Biotic Stresses Research Articles

Titanium Dioxide Nanoparticle: A Comprehensive Review on Synthesis, Applications and Toxicity

Nanotechnology has garnered significant interest worldwide due to its wide-ranging applications across various industries. Titanium dioxide nanoparticles are one type of nanoparticle that is commonly utilised in everyday use and can be synthesized by different techniques using physical, chemical and biological extracts. Green synthesis is an economical, environmentally benign and non-toxic method of synthesising nanoparticles. Titanium dioxide nanoparticles have a positive impact on plant physiology, particularly in response to biotic and abiotic stresses, depending on various factors like size, concentration, exposure of the nanoparticles and other variables. Further, titanium dioxide nanoparticles have many applications, such as being used as nano-fertilizers, adsorption of heavy metal from industrial wastewater and antimicrobial activity, as discussed in this review paper. Previous studies investigated whether titanium dioxide nanoparticles also induce genotoxicity may be due to mishandling procedure, exposure time, size, concentration and other variables. This is still contradictory and requires more research. The present review is a pragmatic approach to summarize the synthesis, application, nanotoxicity, genotoxicity and eco-friendly method of nanoparticle synthesis and disposable.

Citrus bliss: potassium, sodium, and calcium silicates secrets for post-harvest diseases of fruit defense

Biotic stress significantly challenges the global citrus industry. Major post-harvest issues include diseases caused by Penicillium digitatum, Penicillium italicum, Geotrichum citri-aurantii, Alternaria alternata, and Phytophthora citrophthora. The negative impact of chemical fungicides on the environment and health necessitates eco-friendly alternatives. This study examines the effectiveness of sodium, potassium, and calcium silicates against common citrus diseases. In vitro tests evaluated mycelial growth inhibition using silicate concentrations from 0 to 10,000 ppm after 7 days at 25°C. Sodium silicate showed the highest efficacy, completely inhibiting P. digitatum and P. italicum at 2000 ppm. Potassium and calcium silicates achieved 100% inhibition against Penicillium spp. at a concentration of 1%. In vivo tests on Sidi Aissa clementines assessed the preventive and curative effects of 1, 2, and 6% silicate salt solutions. Sodium silicate prevented 41% of brown rot, 72% of sour rot, and 100% of green mold at 6%. Calcium silicate at 6% significantly reduced blue mold and black rot by 32% and 74%, respectively. Sodium silicate was most effective in curative treatments, suggesting its potential as a pre- or post-harvest spray to control P. digitatum, P. italicum, and G. citri-aurantii.

Interspecific hybridization and cell engineering of lettuce (Lactuca L.)

Lactuca sativa L. is a leafy vegetable crop of the Asteraceae family, widely cultivated throughout the world. The main breeding trends for lettuce include higher yields, better taste quality, earliness, and resistance to abiotic and biotic stressors. Some wild Lactuca spp. have actively been employed by lettuce breeders as donors of resistance to various diseases. Conventional and biotechnological breeding methods are both currently used to develop new lettuce cultivars. This is an overview of the main advances in the production of interspecific Lactuca hybrids, including the use of cell and tissue culture techniques, and genetic engineering. Studying artificial hybridization and natural populations makes it possible to identify evolutionary relationships among various Lactuca spp. Somatic hybridization is an overlooked but promising technology in Lactuca breeding: it allows a breeder to obtain a wider range of variations, and is beyond the strict control by GMO laws. This technique faces problems associated with complicated protoplast regeneration and the loss of reproductive ability in hybrids. Genome-editing methods are more effective and better controllable, but society is still wary of any interference with the plant genome and legally regulates the sale of GM products as food. Thus, researchers are challenged with the task to improve these techniques.

Potato β-aminobutyric acid receptor IBI1 manipulates VOZ1 and VOZ2 transcription factor activity to promote disease resistance.

