Basal Defense Research Articles

고려·몽골 전쟁기 방호별감(防護別監)의 운영과 내륙 입보의 보완

Goryeo had been preparing military forces in according to the continuing changes in the external environment. Goryeo built the castle from the beginning of its foundation, and also placed Jujingun(州鎭軍) on Yanggye(兩界) and juhyungun(州縣軍) on O-Do(五道). In addition, troops from the south were moved and deployed to Yanggye(兩界), and in case of emergency, the troops was organized in the capital. This is summarized as follows. First, defense each castle, and then the troops are organized from the center, and released and intercepted the enemy.<BR> Goryeo had changed the way responding to its new enemy, Mongolia. After the Battle of Gang-dong(江東) Castle in 1218, Goryeo had discussed response to Mongol invasions. Continuously It decided to organize troops as usual, but also concentrated its military strength by advancing to a large castle on the road on the border leading to the capital. At this time, the existing Bangsugun deployment areas were center of the deployment of each defensive hub. Many of the areas except the defensive hubs moved to the island to protect the people and preserve military.<BR> Second Mongol invasion to Goryeo, Goryeo expanded this deploying strategy all around the country. But there were some problems. Due to The presence of Sokhyun(屬縣), there was a fear to increasing the distance between each defensive hub, alike putting the additional defensive hubs resulting a lack of commanders in the region O-do. Therefore, Goryeo dispatched new commanders named Banghobyulgam(防護別監) to a certain region on the Third Mongol invasion to Goryeo. Banghobyulgam’s status was roughly around sixth pum(品), as the similar status as Jijubugunsa(知州府郡事), and were dispatched except the castle where Suryung(守令) defended. Thus Goryeo has established an additional defensive hubs within the main area, enabling organic warfare.<BR> When deployed strategy was preceeded, the area that existed on a plane basis was reorganized into a point-by-point basis. Given the examples of areas where Banghobyulgam was operated, defensive hubs within the area were formed in relation to the road. In particular, Banghobyulgam was deployed in consideration of roads and expected enemy intrusion routes and local circumstances at the time from a national perspective.<BR> The implementation of deployed strategy and the operation of Banghobyulgam were maintained for a period of time and served as the basic defense system of Goryeo at that time. With the circumstance of changing Goryeo’s traditional military system, it shows Goryeo’s agony of having to oppose an all-out war with a new enemy called Mongolia. Therefore, it shows the characteristics of this period.

Fusarium head blight resistance in European winter wheat: insights from genome-wide transcriptome analysis

BackgroundFusarium head blight (FHB) is a devastating disease of wheat worldwide. Resistance to FHB is quantitatively controlled by the combined effects of many small to medium effect QTL. Flowering traits, especially the extent of extruded anthers, are strongly associated with FHB resistance.ResultsTo characterize the genetic basis of FHB resistance, we generated and analyzed phenotypic and gene expression data on the response to Fusarium graminearum (Fg) infection in 96 European winter wheat genotypes, including several lines containing introgressions from the highly resistant Asian cultivar Sumai3. The 96 lines represented a broad range in FHB resistance and were assigned to sub-groups based on their phenotypic FHB severity score. Comparative analyses were conducted to connect sub-group-specific expression profiles in response to Fg infection with FHB resistance level. Collectively, over 12,300 wheat genes were Fusarium responsive. The core set of genes induced in response to Fg was common across different resistance groups, indicating that the activation of basal defense response mechanisms was largely independent of the resistance level of the wheat line. Fg-induced genes tended to have higher expression levels in more susceptible genotypes. Compared to the more susceptible non-Sumai3 lines, the Sumai3-derivatives demonstrated higher constitutive expression of genes associated with cell wall and plant-type secondary cell wall biogenesis and higher constitutive and Fg-induced expression of genes involved in terpene metabolism. Gene expression analysis of the FHB QTL Qfhs.ifa-5A identified a constitutively expressed gene encoding a stress response NST1-like protein (TraesCS5A01G211300LC) as a candidate gene for FHB resistance. NST1 genes are key regulators of secondary cell wall biosynthesis in anther endothecium cells. Whether the stress response NST1-like gene affects anther extrusion, thereby affecting FHB resistance, needs further investigation.ConclusionInduced and preexisting cell wall components and terpene metabolites contribute to resistance and limit fungal colonization early on. In contrast, excessive gene expression directs plant defense response towards programmed cell death which favors necrotrophic growth of the Fg pathogen and could thus lead to increased fungal colonization.

