Pathogen-infected Plants Research Articles

Rhizosphere microbiome analysis of healthy and infected cumin (Cuminum cyminum L.) varieties from Gujarat, India.

Cumin (Cuminum cyminum L.; Jeera) is a popular herbal seed spice used in culinary preparation in India. Gujarat and Rajasthan are the largest producer states of cumin seeds from India, while India is also the largest supplier and exporter of cumin across the globe. However, production of cumin is suffering from loss of crop production due to the plant pathogen infections, especially from Fusarium oxysporium sp. Rhizomicrobiome is the key modulator of plant health, revitalizing nutrients and disease response against plant pathogens. The secretion of different metabolites such as root exudates plays an important role in host plant rhizosphere microbial interactions influencing the plant health, growth and development, nutrient acquisition, and disease resistance. Therefore, in this research study, we have examined the microbial diversity from the healthy and fungal infected rhizosphere samples of the three different Gujarat Cumin (GC-2, GC-3, and GC-4) varieties using 16S ribosomal RNA (rRNA) gene sequencing on Ion Torrent S5 sequencing platform. The findings revealed the major dominant family represented by Bacillaceae, Solibacteraceae, Nostocaceae, Paenibacillaceae, Scytonemataceae, and Halothiobacillaceae, while at genera level of taxonomic abundance were represented by Bacillus, Candidatus Solibacter, Synechococcus, Nostoc, Anabaena, and Oscillatoria. The research findings should enhance our understanding of healthy and infected plant rhizosphere microbiome for better crop productivity, disease resistance and management of the crop varieties against plant pathogens.

Rapid Detection and Quantification of Plant Innate Immunity Response Using Raman Spectroscopy.

We have developed a rapid Raman spectroscopy-based method for the detection and quantification of early innate immunity responses in Arabidopsis and Choy Sum plants. Arabidopsis plants challenged with flg22 and elf18 elicitors could be differentiated from mock-treated plants by their Raman spectral fingerprints. From the difference Raman spectrum and the value of p at each Raman shift, we derived the Elicitor Response Index (ERI) as a quantitative measure of the response whereby a higher ERI value indicates a more significant elicitor-induced immune response. Among various Raman spectral bands contributing toward the ERI value, the most significant changes were observed in those associated with carotenoids and proteins. To validate these results, we investigated several characterized Arabidopsis pattern-triggered immunity (PTI) mutants. Compared to wild type (WT), positive regulatory mutants had ERI values close to zero, whereas negative regulatory mutants at early time points had higher ERI values. Similar to elicitor treatments, we derived an analogous Infection Response Index (IRI) as a quantitative measure to detect the early PTI response in Arabidopsis and Choy Sum plants infected with bacterial pathogens. The Raman spectral bands contributing toward a high IRI value were largely identical to the ERI Raman spectral bands. Raman spectroscopy is a convenient tool for rapid screening for Arabidopsis PTI mutants and may be suitable for the noninvasive and early diagnosis of pathogen-infected crop plants.

Using arbuscular mycorrhizal fungi (Gigaspora margarita) as a growth promoter and biocontrol of leaf blight disease in eucalyptus seedlings caused by Cylindrocladium quinqueseptatum

The leaf blight disease is a common threat to the growth and production of eucalyptus seedlings in Thailand. This work then aimed to apply a biocontrol approach to help plants survive the disease. Cylindrocladium quinqueseptatum KKU-H4-B12, a pathogen causing leaf blight disease, was isolated from the lesion of eucalyptus leaves. Its pathogenicity was confirmed before use in the field experiments. An AMF Gigaspora margarita KKU-BH-01, previously proved to efficiently promote growth of eucalyptus, was pre-inoculated into eucalyptus seedlings for 30 days prior to pathogen infection. The results showed that an AMF could successfully colonize eucalyptus roots even in the pathogen-infected plants (≥56%). The disease assessment indicated that plants pre-inoculated with AMF and later infected with the pathogen (PM) had a disease reduction of 33.4%. Plant height, SPAD, fresh weights of roots and shoots in PM plants were relatively equal to those of the control plants, suggesting that AMF could relieve detrimental effects of the disease in plants. Moreover, we found that AMF induced plant chitinase and β-1,3-glucanase enzymes resulting in improved disease resistance in plants. This work is the first to report the application of a single AMF species to effectively enhance the growth and help eucalyptus seedlings to survive leaf blight disease.

