Project description:Most northern insect species experience a period of developmental arrest, diapause, which enables them to survive over the winter and postpone reproduction until favorable conditions. We studied the timing of reproductive diapause and its long-term effects on the cold tolerance of Drosophila montana, D. littoralis and D. ezoana females in seasonally varying environmental conditions. At the same time we traced expression levels of 219 genes in D. montana using a custom-made microarray. We show that the seasonal switch to reproductive diapause occurs over a short time period, and that overwintering in reproductive diapause has long-lasting effects on cold tolerance. Some genes, such as Hsc70, Jon25bi and period, were upregulated throughout the diapause, while others, including regucalcin, couch potato and Thor, were upregulated only at its specific phases. Some of the expression patterns induced during the sensitive stage, when the females either enter diapause or not, remained induced regardless of the later conditions. qPCR analyses confirmed the findings of the microarray analysis in D. montana and revealed similar gene expression changes in D. littoralis and D. ezoana. The present study helps to achieve a better understanding of the genetic regulation of diapause and of the plasticity of seasonal responses in general. Custom made DNA microarray for Drosophila montana and D. virilis. Current experiment includes 8 samples (7 to 250 days old diapausing or non-diapausing D. montana females) with two or three biological replicates
Project description:Background: Vernicia fordii (Tung oil tree) is a popular tree for biodiesel production in China. Unfortunately, the devastating Fusarium wilt disease caused great losses in production. Its sister species (Vernicia montana) was shown resistant to this pathogen. Vernicia fordii and Vernicia montana are main Vernicia species. V. fordii owns superior oil and agronomic traits, but susceptible to tung wilt disease, while V. nontana is resistant the wilt. However, the plants response mechanism remains largely unknown. Method: To define the divergence of gene expression modules between the resistant and susceptible Vernicia species responding to tung wilt pathogen, we generated comparative transcriptome atlases of two species during the process of infection with the pathogen F. oxysporum by RNA Sequencing in three biological replicates. Results: We describe the de novo assembly of the transcriptome of V. fordii and V. montana, comprising 258,430 and 245,240 non-redundant transcripts with N50 of 1,776 and 2,452 respectively. About 44,310 pair of putatively one-to-one orthologous genes between V. fordii and V. montana transcriptoms were identified. Overall, a high proportion of orthologous genes shared remarkably similar expression mode between Vernicia species. K means clustering indicated 2 cluster appear opposite expression mode. The highly connected gene expression analysis were conducted among genes with significantly differential expression mode, and the result indicated D6PK and LRR-RLK CLAVATA2 were top hub genes and hub genes glycosyltransferase (Gts), GLABRA2, PERK15 and EREBP-like factor were significantly associated with pathologic grades in resistant V. montana. Moreover, the result showed the resistant is a crucial signaling network, where MAPK signaling pathway, Plant-pathogen interaction, Circadian rhythm, Calcium signaling pathway and apoptosis fulfill distinct function. Additionally, dozens of unigenes were validated by quantitative real-time PCR (qRT-PCR). The study provided insight into the resistance gene expression modules. Conclusion: We first conducted a system analyses of the dynamics of gene expression both in susceptible and resistant Vernicia species with pathogen F. oxysporum infection. The results will serve as the important foundation to further deeply validation the resistance mechanism and breeding of the woody biodiesel plants V. fordii and V. montana.
Project description:Most northern insect species experience a period of developmental arrest, diapause, which enables them to survive over the winter and postpone reproduction until favorable conditions. We studied the timing of reproductive diapause and its long-term effects on the cold tolerance of Drosophila montana, D. littoralis and D. ezoana females in seasonally varying environmental conditions. At the same time we traced expression levels of 219 genes in D. montana using a custom-made microarray. We show that the seasonal switch to reproductive diapause occurs over a short time period, and that overwintering in reproductive diapause has long-lasting effects on cold tolerance. Some genes, such as Hsc70, Jon25bi and period, were upregulated throughout the diapause, while others, including regucalcin, couch potato and Thor, were upregulated only at its specific phases. Some of the expression patterns induced during the sensitive stage, when the females either enter diapause or not, remained induced regardless of the later conditions. qPCR analyses confirmed the findings of the microarray analysis in D. montana and revealed similar gene expression changes in D. littoralis and D. ezoana. The present study helps to achieve a better understanding of the genetic regulation of diapause and of the plasticity of seasonal responses in general.
Project description:The leaf transcriptome of the nickel hyperaccumulator specie Noccaea caerulescens subsp. fimiensis living on serpentine soils were compared to the closely related non-nickel-accumulators Noccaea caerulescens "Viviez" growing on a zinc mining site and Noccaea montana living on serpentine soil, to identity differentially expressed genes potentially involved in Ni hyperaccumulation.