Upon infection with non-pathogenic microorganisms or treatment with natural or synthetic compounds, plants exhibit a more rapid and potent response to both biotic and abiotic stresses. However, the molecular mechanisms behind this phenomenon, known as defense priming, are poorly understood. β-aminobutyric acid (BABA) is an endogenous stress metabolite that enhances plant tolerance to various abiotic stresses and primes plant defense responses, providing the ability to resist a variety of pathogens (broad-spectrum resistance). In this study, we identified an aspartyl-tRNA synthetase (AspRS), StIBI1 (named after Arabidopsis IMPAIRED IN BABA-INDUCED IMMUNITY 1; IBI1), as a BABA receptor in Solanum tuberosum. We elucidated the regulatory mechanisms by which StIBI1 interacts with two NAC (NAM, ATAF1, 2, and CUC2) transcription factors (TFs), StVOZ1 and StVOZ2 (VASCULAR PLANT ONE ZINC FINGER, VOZ), to activate BABA-induced resistance (BABA-IR). StVOZ1 represses, whereas StVOZ2 promotes, immunity to the late blight pathogen Phytophthora infestans. Interestingly, BABA and StIBI1 influence StVOZ1- and StVOZ2-mediated immunity. StIBI1 interacts with StVOZ1 and StVOZ2 in the cytoplasm, reducing the nuclear accumulation of StVOZ1 and promoting the nuclear accumulation of StVOZ2. Our findings indicate that StVOZ1 and StVOZ2 finely regulate potato resistance to late blight through distinct signaling pathways. In summary, our study provides insights into the interaction between the potato BABA receptor StIBI1 and the TFs StVOZ1 and StVOZ2, which affects StVOZ1 and StVOZ2stability and nuclear accumulation to regulate late blight resistance during BABA-IR. This research advances our understanding of the primary mechanisms of BABA-IR in potato and contributes to a theoretical basis for the prevention and control of potato late blight using BABA-IR.

Isolation and characterization of salt-stress-tolerant rhizosphere soil bacteria and their effects on plant growth-promoting properties

PGPR has a higher potential impact on agricultural crops. It enhances plant growth and development in a variety of adverse environmental conditions, including biotic and abiotic stresses. The PGPR is commercially vital since it is more efficient, safe for the environment, and beneficial to the economy. Nowadays, salt stress has an impact on the agricultural ecosystem. Salt-tolerant PGPR can directly stimulate plant growth and development by producing a variety of metabolites and phytohormones. The current study looked at the isolation of salt-tolerant bacterial species and their ability to stimulate plant development. Four bacterial species were chosen for their better salt stress tolerance (0–5%). They were identified by 16S rRNA sequencing: Solibacillus silvestris BR1, Peribacillus frigoritolerans BR2, Paenibacillus taichungensis CR1, and Solibacillus isronensis CR2. These strains were positive production of indole acetic acid with varying incubation periods (19.66 ± 1.528 to 646.111 ± 8.058 µg/mL), salt stress (ranging from 29.556 ± 1.171 to 147.8111 ± 2.086 µg/mL), phosphate solubilization (0.145 ± 0.011 to 0.921 ± 0.007 µg/mL), ammonium production (0.299 ± 0.047 to 1.202 ± 0.142 µg/mL), HCN production (0.308 ± 0.051 to 4.269 ± 0.069 µg/mL), and siderophore production (0.190 ± 0.064 to 1.543 ± 0.108 µg/mL) for control strains were used without salt stress. The production level was expressed using a standard curve containing various standards.