Investigation of long non-coding RNAs as regulatory players of grapevine response to powdery and downy mildew infection

BackgroundLong non-coding RNAs (lncRNAs) are regulatory transcripts of length > 200 nt. Owing to the rapidly progressing RNA-sequencing technologies, lncRNAs are emerging as considerable nodes in the plant antifungal defense networks. Therefore, we investigated their role in Vitis vinifera (grapevine) in response to obligate biotrophic fungal phytopathogens, Erysiphe necator (powdery mildew, PM) and Plasmopara viticola (downy mildew, DM), which impose huge agro-economic burden on grape-growers worldwide.ResultsUsing computational approach based on RNA-seq data, 71 PM- and 83 DM-responsive V. vinifera lncRNAs were identified and comprehensively examined for their putative functional roles in plant defense response. V. vinifera protein coding sequences (CDS) were also profiled based on expression levels, and 1037 PM-responsive and 670 DM-responsive CDS were identified. Next, co-expression analysis-based functional annotation revealed their association with gene ontology (GO) terms for ‘response to stress’, ‘response to biotic stimulus’, ‘immune system process’, etc. Further investigation based on analysis of domains, enzyme classification, pathways enrichment, transcription factors (TFs), interactions with microRNAs (miRNAs), and real-time quantitative PCR of lncRNAs and co-expressing CDS pairs suggested their involvement in modulation of basal and specific defense responses such as: Ca2+-dependent signaling, cell wall reinforcement, reactive oxygen species metabolism, pathogenesis related proteins accumulation, phytohormonal signal transduction, and secondary metabolism.ConclusionsOverall, the identified lncRNAs provide insights into the underlying intricacy of grapevine transcriptional reprogramming/post-transcriptional regulation to delay or seize the living cell-dependent pathogen growth. Therefore, in addition to defense-responsive genes such as TFs, the identified lncRNAs can be further examined and leveraged to candidates for biotechnological improvement/breeding to enhance fungal stress resistance in this susceptible fruit crop of economic and nutritional importance.

Role of silymarin induced rice immunity against blast pathogen Magnaporthe oryzae through regulation of resistance genes expression

The effect of silymarin as an active ingredient of milk thistle seed as an systemic acquired resistance (SAR) substance in rice (Oryza sativa L.) against rice blast disease caused by Magnaporthe oryzae was investigated in this study. Silymarin is considered as a medication substance on human drug and has a metabolic and cell-regulating effect and scavenging oxygen radicals reactions. Results showed that, silymarin do not inhibits fungus linear growth in vitro. Significant improvement of resistance under greenhouse conditions with different concentrations 10, 25, 50, 125, 250, 500, 1000 and 2000 mg/L of silymarin was recorded. The most suitable concentration was 500 mg/L. The recorded disease severity was 23.5% when applied five days before inoculation and significantly reduced disease severity under field condition at both experimental seasons. Gene expression for some indicators for salicylic acid (SA) pathway such as OsWRKY45 and OsNPR1, jasmonic acid (JA) pathway such as AOS2, JAMYB and PBZ1 (OsPR10) and ethylene (ET) pathway such as ACO7 was studied. Salicylic acid effect on the pathway related to salicylic acid is evident through both genes (OsWRKY45 and OsNPR1), not jasmonic acid and ethylene pathways, while the effect of silymarin is not clear through the genes studied in all pathways. Finally, the results suggested that silymarin activates SAR at least in part by reinforcing basal plant defense responses on induced defense state.

