Project description:In the fall, Eastern North American monarch butterflies (Danaus plexippus) undergo a magnificent long-range migration. In contrast to spring and summer butterflies, fall migrants are juvenile hormone deficient, which leads to reproductive arrest and increased longevity. Migrants also use a time-compensated sun compass to help them navigate in the south/southwesterly direction en route for Mexico. Central issues in this area are defining the relationship between juvenile hormone status and oriented flight, critical features that differentiate summer monarchs from fall migrants, and identifying molecular correlates of behavioral state. Here we show that increasing juvenile hormone activity to induce summer-like reproductive development in fall migrants does not alter directional flight behavior or its time-compensated orientation, as monitored in a flight simulator. Reproductive summer butterflies, in contrast, uniformly fail to exhibit directional, oriented flight. To define molecular correlates of behavioral state, we used microarray analysis of 9417 unique cDNA sequences. Gene expression profiles reveal a suite of 40 genes whose differential expression in brain correlates with oriented flight behavior in individual migrants, independent of juvenile hormone activity, thereby separating molecularly fall migrants from summer butterflies. Intriguing genes that are differentially regulated include the clock gene vrille and the locomotion-relevant tyramine beta hydroxylase gene. In addition, several differentially regulated genes (37.5% of total) are not annotated, suggesting unique functions associated with oriented flight behavior. We also identified 23 juvenile hormone-dependent genes in brain, which separate reproductive from non-reproductive monarchs; genes involved in longevity, fatty acid metabolism, and innate immunity are upregulated in non-reproductive (juvenile-hormone deficient) migrants. The results link key behavioral traits with gene expression profiles in brain that differentiate migratory from summer butterflies and thus show that seasonal changes in genomic function help define the migratory state.

Project description:Honey bees move through a series of in-hive tasks (M-bM-^@M-^\nursingM-bM-^@M-^]) to outside tasks (M-bM-^@M-^\foragingM-bM-^@M-^]) that coincident with an intense increase in metabolic activity. Social context can cause worker bees to speed up, or slow down this process and foragers may revert back to their earlier in hive tasks accompanied by reversion to earlier physiological states. To determine if the transcriptional profile of forager bees can revert, or if the effects of flight on gene expression are irreversible, we used whole-genome microarrays. Brain tissue and flight muscle exhibited independent patterns of expression during behavioral transitions, with patterns of expression in the brain reflecting both age and behavior, while flight muscle exhibited primarily age-related patterns of expression. Our data suggest that the transition from little to no flight (nurse) to intense flight (forager), rather than the amount of flight has a major effect on gene expression. Following behavioral reversion there was a partial reversion in gene expression but some aspects of forager expression patterns, such as those for genes involved in immune function, remained. These data suggest an epigenetic control and energy balance role in honey bee functional senescence. Brains and thoraces from the same individuals of all behavioral groups were compared on a total of 132 arrays. The samples were hybridized against each other using a loop design. The groups tested are outlined as follows: Typical aged nurse 'YN' (8-10 days old; <1 day flight experience), Precocious forager 'PF' (8 to 10 days old; 2 to 3 days flight experience), Overaged nurse 'ON' (19 to 22 days old; < 1 day flight experience), Forager - low flight 'TFL' (19 to 22 days old; 2 to 3 days flight experience), Forager - high flight 'TFH' ( 19 to 22 days old; 7 to 9 days flight experience), Forager - old 'OF' (25 to 26 days old; 10 to 12 days flight experience), Reverted nurse 'RN' (25 to 26 days old; 7 to 9 days flight experience). The comparisons are outlined as follows: YN:ON (6 arrays), ON:RN (6 arrays), RN:TFH (6 arrays), TFH:TFL (6 arrays), TFL:PF (6 arrays), PF:YN (6 arrays), ON:TFL (12 arrays), YN:OF (6 arrays), OF:RN (6 arrays), RN:YN (6 arrays). Each comparison was done for individual brains and thoraces. Total: 132 arrays