Genome-Wide Identification and Expression Analysis of the Melon Aldehyde Dehydrogenase (ALDH) Gene Family in Response to Abiotic and Biotic Stresses

Through the integration of genomic information, transcriptome sequencing data, and bioinformatics methods, we conducted a comprehensive identification of the ALDH gene family in melon. We explored the impact of this gene family on melon growth, development, and their expression patterns in various tissues and under different stress conditions. Our study discovered a total of 17 ALDH genes spread across chromosomes 1, 2, 3, 4, 5, 7, 8, 11, and 12 in the melon genome. Through a phylogenetic analysis, these genes were classified into 10 distinct subfamilies. Notably, genes within the same subfamily exhibited consistent gene structures and conserved motifs. Our study discovered a pair of fragmental duplications within the melon ALDH gene. Furthermore, there was a noticeable collinearity relationship between the melon’s ALDH gene and that of Arabidopsis (12 times), and rice (3 times). Transcriptome data reanalysis revealed that some ALDH genes consistently expressed highly across all tissues and developmental stages, while others were tissue- or stage-specific. We analyzed the ALDH gene’s expression patterns under six stress types, namely salt, cold, waterlogged, powdery mildew, Fusarium wilt, and gummy stem blight. The results showed differential expression of CmALDH2C4 and CmALDH11A3 under all stress conditions, signifying their crucial roles in melon growth and stress response. RT-qPCR (quantitative reverse transcription PCR) analysis further corroborated these findings. This study paves the way for future genetic improvements in melon molecular breeding.

Differential regulation of glucosinolate-myrosinase mediated defense determines host-aphid interaction in Indian mustard Brassica juncea L.

India's oilseed economy falls short of self-sufficiency and is supplemented by huge imports every year. Increasing national productivity of the major oilseeds is confronted with yield losses due to diverse biotic and abiotic stresses. The productivity of Indian mustard (Brassica juncea Linnaeus), belonging to the family Brassicaceae, is significantly reduced due to damage caused by mustard aphids (Lipaphis erysimi Kaltenbach, Hemiptera: Aphididae). Rapid colonization by the nymphs makes it difficult to protect the crop through agrochemicals. Aphids release effector molecules to modulate the host-defence responses. Glucosinolates (GSLs) extensively found in Brassicaceae family, are hydrolysed by myrosinase into toxic compounds that deter herbivore insects. Here, we investigated the differential activation of the glucosinolate-myrosinase pathway in mustard manifesting susceptibility and resistance to different aphid species. Mustard plants were challenged by two different aphid species mustard aphid and cowpea aphid (Aphis craccivora Koch, Hemiptera: Aphididae) leading to complete host-susceptibility in one case and resistance in the other, respectively. Differential regulation of the GSL biosynthetic pathway and myrosinase activity was assessed by gene expression study and ultra-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry (UPLC- QToF-ESL-MS). Gene expression study identified selective transcriptional attenuation of the key GSL biosynthetic and myrosinase gene in mustard when challenged with mustard aphid. In contrary, the activation of GSL biosynthetic genes in conjunction with myrosinase at the transcriptional level was profound in mustard, when challenged with cowpea aphid. UPLC-MS analysis showed higher turnover in the hydrolysis of glucosinolates by myrosinase which led to concomitant generation of glucose as byproduct in response to cowpea aphid in mustard plants. GSL-myrosinase pathway is specifically attenuated by the successful aphid species in mustard and thus plays a pivotal role in determining the outcome of the B. juncea-aphid interaction. The results open up a new genetic modification strategy for developing resistance against aphids.

Transcriptomic Analysis of the Combined Effects of Methyl Jasmonate and Wounding on Flavonoid and Anthraquinone Biosynthesis in Senna tora.

