Project description:Yellow stem borer (YSB), Scirpophaga incertulas (Walker) (Lepidoptera: Crambidae), is a major pest of rice in India, that can lead to 20-60% loss in rice production. Effective management of YSB infestation is challenged by the non-availability of adequate source of resistance and poor understanding of resistance mechanisms, thus necessitating studies for generating resources to breed YSB resistant rice and to understand rice-YSB interaction. Here we performed transcritpomics profiling of rice lines with contrasting response to YSB. RNA-sequencing of the susceptible (SM) and tolerant (SM92 lines revealed multiple genes to be differentially regulated upon YSB infestation. Comparative transcriptome analysis revealed a putative candidate gene that was predicted to encode an alpha-amylase inhibitor. Analysis of the transcriptome and metabolite profiles further revealed a possible link between phenylpropanoid metabolism and YSB tolerance.
Project description:We characterized sperm from the seminal vesicles of male monarch butterflies (Danaus plexippus), in triplicate, identifying 548 high confidence proteins. As with all but the most basal lepidopteran species male monarch butterflies are sperm heteromorphic, producing fertilization competent and anucleate fertilization incompetent sperm morphs. Comparing this data to the sperm proteomes of the Carolina sphinx moth (Manduca sexta) and the fruit fly (Drosophila melanogaster) demonstrated high levels of functional coherence across proteomes, and conservation at the level of protein abundance and post-translational modification within Lepidoptera. Comparative genomic analyses revealed a significant reduction in orthology among Monarch sperm genes relative to the remainder of the genome in non-Lepidopteran insects. A substantial number of sperm proteins were found to be specific to Lepidoptera, lacking detectable homology outside this taxa. These findings are consistent with a burst of genetic novelty in the sperm proteome concurrent with the origin of heteromorphic spermatogenesis early in Lepidoptera evolution.
Project description:In insects, male accessory gland proteins (ACPs) are important reproductive proteins secreted by male accessory glands (MAGs) of the internal male reproductive system. During mating, ACPs were transferred along with sperms inside female bodies and have a significant impact on the physiology of female reproduction. Under sexual selection pressures, the ACPs exhibit remarkably rapid and divergent evolution and varies from species to species. The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), is a major insect pest of cruciferous vegetables worldwide. The reproductive physiology on post-mating state of this species is still largely unknown, which is important for management of this pest. In this study, the ACPs transferred into females during mating were identified by using a tandem mass tags quantitative proteomic analysis. The MAGs were compared before and after mating immediately. In total, we identified 123 putative secreted ACPs, including most important physiological: regulators of proteolysis, transporters and protein export machinery, signal transduction and immunity. Comparing P. xylostella with other four insect ACPs, trypsins were the only ACPs detected in all insect species. This was the first time to identify and analyze ACPs in P. xylostella. Our results have provided an important list of putative secreted ACPs, and have set the stage for further explore functions of these putative proteins in P. xylostella reproduction.
Project description:Larvae of the genus Megalopyge (Lepidoptera: Zygaenoidea: Megalopygidae), called asp or puss caterpillars, produce defensive venoms that cause severe acute pain. Here, we present the anatomy, chemistry, and mode of action of the venom systems of caterpillars of two megalopygid species, the Southern flannel moth Megalopyge opercularis and the black-waved flannel moth Megalopyge crispata. We show that megalopygid venom is produced in secretory cells that lie beneath the cuticle and are connected to the venom spines by canals. Megalopygid venoms consist of larger aerolysin-like pore-forming toxins, which we have named megalysins, and a small number of peptides. Venom potently activates mammalian sensory neurons via membrane permeabilization and causes sustained spontaneous pain behaviours and paw swelling in mice. These bioactivities can be easily ablated by treatment with heat, organic solvents, or proteases, suggesting they are mediated by larger proteins, most likely the megalysins. We show that the megalysins were recruited as venom toxins in the Megalopygidae following horizontal transfer of genes from bacteria to the ancestors of Lepidoptera. The megalopygid venom system differs markedly from those of previously studied venomous zygaenoids of the family Limacodidae, suggestive of independent origins. Megalopygids have recruited aerolysin-like proteins as venom toxins convergently with centipedes, cnidarians, and fish. This study highlights the role of horizontal gene transfer in venom evolution.
Project description:Amongst the various different insect groups, there is remarkable diversity in the number and size of wings. However the development of the basic body plan in insects is similar to a large extent. The genes of the hox complex regulate various pathways to bring about the development or modification of different organs. Ubx, a gene of the bithorax hox complex is expressed in the third thoracic segment of insects and is known to specify the fate of wing appendage in that segment.To understand the role of Ubx and how its regulatory mechanism has evolved through the course of evolution we have compared its genome wide targets in different insect orders. The identification of regulatory pathways and the key players Ubx regulates is crucial to understand how it has controlled wing development across insect orders. Our lab has previously identified direct targets of Ubx in Drosophila using ChIP-chip (Agrawal et al, 2011). To further our knowledge on the role of regulation in development and modification of hind wing appendage we have studied the targets in the hind wings of other insects (silk moth; Lepidoptera and honeybee; Hymenoptera) and performed a comparative analysis. We have employed ChIP followed by illumina sequencing to identify the targets of Ubx in developing hind and fore wing buds of Bombyx larvae. This is a first next generation sequencing study in Lepidoptera in an attempt to understand wing development.
Project description:Female adult spongy moths vary in their flight capacity depending upon their origin and subspecies. Asian spongy moth (Lymantria dispar asiatica) females (such as the RM strain here) can fly whereas European spongy moth (Lymantria dispar dispar) females cannot (such as the CT strain here). We hypothesized that the genetic origins of these differences in flight capacity would be reflected in differences in gene expression during metamorphosis (the pupal stage). To test this, we compared the gene expression at days 1, 3, 5, 8, and 11 of pupal development of female pupae from CT and RM strains.
Project description:The cultivated almond exhibits self-incompatibility of the gametophytic type regulated by the S-locus, and expressed in pistil (S-RNase) and in pollen (SFB protein). The aim of this study is to clarify the transcription pattern of these 2 S-genes and to identify additional components of the gametophytic self-incompatibility system in almond. With this aim, A2-198 (self compatible) and ITAP-1 (self incompatible) almond selections were used: RNA-seq of pistils of these two accessions both un-pollinated and pollinated with A2-198 pollen were carried out.
Project description:NLRC5 is a member of the NLR family of proteins. The observation that NLRC5 is found in the nucleus prompted us to perform a gene array to identify putative target genes of NLRC5. We generated Jurkat T cell lines that stably express either the wild-type or mutant forms of NLRC5 harboring mutations in the nucleotide binding domain (NBD): Walker A (deficient in nucleotide binding), Walker B (deficient in nucleotide hydrolysis), and the combined Walker AB, carrying both mutations. Site-directed mutagenesis was used to create the NLRC5 NBD mutants: Walker A (K234A), Walker B (E311Q), and Walker AB (both mutations).