Project description:In the fall, Eastern North American monarch butterflies (Danaus plexippus) undergo a magnificent long-range migration. In contrast to spring and summer butterflies, fall migrants are juvenile hormone deficient, which leads to reproductive arrest and increased longevity. Migrants also use a time-compensated sun compass to help them navigate in the south/southwesterly direction en route for Mexico. Central issues in this area are defining the relationship between juvenile hormone status and oriented flight, critical features that differentiate summer monarchs from fall migrants, and identifying molecular correlates of behavioral state. Here we show that increasing juvenile hormone activity to induce summer-like reproductive development in fall migrants does not alter directional flight behavior or its time-compensated orientation, as monitored in a flight simulator. Reproductive summer butterflies, in contrast, uniformly fail to exhibit directional, oriented flight. To define molecular correlates of behavioral state, we used microarray analysis of 9417 unique cDNA sequences. Gene expression profiles reveal a suite of 40 genes whose differential expression in brain correlates with oriented flight behavior in individual migrants, independent of juvenile hormone activity, thereby separating molecularly fall migrants from summer butterflies. Intriguing genes that are differentially regulated include the clock gene vrille and the locomotion-relevant tyramine beta hydroxylase gene. In addition, several differentially regulated genes (37.5% of total) are not annotated, suggesting unique functions associated with oriented flight behavior. We also identified 23 juvenile hormone-dependent genes in brain, which separate reproductive from non-reproductive monarchs; genes involved in longevity, fatty acid metabolism, and innate immunity are upregulated in non-reproductive (juvenile-hormone deficient) migrants. The results link key behavioral traits with gene expression profiles in brain that differentiate migratory from summer butterflies and thus show that seasonal changes in genomic function help define the migratory state. A total of 40 monarch butterflies were used for the microarray analysis. Of the 40, 10 (5 male/5 female) were summer butterflies (Designated as S) and 30 were fall butterflies. The fall butterflies were further divided into three groups: 10 (5 male/5 female) were untreated (F); 10 (5 male/5 female) were treated with methoprene (M), which is a juvenile hormone analog and induces the development of reproductive organs in migrant butterflies; and 10 (5 male/5 female) were treated with vehicle only (V). We collected total brain RNA from each of the 40 butterflies. The brain RNAs were amplified and then used to probe a custom Nimblegen array that was designed to analyze the 9,417 unique cDNA sequences established in our published EST library (http://titan.biotec.uiuc.edu/cgi-bin/ESTWebsite/estima_start?seqSet=butterfly). Our main interest is to find genes involved in migration. This includes genes regulating oriented flight behavior of the butterfly and genes that regulate reproductive status. To identify these genes, we approached the microarray data in two ways. First, we identified the potential genes involved in oriented flight behavior using the following strategy. We compared the summer group to each of the three fall groups (untreated, methoprene-treated, and vehicle-treated) for males and for females, and looked for gene regulation patterns common among the three comparisons for each sex. Because the comparisons were done separately for males and females, and our behavioral data did not show significant sex differences in flight orientation, we focused on the common differentially regulated genes that were shared between males and females. Accordingly, we identified 40 cDNAs that were differentially regulated between summer butterflies and fall migrants, irrespective of sex. Second, we looked for the juvenile hormone-response genes. Again, we performed sex-specific statistical analyses, and compared the summer and the fall groups, and the methoprene-treated and vehicle-treated migrants. We then screened for shared genes between the two groups for each sex. We next examined cDNAs that were differentially regulated in both males and females, to determine juvenile hormone-regulated genes involved in more global processes (e.g., longevity and fatty acid metabolism) that would not be expected to be sex-specific. We identified 23 putative juvenile hormone-response genes that were common between males and females.

Project description:A genomic insight into how an insect pest responds to the infection of a fungal insect pathogen, such as Beauveria bassiana, is critical for alternative strategy of insect pest contol based on fungal insecticides but has not been well probed. Here we constructed three pairs of digital expression libraries (transcriptomes) of Plutella xylostella (global lepidopteran pest) larvae 24, 36 and 48 hours post treatment of infection (hptI) and control (hptC) to reveal the host response to B. bassiana infection at genomic level. The paired libraries comprised 2144, 3200 and 2967 differentially expressed genes (DEGs) of P. xylostella at 24, 36 and 48 hptI/hptC, respectively. These DEGs were enriched in various immune pathways activated by the fungal infection, such as the pathways of complement and coagulation cascades, protein digestion and absorption, and drug metabolism - cytochrome P450. We found that 24 hptI was critical either for the cuticular penetration of B. bassiana or for the initial activation of the host defense system. The host immune response peaked at 36 hptI so that multiple defense mechanisms were activated against the fungal entry into the host hemocoel. At 48 hptI, many host genes involved in immunity and metabolism were downregulated, suggesting a success of fungal localization in the host hemocoel by overcoming the host defense reaction. Finally, we revealed that several fungal pathways could play important roles in the host-pathogen interaction, such as antioxidant activity, peroxidase activity and proteolysis. Up to 1636 fungal genes were co-expressed at the three time points, and 116 of them encode putative secretion proteins. Our results provide a novel insight into the pathogen-insect interaction and help to probe molecular mechanisms involved in the control of P. xylostella by B. bassiana. Here we constructed three pairs of digital expression libraries (transcriptomes) of Plutella xylostella (global lepidopteran pest) larvae 24, 36 and 48 hours post treatment of infection (hptI) and control (hptC) to reveal the host response to B. bassiana infection at genomic level

Dataset Information

Genome-wide transcriptional signatures of migratory flight activity in a globally invasive insect pest

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