Biotic Stresses Research Articles

A Review on the Applications of Biochar in Agricultural Farms: A Low Carbon Emission Technology

Improving the condition of the soil is essential for successful agriculture since it increases crop output and soil fertility. Applying biochar to the soil can boost crop yields and soil fertility. Biochar is a solid carbon-rich substance made by pyrolyzing biomass, which includes trash, wood, and agricultural crop leftovers under low oxygen conditions. Because biochar has potential uses in waste recycling, soil nutrient retention, and greenhouse gas emission reduction, it is significant for sequestering carbon. Over the last two decades, biochar has received substantial attention in agriculture and the environment. Agriculture soil productivity has long been increased by the application of synthetic fertilizers, some of which leached into the environment and released greenhouse gases (GHG). Improving soil microbiology and water retention, as well as increasing fertilizer efficiency, are some of the basic problems facing agricultural practices. Biochar is becoming more and more popular as a soil supplement to increase crop yields and sequester carbon. Biochar is one of the many conservation agricultural techniques that can be used to improve soil fertility, and crop productivity, and slow down global warming. It is also a readily available and important input for sustainable agriculture. Furthering global food security, biochar may improve soils' ability to produce crops under various biotic and abiotic stress. This review examines the numerous uses of biochar to guarantee the long-term, safe enhancement of soil fertility. An overview of the characteristics, manufacturing process, and applications of biochar in agriculture is given in this review. Researchers, farmers, and academics interested in using biochar might find this review to be a helpful resource.

Deciphering the mechanism of E3 ubiquitin ligases in plant responses to abiotic and biotic stresses and perspectives on PROTACs for crop resistance.

With global climate change, it is essential to find strategies to make crops more resistant to different stresses and guarantee food security worldwide. E3 ubiquitin ligases are critical regulatory elements that are gaining importance due to their role in selecting proteins for degradation in the ubiquitin-proteasome proteolysis pathway. The role of E3 Ub ligases has been demonstrated in numerous cellular processes in plants responding to biotic and abiotic stresses. E3 Ub ligases are considered a class of proteins that are difficult to control by conventional inhibitors, as they lack a standard active site with pocket, and their biological activity is mainly due to protein-protein interactions with transient conformational changes. Proteolysis-targeted chimeras (PROTACs) are a new class of heterobifunctional molecules that have emerged in recent years as relevant alternatives for incurable human diseases like cancer because they can target recalcitrant proteins for destruction. PROTACs interact with the ubiquitin-proteasome system, principally the E3 Ub ligase in the cell, and facilitate proteasome turnover of the proteins of interest. PROTAC strategies harness the essential functions of E3 Ub ligases for proteasomal degradation of proteins involved in dysfunction. This review examines critical advances in E3 Ub ligase research in plant responses to biotic and abiotic stresses. It highlights how PROTACs can be applied to target proteins involved in plant stress response to mitigate pathogenic agents and environmental adversities.

Pathogenesis-Related 1 (PR1) Protein Family Genes Involved in Sugarcane Responses to Ustilago scitaminea Stress.

Plant resistance against biotic stressors is significantly influenced by pathogenesis-related 1 (PR1) proteins. This study examines the systematic identification and characterization of PR1 family genes in sugarcane (Saccharum spontaneum Np-X) and the transcript expression of selected genes in two sugarcane cultivars (ROC22 and Zhongtang3) in response to Ustilago scitaminea pathogen infection. A total of 18 SsnpPR1 genes were identified at the whole-genome level and further categorized into four groups. Notably, tandem and segmental duplication occurrences were detected in one and five SsnpPR1 gene pairs, respectively. The SsnpPR1 genes exhibited diverse physio-chemical attributes and variations in introns/exons and conserved motifs. Notably, four SsnpPR1 (SsnpPR1.02/05/09/19) proteins displayed a strong protein-protein interaction network. The transcript expression of three SsnpPR1 (SsnpPR1.04/06/09) genes was upregulated by 1.2-2.6 folds in the resistant cultivar (Zhongtang3) but downregulated in the susceptible cultivar (ROC22) across different time points as compared to the control in response to pathogen infection. Additionally, SsnpPR1.11 was specifically upregulated by 1.2-3.5 folds at 24-72 h post inoculation (hpi) in ROC22, suggesting that this gene may play an important negative regulatory role in defense responses to pathogen infection. The genetic improvement of sugarcane can be facilitated by our results, which also establish the basis for additional functional characterization of SsnpPR1 genes in response to pathogenic stress.