Safinamide prevents lipopolysaccharide (LPS)-induced inflammation in macrophages by suppressing TLR4/NF-κB signaling

Inflammation is a basal host defense response that eliminates the causes and consequences of infection and tissue injury. Macrophages are the primary immune cells involved in the inflammatory response. When activated by LPS, macrophages release various pro-inflammatory cytokines, chemokines, inflammatory mediators, and MMPs. However, unbridled inflammation causes further damage to tissues. Safinamide is a selective and reversible monoamine oxidase B (MAOB) inhibitor that has been used for the treatment of Parkinson's disease. In this study, we aimed to investigate whether safinamide has effects on LPS-treated macrophages. Our results show that safinamide inhibited the expression of pro-inflammatory cytokines such as IL-1α, TNF-α, and IL-6. Furthermore, safinamide suppressed the production of CXCL1 and CCL2, thereby preventing leukocyte migration. In addition, safinamide reduced iNOS-derived NO, COX-2-derived PGE2, MMP-2, and MMP-9. Importantly, the functions of safinamide mentioned above were found to be dependent on its inhibitory effect on the TLR4/NF-κB signaling pathway. Our data indicates that safinamide may exert a protective effect against inflammatory response.

Influence of virus-host interactions on plant response to abiotic stress.

Environmental factors play a significant role in controlling growth, development and defense responses of plants. Changes in the abiotic environment not only significantly alter the physiological and molecular pathways in plants, but also result in attracting the insect pests that carry a payload of viruses. Invasion of plants by viruses triggers the RNA silencing based defense mechanism in plants. In counter defense the viruses have gained the ability to suppress the host RNA silencing activities. A new paradigm has emerged, with the recognition that plant viruses also have the intrinsic capacity to modulate host plant response to environmental cues, in an attempt to favour their own survival. Thus, plant-virus interactions provide an excellent system to understand the signals in crosstalk between biotic (virus) and abiotic stresses. In this review, we have summarized the basal plant defense responses to pathogen invasion while emphasizing on the role of RNA silencing as a front line of defense response to virus infection. The emerging knowledge indicates overlap between RNA silencing with the innate immune responses during antiviral defense. The suppressors of RNA silencing serve as Avr proteins, which can be recognized by the host R proteins. The defense signals also function in concert with the phytohormones to influence plant responses to abiotic stresses. The current evidence on the role of virus induced host tolerance to abiotic stresses is also discussed.

Analysis of soybean transcriptome uncovers differential genomic regulations in response to charcoal rot in resistant and susceptible genotypes

Charcoal rot is an economically important fungal disease of soybean. The molecular basis of charcoal rot pathogen Macrophomina phaseolina and soybean pathogenesis is largely unknown, limiting breeding programs to develop genetic resistance. Hence, the present study was targeted to study the transcriptome of susceptible (JS 95–60) and resistant (JS 20–29) soybean genotypes infected with M. phaseolina to identify the molecular basis of its host-pathogen interaction. Illumina HiSeq 2500 platform was used to generate an overall of 25560 paired end reads. A total of 1683 and 1219 differentially expressed genes were obtained in resistant and susceptible genotypes, respectively. The expression of several signaling genes viz, calcium, kinases, pathogenesis related, etc. were differentially induced in both the genotypes. However, the expression of several leucine-rich repeat genes was differentially up-regulated in R6. Ca2+ ion-mediated basal defense response was observed in both the genotypes. Several WRKY-genes were up-regulated in resistant response, contributing to up-regulation of phenylpropanoid pathway genes. Several other genes differentially expressed in two contrasting genotypes, comprised those involved in hormone-signaling, biosynthesis of secondary metabolism and transcriptional reprogramming during infection. The charcoal rot resistance trait seems to be quantitative, and we propose that genes like WRKY, LysM-RLKs, NBS-LRR, flavonoid pathway genes can be effectively utilized to introgress resistance trait in soybean.

