Expression Of Defense-related Genes Research Articles

The miR172/TOE3 module regulates resistance to tobacco mosaic virus in tobacco.

The outcome of certain plant-virus interaction is symptom recovery, which is accompanied with the emergence of asymptomatic tissues in which the virus accumulation decreased dramatically. This phenomenon shows the potential to reveal critical molecular factors for controlling viral disease. MicroRNAs act as master regulators in plant growth, development, and immunity. However, the mechanism by which miRNA participates in regulating symptom recovery remains largely unknown. Here, we reported that miR172 was scavenged in the recovered tissue of tobacco mosaic virus (TMV)-infected Nicotiana tabacum plants. Overexpression of miR172 promoted TMV infection, whereas silencing of miR172 inhibited TMV infection. Then, TARGET OF EAT3 (TOE3), an APETALA2 transcription factor, was identified as a downstream target of miR172. Overexpression of NtTOE3 significantly improved plant resistance to TMV infection, while knockout of NtTOE3 facilitated virus infection. Furthermore, transcriptome analysis indicated that TOE3 promoted the expression of defense-related genes, such as KL1 and MLP43. Overexpression of these genes conferred resistance of plant against TMV infection. Importantly, results of dual-luciferase assay, chromatin immunoprecipitation-quantitative PCR, and electrophoretic mobility shift assay proved that TOE3 activated the transcription of KL1 and MLP43 by binding their promoters. Moreover, overexpression of rTOE3 (the miR172-resistant form of TOE3) significantly reduced TMV accumulation compared to the overexpression of TOE3 (the normal form of TOE3) in miR172 overexpressing Nicotiana benthamiana plants. Taken together, our study reveals the pivotal role of miR172/TOE3 module in regulating plant immunity and in the establishment of recovery in virus-infected tobacco plants, elucidating a regulatory mechanism integrating plant growth, development, and immune response.

Bacillus velezensis HN-2: a potent antiviral agent against pepper veinal mottle virus.

Pepper veinal mottle virus (PVMV) belongs to the genus Potyvirus within the family Potyviridae and is a major threat to pepper production, causing reduction in yield and fruit quality; however, efficient pesticides and chemical treatments for plant protection against viral infections are lacking. Hence, there is a critical need to discover highly active and environment-friendly antiviral agents derived from natural sources. Bacillus spp. are widely utilized as biocontrol agents to manage fungal, bacterial, and viral plant diseases. Particularly, Bacillus velezensis HN-2 exhibits a strong antibiotic activity against plant pathogens and can also induce plant resistance. The experimental subjects employed in this study were Bacillus velezensis HN-2, benzothiadiazole, and dufulin, aiming to evaluate their impact on antioxidant activity, levels of reactive oxygen species, activity of defense enzymes, and expression of defense-related genes in Nicotiana benthamiana. Furthermore, the colonization ability of Bacillus velezensis HN-2 in Capsicum chinense was investigated. The results of bioassays revealed the robust colonization capability of Bacillus velezensis HN-2, particularly in intercellular spaces, leading to delayed infection and enhanced protection against PVMV through multiple plant defense mechanisms, thereby promoting plant growth. Furthermore, Bacillus velezensis HN-2 increased the activities of antioxidant enzymes, thereby mitigating the PVMV-induced ROS production in Nicotiana benthamiana. Moreover, the application of Bacillus velezensis HN-2 at 5 dpi significantly increased the expression of JA-responsive genes, whereas the expression of salicylic acid-responsive genes remained unchanged, implying the activation of the JA signaling pathway as a crucial mechanism underlying Bacillus velezensis HN-2-induced anti-PVMV activity. Immunoblot analysis revealed that HN-2 treatment delayed PVMV infection at 15 dpi, further highlighting its role in inducing plant resistance and promoting growth and development. These findings underscore the potential of Bacillus velezensis HN-2 for field application in managing viral plant diseases effectively.