Changes in Carotenoids and Polyphenols during the Growth Stages of Orange-Fleshed Sweet Potato (Ipomoea batatas (L.) Lam.)

The storage roots of orange-fleshed sweet potato contain high levels of polyphenols and carotenoids. Little information is available on changes in the content and composition of these secondary metabolites during the growth stages of the root system. We investigated changes in carotenoids, polyphenols, and anthocyanins in the root system of the orange-fleshed sweet potato ‘Tamaakane’ from the post-planting stage. Carotenoids and polyphenols accumulated immediately after root-system formation at 15 days after transplanting (DAT). The levels of carotenoids increased by 45 DAT and decreased once the storage root enlargement began, but increased rapidly thereafter. After 90 DAT, β-carotene accounted for >90% of the total carotenoids, and the frequency remained stable until maturity. Total polyphenol content increased significantly towards 45 DAT and then gradually decreased as the storage roots began to thicken. No anthocyanin was detected in the root systems of ‘Tamaakane’ at any stage. The content and composition of these secondary metabolites are discussed in terms of agronomic aspects, as they might contribute to a strategy to protect storage roots while engaging with each other against biotic or abiotic stresses at the growth stage of the root system.

Genome-wide analysis of salicylic acid and jasmonic acid signalling marker gene families in wheat.

Jasmonic acid (JA) and salicylic acid (SA) phytohormone pathways are important regulators of stress tolerance. Knowledge regarding the diversity, phylogeny and functionality of wheat genes involved in JA and SA response is limited. Using Arabidopsis, rice and wheat genomic and wheat disease transcriptomic data, we deduced the size, phylogenetic diversity and pathogen-responsiveness of seven hormone-responsive gene families, and thus selected 14 candidates as potential hormone responsive gene markers. Gene-specific expression studies assessed the impact of exogenous JA and SA on their transcriptional activation in leaves of two distinct wheat cultivars. RNAseq data were interrogated to assess their disease responsiveness and tissue-specific expression. This study elucidated the number, phylogeny and pathogen-responsiveness of wheat genes from seven families, including 12 TaAOS, 6 TaJAMyb, 256 TaWRKY group III, 85 TaPR1, 205 TaPR2, 76 TaPR3 and 124 TaPR5. This included the first description of the wheat AOS, JAMyb, PR2, PR3 and PR5 gene families. Gene expression studies delineated TaAOS1-5B and TaJAMyb-4A as JA-responsive in leaves, but not significantly responsive to SA treatment, while TaWRKY45-B was a SA- but not a JA-responsive marker. Other candidate genes were either unresponsive or non-specific to SA or JA. Our findings highlight that all seven gene families are greatly expanded in wheat as compared to other plants (up to 7.6-fold expansion), and demonstrate disparity in the response to biotic stress between some homoeologous and paralogous sequences within these families. The SA- and JA-responsive marker genes identified herein will prove useful tools to monitor these signalling pathways in wheat.