Jasmonates, including jasmonic acid (JA) and its derivatives such as methyl jasmonate (MeJA) or jasmonly isoleucine (JA-Ile), regulate plant responses to various biotic and abiotic stresses. In this study, we applied exogenous MeJA onto Senna tora leaves subjected to wounding and conducted a transcriptome deep sequencing analysis at 1 (T1), 3 (T3), 6 (T6), and 24 (T24) h after MeJA induction, along with the pretreatment control at 0 h (T0). Out of 18,883 mapped genes, we identified 10,048 differentially expressed genes (DEGs) between the T0 time point and at least one of the four treatment times. We detected the most DEGs at T3, followed by T6, T1, and T24. We observed the upregulation of genes related to JA biosynthesis upon exogenous MeJA application. Similarly, transcript levels of genes related to flavonoid biosynthesis increased after MeJA application and tended to reach their maximum at T6. In agreement, the flavonols kaempferol and quercetin reached their highest accumulation at T24, whereas the levels of the anthraquinones aloe-emodin, emodin, and citreorosein remained constant until T24. This study highlights an increase in flavonoid biosynthesis following both MeJA application and mechanical wounding, whereas no significant influence is observed on anthraquinone biosynthesis. These results provide insights into the distinct regulatory pathways of flavonoid and anthraquinone biosynthesis in response to MeJA and mechanical wounding.

Combining Ability and Gene Action for Grain Yield and Attributing Traits in Maize (Zea mays L.) Subjected to Drought Stress

Background: Maize production is subdued by many impediments that cause yield minimization. Among various biotic and abiotic stress factors, one significant cause of yield reduction in maize is drought stress. Methods: A set of 15 inbreds which were crossed with 3 narrow base testers in line × tester mating design, and resulting 45 F1s along with the parent inbreds and 3 commercial checks were then, in RCBD, subjected to drought stressed and well-watered conditions to assess their genetic worth during spring 2021. Result: The ANOVA unraveled significant mean sum of squares due to lines, testers and line × tester in pooled analysis for all the ten traits. The inbred EI-2188-2 followed by EI-2448 and EI-03-3 contained fair per se performance and significant high GCA effects over the environments for grain yield/plant, proline content and cob length whereas the cross EI-2448-1 × EI-2156 was found most promising hybrid with significant and high SCA effects across the environments regarding grain yield/plant, proline content and cob girth. Prevalence of non-additive type of genetic variance in governing most of the traits suggests adoption of heterosis breeding will be rewarding for improving yield and drought tolerance. Heterotic pooling of the highlighted inbreds and utilization of the superlative hybrids in further breeding programmes for drought tolerance is proposed.

Jasmonate-mediated polyamine oxidase 6 drives herbivore-induced polyamine catabolism in rice.

Polyamines (PAs) along with their conjugated forms, are important mediators of plant defense mechanisms against both biotic and abiotic stresses. Flavin-containing polyamine oxidases (PAOs) regulate PA levels through terminal oxidation. To date, the role of PAOs in plant-herbivore interaction remains poorly understood. We discovered that infestation by the brown planthopper (BPH) disrupts PA homeostasis within the leaf sheaths of rice plants, which co-occurs with the upregulation of OsPAO6, a tissue-specific inducible, apoplast-localized enzyme that regulates the terminal catabolism of spermidine (Spd) and spermine. Functional analysis using CRISPR-Cas9 genome-edited plants revealed that pao6 mutants accumulated significantly higher levels of Spd and phenylpropanoid-conjugated Spd in response to BPH infestation compared to wild-type controls. In addition, BPH feeding on pao6 mutants led to increased honeydew excretion and plant damage by female adults, consistent with in vitro experiments in which Spd enhanced BPH feeding. Furthermore, OsPAO6 transcription is regulated by jasmonate (JA) signaling, and it is dependent on MYC2, which directly binds to the G-box-like motif in the OsPAO6 promoter. Our findings reveal an important role of OsPAO6 in regulating polyamine catabolism in JA-induced responses triggered by herbivore attacks in rice.