AtSNU13 modulates pre-mRNA splicing of RBOHD and ALD1 to regulate plant immunity

Pre-mRNA splicing is a significant step for post-transcriptional modifications and functions in a wide range of physiological processes in plants. Human NHP2L binds to U4 snRNA during spliceosome assembly; it is involved in RNA splicing and mediates the development of human tumors. However, no ortholog has yet been identified in plants. Therefore, we report At4g12600 encoding the ortholog NHP2L protein, and AtSNU13 associates with the component of the spliceosome complex; the atsnu13 mutant showed compromised resistance in disease resistance, indicating that AtSNU13 is a positive regulator of plant immunity. Compared to wild-type plants, the atsnu13 mutation resulted in altered splicing patterns for defense-related genes and decreased expression of defense-related genes, such as RBOHD and ALD1. Further investigation shows that AtSNU13 promotes the interaction between U4/U6.U5 tri-snRNP-specific 27 K and the motif in target mRNAs to regulate the RNA splicing. Our study highlights the role of AtSNU13 in regulating plant immunity by affecting the pre-mRNA splicing of defense-related genes.

One stone two birds: Endophytes alleviating trace elements accumulation and suppressing soilborne pathogen by stimulating plant growth, photosynthetic potential and defense related gene expression

In the present investigation, we utilized zinc nanoparticles (Zn-NPs) and bacterial endophytes to address the dual challenge of heavy metal (HM) toxicity in soil and Rhizoctonia solani causing root rot disease of tomato. The biocontrol potential of Bacillus subtilis and Bacillus amyloliquefaciens was harnessed, resulting in profound inhibition of R. solani mycelial growth and efficient detoxification of HM through strong production of various hydrolytic enzymes and metabolites. Surprisingly, Zn-NPs exhibited notable efficacy in suppressing mycelial growth and enhancing the seed germination (%) while Gas chromatography-mass spectrometry (GC-MS) analysis unveiled key volatile compounds (VOCs) crucial for the inhibition of pathogen. Greenhouse trials underscored significant reduction in the disease severity (%) and augmented biomass in biocontrol-mediated plants by improving photosynthesis-related attributes. Interestingly, Zn-NPs and biocontrol treatments enhanced the antioxidant enzymes and mitigate oxidative stress indicator by increasing H2O2 concentration. Field experiments corroborated these findings, with biocontrol-treated plants, particularly those receiving consortia-mediated treatments, displayed significant reduction in disease severity (%) and enhanced the fruit yield under field conditions. Root analysis confirmed the effective detoxification of HM, highlighting the eco-friendly potential of these endophytes and Zn-NPs as fungicide alternative for sustainable production that foster soil structure, biodiversity and promote plant health.

Hydrogen sulfide enhances kiwifruit resistance to soft rot by regulating jasmonic acid signaling pathway

As the third active gas signal molecule in plants, hydrogen sulfide (H2S) plays important roles in physiological metabolisms and biological process of fruits and vegetables during postharvest storage. In the present study, the effects of H2S on enhancing resistance against soft rot caused by Botryosphaeria dothidea and the involvement of jasmonic acid (JA) signaling pathway in kiwifruit during the storage were investigated. The results showed that 20 μL L−1 H2S fumigation restrained the disease incidence of B. dothidea-inoculated kiwifruit during storage, and delayed the decrease of firmness and the increase of soluble solids (SSC) content. H2S treatment increased the transcription levels of genes related to JA biosynthesis (AcLOX3, AcAOS, AcAOC2, and AcOPR) and signaling pathway (AcCOI1, AcJAZ5, AcMYC2, and AcERF1), as well as the JA accumulation. Meanwhile, H2S promoted the expression of defense-related genes (AcPPO, AcSOD, AcGLU, AcCHI, AcAPX, and AcCAT). Correlation analysis revealed that JA content was positively correlated with the expression levels of JA biosynthesis and defense-related genes. Overall, the results indicated that H2S could promote the increase of endogenous JA content and expression of defense-related genes by regulating the transcription levels of JA pathway-related genes, which contributed to the inhibition on the soft rot occurrence of kiwifruit.

Multigenerational Adaptation Can Enhance the Pathogen Resistance of Plants via Changes in Rhizosphere Microbial Community Assembly.

Plants withstand pathogen attacks by recruiting beneficial bacteria to the rhizosphere and passing their legacy on to the next generation. However, the underlying mechanisms involved in this process remain unclear. In our study, we combined microbiomic and transcriptomic analyses to reveal how the rhizosphere microbiome assembled through multiple generations and defense-related genes expressed in Arabidopsis thaliana under pathogen attack stress. Our results showed that continuous exposure to the pathogen Pseudomonas syringae pv tomato DC3000 led to improved growth and increased disease resistance in a third generation of rps2 mutant Arabidopsis thaliana. It could be attributed to the enrichment of specific rhizosphere bacteria, such as Bacillus and Bacteroides. Pathways associated with plant immunity and growth in A. thaliana, such as MAPK signaling pathways, phytohormone signal transduction, ABC transporter proteins, and flavonoid biosynthesis, were activated under the influence of rhizosphere bacterial communities. Our findings provide a scientific basis for explaining the relationship between beneficial microbes and defense-related gene expression. Understanding microbial communities and the mechanisms involved in plant responses to disease can contribute to better plant management and reduction of pesticide use.