Study the Performance of High Yielding Tomato Hybrids in Dharmapuri District, Tamil Nadu, India

Tomato (Solanum lycopersicum L.) is an economically important vegetable crop in the globe and affected by various biotic and abiotic stresses to which the plants were exposed during growth. In this study, three tomato hybrids viz., Arka Abeth, CoTH4 4 and Sivam were evaluated the resistant to pest and diseases including biochemical analysis and yield assessment. The experiment results revealed that highest average yield was recorded in Arka Abeth (712.7 q/ha) followed by CoTH4 4 (650.01 q/ha) and lowest in Sivam (574.58 q/ha). Regarding pest and disease, Pin worm was recorded 21.8 % to 41.6% and leaf miner damage was recorded 8.25 % to 12.80 %, Leaf curl virus disease incidence was 0.40 % to 0.61% and wilt incidence was 7.30% to 13.65%. Among the three tomato cultivars arka abeth was performed higher in the biochemical parameters such as ascorbic acid (38.2 mg/ 100g) and lycopene (3.01 mg/100g).

Morpho-physiological characterization of second generation colchiploids in sweet orange (<i>Citrus sinensis </i>(L.) Osbeck) cv. Mosambi

Induction of tetraploidy in citrus is commonly meant for the development of triploid seedless cultivars as well as resistance against abiotic and biotic stresses. Three-year-old, 20 second-generation colchicine treated (0.05, 0.10, 0.15 and 0.20%) plants (colchiploids), established from the putative tetraploid branches of the first generation colchiploids of sweet orange (Citrus sinensis (L.) Osbeck) cv. Mosambi vegetatively propagated on Jatti khatti rootstock, along with their wild (parent) type, were characterized based on morphological and physiological traits. Plant height and canopy volume were reduced, but stem girth, nodes per shoot and bark: wood increased in the majority of the second-generation colchiploids related to the wild type. Colchiploids also possessed improved flower characteristics in terms of length and width. The stomatal dimensions increased, but stomatal concentration reduced in all the colchiploids. Colchicine treatment also caused significant variations in leaf gas exchange parameters, including photosynthetic rate, intercellular CO2 concentration, leaf net transpiration rates, stomatal conductance, and intrinsic water use efficiency in colchiploids affecting their photosynthetic activities. The solid tetraploids identified on the basis of morpho-physiological characterization can be used in future breeding programmes for the development of triploid seedless citrus cultivars or can be used for the mitigation of biotic and abiotic stresses.

Morpho-physiological characterization of second generation colchiploids in sweet orange (<i>Citrus sinensis </i>(L.) Osbeck) cv. Mosambi

Induction of tetraploidy in citrus is commonly meant for the development of triploid seedless cultivars as well as resistance against abiotic and biotic stresses. Three-year-old, 20 second-generation colchicine treated (0.05, 0.10, 0.15 and 0.20%) plants (colchiploids), established from the putative tetraploid branches of the first generation colchiploids of sweet orange (Citrus sinensis (L.) Osbeck) cv. Mosambi vegetatively propagated on Jatti khatti rootstock, along with their wild (parent) type, were characterized based on morphological and physiological traits. Plant height and canopy volume were reduced, but stem girth, nodes per shoot and bark: wood increased in the majority of the second-generation colchiploids related to the wild type. Colchiploids also possessed improved flower characteristics in terms of length and width. The stomatal dimensions increased, but stomatal concentration reduced in all the colchiploids. Colchicine treatment also caused significant variations in leaf gas exchange parameters, including photosynthetic rate, intercellular CO2 concentration, leaf net transpiration rates, stomatal conductance, and intrinsic water use efficiency in colchiploids affecting their photosynthetic activities. The solid tetraploids identified on the basis of morpho-physiological characterization can be used in future breeding programmes for the development of triploid seedless citrus cultivars or can be used for the mitigation of biotic and abiotic stresses.

Genome-wide investigation and analysis of NAC transcription factor family in Populus tomentosa and expression analysis under salt stress.

