Project description:During plant life, roots support beneficial associations with soil inhabiting microbes, mainly fungi and bacteria. Increasing evidence suggests that plant-associated microorganisms can promote plant growth and expand immune functions of the plant host. The beneficial entomopathogenic fungus Beauveria bassiana colonizes plant tissues in an asymptomatic way, triggering poorly characterized plant metabolic changes, which negatively affect both pest insects and plant pathogens. B. bassiana has an extremely broad host spectrum, including tomato (Solanum lycopersicum L.). In order to obtain a great overall snapshot of molecular events regulating tomato-B. bassiana interaction, plant proteome and hormonome changes induced over the time by the fungus have been in-depth analyzed by using a combination of high throughput profiling techniques and bioinformatics tools. The proteomics data highlighted interesting molecular pathways affected by B. bassiana related to primary and secondary metabolism and plant growth. Additionally, downregulation of a member of the endochitinase family and upregulation of calcium channel and transporter proteins suggested well-established plant-fungus symbiosis. The molecular pathways linked to protein/amino acids turn-over and to the biosynthesis of energy compounds shed some light on the strategies exploited by the plant to get the most out of the beneficial interaction in improving growth and development.
Project description:BACKGROUND: The tomato psyllid, Bactericera cockerelli Šulc (Hemiptera: Triozidae), is a pest of solanaceous crops such as tomato (Solanum lycopersicum L.) in the U.S. and vectors the disease-causing pathogen ‘Candidatus Liberibacter solanacearum’. Currently, the only effective strategies for controlling the diseases associated with this pathogen involve regular pesticide applications to manage psyllid population density. However, such practices are unsustainable and will eventually lead to widespread pesticide resistance in psyllids. Therefore, new control strategies must be developed to increase host-plant resistance to insect vectors. For example, expression of constitutive and inducible plant defenses can be improved through selection. Currently, it is still unknown whether psyllid infestation has any lasting consequences on tomato plant defense or tomato plant gene expression in general. RESULTS: To characterize the genes putatively involved in tomato defense against psyllid infestation, RNA was extracted from psyllid-infested and uninfested tomato leaves (Moneymaker) three weeks post-infestation. Transcriptome analysis identified 362 differentially expressed genes. These differentially expressed genes were primarily associated with defense responses to abiotic/biotic stress, transcription/translation, cellular signaling/transport, and photosynthesis. These gene expression changes suggested that tomato plants underwent a reduction in plant growth/health in exchange for improved defense against stress that was observable three weeks after psyllid infestation. Consistent with these observations, tomato plant growth experiments determined that the plants were shorter three weeks after psyllid infestation. Furthermore, psyllid nymphs had lower survival rates on tomato plants that had been previously psyllid infested. CONCLUSION: These results suggested that psyllid infestation has lasting consequences for tomato gene expression, defense, and growth.
Project description:Alternative splicing (AS) is a critical post-transcriptional regulatory mechanism in eukaryotes. While infection with Ralstonia solanacearum GMI1000 significantly alters plant AS patterns, the underlying molecular mechanisms remain unclear. Herein, we investigate the effects of GMI1000 Type III secretion system (T3SS) effector proteins on AS in the tomato cultivar Heinz 1706. RNA sequencing (RNA-seq) confirmed genome-wide AS changes induced by the T3SS in tomato, in-cluding 1386 differential alternative splicing events in 1023 differentially alternatively spliced genes, many of which are associated with plant defense. Seven nucleus-localized Type III effec-tors(T3Es) were transiently expressed in an RLPK splicing reporter system transgenic tobacco, identifying RipP2 as an effector that modulates AS levels. Sequence analysis, protein-protein in-teraction assays, and AlphaFold2 structural predictions revealed that RipP2 interacts with the tomato splicing factor SR34a.Furthermore, RipP2 acetylates a conserved lysine at position 132 within the SWQDLKD motif of SR34a, regulating its splicing pattern in defense-related genes and modulating plant immunity. This study elucidates how the "Rip-SR34a module" influences plant immune responses by regulating the alternative splicing of immune-related genes, providing new insights into the molecular mechanisms of pathogen-plant interactions, particularly in splicing regulation.