Perillyl alcohol, a natural monoterpene, controls the gray mold on tomato via inducing jasmonic acid and kaempferol production

Perillyl alcohol (POH), a natural monoterpene, exhibits potent anticancer activity and may also play a role in inhibiting plant pathogens. However, its mechanism of action on controlling gray mold of tomato remains unclear. In this study, we investigated the effect of POH on Botrytis cinerea infected tomato. The results demonstrate that POH inhibits the in vitro growth of B. cinerea by disrupting plasma membrane integrity, thereby exhibiting broad-spectrum antimicrobial activity. Metabolomic analysis revealed that POH activated jasmonic acid (JA) biosynthesis and induced JA production in B. cinerea-treated tomato. Furthermore, POH upregulated the expression of defense-related genes and induced ROS accumulation. Specifically, POH induced the accumulation of kaempferol in tomato and exogenous kaempferol disrupted the plasma membrane of B. cinerea and induced ROS production. Taken together, POH can inhibit the development of gray mold, besides enhancing plant immunity against B. cinerea by inducing JA accumulation and promoting kaempferol biosynthesis.

Beneficial effects of Bacillus mojavensis strain MTC-8 on plant growth, immunity and disease resistance against Magnaporthe oryzae.

Rice blast, a prevalent and highly destructive rice disease that significantly impacts rice yield, is caused by the rice blast fungus. In the present study, a strain named MTC-8, identified as Bacillus mojavensis, was demonstrated has strong antagonistic activity against the rice blast fungus, Rhizoctonia solani, Ustilaginoidea virens, and Bipolaria maydis. The potential biocontrol agents were identified using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) analysis and chromatography. Further investigations elucidated the inhibitory mechanism of the isolated compound and demonstrated its ability to suppress spore germination, alter hyphal morphology, disrupt cell membrane integrity, and induce defense-related gene expression in rice. MTC-8 promoted plant growth and may lead to the development of a biocontrol agent that meets agricultural standards. Overall, the Bacillus mojavensis MTC-8 strain exerted beneficial effects on plant growth, immunity and disease resistance against rice blast fungus. In this study, we isolated and purified a bioactive substance from fermentation broth, and the results provide a foundation for the development and application of biopesticides. Elucidation of the inhibitory mechanism against rice blast fungus provides theoretical support for the identification of molecular targets. The successful development of a biocontrol agent lays the groundwork for its practical application in agriculture.

Biocontrol of Fusarium head blight in rice using Bacillus velezensis JCK-7158.

Fusarium head blight (FHB) is a destructive disease caused by several species of Fusarium, such as Fusarium graminearum and F. asiaticum. FHB affects cereal crops, including wheat, barley, and rice, worldwide. Fusarium-infected kernels not only cause reduced yields but also cause quality loss by producing mycotoxins, such as trichothecenes and zearalenone, which are toxic to animals and humans. For decades, chemical fungicides have been used to control FHB because of their convenience and high control efficacy. However, the prolonged use of chemical fungicides has caused adverse effects, including the emergence of drug resistance to pathogens and environmental pollution. Biological control is considered one of the most promising alternatives to chemicals and can be used for integrated management of FHB due to the rare possibility of environment pollution and reduced health risks. In this study, Bacillus velezensis JCK-7158 isolated from rice was selected as an ecofriendly alternative to chemical fungicides for the management of FHB. JCK-7158 produced the extracellular enzymes protease, chitinase, gelatinase, and cellulase; the plant growth hormone indole-3-acetic acid; and the 2,3-butanediol precursor acetoin. Moreover, JCK-7158 exhibited broad antagonistic activity against various phytopathogenic fungi and produced iturin A, surfactin, and volatile substances as active antifungal compounds. It also enhanced the expression of PR1, a known induced resistance marker gene, in transgenic Arabidopsis plants expressing β-glucuronidase (GUS) fused with the PR1 promoter. Under greenhouse conditions, treatments with the culture broth and suspension concentrate formulation of JCK-7158 at a 1,000-fold dilution inhibited the development of FHB by 50 and 66%, respectively. In a field experiment, treatment with the suspension concentrate formulation of JCK-7158 at a 1,000-fold dilution effectively controlled the development of FHB with a control value of 55% and reduced the production of the mycotoxin nivalenol by 40%. Interestingly, treatment with JCK-7158 enhanced the expression of plant defense-related genes in salicylic acid, jasmonic acid, ethylene, and reactive oxygen species (ROS) signaling pathways before and after FHB pathogen inoculation. Taken together, our findings support that JCK-7158 has the potential to serve as a new biocontrol agent for the management of FHB.