The NAC transcription factor family is one of the largest families of TFs in plants, and members of NAC gene family play important roles in plant growth and stress response. Recent release of the haplotype-resolved genome assembly of P. tomentosa provide a platform for NAC protein genome-wide analysis. A total of 270 NAC genes were identified and a comprehensive overview of the PtoNAC gene family is presented, including gene promoter, structure and conserved motif analyses, chromosome localization and collinearity analysis, protein phylogeny, expression pattern, and interaction analysis. The results indicate that protein length, molecular weight, and theoretical isoelectric points of the NAC TF family vary, while gene structure and motif are relatively conserved. Chromosome mapping analysis showed that the P. tomentosa NAC genes are unevenly distributed on 19 chromosomes. The interchromosomal evolutionary results indicate 12 pairs of tandem and 280 segmental duplications. Segmental duplication is possibly related to amplification of P. tomentosa NAC gene family. Expression patterns of 35 PtoNAC genes from P. tomentosa subgroup were analysed under high salinity, and seven NAC genes were induced by this treatment. Promoter and protein interaction network analyses showed that PtoNAC genes are closely associated with growth, development, and abiotic and biotic stress, especially salt stress. These results provide a meaningful reference for follow-up studies of the functional characteristics of NAC genes in the mechanism of stress response and their potential roles in development of P. tomentosa.

Uncovering the effect of waterlogging stress on plant microbiome and disease development: current knowledge and future perspectives.

Waterlogging is a constant threat to crop productivity and ecological biodiversity. Plants face multiple challenges during waterlogging stress like metabolic reprogramming, hypoxia, nutritional depletion, reduction in gaseous exchange, pH modifications, microbiome alterations and disease promotion all of which threaten plants survival. Due to global warming and climatic change, the occurrence, frequency and severity of flooding has dramatically increased posing a severe threat to food security. Thus, developing innovative crop management technologies is critical for ensuring food security under changing climatic conditions. At present, the top priority among scientists is to find nature-based solutions to tackle abiotic or biotic stressors in sustainable agriculture in order to reduce climate change hazards to the environment. In this regard, utilizing plant beneficial microbiome is one of the viable nature based remedial tool for mitigating abiotic stressors like waterlogging. Beneficial microbiota provides plants multifaceted benefits which improves their growth and stress resilience. Plants recruit unique microbial communities to shield themselves against the deleterious effects of biotic and abiotic stress. In comparison to other stressors, there has been limited studies on how waterlogging stress affects plant microbiome structure and their functional traits. Therefore, it is important to understand and explore how waterlogging alters plant microbiome structure and its implications on plant survival. Here, we discussed the effect of waterlogging stress in plants and its microbiome. We also highlighted how waterlogging stress promotes pathogen occurrence and disease development in plants. Finally, we highlight the knowledge gaps and areas for future research directions on unwiring how waterlogging affects plant microbiome and its functional traits. This will pave the way for identifying resilient microbiota that can be engineered to promote their positive interactions with plants during waterlogging stress.

CmERF1 acts as a positive regulator of fruits and leaves growth in melon (Cucumis melo L.).

Melon (Cucumis melo L.) is an important horticultural and economic crop. ETHYLENE RESPONSE FACTOR1 (ERF1) plays an important role in regulating plant development, and the resistance to multiple biotic and abiotic stresses. In this study, developmental biology, molecular biology and biochemical assays were performed to explore the biological function of CmERF1 in melon. Abundant transcripts of CmERF1 were found in ovary at green-yellow bud (GYB) and rapid enlargement (ORE) stages. In CmERF1 promoter, the cis-regulatory elements for indoleacetic acid (IAA), methyl jasmonate (MeJA), salicylic acid (SA), abscisic acid (ABA), gibberellic acid (GA), light and low temperature responses were found. CmERF1 could be significantly induced by ethylene, IAA, MeJA, SA, ABA, and respond to continuous light and low temperature stresses in melon. Ectopic expression of CmERF1 increased the length of siliqua and carpopodium, and expanded the size of leaves in Arabidopsis. Knockdown of CmERF1 led to smaller ovary at anthesis, mature fruit and leaves in melon. In CmERF1-RNAi #2 plants, 75 genes were differently expressed compared with control, and the promoter regions of 28 differential expression genes (DEGs) contained the GCC-box (AGCCGCC) or DRE (A/GCCGAC) cis-acting elements of CmERF1. A homolog of cell division cycle protein 48 (CmCDC48) was proved to be the direct target of CmERF1 by the yeast one-hybrid assay and dual-luciferase (LUC) reporter (DLR) system. These results indicated that CmERF1 was able to promote the growth of fruits and leaves, and involved in multiple hormones and environmental signaling pathways in melon.

