Working group session:
Functional Genomics
Presentation type:
poster
Authors:
Zhang, Yan; Wang, Xingfen; Dai, He; Zhang, Guirong; Ding, Zeguo; Shang, Yuanyuan; Li, Zhikun; Zhang, Guiyin; Ma, Zhiying
Presenter:
Zhang, Yan; Wang, Xingfen; Dai, He; Zhang, Guirong; Ding, Zeguo; Shang, Yuanyuan; Li, Zhikun; Zhang, Guiyin
Correspondent:
Ma, Zhiying
Abstract:
Verticillium wilt, caused by Verticillium dahliae, brings serious damage to cotton production. Gossypium barbadense is one of the most important resistance sources. The knowledge of mechanism underlying its resistance to Verticillium wilt is still limited. To get an overview of transcriptome characteristic in roots of Gossypium barbadense resistant cultivar Pima90-53 compared to G. hirsutum susceptible cultivar CCRI8 during infection by V. dahliae, a high-throughput RNA sequencing based on next generation sequencing (NGS) were performed.
Totally, 83,964 unigenes were generated and assigned to known protein databases including NCBI non-redundant protein database (nr) (43,248, 51.51%), Swiss-Prot (27,414, 32.65%), Clusters of orthologous groups (COG) (16,723, 19.92%) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) (10,437, 12.4%), as determined by Blastx search. With another NGS based platform, the method described by Audic et al. was applied to identify differentially expressed genes from the normalized DGE data by pair-wise comparisons between the “Pima90-53”and “CCRI8” at five infection stages (6, 12, 24, 36 and 48 hpi), with the aim of identifying genes involved in V. dahliae resistance.
Differentially regulated cotton genes (2-fold or greater change; P≤0.001) upon inoculation with the V. dahliae were identified at different time points when compared with mock-inoculated control plants. V. dahliae inoculation resulted in that most of defense responses in Pima90-53 were more rapidly induced than those in CCRI8. And the difference in response intensity between the resistant and susceptible cultivars is also reflected by the number of induced genes, which amounted to 2628 genes at 36 hpi and 6124 genes at 48 hpi in Pima90-53 and CIR8, respectively. In addition, V. dahliae inoculation resulted in repression of photosynthesis.
To characterize the functional consequences of gene expression changes associated with infection with V. dahliae in the resistant cultivar, pathway analysis of differentially expressed genes was performed, based on the KEGG database using the two-side Fisher’s exact test. Several metabolic pathways that are related to immunity were selected for further analysis. The selected pathways included Perception of PAMPs by Pattern Recognition Receptors, Effector-triggered immunity, Ion fluxes, Transcription factors, Oxidative burst, Pathogenesis-related proteins, Programmed cell death, Plant hormones and Cell wall modification. All differentially expressed unigenes are involved in their cognition of PAMPs, and the high accumulated levels of defense-related transcripts may contribute to V. dahliae resistance in cotton. Based on the transcriptomic comparison of two differentially expressed unigenes between “Pima90-53”and “CCIR8”, a schematic illustration of plant defense in G. barbadense against V. dahliae was constructed.
In all, this study generated a substantial amount of cotton transcript sequences and compared the defense responses against V. dahliae between resistant and susceptible cottons. The results contribute to the identification of candidate genes related to plant resistance in a non-model organism, cotton, and help to improve the current understanding of host-pathogen interactions.