Pathophysiology and transcriptomic responses of Pinus armandii defenses to ophiostomatoid fungi.

Pinus armandii Franch. is an ecologically and economically important evergreen tree species native to western China. Dendroctonus armandi Tsai and Li and pathogenic ophiostomatoid fungi pose substantial threats to P. armandii. With the interplay between species, the defense mechanisms of P. armandii have evolved to withstand external biotic stressors. However, the interactions between P. armandii and pathogenic ophiostomatoid fungal species/strains remain poorly understood. We aimed to analyze the pathophysiological and molecular changes in P. armandii following artificial inoculation with four ophiostomatoid species (Graphilbum parakesiyea, Leptographium qinlingense, Ophiostoma shennongense and Ophiostoma sp. 1). The study revealed that L. qinlingense produced the longest necrotic lesions, and G. parakesiyea produced the shortest. All strains induced monoterpenoid release, and monoterpene levels of P. armandii were positively correlated with fungal virulence (R2=0.93, P<0.01). Co-inoculation of two dominant highly (L. qinlingense) and weakly virulent (O. shennongense) pathogens reduced the pathogenicity of the highly virulent fungi. Transcriptomic analysis of P. armandii (LQ: L. qinlingense treatments, QS: co-inoculation treatments and OS: O. shennongense treatments) showed that the expression pattern of differentially expressed genes (DEGs) between QS and OS was similar, but different from that of LQ. The DEGs (LQ vs QS) involved in flavonoid biosynthesis and phenylpropanoid biosynthesis were downregulated. Notably, compared with LQ, QS significantly decreased the expression of host defense-related genes. This study provides a valuable theoretical basis for managing infestations of D. armandi and associated ophiostomatoid fungi.

Rice SRO1a contributes to Xanthomonas TAL effector-mediated expression of host susceptible gene.

Xanthomonas species infect many important crops and cause huge yield loss. These pathogens deliver transcription activator-like (TAL) effectors into the cytoplasm of plant cells. TAL effectors move to host nuclei, directly bind to the promoters of host susceptible genes, and activate their transcription. However, the molecular mechanisms by which TAL effectors induce host transcription remain unclear. We herein demonstrated that TAL effectors interacted with the SIMILAR TO RCD ONE (SRO) family proteins OsSRO1a and OsSRO1b in nuclei. A transactivation assay using rice protoplasts indicated that OsSRO1a and OsSRO1b enhanced the activation of the OsSWEET14 promoter by the TAL effector AvrXa7. The AvrXa7-mediated expression of OsSWEET14 was significantly reduced in ossro1a mutants. However, the overexpression of OsSRO1a increased disease resistance by up-regulating the expression of defense-related genes, such as WRKY62 and PBZ1. This was attributed to OsSRO1a and OsSRO1b also enhancing the transcriptional activity of WRKY45, a direct regulator of WRKY62 expression. Therefore, OsSRO1a and OsSRO1b appear to positively contribute to transcription mediated by bacterial TAL effectors and rice transcription factors.

GDSL Lipase Gene HTA1 Negatively Regulates Heat Tolerance in Rice Seedlings by Regulating Reactive Oxygen Species Accumulation.