Exploring CDF gene family in wild potato under salinity stress unveils promising candidates for developing climate-resilient crops

The DNA-binding with one finger (Dof) gene family is a class of plant-specific transcription factors involved in diverse biological processes, including response to biotic and abiotic stresses. Members of this family have been reported in the cultivated potato Solanum tuberosum, but clues to the roles of several Dof genes are still lacking. Potato wild relatives represent a genetic reservoir for breeding as they could provide useful alleles for adaptation to the environment and tolerance to biotic and abiotic stresses. We performed an in silico analysis to identify genes belonging to the Dof family in the wild potato S. commersonii, confirming that the identified Dof genes can be grouped in four classes (A, B, C, D), as reported for cultivated potato. A special focus was dedicated to Cycling Dof Factors (CDFs), which play a crucial role in plant responses to abiotic stresses. Analysis of available RNA-seq data confirmed CDF genes as regulated by stresses and often in a tissue specific manner. To ascertain their involvement in the stress response, S. tuberosum and S. commersonii plantlets growing in vitro were subjected to salt stress (80mM NaCl) for short (2 days) and prolonged (7 days) times. Analysis of phenotypic traits and qRT-PCR expression profiles of target CDF genes in aerial and root tissues showed differences between the two species. In addition, after saline treatment, changes in total phenols, proline, and malondialdehyde suggested a diverse perception of saline stress in S. commersonii vs. S. tuberosum. Overall, this study provided useful clues to the involvement of CDF genes in salt response and promoted the identification of potential candidate genes for further functional studies.

Integrated stress responses in okra plants (cv. ‘’Meya’]: unravelling the mechanisms underlying drought and nematode co-occurrence

BackgroundClimate change threatens sub-Saharan Africa’s agricultural production, causing abiotic and biotic stressors. The study of plant responses to joint stressors is crucial for understanding molecular processes and identifying resilient crops for global food security. This study aimed to explore the shared and tailored responses of okra plants (cv. ‘’Meya’), at the biochemical and molecular levels, subjected to combined stresses of drought and Meloidogyne incognita infection.DesignThe study involved 240 okra plants in a completely randomized design, with six treatments replicated 20 times. Okra plants were adequately irrigated at the end of every 10-days water deficit that lasted for 66 days (D). Also, the plants were infected with M. incognita for 66 days and irrigated at 2-days intervals (R). The stresses were done independently, in sequential combination (D before R and R before D) and concurrently (R and D). All biochemical and antioxidant enzyme assays were carried out following standard procedures.ResultsSignificant reductions in leaf relative water content were recorded in all stressed plants, especially in leaves of plants under individual drought stress (D) (41.6%) and plants stressed with root-knot nematode infection before drought stress (RBD) (41.4%). Malondialdehyde contents in leaf tissues from plants in D, nematode-only stress (RKN), drought stress before root-knot nematode infection (DBR), RBD, and concurrent drought-nematode stress (RAD) significantly increased by 320.2%, 152.9%, 186.5%, 283.7%, and 109.6%, respectively. Plants in D exhibited the highest superoxide dismutase activities in leaf (147.1% increase) and root (105.8% increase) tissues. Catalase (CAT) activities were significantly increased only in leaves of plants in D (90.8%) and RBD (88.9%), while only roots of plants in D exhibited a substantially higher CAT activity (139.3% increase) in comparison to controlled plants. Okra plants over-expressed NCED3 and under-expressed Me3 genes in leaf tissues. The NCED3 gene was overexpressed in roots from all treatments, while CYP707A3 was under-expressed only in roots of plants in RBD and RKN. CYP707A3 and NCED3 were grouped as closely related genes, while members of the Me3 genes were clustered into a separate group.ConclusionThe biochemical and molecular responses observed in okra plants (cv. ‘’Meya’) subjected to combined stresses of drought and Meloidogyne incognita infection provide valuable insights into enhancing crop resilience under multifaceted stress conditions, particularly relevant for agricultural practices in sub-Saharan Africa facing increasing climatic challenges.

