Deciphering the role of nitric oxide in mitigation of systemic fungicide induced growth inhibition and oxidative damage in wheat.

Consento (CON) poses a significant environmental hazard as a systemic fungicide, adversely affecting the health of non-target organisms. Nitric oxide (NO), a signaling molecule, is known to play a crucial role in plant physiology and abiotic stress tolerance. However, whether NO plays any role to enhance fungicide CON tolerance in wheat seedlings is yet unclear. Therefore, we conducted a hydroponic experiment i) to investigate the morpho-physio-biochemical changes of wheat seedlings to fungicide CON stress, and ii) to examine the effects of NO and fungicide CON treatments on oxidative damage, antioxidant system, secondary metabolism and detoxification of systemic fungicide in wheat seedlings. The results showed that CON fungicide at the highest (4X) concentration significantly decreased wheat seedlings fresh weight (46.89%), shoot length (40.26%), root length (56.11%) and total chlorophyll contents (67.44%) in a dose response relationship. Moreover, CON significantly increased hydrogen peroxide, malondialdehyde, catalase, ascorbate peroxidase, glutathione-S-transferase, and peroxidase activities while decreased reduced glutathione (GSH) content. This ultimately impaired the redox homeostasis of cells, leading to oxidative damage in cell membrane. Under fungicide treatment, the addition of NO reduced the fungicide phytotoxicity, with an increase of over 60% in seedling growth. The NO application mitigated CON phytotoxicity as reflected by significantly increased chlorophyll pigments (69.88%) and decreased oxidative damage in wheat leaves. Indeed, the NO alleviatory effect was able to increase the tolerance of seedlings to fungicide, which resulted increments in antioxidant and detoxification enzymes activity, with the enhanced GSH level (78.54%). Interestingly, NO alleviated CON phytotoxicity through the phenylpropanoid pathway by enhancing the activity of secondary metabolism enzymes such as phenylalanine ammonia-lyase (47.28%), polyphenol oxidase (9%), and associated metabolites such as phenolic acids (77.62%), flavonoids (34.33%) in wheat leaves. Our study has provided evidence that NO plays a key role in the metabolism and detoxification of systemic fungicide in wheat through enhanced activity of antioxidants, detoxifications and secondary metabolic enzymes.

Exploring the Potential of Macroalgae for Sustainable Crop Production in Agriculture.

Marine macroalgae, which typically colonize coastal areas, are simple plant organisms. They live on rocks in coastal regions and are classified into red, brown, and green macroalgae. These algae are an important natural resource in agriculture due to their ability to enhance the structural, chemical, and biological properties of soil. Marine macroalgae can be used to produce various biocidal molecules that are effective in controlling plant pathogens. Much of the literature on marine macroalgae and their derivatives focuses primarily on the pharmaceutical field, while their use in agriculture is still considered secondary. However, various studies and experiments have demonstrated their potential to play a significant role in crop protection and enhancement. This review aims to highlight the various applications of macroalgae in plant production. It also emphasizes the biotechnological importance of marine macroalgae derivatives as biofertilizers, molecules for controlling insects and microorganisms, and as plant growth conditioners. Compounds from macroalgae, such as fatty acids, carotenoids, polyphenols, and carbohydrates, are being investigated for their fungicidal, antimicrobial, and antiviral effects against various plant pathogens. Beyond enhancing crop production, macroalgae can also be considered multifunctional bioinoculants suitable for use in organic farming.

Feeding and Growth Response of Fall Armyworm Spodoptera frugiperda (Lepidoptera: Noctuidae) towards Different Host Plants.