High temperature is a significant environmental stress that limits plant growth and agricultural productivity. GDSL lipase is a hydrolytic enzyme with a conserved GDSL sequence at the N-terminus, which has various biological functions, such as participating in plant growth, development, lipid metabolism, and stress resistance. However, little is known about the function of the GDSL lipase gene in the heat tolerance of rice. Here, we characterized a lipase family protein coding gene HTA1, which was significantly induced by high temperature in rice. Rice seedlings in which the mutant hta1 was knocked out showed enhanced heat tolerance, whereas the overexpressing HTA1 showed more sensitivity to heat stress. Under heat stress, hta1 could reduce plant membrane damage and reactive oxygen species (ROS) levels and elevate the activity of antioxidant enzymes. Moreover, real-time quantitative PCR (RT-qPCR) analysis showed that mutant hta1 significantly activated gene expression in antioxidant enzymes, heat response, and defense. In conclusion, our results suggest that HTA1 negatively regulates heat stress tolerance by modulating the ROS accumulation and the expression of heat-responsive and defense-related genes in rice seedlings. This research will provide a valuable resource for utilizing HTA1 to improve crop heat tolerance.

Simultaneously enhancing plant growth and immunity through the application of engineered Bacillus subtilis expressing a microbial pattern1

Simultaneously enhancing plant growth and disease resistance is an ideal goal in Agriculture. Significant efforts have been made to promote plant growth or immunity through the use of biological reagents, such as the application of beneficial microbes and plant immunity inducers. However, balancing plant immunity and growth remains a challenging task. In this study, we engineered the plant growth-promoting bacterium Bacillus subtilis OKB105 to express a secreted microbial pattern, flg22, and accessed its activity in enhancing both plant growth and disease resistance. The OKB105 (flg22) strain exhibited plant growth-promoting activity similar to the OKB105 strain containing an empty vector, OKB105 (EV). Furthermore, the OKB105 (flg22) strain significantly enhanced plant resistance against two distinct pathogens, Pseudomonas syringae DC3000 ΔhopQ1-1 and Phytophthora parasitica, compared to OKB105 (EV), confirming that the engineered OKB105 (flg22) effectively enhances plant disease resistance. Interestingly, root irrigation with OKB105 (flg22) also markedly boosted the plant’s aboveground resistance to pathogens compared to OKB105 (EV). We further demonstrated that OKB105 (flg22) can be applied to confer resistance to pathogens in other plants that recognize flg22. Finally, RNA-Seq and qRT-PCR analyses illustrated that OKB105 (flg22) effectively induced the expression of defense-related genes in pattern-triggered immunity. Our results prove that employing an engineered beneficial microbe expressing a microbial pattern is a promising strategy for simultaneously enhancing plant growth and immunity.

Bacillus tequilensis influences metabolite production in tomato and restores soil microbial diversity during Fusarium oxysporum infection.

This study evaluates cellular damage, metabolite profiling, and defence-related gene expression in tomato plants and soil microflora during Fusarium wilt disease after treatment with B. tequilensis PBE-1. Histochemical analysis showed that PBE-1 was the primary line of defence through lignin deposition and reduced cell damage. GC-MS revealed that PBE-1 treatment ameliorated stress caused by F. oxysporum infection. PBE-1 also improved transpiration, photosynthesis, and stomatal conductance in tomato. qRT-PCR suggested that the defence-related genes FLS2, SERK, NOS, WRKYT, NHO, SAUR, and MYC2, which spread infection, were highly upregulated during F. oxysporum infection, but either downregulated or expressed normally in PBE-1 + P treated plants. This indicates that the plant not only perceives the bio-control agent as a non-pathogen entity but its presence in normal metabolism and gene expression within the host plant is maintained. The study further corroborated findings that application of PBE-1 does not cause ecological disturbances in the rhizosphere. Activity of soil microflora across four treatments, measured by Average Well Colour Development (AWCD), showed continuous increases from weeks 1 to 4 post-pathogen infection, with distinct substrate usage patterns like tannic and fumaric acids impacting microbial energy source utilization and diversity. Principal Component Analysis (PCA) and diversity indices like McIntosh, Shannon, and Simpson further illustrated significant microbial community shifts over the study period. In conclusion, our findings demonstrate that B. tequilensis PBE-1 is an ideal bio-agent for field application during Fusarium wilt disease management in tomato.