The soil-borne ultimatum, microbial biotechnology and sustainable agriculture.

The soil-borne ultimatum, microbial biotechnology and sustainable agriculture.

Plant pathogen infection risk tracks global crop yields under climate change

Global food security is strongly determined by crop production. Climate change-induced losses to production can occur directly or indirectly, including via the distributions and impacts of plant pathogens. However, the likely changes in pathogen pressure in relation to global crop production are poorly understood. Here we show that temperature-dependent infection risk, r(T), for 80 fungal and oomycete crop pathogens will track projected yield changes in 12 crops over the twenty-first century. For most crops, both yields and r(T) are likely to increase at high latitudes. In contrast, the tropics will see little or no productivity gains, and r(T) is likely to decline. In addition, the United States, Europe and China may experience major changes in pathogen assemblages. The benefits of yield gains may therefore be tempered by the greater burden of crop protection due to increased disease and unfamiliar pathogens.

Screening of sunflower associated bacteria as biocontrol agents for plant growth promotion.

Deleterious effects of artificially applied chemicals have highlighted the significance of biocontrol agents as suitable substitute for sustainable agriculture. In present study, three endophytic bacterial strains SV7, SV10 and LV19 showed extensive range of antifungal as well as plant growth promoting activities signifying potential to accomplish the requirement. Phylogenetic analysis revealed 100% similarity of three strains with taxon Firmicute. However, there was division among these isolates on basis of subgroups as SV7 belonged to Exiguobacterium auranticum, SV10 belonged to Paenibacillus sp. and LV19 was best fit in subgroup Priestia koreensis. All strains showed antifungal activity against Fusarium oxysporum on three different media (PDA, NA, LA) with maximum activity (53%) of LV19 strain on NA and least activity (13%) on PDA medium as recorded by zones of inhibition. In growth promotion experiments, combination of LV19 with Fusarium significantly suppressed chances of Fusarium wilt which is commonly caused by Fusarium oxysporum in sunflower plants. Diverse growth parameters (seed germination percentage, lengths and fresh weights of root and shoot) were significantly increased from 34 to 909% over pathogen infected plants only which was further proved by their root colonization analysis. Based on most efficient growth promotion by LV19 strain, expression of five plant defense related genes (SOD, PAL, NPR1, PR5, Chitinase) was evaluated revealing enhanced expression by 1.7-270-folds in consortium of LV19 and Fusarium. Thus, current study provided a scientific justification that bacterial strains in specific LV19 (Priestia koreensis) could be further developed as biocontrol agent with potential of plant growth promotion.

Aphids show interspecific and intraspecific variation in life history responses to host plant infection by the fungal pathogen Botrytis cinerea

AbstractThe life histories of insect herbivores are affected by variation in host plant quality, with poor quality typically being associated with reduced herbivore fecundity, size and longevity. Plant pathogens are ubiquitous in nature and can alter host plant quality as experienced by insect herbivores. We asked how host plant infection by the widespread and economically important fungal pathogen Botrytis cinerea affected the life history traits of two aphid species. We found that the life history traits of the black bean aphid Aphis fabae were negatively affected by being reared on infected host plants, showing reduced fecundity, population growth rate, size, off‐plant survival time and development rate. In contrast, we found that pea aphids Acyrthosiphon pisum benefitted from being reared on infected plants, and that the degree of benefit varied between pea aphid clonal lines. This work suggests that the ecological and economic consequences of plant pathogen infection on the dynamics of aphid pests could be difficult to predict.