Genetic Analysis of a Horizontal Resistance Locus BLMR2 in Brassica napus.

Leptosphaeria maculans causes blackleg disease in Brassica napus. The blackleg disease is mainly controlled by resistance genes in B. napus. Previous studies have shown that the blackleg resistant BLMR2 locus that conferred horizontal resistance under field conditions, is located on chromosome A10 of B. napus. The purpose of this study is to fine map this locus and hence identify a candidate gene underlying horizontal resistance. The spectrum of resistance to L. maculans isolates of the resistance locus BLMR2 was analyzed using near isogenic lines, resistant, and susceptible cultivars. The results showed that this locus was horizontally resistant to all isolates tested. Sequence characterized amplified regions (SCAR), simple sequence repeats (SSR), and single nucleotide polymorphism (SNP) markers were developed in the chromosome region of BLMR2 and a fine genetic map was constructed. Two molecular markers narrowed BLMR2 in a 53.37 kb region where six genes were annotated. Among the six annotated genes, BnaA10g11280D/BnaA10g11290D encoding a cytochrome P450 protein were predicted as the candidate of BLMR2. Based on the profiling of pathogen induced transcriptome, three expressed genes in the six annotated genes were identified while only cytochrome P450 showed upregulation. The candidate corresponds to the gene involved in the indole glucosinolate biosynthesis pathway and plant basal defense in Arabidopsis thaliana. The molecular markers identified in this study will allow the quick incorporation of the BLMR2 allele in rapeseed cultivars to enhance blackleg resistance.

Extensins: Self-Assembly, Crosslinking, and the Role of Peroxidases.

The extensin (EXT) network is elaborated by the covalent intermolecular crosslinking of EXT glycoprotein monomers, and its proper assembly is important for numerous aspects of basic wall architecture and cellular defense. In this review, we discuss new advances in the secretion of EXT monomers and the molecular drivers of EXT network self-assembly. Many of the functions of EXTs are conferred through covalent crosslinking into the wall, so we also discuss the different types of known intermolecular crosslinks, the enzymes that are involved, as well as the potential for additional crosslinks that are yet to be identified. EXTs also function in wall architecture independent of crosslinking status, and therefore, we explore the role of non-crosslinking EXTs. As EXT crosslinking is upregulated in response to wounding and pathogen infection, we discuss a potential regulatory mechanism to control covalent crosslinking and its relationship to the subcellular localization of the crosslinking enzymes.

Priming Soybean cv. Primus Leads to Successful Systemic Defense Against the Root-Lesion Nematode, Pratylenchus penetrans.

Root lesion nematodes, Pratylenchus penetrans, are major pests of legumes with little options for their control. We aimed to prime soybean cv. Primus seedlings to improve basic defense against these nematodes by root application of N-3-oxo-tetradecanoyl-L-homoserine lactone (oxo-C14-HSL). The invasion of soybean roots by P. penetrans was significantly reduced in plants that were pre-treated with the oxo-C14-HSL producing rhizobacterium Ensifer meliloti strain ExpR+, compared to non-inoculated plants or plants inoculated with the nearly isogenic strain E. meliloti AttM with plasmid-mediated oxo-C14-HSL degradation. The nematodes were more clustered in the root tissues of plants treated with the AttM strain or the control compared to roots treated with the ExpR+ strain. In split-root systems primed on one side with strain ExpR+, root invasion was reduced on the opposite side compared to non-primed plants indicating a systemic plant response to oxo-C14-HSL. No additional local effect was detected, when inoculating nematodes on the ExpR+ primed side. Removal of oxo-C14-HSL after root exposure resulted in reduced root invasion compared to non-primed plants when the nematodes were added 3, 7, or 15 days later. Thus, probably the plant memorized the priming stimulus. Similarly, the plants were primed by compounds released from the surface of the nematodes. HPLC analysis of the root extracts of oxo-C14-HSL treated and untreated plants revealed that priming resulted in enhanced phytoalexin synthesis upon P. penetrans challenge. Without root invading nematodes, the phytoalexin concentrations of primed and non-primed plants did not significantly differ, indicating that priming did not lead to a persistently increased stress level of the plants. Upon nematode invasion, the phytoalexins coumestrol, genistein, and glyceollin increased in concentration in the roots compared to control plants without nematodes. Glyceollin synthesis was significantly more triggered by nematodes in primed plants compared to non-primed plants. The results indicated that the priming of soybean plants led to a more rapid and strong defense induction upon root invasion of nematodes.

