined based on a 0-10 scale. The result showed that the treatments varied significantly in root knot index and number of galls per root system and fresh root weight per plant. The lowest gall index was observed in T. harzianum - Nemastin (1.6), followed by T. harzianum (T22) - Rootshield Plus (2.37) and T. viride (Ashtha TV) (3.43). Similarly, lowest numbers of galls (9.13) was observed in T. harzianum - Nemastin than all other treatments. There was no significant difference in fresh root weight per plant of tomato among the treatments except T. harzianum and T. harzianum (T22). Significantly highest suppressive effect on the nematode population was achieved by T. harzianum- Nemastin (Rf 0.45), followed by T. harzianum, (T22) (Rf 0.61), and T. viride, (Ashtha TV) (Rf 1.43). Different isolates of T. harzianum suppressed root knot disease of tomato as compare the isolates of T. viride. Hence, T. harzianum - Nemastin can be applied as a biological control agent to reduce the nematode population.