Fabatin induce defense-related enzymes in cucumber against soil born pathogen, Fusarium oxysporum

Fusarium oxysporum is one of the most common soil borne pathogens over the world. This work tried to introduce safe and efficient agent in controlling this pathogen infection in cucumber plants, beside that understanding the mechanism at which fabitine enables the cucumber plants to fight wilt disease. Also, this works introduce a molecular modeling for the direct interaction between fabatin and the Fusarium oxysporum. We evaluated the impact of defensin isolated from broad bean debris (fabatin) against the Fusarium wilt disease in the greenhouse, followed by the analysis of defense-related enzymes, including superoxide dismutase, polyphenol oxidase, soluble peroxidase, cell wall-bound peroxidase, catalase, lactate dehydrogenase, phenylalanine ammonia-lyase, chitinase, and glucanase. Moreover, the growth-regulating protein of the fungus (Snt2, a BAH/PHD) was docked with the fabatin. Fabatin reduced the disease severity from 18.52 to 0.0% by 100% disease reduction, 30 days after transplanting, and from 66.67 to 33.33% by 50.01% disease reduction after 60 days. Interestingly fabatin spray induced upregulation of the studied defense enzymes. The sprayed group showed significant continuous increase in defense related enzymes under infection. Furthermore, fabatin showed a high binding affinity to the Bromo-adjacent domain (BAH) of the Snt2 by - 214.42 kacl/mol and this can prevent the transcriptional regulation processes of the fungus. The present study proved that the exogenous spray fabatin is an effective way in controlling cucumber Fusarium wilt. This is achieved through the enhancement the defense related enzymes which regulate the resistance mechanism in the plants. Moreover, fabatin can directly influence the fungal growth.

Development of antioxidant materials based on Persian gum and Zataria essential oil: Modulation of superoxide-producing and nitric oxide-producing enzymes in wheat seedlings

Hydrogen peroxide and nitric oxide at low levels participate in various physiological functions, from plant development to defense responses including regulation of plant growth, pathogen infection, senescence, and seeds and rood development. In the present study, the stimulatory effects of Zataria multiflora essential oil (ZMEO) incorporated in the Persian gum on the activity and expression of superoxide-producing enzyme and nitric oxide-producing enzyme-like; NADPH oxidase (NOX), glutathione peroxidase (GPX), superoxide dismutase (SOD), catalase (CAT), nitric oxide synthase (NOS), nitrite reductase (NIR), polyamine oxidase (POX) and nitrate reductase (NAR) were investigated in the wheat seedlings. Carvacrol, γ-terpinene, α-terpinene, and p-cymene are the main components of ZMEO. ZMEO efficiently encapsulated in Persian gum dispersion and displayed low surface tension, low conductivity, low zeta-potential, acidic pH, nanoscale particle size and low Newtonian viscosity. Persian gum-ZMEO dispersion upregulated the activity and expression of NOX, SOD, CAT, GPX, NOS, NAR, NIR, and POX at 50 μg/ml as well as hydrogen peroxide and nitric oxide production. Briefly, the potent antioxidant capacity of the emulsified ZMEO implies that at low concentration it can effectively be used as a promising biostimulator to improve redox status in the wheat seedling.

The arbuscular mycorrhizal fungus Rhizophagus intraradices reduces the root rot caused by Fusarium pseudograminearum in wheat