Quantitative resistance differences between and within natural populations of Solanum chilense against the oomycete pathogen Phytophthora infestans.

The wild tomato species Solanum chilense is divided into geographically and genetically distinct populations that show signs of defense gene selection and differential phenotypes when challenged with several phytopathogens, including the oomycete causal agent of late blight Phytophthora infestans. To better understand the phenotypic diversity of this disease resistance in S. chilense and to assess the effect of plant genotype versus pathogen isolate, respectively, we evaluated infection frequency in a systematic approach and with large sample sizes. We studied 85 genetically distinct individuals representing nine geographically separated populations of S. chilense. This showed that differences in quantitative resistance can be observed between but also within populations at the level of individual plants. Our data also did not reveal complete immunity in any of the genotypes. We further evaluated the resistance of a subset of the plants against P. infestans isolates with diverse virulence properties. This confirmed that the relative differences in resistance phenotypes between individuals were mainly determined by the plant genotype under consideration with modest effects of pathogen isolate used in the study. Thus, our report suggests that the observed quantitative resistance against P. infestans in natural populations of a wild tomato species S. chilense is the result of basal defense responses that depend on the host genotype and are pathogen isolate‐unspecific.

Diversity and genomic determinants of the microbiomes associated with COVID-19 and non-COVID respiratory diseases

The novel coronavirus disease 2019 (COVID-19) is a rapidly emerging and highly transmissible disease caused by the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2). Understanding the microbiomes associated with the upper respiratory tract infection (URTI), chronic obstructive pulmonary disease (COPD) and COVID-19 diseases has clinical interest. We hypothesize that microbiome diversity and composition, and their genomic features are associated with different pathological conditions of these human respiratory tract diseases. To test this hypothesis, we analyzed 21 RNASeq metagenomic data including eleven COVID-19 (BD = 6 and China = 5), six COPD (UK = 6) and four URTI (USA = 4) samples to unravel the microbiome diversity and related genomic metabolic functions. The metagenomic data mapped to 534 bacterial, 60 archaeal and 61 viral genomes with distinct variation in the microbiome composition across the samples (COVID-19 > COPD > URTI). Notably, 94.57%, 80.0% and 24.59% bacterial, archaeal and viral genera shared between the COVID-19 and non-COVID samples, respectively. However, the COVID-19 related samples had sole association with 16 viral genera other than SARS-CoV-2. Strain-level virome profiling revealed 660 and 729 strains in COVID-19 and non-COVID samples, respectively, and of them 34.50% strains shared between the conditions. Functional annotation of the metagenomic data identified the association of several biochemical pathways related to basic metabolism (amino acid and energy), ABC transporters, membrane transport, virulence, disease and defense, regulation of virulence, programmed cell death, and primary immunodeficiency. We also detected 30 functional gene groups/classes associated with resistance to antibiotics and toxic compounds (RATC) in both COVID-19 and non-COVID microbiomes. Furthermore, we detected comparatively higher abundance of cobalt-zinc-cadmium resistance (CZCR) and multidrug resistance to efflux pumps (MREP) genes in COVID-19 metagenome. The profiles of microbiome diversity and associated microbial genomic features found in both COVID-19 and non-COVID (COPD and URTI) samples might be helpful in developing microbiome-based diagnostics and therapeutics for COVID-19 and non-COVID respiratory diseases. However, future studies might be carried out to explore the microbiome dynamics and the cross-talk between host and microbiomes employing larger volume of samples from different ethnic groups and geoclimatic conditions.