The fall armyworm, Spodoptera frugiperda, is a major migratory polyphagous insect pest of various crops. The essential nutrient and mineral profile of the host plants determines the feeding fitness of herbivorous insects. As a result, the growth and development of insects is affected. To determine the effect of the nutrient and mineral profile of different host plants (maize, castor bean, cotton, cabbage, okra, and sugarcane) on the growth and development of S. frugiperda, biological parameters like larval weight, pupal weight (male/female), and feeding and growth indices were calculated. The proximate compositions such as crude protein, crude fat, crude fibre, and ash and mineral contents of the tested host plants showed significant differences (p < 0.05). The feeding indices on these host plants also differed significantly (p < 0.05). The maximum relative growth rate (RGR), relative consumption rate (RCR), and consumption index (CI) were recorded in S. frugiperda larvae that fed on maize and castor bean leaves. The crude protein, dry matter, and ash contents in maize and castor bean were significantly higher and positively correlated with the RGR and RCR of S. frugiperda larvae. The larval, male and female pupal weights were the maximum in the larvae feeding on the castor bean host plant. These findings provide novel information based on nutritional ecology to develop sustainable integrated pest management strategies using selective crop rotation.

Silicon nanoparticles and indole butyric acid positively regulate the growth performance of Freesia refracta by ameliorating oxidative stress under chromium toxicity.

Chromium (Cr) toxicity hampers ornamental crops' growth and post-harvest quality, especially in cut flower plants. Nano-enabled approaches have been developing with phenomenal potential towards improving floricultural crop production under heavy metal-stressed conditions. The current pot experiment aims to explore the ameliorative impact of silicon nanoparticles (Si-NPs; 10 mM) and indole butyric acid (IBA; 20 mM) against Cr stress (0.8 mM) in Freesia refracta. The results showed that Cr stress significantly reduced morphological traits, decreased roots-stems biomass, abridged chlorophyll (14.7%) and carotenoid contents (27.2%), limited gas exchange attributes (intercellular CO2 concentration (Ci) 24.8%, stomatal conductance (gs) 19.3% and photosynthetic rate (A) 28.8%), condensed proline (39.2%) and total protein (40%) contents and reduced vase life (15.3%) of freesia plants by increasing oxidative stress. Contrarily, antioxidant enzyme activities, MDA and H2O2 levels, and Cr concentrations in plant parts were remarkably enhanced in Cr-stressed plants than in the control. However, foliar supplementation of Si-NPs + IBA (combined form) to Cr-stressed plants increased defense mechanism and tolerance as revealed by improved vegetative and reproductive traits, increased biomass, photosynthetic pigments (chlorophyll 30.3%, carotenoid 57.2%) and gaseous exchange attributes (Ci 33.3%, gs 25.6%, A 31.1%), proline (54.5%), total protein (55.1%), and vase life (34.9%) of metal contaminated plants. Similarly, the improvement in the activities of peroxidase, catalase, and superoxide dismutase was recorded by 30.8%, 52.4%, and 60.8%, respectively, compared with Cr-stressed plants. Meanwhile, MDA (54.3%), H2O2 (32.7%) contents, and Cr levels in roots (43.3), in stems (44%), in leaves (52.8%), and in flowers (78.5%), were remarkably reduced due to combine application of Si-NPs + IBA as compared with Cr-stressed nontreated freesia plants. Thus, the hypothesis that the synergistic application of Si-NPs + IBA will be an effective approach in ameliorating Cr stress is authenticated from the results of this experiment. Furthermore, the study will be significant since it will demonstrate how Si-NPs and IBA can work synergistically to combat Cr toxicity, and even when added separately, they can improve growth characteristics both under stressed and un-stressed conditions.

Integrated use of phosphorus fertilizer and farmyard manure improves wheat productivity by improving soil quality and P availability in calcareous soil under subhumid conditions.