Allogamy, metaxenia and hybrids in orchids, what do we know about it?

Orchids are a diverse group of plants, also manifested in their great diversity of flowers. Despite this, orchids are pollinated either through autogamy or allogamy (geitonogamy and xenogamy). Although there are some autogamous orchids, the majority are allogamous, mainly pollinated by xenogamy since they present physical or genetic barriers that prevent self-pollination. In addition, orchids are known for their capacity for interspecific pollination, which could influence fruits (metaxenia) and seeds (xenia) production. Its capacity for hybridization represents an opportunity to produce organisms tolerant to biotic or abiotic stress, in addition to exhibiting new shapes, colors and fragrances; this would be important in horticulture, where the proper selection of parents provides those advantages to the descendant hybrids. This review addresses the characteristics of each type of reproduction systems in orchids, as well as their advantages and disadvantages. At the same time, the study of the induction effect of metaxenia and xenia in this family is proposed. Finally, the production of orchid hybrids is contextualized and the opportunities of this approach in the near future.

Sesame Genomic Web Resource (SesameGWR): a well-annotated data resource for transcriptomic signatures of abiotic and biotic stress responses in sesame (Sesamum indicum L.).

Sesame (Sesamum indicum L.) is a globally cultivated oilseed crop renowned for its historical significance and widespread growth in tropical and subtropical regions. With notable nutritional and medicinal attributes, sesame has shown promising effects in combating malnutrition cancer, diabetes, and other diseases like cardiovascular problems. However, sesame production faces significant challenges from environmental threats such as charcoal rot, drought, salinity, and waterlogging stress, resulting in economic losses for farmers. The scarcity of information on stress-resistance genes and pathways exacerbates these challenges. Despite its immense importance, there is currently no platform available to provide comprehensive information on sesame, which significantly hinders the mining of various stress-associated genes and the molecular breeding of sesame. To address this gap, here a free, web-accessible, and user-friendly genomic web resource (SesameGWR, http://backlin.cabgrid.res.in/sesameGWR/) has been developed This platform provides key insights into differentially expressed genes, transcription factors, miRNAs, and molecular markers like simple sequence repeats, single nucleotide polymorphisms, and insertions and deletions associated with both biotic and abiotic stresses.. The functional genomics information and annotations embedded in this web resource were predicted through RNA-seq data analysis. Considering the impact of climate change and the nutritional and medicinal importance of sesame, this study is of utmost importance in understanding stress responses. SesameGWR will serve as a valuable tool for developing climate-resilient sesame varieties, thereby enhancing the productivity of this ancient oilseed crop.

Optimizing Agriculture: A Review of Chemical Priming in Crop Production

Agricultural productivity faces increasing challenges due to climate change, soil degradation, and the need for sustainable practices. Chemical priming, a technique involving the pre-treatment of seeds or plants with specific compounds, has emerged as a promising approach to enhance crop resilience, productivity, and stress tolerance. This review synthesizes current literature on the application of chemical priming in crop production, focusing on its mechanisms, effects on plant physiology, and its potential to optimize agricultural practices. Chemical priming operates through diverse mechanisms, including the induction of stress-responsive genes, enhancement of antioxidant activity, and modulation of hormone signaling pathways. These mechanisms result in improved germination rates, accelerated seedling growth, increased nutrient uptake, and enhanced tolerance to various abiotic and biotic stresses. Moreover, chemical priming has been shown to promote crop yield and quality under adverse environmental conditions, making it a valuable tool for sustainable agriculture. The effectiveness of chemical priming depends on various factors, such as the type of priming agent, concentration, timing of application, and the specific crop species. Furthermore, interactions with other agricultural practices, such as irrigation regimes and fertilization strategies, can influence its outcomes. Therefore, optimizing chemical priming protocols requires a comprehensive understanding of crop-specific responses and environmental factors. Despite its potential benefits, the widespread adoption of chemical priming in agriculture faces challenges related to cost-effectiveness, regulatory approval, and potential ecological impacts. Addressing these challenges requires further research to refine priming protocols, assess long-term effects on soil health and ecosystem functioning, and develop sustainable approaches for large-scale implementation.

