Annotated expressed sequence tags for studies of the regulation of reproductive modes in aphids

Abstract

The damaging effect of aphids to crops is largely determined by the spectacular rate of increase of populational expansion due to their parthenogenetic generations. Despite this, the molecular processes triggering the transition between the parthenogenetic and sexual phases between their annual life cycle have received little attention. Here, we describe a collection of genes from the cereal aphid Rhopalosiphum padi expressed during the switch from parthenogenetic to sexual reproduction. After cDNA cloning and sequencing, 726 expressed sequence tags (EST) were annotated. The R. padi EST collection contained a substantial number (139) of bacterial endosymbiont sequences. The majority of R. padi cDNAs encoded either unknown proteins (56%) or housekeeping polypeptides (38%). The large proportion of sequences without similarities in the databases is related to both their small size and their high GC content, corresponding probably to the presence of 5'-unstranslated regions. Fifteen genes involved in developmental and differentiation events were identified by similarity to known genes. Some of these may be useful candidates for markers of the early steps of sexual differentiation.

Psyllid Biology: Expressed Genes in Adult Asian Citrus Psyllids, Diaphorina citri Kuwayama

“…Definition according to The International Union of Biochemistry and Molecular Biology's Enzyme classification system. diate information on psyllid biology and provide sequences for further functional genomics [16,17,33]. While the number of functional genes is not correlated to genome size [34] http://genomesize.com/results/) the psyllid genome was estimated to be (~0.35 pg) about a third the size of the whitefly Bemisia argentifolii (~1.1 pg [33], three and a half times smaller than the glassy-winged sharpshooter (~1.24 pg,…”

“…Sequence tags offered an invaluable resource for the identification of genes associated with the specific biology of psyllids [8][9][10]. Application of a transcriptome approach has also led to other important discoveries such as insect pathogens, as in the discovery of the first virus in D. citri [11], the first viral pathogens of the red imported fire ant [12,13] and viruses in the glassy-winged sharpshooter, Homalodisca coagulata virus 1, HoCV-1 [14,15], the discovery and identification of genes linked to the development and reproduction of aphids [16,17], and in discoveries made in the studies of the specialized cells that harbor aphid endosymbionts [18,19]. Additionally, ESTs and their accompanying cDNAs provide the means to construct arrays that can be used for transcript profiling on a genome-wide scale [20][21][22][23].…”

Comparative gut transcriptome analysis reveals differences between virulent and avirulent Russian wheat aphids, Diuraphis noxia

“…The ingestion and digestion of plant nutrients by aphids involves a series of molecular, biochemical and physiological reactions (Terra andFerriera, 2005, Tagu et al 2005) aimed at neutralizing host plant defense allelochemicals or manipulating plant defense machinery. Various transcriptome studies have characterized aphid gut genes involved in detoxification and digestion (Hunter et al 2003, Tagu et al 2004, Sabater-Munoz et al 2006, Ramsey et al 2007 as well as other phytophagous insects (Goates et al 2008, Khajuria et al 2009, Pedra et al 2003, Chi et al 2009, Simpson et al 2007, Sinha et al 2011. However, little is known about D. noxia gut proteins, and a need exists to understand the gut transcriptomes of D. noxia biotypes.…”

Analysis and comparison of a set of expressed sequence tags of the parthenogenetic water flea Daphnia carinata

“…It has already been successfully used in development and reproduction biology studies, especially for identifying sex-biased genes. For example, female-speciWc genes of Culex pipiens pallens , sex-related genes in giant tiger shrimp (Preechaphol et al 2007) and reproductive switching genes from Rhopalosiphum padi were all studied using EST-based strategies (Tagu et al 2004). The Wrst Daphnia cDNA library was created from Daphnia magna, and the expression proWles were analyzed using ESTs (Tagu et al 2004).…”

“…For example, female-speciWc genes of Culex pipiens pallens , sex-related genes in giant tiger shrimp (Preechaphol et al 2007) and reproductive switching genes from Rhopalosiphum padi were all studied using EST-based strategies (Tagu et al 2004). The Wrst Daphnia cDNA library was created from Daphnia magna, and the expression proWles were analyzed using ESTs (Tagu et al 2004). The cDNA clones and EST sequence information were useful in subsequent functional analysis of Daphnia biology, as well as investigation of the links between ecology and genomics (Shaw et al 2007).…”