Introduction: Low soil fertility and high fertilizer costs are constraints to wheat production, which may be resolved with integrating fertilizer phosphorus (P) and farm-yard manure (FYM). Study objectives were to evaluate P source impacts on soil, P efficiency, and wheat growth in a calcareous soil. Methods: Treatments included P fertilizer (0, 17, 26, or 39 kg P ha-1) and/or FYM (0 or 10 T ha-1) in a: 1) incubation experiment and 2) wheat (Triticum aestivum spp.) field experiment. Results and Discussion: Soil organic matter increased (30-72%) linearly for both fertilizer and FYM, whereas pH decreased (0.1-0.3 units) with fertilizer only. Addition of fertilizer and FYM increased plant available P (AB-DTPA extractable soil P) an average of 0.5 mg P kg-1 soil week-1 with incubation. The initial increase was 1-9 mg P kg-1, with further increase after 84 d of ~3-17 mg P kg-1. There was also a significant increase of available P in the soil supporting plants in the field study, although the magnitude of the increase was only 2 mg kg-1 at most for the highest fertilizer rate + FYM. Grain (66 to 119%) and straw (25-65%) yield increased significantly, peaking at 26 kg P ha-1 + FYM. The P Absorption Efficiency (PAE), P Balance (PB), and P Uptake (PU) increased linearly with P rate, with the highest levels at the highest P rate. The P Use Efficiency (PUE) was highest at the lowest rates of P, with general decreases with increasing P, although not consistently. Principal component analysis revealed that 94.34 % of the total variance was accounted for with PC1 (84.04 %) and PC2 (10.33 %), with grain straw yield significantly correlated to SOM, PU, and PAE. Regression analysis showed highly significant correlation of PB with P-input (R2= 0.99), plant available P (R2= 0.85), and PU (R2= 0.80). The combination of FYM at the rate of 10 T ha-1 and fertilizer P at 26 kg P ha-1 was found as the optimum dose that significantly increased yield. It is concluded that FYM concoction with fertilizer-P not only improved SOM and residual soil P, but also enhanced wheat yields with reasonable P efficiency.

Characterization of Invasiveness, Thermotolerance and Light Requirement of Nine Invasive Species in China.

Understanding responsible functional traits for promoting plant invasiveness could be important to aid in the development of adequate management strategies for invasive species. Seed traits play an important role in the plant life cycle by affecting dispersal ability, formation of the soil seed bank, type and level of dormancy, germination, survival and/or competitive ability. We assessed seed traits and germination strategies of nine invasive species under five temperature regimes and light/dark treatments. Our results showed a considerable level of interspecific variation in germination percentage among the tested species. Both cooler (5/10 °C) and warmer (35/40 °C) temperatures tended to inhibit germination. All study species were considered small-seeded, and seed size did not affect germination in the light. Yet, a slightly negative correlation was found between germination in the dark and seed dimensions. We classified the species into three categories according to their germination strategies: (i) risk-avoiders, mostly displaying dormant seeds with low G%; (ii) risk-takers, reaching a high G% in a broad range of temperatures; (iii) intermediate species, showing moderate G% values, which could be enhanced in specific temperature regimes. Variability in germination requirements could be important to explain species coexistence and invasion ability of plants to colonize different ecosystems.

Storage on Maternal Plants Affects Temperature Requirements during Germination in Rumex obtusifolius.

Aerial seed banks facilitate population persistence by extending the temporal range of seed dispersal. Knowing the temporal range of germination will improve our understanding of the relationship between seed germination dynamics and aerial seed bank storage duration. We tested the effects of temperature (12/12 h of 5/10, 10/20, 20/30 and 25/35 °C) and light variation (12 h light/12 h darkness and 24 h darkness per day) on germination of Rumex obtusifolius L. seeds retained in an aerial seed bank for 0, 2, 4, 6, 8 and 10 months. Freshly harvested R. obtusifolius were non-dormant and exhibited germination rates of up to 92%. Overall, seeds of R. obtusifolius germinated reliably at all but the lowest temperature (5/10 °C). Seeds maintained high viability throughout the collection period, indicating that fluctuating weather conditions had little influence on seed germination. Thus, the species can maintain viable seeds in aerial storage for up to 10 months and contribute viable seeds to the soil seed bank year-round. This ability to maintain a renewed soil seed bank contributes to the species' strong resilience in colonizing disturbed areas and makes it a difficult weed to control.