Screening for disease resistance and profiling the expression of defense-related genes contributing to resistance against bacterial blight (Xanthomonas oryzae pv. oryzae) in rice genotypes

Bacterial Bight profoundly affects global rice-growing regions. Breeding resistant cultivars is a reliable, effective, and eco-friendly way to control bacterial blight. The study was conducted during 2021–2022 to evaluate the resistance of rice genotypes to bacterial blight under glasshouse conditions. A total of 137 rice genotypes were screened for their resistance against two Xanthomonas oryzae pv. oryzae strains (TXO01 and TXO08) using the leaf clipping method. The results revealed diverse disease reactions among the genotypes, with some exhibiting high levels of resistance characterized by hypersensitive reactions and shorter lesion lengths. To further investigate the genetic basis of resistance, we screened moderately resistant and resistant genotypes for major bacterial blight resistance genes, including Xa21, xa5, and xa13, using gene-specific markers. Five genotypes viz., ADT55, CB MAS 13056, CB MAS 13060, CB MAS 13066, and ACM 18234 confirmed the presence of all R genes in a homozygous state, indicating a potentially robust resistance background. In addition, we examined the expression patterns of five defense-related genes involved in the salicylic acid (SA) and jasmonic acid (JA) signaling pathways using quantitative real-time PCR (qRT-PCR). The resistant genotypes exhibited significantly elevated expression levels of OsNPR1, OsWRKY45, OsPAL1, OsPR1a, and OsPR10a, ranging from 2 to 20-fold changes compared with the susceptible genotype. In conclusion, our findings suggest that the resistant genotypes not only harbor multiple bacterial blight resistance genes but also manifest up regulated defense responses against Xanthomonas oryzae pv. oryzae, possibly substantiating their elevated level of disease resistance.

Biochemical and Molecular Basis of Chemically Induced Defense Activation in Maize against Banded Leaf and Sheath Blight Disease.

Maize is the third most vital global cereal, playing a key role in the world economy and plant genetics research. Despite its leadership in production, maize faces a severe threat from banded leaf and sheath blight, necessitating the urgent development of eco-friendly management strategies. This study aimed to understand the resistance mechanisms against banded leaf and sheath blight (BLSB) in maize hybrid "Vivek QPM-9". Seven fungicides at recommended doses (1000 and 500 ppm) and two plant defense inducers, salicylic acid (SA) and jasmonic acid (JA) at concentrations of 50 and 100 ppm, were applied. Fungicides, notably Azoxystrobin and Trifloxystrobin + Tebuconazole, demonstrated superior efficacy against BLSB, while Pencycuron showed limited effectiveness. Field-sprayed Azoxystrobin exhibited the lowest BLSB infection, correlating with heightened antioxidant enzyme activity (SOD, CAT, POX, β-1,3-glucanase, PPO, PAL), similar to the Validamycin-treated plants. The expression of defense-related genes after seed priming with SA and JA was assessed via qRT-PCR. Lower SA concentrations down-regulated SOD, PPO, and APX genes but up-regulated CAT and β-1,3-glucanase genes. JA at lower doses up-regulated CAT and APX genes, while higher doses up-regulated PPO and β-1,3-glucanase genes; SOD gene expression was suppressed at both JA doses. This investigation elucidates the effectiveness of certain fungicides and plant defense inducers in mitigating BLSB in maize hybrids and sheds light on the intricate gene expression mechanisms governing defense responses against this pathogen.

Comparative transcriptional analysis of Persea americana MYB, WRKY and AP2/ERF transcription factors following Phytophthora cinnamomi infection.

Plant cells undergo extensive transcriptional reprogramming following pathogen infection, with these reprogramming patterns becoming more complex when pathogens, such as hemibiotrophs, exhibit different lifestyles. These transcriptional changes are often orchestrated by MYB, WRKY and AP2/ERF transcription factors (TFs), which modulate both growth and defence-related gene expression. Transcriptional analysis of defence-related genes in avocado (Persea americana) infected with Phytophthora cinnamomi indicated differential immune response activation when comparing a partially resistant and susceptible rootstock. This study identified 226 MYB, 82 WRKY, and 174 AP2/ERF TF-encoding genes in avocado, using a genome-wide approach. Phylogenetic analysis revealed substantial sequence conservation within TF groups underscoring their functional significance. RNA-sequencing analysis in a partially resistant and susceptible avocado rootstock infected with P. cinnamomi was indicative of an immune response switch occurring in either rootstock after 24 and 6 h post-inoculation, respectively. Different clusters of co-expressed TF genes were observed at these times, suggesting the activation of necrotroph-related immune responses at varying intervals between the two rootstocks. This study aids our understanding of avocado immune response activation following P. cinnamomi infection, and the role of the TFs therein, elucidating the transcriptional reprogramming disparities between partially resistant and susceptible rootstocks.