Pathogenesis-Related Protein 10 Family Genes Involved in Sugarcane Responses to Biotic Stressors and Salicylic Acid

Pathogenesis-Related Protein 10 Family Genes Involved in Sugarcane Responses to Biotic Stressors and Salicylic Acid

Brown algae (Phaeophyceae) stressors and illnesses: a review for a sustainable aquaculture under climate change

Brown algae (Phaeophyceae) dominate intertidal and shallow subtidal areas globally, where larger species form extensive underwater forests. These structurally complex and highly productive habitats enhance local biodiversity and support food webs in coastal areas through secondary production, thereby shaping local oceanography and ecology. Macroalgal aquaculture is an important and growing sector, where approximately 40% of all cultivated algae belong to Phaeophyceae. However, both cultured and natural brown algae have been under increasing pressure due to climate-driven factors, such as ocean warming, eutrophication, and herbivore outbreaks. We conducted a comprehensive literature review on abiotic (temperature, light intensity, and UV radiation, nutrients, water motion, salinity, and substrata and sediment) and biotic (bacteria, viruses, fungi, eukaryotic endophytes and endoparasites, epiphytes, and grazers) stressors and illnesses in marine brown macroalgae, as well as brown algae defense mechanisms, and discuss how these parameters may affect the production of a sustainable crop for the aquaculture industry under future climate change scenarios.

Seaweed Extract for Sustainable Rice Production- A Review

Seaweed extract is a bio-simulant that obtain from seaweeds like Agar, and Alginate and many more species of seaweed. By application of seaweed extract in rice crop (Oryza sativa L.) can increase the growth, grain yield, biological yield and improves the nutrient content in grain. Seaweed extract application also reduces the biotic and abiotic stress on crops. This seaweed extract can be applied in many ways to crop plants like foliar spray, soil incorporation, etc., based on crop type. It can impact the cellular respiration of plants and incorporates many enzymes like NAA, auxins, vitamins, cytokinin’s and many other growths promoting hormones in plants. This extract also has growth stimulating properties. It can increase nutrient absorption capacity by increasing root growth. Most of the marine algae are rich in auxins that increase root growth. The application of seaweed extract in soil can improve the physical, chemical, and biological properties of the soil. It can improve Arbuscular mycorrhiza by providing potassium to plant. Application of seaweed extract to soil can improve the availability of nutrients like calcium, nitrogen, phosphorus, potassium, and magnesium. Moreover, foliar spray of seaweed extract in rice crop increases crop growth, yield, nutrient uptake, water uptake, increases photosynthesis, and stomatal conductance. So, seaweed extract incorporation in rice cultivation could be a better approach to gain long-term sustainable production.

Two structurally different oomycete lipophilic microbe-associated molecular patterns induce distinctive plant immune responses.