Parent-child relationship in psychogenesis of female psychogenic infertility (psychoanalytic perspective)

Horney, D. Pines, T. Benedek, M. Bydlowski, F. Tyson and R. Tyson, K. Brisch. The object of this research is the phenomenon of psychogenic infertility in female development. The subject is the parent-child relationship in the context of women with psychogenic infertility. The article reveals the unspecified features of development of women with infertility: personality traits, leading mental conflicts, fixations, defense mechanisms, type of attachment, experience of object relationship. The article traces the dependence of woman&amp;rsquo;s reproductive function in symptom cluster of infertility on her psyche, as well as influence of object relationship and attachment pattern on the occurrence of mental conflicts that lead to infertility. The following possible factors of psychogenic infertility are determined: 1. Pathological fixation in the early infantile period. Inability to separate from the mother, 2. Inability to identify with the mother. 3. Infertility as defense against regression, i.e. fear to encounter internal conflicts. &amp;nbsp;4. Hatred and ambivalent attitude towards the mother. Unwillingness to pass on the &amp;ldquo;mandate of life&amp;rdquo;. &amp;nbsp;5. Confusion of identity, improper gender-role identification with the mother due to improper distribution of roles in family, disturbance of personal boundaries, &amp;nbsp;and pathological symbiosis. The article reveals similar prerequisites for the formation of psychogenic infertility: type of attachment, disturbance of early object relationship, leading mental conflict, basic defense, and the impact of transgenerational experience. Defensive strategies that are intended for coping with intense inner anxiety create an unconscious compromise between mental state and body, which leads to psychogenic infertility. &amp;nbsp;

Monoklonal Antikorlar ve Tedavide Kullanımı

Bağışıklık sistemi vücudu hastalık yapıcı patojenlere karşı koruyan temel savunma sistemidir. Bu savunma sistemi farklı mekanizmalarla etkili olmaktadır. Bağışıklık sistemi, antijen adı verilen vücudun kalıtsal yapısına yabancı olan her türlü yapıya karşı etki gösterir. Vücuda dışarıdan gelen hastalık etkenleri öncelikle doğal bariyerlerle karşılaşmaktadır. Doğal bariyerleri aşmayı başaran etkenler kemik iliği, timus, lenf bezleri ve dalak gibi özelleşmiş organlarda üretilen savunma hücreleri ile karşılaşır. İlk aşamada makrofajlar ve fagositler devreye girer daha sonraki aşamada ise B ve T lenfositleri sürece dahil olurlar. B lenfositlerinden salgılanan antikorlar bağışık sisteminin en önemli savunma mekanizmalarından birini oluşturmaktadır. Antikor moleküllerinin vücudun savunmasındaki bu önemi bilim insanlarını bu alanda çalışmaya yöneltmiştir. Bu doğrultuda 1975 yılında Georges Köhler ve Cesar Milstein, koyun alyuvarları ile immunize ettikleri farelerin B lenfositleri ile fare myeloma hücrelerini birleştirerek oluşturdukları hibrit hücreler ile yeni bir tedavi stratejisinin kapısını açmışlardır. Bu hibrit hücreler sadece istenen antijene bağlanan monoklonal antikor sentezleyebilme yeteneğine sahiptir. Monoklonal antikorlar tıp dünyasında hastalıkların teşhisi, tedavisi ve biyokimyasal analizler gibi birçok alanda kullanmaktadır. Günümüzde hala monoklonal antikora dayalı tedavi ve tedavi seçenekleri üzerinde çalışmalar devam etmektedir. Bu derlemede monoklonal antikorlar ve tedavide kullanımı üzerine genel bilgiler verilecektir.