Soil amendments with nanoparticles control cucumber wilt caused by Fusarium oxysporium

Management of Fusarium wilt, a destructive plant disease, mainly relies on chemicals, but research on novel and eco-friendly methods is needed due to the hazardous effects of chemical pesticides. This study explored the soil application of zinc oxide nanoparticles (ZnONPs) to manage Fusarium wilt disease in cucumber plants. The antifungal activity of ZnONPs against in-vitro growth of Fusarium oxysporum was tested through food poisoning test on the potato dextrose agar medium. The in-vivo potential of NPs for managing Fusarium wilt was checked in pot experiment. In-vitro results confirmed the concentration-dependent in-vitro antifungal activity. The NPs application at 500 µg/ml and 600 µg/ml concentrations showed phytotoxicity and significantly inhibited seed germination and growth of cucumber plants. However, NPs at 300 µg/ml significantly suppressed the pathogenic effects of F. oxysporum on cucumber plants without any phytotoxic effect. The pathogen-inoculated cucumber plants grown in soil amended with NPs showed significantly enhanced growth, lower disease severity, and improved root physiology compared to untreated plants. The plants under NPs treatment showed higher chlorophyll and nitrogen content while decreased membrane permeability and malondialdehyde content. Along with direct antifungal activity, the application of NPs caused an increased expression of defense-related genes and higher activities of defense-related enzymes. These findings verified the efficiency of ZnONPs for suppressing Fusarium wilt disease in cucumber crops, thereby promoting a non-chemical and environmentally friendly approach to controlling Fusarium wilt disease.

Transcriptome analysis of sea cucumber (Apostichopus japonicus) in southern China under heat stress

Sea cucumber (Apostichopus japonicus) is a significant aquatic economic species globally. However, the advancement of the sea cucumber aquaculture industry is impeded by its high susceptibility to elevated temperatures. To elucidate the impact of high temperature on physiological changes, gene expression, and metabolic responses in sea cucumbers, we conducted transcriptional profiling of A. japonicus under heat stress. Our results revealed 3691 differentially expressed genes (DEGs), comprising 1629 up-regulated and 2062 down-regulated genes, between the control and treatment groups. Analysis of the Kyoto Encyclopedia of Genes and Genomes (KEGG), Gene Ontology (GO), and Protein-Protein Interaction Networks (PPI) indicated that high-temperature stress triggered the expression of stress defense-related genes while inhibiting the expression of genes associated with development and metabolism. Furthermore, 30 out of 39 DEGs were annotated to heat shock protein genes, underscoring the crucial role of these genes in the regulatory mechanism of A. japonicus in response to heat stress. In summary, our findings provide fundamental insights for further investigation into the molecular mechanisms in A. japonicus under high-temperature stress and may contribute to the development of novel strategies for identifying heat-tolerant candidate genes through the analysis of their transcriptional changes in the future.

TaCRT3 Is a Positive Regulator of Resistance to Blumeria graminis f. sp. tritici in Wheat.

Wheat powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), is one of the most prevalent diseases of wheat worldwide and can lead to severe yield reductions. Identifying genes involved in powdery mildew resistance will be useful for disease resistance breeding and control. Calreticulin (CRT) is a member of multigene family widely found in higher plants and is associated with a variety of plant physiological functions and defense responses. However, the role of CRT in wheat resistance to powdery mildew remains unclear. TaCRT3 was identified from the proteomic sequence of an incompatible interaction between the wheat (Triticum aestivum) cultivar Xingmin 318 and the Bgt isolate E09. Following analysis of transient expression of the GFP-TaCRT3 fusion protein in Nicotiana benthamiana leaves, TaCRT3 was localized in the nucleus, cytoplasm, and cell membrane. Transcript expression levels of TaCRT3 were significantly upregulated in the wheat-Bgt incompatible interaction. More critically, knockdown of TaCRT3 using virus-induced gene silencing resulted in attenuated resistance to Bgt in wheat. Histological analysis showed a significant increase in Bgt development in TaCRT3-silenced plants, whereas the pathogen-related gene was significantly downregulated in TaCRT3-silenced leaves. In addition, overexpression of TaCRT3 in wheat enhanced the resistance to powdery mildew, the growth of Bgt was significantly inhibited, and the area of H2O2 near the infection site and the expression of defense-related genes of the salicylic acid pathway significantly increased. These findings imply that TaCRT3 may act as a disease resistance factor that positively regulates resistance to powdery mildew, during which SA signaling is probably activated.