Mean Performance and Heterotic Pattern of Maize (Zea mays L.) Inbred Lines Adapted to Sub-humid Central Highland of Ethiopia

In spite of abiotic and biotic stresses and low availability of high-yielding cultivars restrict potential production of maize, it is a major food crop in Africa. To overcome this production barrier, promising germplasm must be chosen, combining ability must be understood, and heterotic groups must be formed in order to generate high-yielding maize varieties. The study set out to evaluate plant height, ear height, ear diameter, thousand seed weight, kernel per row, kernel row per ear, and number of ear per plant in order to assess the performance evaluation and heterotic pattern of inbred lines. In 2019, twenty-six inbred lines and two single cross testers were crossed using a line by tester mating design to create fifty-two three way cross F1 hybrids. The experiment, which used an alpha lattice design with two replications, was conducted at the Ambo and Kulumsa Agricultural Research Centers during the 2020 cropping season. Analyses of variance revealed that among the parameters with significant mean squares arising from crosses and lines both within and across locations were grain yield, anthesis date, silking date, plant height, ear height, kernel row per ear, and number of ears per plant. Because of the lines, testers, and crossings for grain yield, anthesis date, silking date, plant height, ear height, kernel row per ear, and number of ear per plant, the line x tester ANOVA results revealed significant mean squares. Due to line x site, line x tester, tester x site, and line x tester x site, there was a noticeable difference in plant height, ear height, and the number of ears per plant. This proved that different environment have different selection criteria for materials and different performance levels. This genetic study Categorized, L1, L22, and L24 under heterotic group A (CEL08008/CEL08047), while L8, L10, L14, L17, L20, and L26 were placed under heterotic group-B (CEL08024/CML561).

WRKY Transcription Factors (TFs) as Key Regulators of Plant Resilience to Environmental Stresses: Current Perspective

Plants encounter various stresses in their natural environments and can effectively respond to only one stress at a time. Through a complex gene network, transcription factors (TFs) such as WRKY TFs regulate a diverse array of stress responses. The clarification of the structural characteristics of WRKY proteins, along with recent advancements in molecular dynamics simulations, has shed light on the formation, stability, and interactions of DNA–protein complexes. This has provided a novel viewpoint regarding the control of WRKY TFs. The investigation of superfamilies, encompassing their historical development, diversity, and evolutionary patterns, has become feasible due to the transcriptome approach’s capacity to provide extensive and comprehensive transcripts. The significance of WRKY TFs lies in their pivotal role within several signaling cascades and regulatory networks that influence plant defense responses. The present review summarizes the functional aspects of the high-volume sequence data of WRKY TFs from different species studied to date. Moreover, a comparative analysis approach was utilized to determine the functions of the identified WRKY TFs in response to both abiotic and biotic stresses, as revealed through numerous studies on different plant species. The results of this review will be pivotal in understanding evolutionary events and the significance of WRKY TFs in the context of climate change, incorporating new scientific evidence to propose an innovative viewpoint.

Genome-Wide Identification of MKK Gene Family and Response to Hormone and Abiotic Stress in Rice.

Mitogen-activated protein kinase (MAPK/MPK) cascades are pivotal and highly conserved signaling modules widely distributed in eukaryotes; they play essential roles in plant growth and development, as well as biotic and abiotic stress responses. With the development of sequencing technology, the complete genome assembly of rice without gaps, T2T (Telomere-to-Telomere)-NIP (version AGIS-1.0), has recently been released. In this study, we used bioinformatic approaches to identify and analyze the rice MPK kinases (MKKs) based on the complete genome. A total of seven OsMKKs were identified, and their physical and chemical properties, chromosome localization, gene structure, subcellular localization, phylogeny, family evolution, and cis-acting elements were evaluated. OsMKKs can be divided into four subgroups based on phylogenetic relationships, and the family members located in the same evolutionary branch have relatively similar gene structures and conserved domains. Quantitative real-time PCR (qRT-PCR) revealed that all OsMKKs were highly expressed in rice seedling leaves. The expression levels of all OsMKKs were more or less altered under exogenous hormone and abiotic stress treatments, with OsMKK1, OsMKK6, and OsMKK3 being induced under almost all treatments, while the expression of OsMKK4 and OsMKK10-2 was repressed under salt and drought treatments and IAA treatment, respectively. In this study, we also summarized the recent progress in rice MPK cascades, highlighted their diverse functions, and outlined the potential MPK signaling network, facilitating further studies on OsMKK genes and rice MPK cascades.