Project description:MicroRNAs are crucial regulator of reprogramming of gene expression cascade during plant-pathogen interaction. We have used tomato (Pusa Ruby) plant and early blight pathogen, Alternaria for the analysis of tomato miRNA expression profiles in a compatible interaction. Illumina next generation sequencing (NGS) technique based whole transcriptome analysis revealed that, (i) about 188 known miRNAs, ranging from 18nt to 24nt expressed in tomato, which belonged to 124 miRNA families and (ii) both conserved and Solanaceae specific miRNAs were differentially expressed. Most of the miRNAs were down-regulated, and around 7 miRNAs were highly differentially regulated (log2FC ≥ ±3). Furthermore, using stringent selection criteria we could detect approximately 74 putative novel miRNAs. GO terms enrichment and KEGG pathway analyses of predicted targets of differentially expressed miRNAs have been performed to identify the pathways that were perturbed during the infection. Supported by DBT, Govt. of India.
Project description:Three Gram-stain-positive, irregular-rod-shaped, non-motile, non-spore-forming bacteria were isolated from nematodes collected from Santa Antao, Cabo Verde (CBX151T, CBX152T) and Kakegawa, Japan (CBX130T). Based on 16S rRNA gene sequence similarity, strains CBX130T, CBX151T and CBX152T were shown to belong to the genus Leucobacter. This affiliation was supported by chemotaxonomic data (2,4-diaminobutyric acid in the cell wall; major respiratory quinones MK-10 and MK-11; major polar lipids phosphatidylglycerol and diphosphatidylglycerol; major fatty acids anteiso-C15 : 0, anteiso-C17 : 0 and iso-C16 : 0). Strains CBX130T and CBX152T were found to share salient characteristics. Based on morphological, physiological, chemotaxonomic and biochemical analysis, strain CBX152T represents a novel species of the genus Leucobacter, for which the name Leucobacter musarum sp. nov. (type strain CBX152T = DSM 27160T = CIP 110721T) is proposed. Two subspecies of Leucobacter musarum sp. nov. are proposed: Leucobacter musarum sp. nov. subsp. musarum subsp. nov. (type strain CBX152T = DSM 27160T = CIP 110721T) and Leucobacter musarum sp. nov. subsp. japonicus subsp. nov. (type strain CBX130T = DSM 27158T = CIP 110719T). The third novel strain, CBX151T, showed genetic similarities with Leucobacter celer NAL101T indicating that these strains belong to the same species. Based on morphological, physiological, chemotaxonomic and biochemical differences it is proposed to split the species Leucobacter celer into two novel subspecies, Leucobacter celer subsp. celer subsp. nov. (type strain NAL101T = KACC 14220T = JCM 16465T) and Leucobacter celer subsp. astrifaciens subsp. nov. (type strain CBX151T = DSM 27159T = CIP 110720T), and to emend the description of Leucobacter celerShin et al. 2011.
Project description:Arbuscular mycorrhizal symbiosis is a predominant relationship between plant and arbuscular mycorrhizal fungi. To idendify arbuscular mycorrhiza responsive miRNAs, small RNA libraries were constructed in tomato roots colonized with Rhizophagus irregularis and without Rhizophagus irregularis. We identify miRNAs in tomato roots and provide a new profile of tomato miRNAs. And we found that some miRNAs were responsive to arbuscular mycorrhiza by comparing miRNAs in treatment with that in control. Examination of arbuscular mycorrhiza responsive miRNAs in tomato through high-throughput small RNA sequencing of roots with Rhizophagus irregularis and that without Rhizophagus irregularis
Project description:The gram- positive bacterial pathogen Clavibacter michiganensis subsp. michiganensis (Cmm) causes huge economic losses by infecting tomato plants worldwide. Cmm can be spread by contaminated seeds and transplants, penetrating the plant through natural openings or wounds and is transferred through the plant xylem. While in recent years significant progress has been made to elucidate plant responses to pathogenic gram-negative bacteria by gene expression studies, the molecular mechanisms that lead to disease symptoms caused by gram-positive bacteria like Cmm remain elusive. An indigenous virulent Cmm strain isolated from a farm crop of Pomodoro tomatoes in southern Greece was used for the infection of EKSTASIS F1 hybrid tomato seedlings. Here, we present the results of a deep RNA- sequencing (RNA-seq) analysis performed to characterize the dynamic expression profile of tomato genes upon Cmm infection.