Salicylic Acid: Biosynthesis and Signaling.

Salicylic acid (SA) is an essential plant defense hormone that promotes immunity against biotrophic and semibiotrophic pathogens. It plays crucial roles in basal defense and the amplification of local immune responses, as well as the establishment of systemic acquired resistance. During the past three decades, immense progress has been made in understanding the biosynthesis, homeostasis, perception, and functions of SA. This review summarizes the current knowledge regarding SA in plant immunity and other biological processes. We highlight recent breakthroughs that substantially advanced our understanding of how SA is biosynthesized from isochorismate, how it is perceived, and how SA receptors regulate different aspects of plant immunity. Some key questions in SA biosynthesis and signaling, such as how SA is produced via another intermediate, benzoic acid, and how SA affects the activities of its receptors in the transcriptional regulation of defense genes, remain to be addressed.

Molecular and Cellular Mechanisms Involved in Host-Specific Resistance to Cyst Nematodes in Crops.

Cyst nematodes are able to infect a wide range of crop species and are regarded as a major threat in crop production. In response to invasion of cyst nematodes, plants activate their innate immune system to defend themselves by conferring basal and host-specific defense responses depending on the plant genotype. Basal defense is dependent on the detection of pathogen-associated molecular patterns (PAMPs) by pattern recognition receptors (PRRs), while host-specific defense mainly relies on the activation of canonical and non-canonical resistance (R) genes or quantitative trait loci (QTL). Currently, application of R genes and QTLs in crop species is a major approach to control cyst nematode in crop cultivation. However, emerging virulent cyst nematode field populations are threatening crop production due to host genetic selection by the application of a limited set of resistance genes in current crop cultivars. To counteract this problem, increased knowledge about the mechanisms involved in host-specific resistance mediated by R genes and QTLs to cyst nematodes is indispensable to improve their efficient and sustainable use in field crops. Despite the identification of an increasing number of resistance traits to cyst nematodes in various crops, the underlying genes and defense mechanisms are often unknown. In the last decade, indebt studies on the functioning of a number of cyst nematode R genes and QTLs have revealed novel insights in how plants respond to cyst nematode infection by the activation of host-specific defense responses. This review presents current knowledge of molecular and cellular mechanisms involved in the recognition of cyst nematodes, the activation of defense signaling and resistance response types mediated by R genes or QTLs. Finally, future directions for research are proposed to develop management strategies to better control cyst nematodes in crop cultivation.

Development and Use of a Seedling Growth Retardation Assay to Quantify and Map Loci Underlying Variation in the Maize Basal Defense Response

The pattern-triggered immune (PTI) response in plants is caused by the recognition of conserved microbe‐ or pathogen‐associated molecular patterns (MAMPs) by plant pattern recognition receptors at the cell surface. The goal of this study was to develop a simple, robust assay to quantify the PTI response in maize and to determine whether it could be used to predict levels of disease resistance. Flg22, an epitope derived from bacterial flagellin, is a commonly studied MAMP. We developed a seedling growth retardation (SGR) assay by which we could measure growth retardation in maize seedlings exposed to the bacterial MAMP flg22. We observed variation across 21 maize inbred lines. We used 161 lines from a recombinant inbred line (RIL) population derived from a cross between the lines CML228 (a high responder) and B73 (a low responder) to map quantitative trait loci (QTL) for this response. We found heritable variation in the RIL population and identified flg22 response QTL on chromosomes 1, 2, and 8. We did not observe strong correlations between SGR traits and levels of flg22-induced reactive oxygen production or with other disease resistance or defense response traits we had previously measured in the same population. We discuss the implications of these findings. [Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

GhWRKY1-like enhances cotton resistance to Verticillium dahliae via an increase in defense-induced lignification and S monolignol content