Root colonization with arbuscular mycorrhizal fungi (AMF) improves plant tolerance against soil-borne pathogens. The purpose of the present study was to explore the efficacy of the AMF Rhizophagus intraradices (N.C. Schenck & G.S. Sm.) as a biocontrol agent against Fusarium pseudograminearum (O'Donnell and Aoki) in wheat plants grown under greenhouse conditions. Parameters here analyzed included disease severity, plant morphological features, mycorrhizal structures within roots, and oxidative stress levels. AMF inoculation significantly counteracted on the negative effects of the pathogen F. pseudograminearum on plant parameters such as aerial and root biomass, number of spikes and plant height. These results suggest that AMF inoculation considerably reduced the F. pseudograminearum population density (75.7%) and disease severity (39%) compared to control. In addition, when compared with pathogen-infected plants, AMF-inoculated plants exhibited significant increases in the activity of antioxidant enzymes, along with a decrease in the levels of lipid peroxidation. This is the first work to show R. intraradices plays a significant role in wheat tolerance to F. pseudograminearum infection by maintaining the redox balance and competing for root sites to colonize.

Transgenic expression of TaTLP1, a thaumatin-like protein gene, reduces susceptibility to common root rot and leaf rust in wheat

Thaumatin-like protein (TLP) plays an important role in combating plant pathogen infection. Common root rot caused by Bipolaris sorokiniana and leaf rust caused by Puccinia triticina (Pt) are major fungal diseases in wheat. The disease responses of TaTLP1-overexpressing transgenic lines (TaTLP1-OE) were evaluated after inoculation with each pathogen. The TaTLP1-OE lines had no apparent differences in tiller number and 1000-kernel weight from the wild type Jinan Wheat No. 1 (JW1), whereas resistance to leaf rust and common root rot was improved, resulting from activated peroxidase and β-1,3-glucanase after B. sorokiniana infection, and reactive oxygen species-related genes were upregulated in TaTLP1-OE lines after Pt infection. These results indicated that stable expression of TaTLP1 increased resistance against both diseases.

The expression of chili defense gene due to oviposition of fruit fly (Bactrocera dorsalis)

Ovipositions of fruit flies typically leave some wounds on the chili fruits. These punctures might allow some pathogenic microorganisms to get into the fruits and eventually cause the secondary infections. Taking this into account, this study aimed at determining the expression of chili defense gene (CaRGA2) due to pathogenic fungus infection which occurred following the fruit fly oviposition activities. The research was carried out from April to October 2018 in two research facilities located in West Java, Indonesia, i.e. the Molecular Laboratory of IVEGRI (West Bandung) and the Molecular Biology Laboratory of the Biotechnology and Bioindustry Research Center (Bogor). Chili fruits of three chili varieties with different levels of resistance againts fruit fly infestations (i.e. susceptible, moderately resistant, and resistant) were used in this study. Moreover, the RNA of each of the varieties was isolated before and after the fruit fly oviposition. The chili defense gene of CaRGA2 was tested in this study whereas the housekeeping gene used was Actin. The gene was amplified by using the RT-PCR method and afterwards, the data from the amplification were analyzed by employing the Livak method. The results showed that chili defense gene expression increased significantly in the susceptible chili variety, but did otherwise in both the moderately resistant and resistant varieties. Eventually, this result supported the previous studies that revealed the increased fungal pathogen infections in host plants due to the injuries caused by fruit fly oviposition.

Machine learning for phytopathology: from the molecular scale towards the network scale.

With the increasing volume of high-throughput sequencing data from a variety of omics techniques in the field of plant-pathogen interactions, sorting, retrieving, processing and visualizing biological information have become a great challenge. Within the explosion of data, machine learning offers powerful tools to process these complex omics data by various algorithms, such as Bayesian reasoning, support vector machine and random forest. Here, we introduce the basic frameworks of machine learning in dissecting plant-pathogen interactions and discuss the applications and advances of machine learning in plant-pathogen interactions from molecular to network biology, including the prediction of pathogen effectors, plant disease resistance protein monitoring and the discovery of protein-protein networks. The aim of this review is to provide a summary of advances in plant defense and pathogen infection and to indicate the important developments of machine learning in phytopathology.

Genetic Causes of Non-pathogenic Pseudomonas syringae pv. actinidiae Isolates in Kiwifruit Orchards.