Metallothionein family genes in kiwifruit: characterization and determining their roles in plant’s response to different stresses

Kiwifruit growth and development are severely affected by various biotic and abiotic stresses, especially cold stress and the bacterial disease caused by Pseudomonas syringae pv. actinidiae (Psa). Metallothioneins (MTs) are a group of cysteine-rich proteins that play crucial roles in stress response, metal detoxification, and homeostasis in plants. However, the protective role of these MTs in kiwifruit remains to be elucidated. In the present study, four AcMT genes were identified in the Hongyang kiwifruit genome, namely, two Type 2 isoforms (AcMT2 and AcMT2a) and two Type 3 isoforms (AcMT3a and AcMT3b) located separately on four different chromosomes. The hormones and stress response cis-elements within the promoter regions of these AcMTs were characterized. It was revealed that the four AcMT genes exhibited different expression patterns in different tissues: AcMT2 and AcMT2a were expressed at much higher levels in the fruit, male flower, female flower, root, and bark, while AcMT3a was expressed mainly in the fruit and AcMT3b was expressed highly in the bark. The expression patterns of these AcMT genes after exposure to Psa infection and different phytohormones, including gibberellic acid A3(GA3), ethylene (ET), and abscisic acid (ABA), were evaluated. It was revealed that in response to Psa infection, the main AcMTs in each tissue (those with expression levels higher compared to the other MTs in that tissue) were downregulated during the early stage in kiwifruits, followed by a recovery phase. In addition, most AcMTs were downregulated after exposure to ET and GA3, while type 2 AcMTs (AcMT2 and AcMT2a) were upregulated after treatment with ABA. The overexpression of AcMTs in Escherichia coli presented a higher tolerance to H2O2, heavy metals, low temperature, and high temperature. Collectively, these findings demonstrated the protective roles of AcMTs in terms of stress resistance conferred through plant hormone-related signal pathways.

Nano-enhanced storage of American cotton using metal-oxide nanoparticles for improving seed quality traits.

Cotton seeds have poorer germination than other crops because of their high sensitivity towards insect pests and other biotic and abiotic stresses during the germination process. In the present study, inorganic bulk and nano nutrients of zinc oxide (ZnO) and titanium oxide (TiO2) nanoparticles were synthesized using the chemical reduction method and invigourated with cotton seeds. The characterization of nanoparticles was done by FESEM, HRTEM, UV/Vis analysis and FTIR. The delinted and fuzzy seeds of two American cotton varieties (H 1300 and H 1098-i) were nano-primed for 10h with zinc oxide nanoparticles (ZnONPs) @ 400ppm and titanium dioxide nanoparticles (TiO2NPs) @ 100ppm. After nanoparticle invigouration, the seeds were analyzed for various parameters at different intervals (0months, 3months, 6months, 9months and 12months) such as germination percentage, seedling length, seedling dry weight, electrical conductivity, dehydrogenase activity, antioxidant enzyme activity. The results indicated that that different storage periods and nanopriming treatments had significant effects on all seed quality parameters except the effect of nanopriming treatments on germination percentage (excluding delinted seeds of H 1098-i). It is also revealed that the interaction effect of nanopriming treatment and storage period was non-significant on all parameters except EC. Maximum reduction in seed quality parameters was observed in control treatment and minimum was found when seeds were nanoprimed with ZnONPs @ 400ppm. The differences in the response for both NPs can be attributed to their surface charge, and concentration used. Overall, ZnONPs and TiO2NPs could hold seed quality and vigour during the storage of cotton seeds of American varieties (H 1300 and H 1098-i).