Cotton is one of the most important economic crops and is cultivated globally. Verticillium wilt, caused by the soil-borne hemibiotrophic fungus Verticillium dahliae, is the most destructive disease in cotton production for its infection strategies and great genetic plasticity. Recent studies have identified the accumulation of lignin is a general and basal defense reaction in plant immunity and cotton resistance to V. dahliae. However, the functions and regulatory mechanisms of transcription factors in cotton defense-induced lignification and lignin composition alteration were less reported. Here, we identified a WRKY transcription factor GhWRKY1-like from upland cotton (Gossypium hirsutum) as a positive regulator in resistance to V. dahliae via directly manipulating lignin biosynthesis. Further analysis revealed that GhWRKY1-like interacts with the promoters of lignin biosynthesis related genes GhPAL6 and GhCOMT1, and activates the expression of GhPAL6 and GhCOMT1, which led to enhanced total lignin especially S monomers biosynthesis. These results demonstrate that GhWRKY1-like enhances Verticillium wilt resistance via an increase in defense-induced lignification and broaden our knowledge of the roles of lignification and the lignin composition in plant defense responses.

Mechanostimulation: a promising alternative for sustainable agriculture practices.

Plants memorize events associated with environmental fluctuations. The integration of environmental signals into molecular memory allows plants to cope with future stressors more efficiently-a phenomenon that is known as 'priming'. Primed plants are more resilient to environmental stresses than non-primed plants, as they are capable of triggering more robust and faster defence responses. Interestingly, exposure to various forms of mechanical stimuli (e.g. touch, wind, or sound vibration) enhances plants' basal defence responses and stress tolerance. Thus, mechanostimulation appears to be a potential priming method and a promising alternative to chemical-based priming for sustainable agriculture. According to the currently available method, mechanical treatment needs to be repeated over a month to alter plant growth and defence responses. Such a long treatment protocol restricts its applicability to fast-growing crops. To optimize the protocol for a broad range of crops, we need to understand the molecular mechanisms behind plant mechanoresponses, which are complex and depend on the frequency, intervals, and duration of the mechanical treatment. In this review, we synthesize the molecular underpinnings of plant mechanoperception and signal transduction to gain a mechanistic understanding of the process of mechanostimulated priming.

Detection of candidate genes and development of KASP markers for Verticillium wilt resistance by combining genome-wide association study, QTL-seq and transcriptome sequencing in cotton.

Combining GWAS, QTL-seq and transcriptome sequencing detected basaldefense-related genes showing gDNA sequence variation and expression difference in diverse cotton lines, which might be the molecular mechanisms of VW resistance in G. hirsutum. Verticillium wilt (VW), which is caused by the soil-borne fungus Verticillium dahliae, is a major disease in cotton (Gossypim hirsutum) worldwide. To facilitate the understanding of the genetic basis for VW resistance in cotton, a genome-wide association study (GWAS), QTL-seq and transcriptome sequencing were performed. The GWAS of VW resistance in a panel of 120 core elite cotton accessions using the Cotton 63K Illumina Infinium SNP array identified 5 QTL from 18 significant SNPs meeting the 5% false discovery rate threshold on 5 chromosomes. All QTL identified through GWAS were found to be overlapped with previously reported QTL. By combining GWAS, QTL-seq and transcriptome sequencing, we identified eight candidate genes showing both gDNA sequence variation and expression difference between resistant and susceptible lines, most related to transcription factors (TFs), flavonoid biosynthesis and those involving in the plantbasaldefense and broad-spectrum disease resistance. Ten KASP markers were successfully validated in diverse cotton lines and could be deployed in marker-assisted breeding to enhance VW resistance. These results supported our inference that the gDNA sequence variation or expression difference of those genes involving in thebasaldefense in diverse cotton lines might be the molecular mechanisms of VW resistance in G. hirsutum.