Bacterial canker disease has become the largest threat to kiwifruit cultivation and production. A monomorphic subpopulation of Pseudomonas syringae pv. actinidiae biovar 3 (Psa3) is responsible for the pandemic worldwide. Diversity in pathogenicity has been found in the pandemic subpopulation and in other Psa3 subpopulations causing epidemics in China. However, the genetic bases have not yet been elucidated. In this study, 117 Psa3 isolates were identified by Psa- and Psa3-specific primers, and evaluated for pathogenicity. Three isolates G4, G40, and S2 are not pathogenic to kiwifruit and do not elicit hypersensitivity responses (HRs) in non-host Nicotiana benthamiana leaves. Two isolates, G25 and G35, exhibited attenuated HR-eliciting activity in non-host N. benthamiana, but they exhibited greatly and slightly reduced pathogenicity in host plants, respectively. The genomes of the five isolates were sequenced and compared with closely related isolates revealed by MLVA and whole-genome typing methods. The candidate genetic loci responsible for the changes in pathogenicity and HR elicitation, were further evaluated by allele replacement experiments. We found that the three non-pathogenic isolates were formed due to the independent, identical insertion events of ISPsy36 transposon in the hrpR gene, encoding a key regulator of type III secretion system (T3SS) and type III effectors (T3Es). In the symptomatic sample from which G4 was isolated, 27% HR negative isolates were detected. In isolate G25, transposon insertion of ISPsy32 at the non-coding sequence upstream of the hrpR gene was detected, similar to a previously reported low-virulent Psa3 strain M227. In isolate G35, we detected disruptions of T3Es hopBB1-1 and hopBB1-2, which induce HR in N. benthamiana leaves revealed by Agrobacterium tumefaciens infiltration. These phenotype-changed isolates were formed at low frequencies during the course of pathogen infection in host plants, supported by the binding assay of ISPsy32 and the non-coding DNA sequences upstream of the hrpR gene, the co-isolation of the virulent isolates belonging to the same MLVA clade, and the low levels of transcription of the transposon genes. Taken together, in terms of short-term field evolution, transposon insertions in the T3SS-related genes resulted in the formation of non-pathogenic and low-virulent Psa3 isolates.

Selective Interaction of Sugarcane eIF4E with VPgs from Sugarcane Mosaic Pathogens.

Eukaryotic translation initiation factor 4E (eIF4E) plays a key role in the infection of potyviruses in susceptible plants by interacting with viral genome-linked protein (VPg). Sugarcane (Saccharum spp.) production is threatened by mosaic disease caused by Sugarcane mosaic virus (SCMV), Sorghum mosaic virus (SrMV), and Sugarcane streak mosaic virus (SCSMV). In this study, two eIF4Es and their isoform eIF(iso)4E and 4E-binding protein coding genes were cloned from sugarcane cultivar ROC22 and designated SceIF4Ea, SceIF4Eb, SceIF(iso)4E, and ScnCBP, respectively. Real-time quantitative PCR analysis showed different expression profiles of these four genes upon SCMV challenge. A subcellular localization assay showed that SceIF4Ea, SceIF4Eb, SceIF(iso)4E, and ScnCBP were distributed in the nucleus and cytoplasm. Yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assays showed that SceIF4Ea/b and SceIF(iso)4E were selectively employed by different sugarcane mosaic pathogens, i.e., SCMV-VPg interacted with SceIF4Ea/b and SceIF(iso)4E, SrMV-VPg interacted with both SceIF4Eb and SceIF(iso)4E, and SCSMV-VPg interacted only with SceIF(iso)4E. Intriguingly, the BiFC assays, but not the Y2H assays, showed that ScnCBP interacted with the VPgs of SCMV, SrMV, and SCSMV. Competitive interaction assays showed that SCMV-VPg, SrMV-VPg, and SCMV-VPg did not compete with each other to interact with SceIF(iso)4E, and SceIF(iso)4E competed with SceIF4Eb to interact with SrMV-VPg but not SCMV-VPg. This study sheds light on the molecular mechanism of sugarcane mosaic pathogen infection of sugarcane plants and benefits sugarcane breeding against the sugarcane mosaic disease.