Plants recognize a variety of external signals and induce appropriate mechanisms to increase their tolerance to biotic and abiotic stresses. Precise recognition of attacking pathogens and induction of effective resistance mechanisms are critical functions for plant survival. Some molecular patterns unique to a certain group of microbes, microbe-associated molecular patterns (MAMPs), are sensed by plant cells as nonself molecules via pattern recognition receptors. While MAMPs of bacterial and fungal origin have been identified, reports on oomycete MAMPs are relatively limited. This study aimed to identify MAMPs from an oomycete pathogen Phytophthora infestans, the causal agent of potato late blight. Using reactive oxygen species (ROS) production and phytoalexin production in potato (Solanum tuberosum) as markers, two structurally different groups of elicitors, namely ceramides and diacylglycerols, were identified. P. infestans ceramides (Pi-Cer A, B, and D) induced ROS production, while diacylglycerol (Pi-DAG A and B), containing eicosapentaenoic acid (EPA) as a substructure, induced phytoalexins production in potato. The molecular patterns in Pi-Cers and Pi-DAGs essential for defense induction were identified as 9-methyl-4,8-sphingadienine (9Me-Spd) and 5,8,11,14-tetraene-type fatty acid (5,8,11,14-TEFA), respectively. These structures are not found in plants, but in oomycetes and fungi, indicating that they are microbe molecular patterns recognized by plants. When Arabidopsis (Arabidopsis thaliana) was treated with Pi-Cer D and EPA, partially overlapping but different sets of genes were induced. Furthermore, expression of some genes is upregulated only after the simultaneous treatment with Pi-Cer D and EPA, indicating that plants combine the signals from simultaneously recognized MAMPs to adapt their defense response to pathogens.

The bacterial and viral communities associated with onion bacterial bulb rot

Microbes occur in complex communities within plants as endophytes and establish a network of interactions that can influence plant health positively or negatively. Positive interactions may be synergistic and confer abiotic and biotic stress tolerance. The aim of this study was to identify bacteria and viruses present in storage onion bulbs that were symptomatic and asymptomatic for bacterial bulb rot, from crops grown in Georgia and Washington states; and to assess their potential role in the bulbs based on functions of bacterial and viral genes detected. DNA was extracted from nine asymptomatic bulbs and nine bulbs displaying symptoms of bacterial bulb rot and subjected to 16S rRNA amplicon sequencing and Metagenomic Assembled Genome (MAG) analysis. The Illumina platform was used to sequence the hypervariable region (V3-V4) of the 16S rRNA gene. The 16S rRNA amplicon profiling revealed the presence of numerous bacteria including potential onion pathogens in the genera Panteoa and Burkholderia. MAG assembly identified P. agglomerans. B. gladioli and B. cepacia, known bulb rot pathogens, including genes linked to fitness and those involved in the Type II and III secretion systems. Eighty-nine unique viral genomes were identified, of which 67 could be classified taxonomically. The bacterial and viral genomes differed significantly in asymptomatic versus symptomatic bulbs. Viral genomes showed evidence of auxiliary metabolic genes (AMGs), including genes involved in fitness and pathogenicity to bacterial hosts. The bulbs hosted endophytic bacteria and viruses, some of which were potentially beneficial, and others potentially pathogenic to onion or as hosts to bacteriophages.

A symbiont fungal effector relocalizes a plastidic oxidoreductase to nuclei to induce resistance to pathogens and salt stress

The root endophytic fungus Serendipita indica establishes beneficial symbioses with a broad spectrum of plants and enhances host resilience against biotic and abiotic stresses. However, little is known about the mechanisms underlying S.indica-mediated plant protection. Here, we report S.indica effector (SIE) 141 and its host target CDSP32, a conserved thioredoxin-like protein, and underlying mechanisms for enhancing pathogen resistance and abiotic salt tolerance in Arabidopsis thaliana. SIE141 binding interfered with canonical targeting of CDSP32 to chloroplasts, leading to its re-location into the plant nucleus. This nuclear translocation is essential for both their interaction and resistance function. Furthermore, SIE141 enhanced oxidoreductase activity of CDSP32, leading to CDSP32-mediated monomerization and activation of NON-EXPRESSOR OF PATHOGENESIS-RELATED 1 (NPR1), a key regulator of systemic resistance. Our findings provide functional insights on how S.indica transfers well-known beneficial effects to host plants and indicate CDSP32 as a genetic resource to improve plant resilience to abiotic and biotic stresses.