Managing Weed-Crop Interactions Enhances Chickpea (Cicer arietinum L.) Chemical Components.

Chickpea (Cicer arietinum L.) is a major pulse crop worldwide, renowned for its nutritional richness and adaptability. Weeds are the main biotic factor deteriorating chickpea yield and nutritional quality, especially Asphodelus tenuifolius Cav. The present study concerns a two-year (2018-19 and 2019-20) field trial aiming at evaluating the effect of weed management on chickpea grain quality. Several weed management practices have been here implemented under a factorial randomized complete block design, including the application of four herbicides [bromoxynil (C7H3Br2NO) + MCPA (Methyl-chlorophenoxyacetic acid) (C9H9ClO3), fluroxypyr + MCPA, fenoxaprop-p-ethyl (C18H16ClNO5), pendimethalin (C13H19N3O4)], the extracts from two allelopathic weeds (Sorghum halepense and Cyperus rotundus), two mulches (wheat straw and eucalyptus leaves), a combination of A. tenuifolius extract and pendimethalin, and an untreated check (control). Chickpea grain quality was measured in terms of nitrogen, crude protein, crude fat, ash, and oil content. The herbicides pendimethalin (Stomp 330 EC (emulsifiable concentrate) in pre-emergence at a rate of 2.5 L ha-1) and fenoxaprop-p-ethyl (Puma Super 7.5 EW (emulsion in water) in post-emergence at a rate of 1.0 L ha-1), thanks to A. tenuifolius control, showed outstanding performance, providing the highest dietary quality of chickpea grain. The herbicides Stomp 330 EC, Buctril Super 40 EC, Starane-M 50 EC, and Puma Super 7.5 EW provided the highest levels of nitrogen. Outstanding increases in crude protein content were observed with all management strategies, particularly with Stomp 330 EC and Puma Super 7.5 EW (+18% on average). Ash content was highly elevated by Stomp 330 EC and Puma Super 7.5 EW, along with wheat straw mulching, reaching levels of 2.96% and 2.94%. Crude fat content experienced consistent elevations across all treatments, with the highest improvements achieved by Stomp 330 EC, Puma Super 7.5 EW, and wheat straw mulching applications. While 2018-19 displayed no significant oil content variations, 2019-20 revealed the highest oil content (5.97% and 5.96%) with herbicides Stomp 330 EC and Puma Super 7.5 EW, respectively, followed by eucalyptus leaves mulching (5.82%). The results here obtained are of key importance in the agricultural and food sector for the sustainable enhancement of chickpea grain's nutritional quality without impacting the environment.

The Green Synthesis of Silver Nanoparticles from Avena fatua Extract: Antifungal Activity against Fusarium oxysporum f.sp. lycopersici.

Using plant extracts as eco-friendly reducing and stabilizing agents for the synthesis of nanoparticles has gained significant attention in recent years. The current study explores the green synthesis of silver nanoparticles (AgNPs) using the Avena fatua extract and evaluates their antifungal activity against Fusarium oxysporum f.sp. lycopersici (Fol), a fungal plant pathogen. A green and sustainable approach was adopted to synthesize silver nanoparticles before these nanoparticles were employed for anti-fungal activity. The primary indication that AgNPs had formed was performed using UV-vis spectroscopy, where a strong peak at 425 nm indicated the effective formation of these nanoparticles. The indication of important functional groups acting as reducing and stabilizing agents was conducted using the FTIR study. Additionally, morphological studies were executed via SEM and AFM, which assisted with more effectively analyzing AgNPs. Crystalline behavior and size were estimated using powder XRD, and it was found that AgNPs were highly crystalline, and their size ranged from 5 to 25 nm. Synthesized AgNPs exhibited significant antifungal activity against Fol at a concentration of 40 ppm. Furthermore, the inhibitory index confirmed a positive correlation between increasing AgNPs concentration and exposure duration. This study suggests that the combined phytochemical mycotoxic effect of the plant extract and the smaller size of synthesized AgNPs were responsible for the highest penetrating power to inhibit Fol growth. Moreover, this study highlights the potential of using plant extracts as reducing and capping agents for the green synthesis of AgNPs with antifungal properties. The study concludes that A. fatua extract can synthesize antifungal AgNPs as a sustainable approach with robust antifungal efficacy against Fol, underscoring their promising potential for integration into plant protection strategies.