Dry Root Rot Disease Assays in Chickpea: a Detailed Methodology.

Dry root rot (DRR) disease is an emerging biotic stress threat to chickpea cultivation around the world. It is caused by a soil-borne fungal pathogen, Rhizoctonia bataticola. In the literature, comprehensive and detailed step-by-step protocols on disease assays are sparse. This article provides complete details on the steps involved in setting up a blotting paper technique for quickly screening genotypes for resistance to DRR. The blotting paper technique is easy and less expensive. Another method, based on the sick pot approach, is a mimic of natural infection and can be applied to study the interacting components-plant, pathogen, and environment-involved in the disease triangle. Moreover, in nature, DRR occurs mostly in rainfed chickpea cultivation areas, where soil moisture recedes as crop growth advances. Drought stress is known to predispose chickpea plants to DRR disease. Pathomorphological and molecular understanding of plant-pathogen interaction under drought stress can pave the way for the identification of elite DRR-resistant varieties from the chickpea germplasm pool. This article provides a stepwise methodology for the preparation of a sick pot and subsequent disease assay. Overall, the information presented herein will help researchers prepare R. bataticola fungal inoculum, maintain this pathogen, set up the blotting paper technique, prepare sick culture and sick pot, and assess pathogen infection in chickpea plants.

Foliar pathogen-induced assemblage of beneficial rhizosphere consortia increases plant defense against Setosphaeria turcica.

Background: Foliar pathogen infection can induce the enrichment of beneficial microbial consortia in plant rhizosphere, but the mechanism for enhanced plant resistance is unclear. Methods: We investigated the effects of foliar pathogen infection on bacterial communities in maize rhizosphere using high throughput sequencing. Results: Maize plants grown in non-sterilized soils displayed stronger defense against the foliar pathogen Setosphaeria turcica than those in sterilized soils. Foliar pathogen infection further triggered the shift in the structure and composition of rhizosphere bacterial communities. The pathogen-infected plants specially promoted rhizosphere colonization of several bacterial taxa. The Pseudomonas genus increased in the rhizosphere after pathogen infection. Other bacterial genera such as Chitinophaga and Flavobacterium were also greatly enriched in the rhizosphere of pathogen-infected plants. Furthermore, the enriched bacterial species were isolated and were shown to interact synergistically to promote biofilm formation. Although both the Chitinophaga and Flavobacterium species did not induce plant defense, the Pseudomonas species markedly increased the resistance of plants against S. turcica. Furthermore, the consortium consisting of the Pseudomonas, Chitinophaga and Flavobacterium species (CONpcf) conferred long-acting disease resistance of maize plants as compared to the individual Pseudomonas species. Furthermore, the inoculation with the CONpcf significantly induced a marked increase in the levels of DIMBOA in maize leaves, indicating that the consortium-induced increases of DIMBOA levels partially contributed to enhancing disease resistance of plants. Conclusions: Foliar infection of maize plants by S. turcica specifically recruited a group of beneficial rhizosphere bacteria, which conferred enhanced plant defense against pathogen infection. This study provided important evidence that above-ground pathogen infection participated in the mediation of below-ground microbiome for regulating plant defense systems.

