Project description:Verticillium wilt caused by the soil-borne fungus Verticillium dahliae is a common, devastating plant vascular disease notorious for causing economic losses. Despite considerable research on plant resistance genes, there has been little progress in modeling the effects of this fungus owing to its complicated pathogenesis. Here, we analyzed the transcriptional and metabolic responses of Arabidopsis thaliana to V. dahliae inoculation by Illumina-based RNA sequencing (RNA-seq) and nuclear magnetic resonance (NMR) spectroscopy. We identified 13,916 differentially expressed genes (DEGs) in infected compared with mock-treated plants. Gene ontology analysis yielded 11,055 annotated DEGs, including 2,308 for response to stress and 2,234 for response to abiotic or biotic stimulus. Pathway classification revealed involvement of the metabolic, biosynthesis of secondary metabolites, plant-pathogen interaction, and plant hormone signal transduction pathways. In addition, 401 transcription factors, mainly in the MYB, bHLH, AP2-EREBP, NAC, and WRKY families, were up- or downregulated. NMR analysis found decreased tyrosine, asparagine, glutamate, glutamine, and arginine and increased alanine and threonine levels following inoculation, along with a significant increase in the glucosinolate sinigrin and a decrease in the flavonoid quercetin glycoside. Our data reveal corresponding changes in the global transcriptomic and metabolic profiles that provide insights into the complex gene-regulatory networks mediating the plant's response to V. dahliae infection.
Project description:Verticillium wilt is a plant vascular disease causing severe yield and quality losses in many crops and is caused by the soil-borne plant pathogenic fungus Verticillium dahliae. To investigate the molecular mechanisms of the cotton-V. dahliae interaction, a time-course phosphoproteomic analysis of roots of susceptible and resistant cotton lines in response to V. dahliae was performed. In total, 1716 unique phosphoproteins were identified in the susceptible (S) and resistant (R) cotton lines. Of these, 359 phosphoproteins were significantly different in R1 (1 day after V. dahliae inoculation) vs R0 (mock) group and 287 phosphoproteins in R2 (3 days after V. dahliae inoculation) vs R0 group. Moreover, 263 proteins of V. dahliae-regulated phosphoproteins were significantly changed in S1 (1 day after V. dahliae inoculation) vs S0 (mock) group and 197 proteins in S2 (3 days after V. dahliae inoculation) vs S0 group. Thirty phosphoproteins were significantly changed and common to the resistant and susceptible cotton lines following inoculation with V. dahliae. Specifically, 92 phosphoproteins were shared in both in R1 vs R0 and R2 vs R0 but not in susceptible cotton lines. There were 38 common phosphoproteins shared in both S1 vs S0 and S2 vs S0 but not in resistant cotton lines. GO terms and Kyoto Encyclopedia of Genes and Genomes pathway analyses displayed an abundance of known and novel phosphoproteins related to plant-pathogen interactions, signal transduction, and metabolic processes, which were correlated with resistance against fungal infection. These data provide new perspectives and inspiration for understanding molecular defense mechanisms of cotton roots against V. dahliae infection.
Project description:Small RNAs (sRNAs, including small interfering RNAs [siRNAs] and micro RNAs [miRNAs]) are key mediators of RNA silencing (or RNA interference), which play important roles in plant development and response to biotic and abiotic stimulation. Verticillium wilt is a plant vascular disease caused by the soil-borne fungal pathogens, such as Verticillium dahliae. We previously reported that V. dahliae infection increased two plant endogenous miRNAs that were exported to fungal cell to silence virulence genes. To investigate plant sRNAs in genome-wide response to V. dahliae infection, in this study, we constructed two sRNA libraries from Arabidopsis roots with and without V. dahliae infection, respectively. In total, 31 conserved miRNAs were found to be differentially expressed during the early stage of infection with V. dahliae using sRNA sequencing. Among these, the expression levels of miR160, miR164, miR166, miR167, miR390 and miR156h were confirmed by northern blot. Reverse transcription quantitative real time polymerase chain reaction results showed that the induction of miRNAs (miR160, miR164, miR166 and miR167) upon V. dahliae infection downregulated the expression of their targeted genes (ARF10, NAC1, PHV and ARF6), respectively. In addition, we identified specific phased siRNAs generated from distinct regions of two libraries. Profiling of these miRNAs and sRNAs lay the foundation for further understanding and utilising the host-induced gene silencing strategy to control plant vascular pathogens.