Influence of Bacterial Secondary Symbionts in Sitobion avenae on Its Survival Fitness against Entomopathogenic Fungi, Beauveria bassiana and Metarhizium brunneum.

The research was focused on the ability of wheat aphids Sitobion avenae, harboring bacterial secondary symbionts (BSS) Hamiltonella defensa or Regiella insecticola, to withstand exposure to fungal isolates of Beauveria bassiana and Metarhizium brunneum. In comparison to aphids lacking bacterial secondary symbionts, BSS considerably increased the lifespan of wheat aphids exposed to B. bassiana strains (Bb1022, EABb04/01-Tip) and M. brunneum strains (ART 2825 and BIPESCO 5) and also reduced the aphids' mortality. The wheat aphid clones lacking bacterial secondary symbionts were shown to be particularly vulnerable to M. brunneum strain BIPESCO 5. As opposed to wheat aphids carrying bacterial symbionts, fungal pathogens infected the wheat aphids lacking H. defensa and R. insecticola more quickly. When treated with fungal pathogens, bacterial endosymbionts had a favorable effect on the fecundity of their host aphids compared to the aphids lacking these symbionts, but there was no change in fungal sporulation on the deceased aphids. By defending their insect hosts against natural enemies, BSS increase the population of their host society and may have a significant impact on the development of their hosts.

Pyramiding of Four Broad Spectrum Bacterial Blight Resistance Genes in Cross Breeds of Basmati Rice.

Pyramiding of major resistance (R) genes through marker-assisted selection (MAS) is a useful way to attain durable and broad-spectrum resistance against Xanthomonas oryzae pv. oryzae pathogen, the causal agent of bacterial blight (BB) disease in rice (Oryza sativa L.). The present study was designed to pyramid four broad spectrum BB-R genes (Xa4, xa5, xa13 and Xa21) in the background of Basmati-385, an indica rice cultivar with much sought-after qualitative and quantitative grain traits. The cultivar, however, is susceptible to BB and was therefore, crossed with IRBB59 which possesses R genes xa5, xa13 and Xa21, to attain broad and durable resistance. A total of 19 F1 plants were obtained, some of which were backcrossed with Basmati-385 and large number of BC1F1 plants were obtained. In BC1F2 generation, 31 phenotypically superior genotypes having morphological features of Basmati-385, were selected and advanced up to BC1F6 population. Sequence-tagged site (STS)-based MAS was carried out and phenotypic selection was made in each successive generation. In BC1F6 population, potentially homozygous recombinant inbred lines (RILs) from each line were selected and evaluated on the bases of STS evaluation and resistance to local Xanthomonas oryzae pv. oryzae (Xoo) isolates. Line 23 was found pyramided with all four BB-R genes i.e., Xa4, xa5, xa13 and Xa21. Five genotypes including line 8, line 16, line 21, line 27 and line 28 were identified as pyramided with three R genes, Xa4, xa5 and xa13. Pathological study showed that rice lines pyramided with quadruplet or triplet R genes showed the highest level of resistance compared to doublet or singlet R genes. Thus, line 23 with quadruplet, and lines 8, 16, 21, 27, and 28 with triplet R genes, are recommended for replicated yield and resistance trials before release as new rice varieties. Further, traditional breeding coupled with MAS, is a solid way to attain highly effective BB-resistant rice lines with no yield cost.