Project description:We investigated the transcriptional response to thiamethoxam in the Bemisia tabaci using Illumina sequencing technology. A total of 1,338 genes were differently expressed in the thiamethoxam-resistant whiteflies. All the B biotype whiteflies were maintained on cabbage. The susceptible strain (TH-S) was cultured without exposure to any chemical insecticides. Before the sample collected, almost 10,000 thiamethoxam-resistant adult whiteflies were treated with 2,000 mg/L thiamethoxam (~LC80) to eliminate the heterozygous individuals. Then the survivors were collected after 48 hours and designated as the TH-2000 sample. Then approximately 1,500 adult TH-S and TH-2000 were collected, respectively, The RNA was extracted and sequenced using Illumina HiSeq 2000.
Project description:We investigated the transcriptional response to thiamethoxam in the Bemisia tabaci using Illumina sequencing technology. A total of 1,338 genes were differently expressed in the thiamethoxam-resistant whiteflies.
Project description:The whitefly, Bemisia tabaci MEAM1 is a devastating vector capable of transmitting hundreds of plant viruses, including Tomato yellow leaf curl virus (TYLCV), to important food and fiber crops. Here we performed genome-wide profiling of micro RNAs (miRNAs) and piwi-interacting RNAs (piRNAs) in whiteflies after feeding on TYLCV-infected tomato or uninfected tomato for 24, 48 and 72 h. Overall, 160 miRNAs were discovered, 68 of which were conserved and 92 were B. tabaci-specific miRNAs. Majority of the genes that were predicted to be targeted by miRNAs had gene ontologies related to metabolic processes. We identified two miRNAs that were differentially expressed in whiteflies when fed on TYLCV-infected tomato compared to whiteflies that fed on uninfected tomato. The identified piRNAs were expressed as clusters throughout the whitefly genome. A total of 53 piRNA clusters were expressed across all time points and treatments, while 5 piRNA clusters were exclusively expressed in whiteflies that fed on TYLCV-infected tomato, and 24 clusters were exclusively expressed in whiteflies that fed on uninfected tomato. Approximately 62% of all identified piRNAs were derived from non-coding sequences that included intergenic regions, introns, and UTRs with unknown functions. The remaining 38% of piRNAs were derived from coding sequences (CDS) and repeat elements. Transposable elements targeted by piRNA clusters included both class I retrotransposons such as Gypsy, Copia, and LINEs and class II DNA transposons such as MITE, hAT, and TcMar. Lastly, six protein coding genes were targeted in whiteflies that fed on TYLCV-infected tomato. Information on how TYLCV influences miRNA and piRNA expression in whiteflies provides a greater understanding of regulatory pathways involved in mediating whitefly-virus interactions, and will facilitate the identification of novel targets for RNAi control.
Project description:The whitefly Bemisia tabaci (Gennadius) causes tremendous losses to agriculture by direct feeding on plants and by vectoring several families of plant viruses. The B. tabaci species complex comprises over 10 genetic groups (biotypes) that are well defined by DNA markers and biological characteristics. B and Q are amongst the most dominant and damaging biotypes, differing considerably in fecundity, host range, insecticide resistance, virus vectoriality, and the symbiotic bacteria they harbor. We used a spotted B. tabaci cDNA microarray to compare the expression patterns of 6,000 ESTs of B and Q biotypes under standard 25°C regime and heat stress at 40°C. Overall, the number of genes affected by increasing temperature in the two biotypes was similar. Gene expression under 25ºC normal rearing temperature showed clear differences between the two biotypes: B exhibited higher expression of mitochondrial genes, and lower cytoskeleton, heat-shock and stress-related genes, compared to Q. Exposing B-biotype whiteflies to heat stress was accompanied by rapid alteration of gene expression. For the first time, the results here present differences in gene expression between very closely related and sympatric B. tabaci biotypes, and suggest that these clear-cut differences are due to better adaptation of one biotype over another and might eventually lead to changes in the local and global distribution of both biotypes.
Project description:Global analysis of the transcriptional difference between indigenous and invasive whiteflies reveals the possible mechanism of whitefly invasion
Project description:The whitefly, Bemisia tabaci, a notorious agricultural pest, has complex relationships with diverse microbes. It recognizes and degrades pathogens, as other insects do, and also relies on endosymbionts for its survival. Both types of interaction have received great attention, because of their potential importance in developing novel whitefly control technologies. The recent developments in RNA-seq technology allows us to perform a comprehensive investigation of a whitefly’s defense responses after it has ingested the pathogen, Pseudomonas aeruginosa. Compared to uninfected whiteflies, 6 and 24 hour post-infected (hpi) whiteflies showed 1,348 and 1,888 differentially expressed genes, respectively. Functional analysis highlighted the involvement of mitogen associated protein kinase (MAPK) pathway in host-defense regulation. Three knottin-like antimicrobial peptide genes and several components of the humoral and cellular immune response were also activated, indicating that key immune elements recognized in other insect species are also important for the host response of B. tabaci. Our data also suggest that intestinal stem cell mediated epithelium renewal might be an important component of the whitefly’s defense against oral bacterial infection. In addition, we also show stress responses to be an essential component of the defense system. We identify for the first time the key immune-response elements utilized by B. tabaci against bacterial infection. This provides a framework for future research into the complex interactions between whiteflies and microbes.
Project description:The whitefly Bemisia tabaci (Gennadius) causes tremendous losses to agriculture by direct feeding on plants and by vectoring several families of plant viruses. The B. tabaci species complex comprises over 10 genetic groups (biotypes) that are well defined by DNA markers and biological characteristics. B and Q are amongst the most dominant and damaging biotypes, differing considerably in fecundity, host range, insecticide resistance, virus vectoriality, and the symbiotic bacteria they harbor. We used a spotted B. tabaci cDNA microarray to compare the expression patterns of 6,000 ESTs of B and Q biotypes under standard 25°C regime and heat stress at 40°C. Overall, the number of genes affected by increasing temperature in the two biotypes was similar. Gene expression under 25ºC normal rearing temperature showed clear differences between the two biotypes: B exhibited higher expression of mitochondrial genes, and lower cytoskeleton, heat-shock and stress-related genes, compared to Q. Exposing B-biotype whiteflies to heat stress was accompanied by rapid alteration of gene expression. For the first time, the results here present differences in gene expression between very closely related and sympatric B. tabaci biotypes, and suggest that these clear-cut differences are due to better adaptation of one biotype over another and might eventually lead to changes in the local and global distribution of both biotypes. 3 replicates comparing Q biotype under 40 degrees celsius (C) with three replicates under 25 C. The same number of replicates comparing B biotype under 40 C and 25 C, and three replicates comparing B and Q biotypes under 25 C.