Project description:Okra (Abelmoschus esculentus (L.) Moench) has gained more popularity as an economically significant plant for its nutritional and medicinal value, especially in China. During 2014-2016, the root disease of okra was discovered in four okra commercial fields surveyed in China. A fungul was isolated from the infected tissues, and was identified by Verticillium dahliae based on morphological characteristics. Pathogenicity test demonstrated that the fungus was pathogenic on okra, and fulfilled Koch's postulates. The analysis of three sequences revealed 99-100% identity with the reported V. dahliae strain in GenBank. Neighbor-joining analysis of the gene sequences revealed that the representative isolates were clustered with V. dahliae. To the best of our knowledge, this is the first report of Verticillium wilt of okra in China.
Project description:MicroRNAs (miRNAs) and small interfering RNAs (siRNAs) are short (19-25 nucleotides) non-coding RNA molecules that have large-scale regulatory effects on development and stress responses in plants. Verticillium wilt is a vascular disease in plants caused by the fungal pathogen Verticillium dahliae. The objective of this study is to investigate the transcriptional profile of miRNAs and other small non-coding RNAs in Verticillium-inoculated cotton roots. Four small RNA libraries were constructed from mocked and infected roots of two cotton cultured species which are with different Verticillium wilt tolerance ('Hai-7124', Gossypium barbadense L., a Verticillium-tolerant cultivar, and 'Yi-11', Gossypium hirsutum L. a Verticillium-sensitive cultivar). The length distribution of obtained small RNAs was significantly different between libraries. There were a total of 215 miRNA families identified in the two cotton species. Of them 14 were novel miRNAs. There were >65 families with different expression between libraries. We also identified two trans-acting siRNAs and thousands of endogenous siRNA candidates, and hundred of them exhibited altered expression after inoculation of Verticillium. Interesting, many siRNAs were found with a perfect match with retrotransposon sequences, suggested that retrotransposons maybe one of sources for the generation of plant endogenous siRNAs. The profiling of these miRNAs and other small non-coding RNAs lay the foundation for further understanding of small RNAs function in the regulation of Verticillium defence responses in cotton roots.
Project description:Wilt caused by Verticillium dahliae significantly reduces cotton yields, as host resistance in commercially cultivated Gossypium species is lacking. Understanding the molecular basis of disease resistance in non-commercial Gossypium species could galvanize the development of Verticillium wilt resistance in cultivated species. Nucleotide-binding site leucine-rich repeat (NBS-LRR) proteins play a central role in plant defence against pathogens. In this study, we focused on the relationship between a locus enriched with eight NBS-LRR genes and Verticillium wilt resistance in G. barbadense. Independent virus-induced gene silencing of each of the eight NBS-LRR genes in G. barbadense cultivar Hai 7124 revealed that silencing of GbaNA1 alone compromised the resistance of G. barbadense to V. dahliae isolate Vd991. In cultivar Hai 7124, GbaNA1 could be induced by V. dahliae isolate Vd991 and by ethylene, jasmonic acid and salicylic acid. Nuclear protein localization of GbaNA1 was demonstrated by transient expression. Sequencing of the GbaNA1 orthologue in nine G. hirsutum accessions revealed that all carried a non-functional allele, caused by a premature peptide truncation. In addition, all 10 G. barbadense and nine G. hirsutum accessions tested carried a full-length (∼1140 amino acids) homologue of the V. dahliae race 1 resistance gene Gbve1, although some sequence polymorphisms were observed. Verticillium dahliae Vd991 is a non-race 1 isolate that lacks the Ave1 gene. Thus, the resistance imparted by GbaNA1 appears to be mediated by a mechanism distinct from recognition of the fungal effector Ave1.