Identification of Soybean Mosaic Virus Resistant Soybean Genotypes using Gene-Linked Markers

Soybean is widely consumed legumes both in the form of food and feed. In the present scenario, the quality and quantity of soybean production is largely affected by different biotic factors, Soybean Mosaic Virus being one of the major biotic stress. Plant host resistance is an effective major to develop durable resistance from viral diseases, therefore understanding the molecular mechanism and identifying the resistant genotypes can contribute to resistance breeding in soybean. In 2020, ninety genotypes collected from Grain Legume Research Program, local collection and National Agricultural Genetic Resource Center were screened for the presence of resistant genes using gene linked molecular markers. Among them, three genotypes were identified with Soybean Mosaic Virus resistant loci, Rsv1 amplified by linked marker Satt114, four genotypes were identified with resistant loci, Rsv3 with linked marker Sat_424, and eight genotypes were identified with resistant loci, Rsv4 amplified by linked marker Satt558. Thus, showing expression of dominant resistance to some SMV strains. Interestingly, two genotypes (Co 175 and TGx1990-55) possessed both Rsv1 and Rsv3 loci thus showing potential of resisting broad spectrum SMV resistance to all SMV strains. Therefore, this study has identified potential genotypes that can be used as parental materials for resistant gene pyramiding in soybean breeding for SMV resistance

Ontogenesis of the anastomosed laticifers of Allamanda cathartica (Apocynaceae) and the chemical nature of the stem latex.

Laticifers are secretive structures with important roles in controlling abiotic and biotic stress through the external release of viscous and bioactive latex emulsions composed of alkaloids, terpenes, flavonoids, proteins, and mucilage. Allamanda cathartica is an attractive ornamental neotropical shrub that produces abundant latex with medicinal potential. The laticifers of this species, their origins, structural types, and distribution in the primary and secondary structures of the stem were investigated, and the chemical nature of latex was determined. Anatomical, histochemical, and ultrastructural evaluations of the stem apex were performed through light and electronic microscopy. Laticifers are abundant in the primary structure, being distributed in the cortex, outer primary phloem, and pith. Their branching, anastomosing structural type develops by the dissolution of the transverse and lateral walls of precursor meristematic cells, followed by protoplast fusion. The laticifers in the secondary structure are distributed amid the axial parenchyma cells of the phloem. The latex of A. cathartica is an emulsion composed mainly of mucilage and terpenes, and it is the first time that this laticifer system has been described.

Challenges to Seagrass Restoration in the Indian River Lagoon, Florida

Seagrasses provide valuable ecosystem services, including improved water quality, carbon sequestration, and sediment stabilization. Unfortunately, these critical habitats are declining globally due to a range of anthropogenic impacts. Restoration practitioners have made efforts to mitigate loss through the introduction of seagrass transplants. However, seagrass restoration has low success rates and is plagued by water quality concerns and ecosystem degradation. Studies to improve seagrass restoration efforts have targeted different functional taxa to allow for greater stability and recovery of threatened ecosystems, and excluded macro-grazers to limit losses to newly established and restored seagrasses. We hypothesized greater seagrass (Halodule wrightii) health when restored in conjunction with hard clams (Mercenaria mercenaria) and protected from grazers using herbivore exclusion devices (HEDs) in the Indian River Lagoon (IRL), Florida. While our study experienced high rates of seagrass mortality, we were able to observe significant differences in seagrass health between IRL sub-lagoons and observed the positive effects of HEDs on seagrass health. The observed high species mortality highlights how restoration in the IRL is hindered by biotic and abiotic stressors, site selection, and a lack of clear restoration protocols. As we see ongoing declines in water quality and loss of foundational species, informed site selection, greater understanding of grazer presence, and multi-species restoration will provide an informed approach for future seagrass restoration projects globally.