Molecular Cloning and Expression Analysis of Auxilin-Like Gene StAL1 in Potato (Solanum tuberosum)

Auxilin is a J-domain-containing defense-related protein involved in clathrin-mediated endocytosis (CME) and acts on many organisms including yeast, Caenorhabditis elegans, Drosophila, Arabidopsis thaliana and rice. Auxilin regulates biological processes such as signal transduction, antibacterial defense, and stress resistance. To investigate the function of Auxilin gene in response to plant pathogen infection, the full-length of potato (Solanum tuberosum L.) Auxilin gene named StAL1 was cloned. Bioinformatics analysis of the gene revealed that StAL1 consists of 4828 bp, including a 4380 bp open reading frame that encodes a protein with 1443 amino acids. StAL1 is highly similar to Auxilin-like protein in potato and other Solanaceae species. Based on the qRT-PCR assays tissue expression pattern analysis revealed that StAL1 constitutively expressed in potato. StAL1 was induced by Ralstonia solanacearum species complex (RSSC) and up-regulated to varying extents by specific concentrations of exogenous phytohormones, including salicylic acid (SA), methyl jasmonate (MeJA) and abscisic acid (ABA). Examination of tissue localization suggested that StAL1 was primarily expressed in specific tissues (the phloem of the stem and leaf vascular systems). Furthermore, transient expression analysis showed the StAL1-GFP fusion protein was localized in the nucleus of Nicotiana benthamiana leaves cells. More importantly, auxilin is involved in plant immune response and disease resistance as an immune receptor binding protein. The results of the study should lay down the foundation for future research on the functional characterization of the Auxilin in potato plants.

Use of mycorrhizal fungi and compost for improving the growth and yield of tomato and its resistance to Verticillium dahliae

The impact of soil amendment with compost and/or application of arbuscular mycorrhizal fungi (AMF) on the resistance of tomato to Verticillium dahliae was evaluated. The frequency and intensity of mycorrhization decreased in V. dahliae inoculated plants. Application of compost and AMF significantly improved plant growth, stomatal conductance and chlorophyll fluorescence compared to infected and non infected controls. The combination of these biostimulants reduced the disease severity and incidence and the leaf alteration index compared to pathogen-infected control plants. Mycorrhized and compost amended soil recorded a maximum decrease in plants malonyldialdehyde accumulation in the presence of V. dahliae. The combination of compost and AMF resulted in a significant improvement of superoxide dismutase, catalase, peroxidase and polyphenoloxidase activities in tomato leaves and roots compared to the control treatment in the presence of the pathogen. Similarly, yield and quality of tomato fruits were significantly improved by the dual application of compost and AMF.

Identification of candidate genes conferring tolerance to aluminum stress in Pinus massoniana inoculated with ectomycorrhizal fungus

BackgroundPinus massoniana Lamb. is an important afforestation tree species with high economic, ecological and medicinal values. Aluminum (Al) toxicity driven by soil acidification causes dieback of P. massoniana plantations. Previous studies showed that ectomycorrhizal fungi alleviate Al stress damages in Pinus, but the underlying molecular mechanisms and key genes induced by ectomycorrhizal fungi inoculation under Al stress in Pinus have not been explored. Herein, we applied Al stress for 60 days to P. massoniana seedlings inoculated with Suillus luteus (SL) and those non-inoculated. Then, we compared their growth parameters and transcriptome in order to detect candidate genes induced by SL conferring Al tolerance in P. massoniana.ResultOur results showed that SL inoculation confers Al stress tolerance in P. massoniana through improved growth performance, strong antioxidant enzyme activities and reduced malondialdehyde accumulation as compared to non-inoculated seedlings. Transcriptome sequencing further supported these findings as very few genes (51 genes) were transcriptionally altered by Al in SL inoculated plants as compared to non-inoculated plants (2140 genes). We identified three core genes (cox1, cox3 and Nd1) that were strongly up-regulated by Al in the SL inoculated plants but were down-regulated in the non-inoculated plants. We also identified 42 genes specifically regulated by SL inoculated plants under Al stress, which are involved in a wide range of biological processes such as antioxidative response, transporters, hormone signaling and plant pathogen infection responses.ConclusionsAltogether, our data suggest that SL inoculation induces priming of key stress response pathways and triggers specific genes that efficiently alleviate Al stress effects in P. massoniana. The candidate genes resources generated in this study are of utmost importance for functional characterization and molecular studies aiming at improving Al tolerance in plants.