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BackgroundCotton (Gossypium hirsutum L.) is a major fiber crop that is grown worldwide; it faces extensive damage from sap-sucking insects, including aphids and whiteflies. Genome-wide transcriptome analysis was performed to understand the molecular details of interaction between Gossypium hirsutum L. and sap-sucking pests, namely Aphis gossypii (Aphid) and Bemisia tabacci (Whiteflies). Roche’s GS-Titanium was used to sequence transcriptomes of cotton infested with aphids and whiteflies for 2 h and 24 h.ResultsA total of 100935 contigs were produced with an average length of 529 bp after an assembly in all five selected conditions. The Blastn of the non-redundant (nr) cotton EST database resulted in the identification of 580 novel contigs in the cotton plant. It should be noted that in spite of minimal physical damage caused by the sap-sucking insects, they can change the gene expression of plants in 2 h of infestation; further change in gene expression due to whiteflies is quicker than due to aphids. The impact of the whitefly 24 h after infestation was more or less similar to that of the aphid 2 h after infestation. Aphids and whiteflies affect many genes that are regulated by various phytohormones and in response to microbial infection, indicating the involvement of complex crosstalk between these pathways. The KOBAS analysis of differentially regulated transcripts in response to aphids and whiteflies indicated that both the insects induce the metabolism of amino acids biosynthesis specially in case of whiteflies infestation at later phase. Further we also observed that expression of transcript related to photosynthesis specially carbon fixation were significantly influenced by infestation of Aphids and Whiteflies.ConclusionsA comparison of different transcriptomes leads to the identification of differentially and temporally regulated transcripts in response to infestation by aphids and whiteflies. Most of these differentially expressed contigs were related to genes involved in biotic, abiotic stresses and enzymatic activities related to hydrolases, transferases, and kinases. The expression of some marker genes such as the overexpressors of cationic peroxidase 3, lipoxygenase I, TGA2, and non-specific lipase, which are involved in phytohormonal-mediated plant resistance development, was suppressed after infestation by aphids and whiteflies, indicating that insects suppressed plant resistance in order to facilitate their infestation. We also concluded that cotton shares several pathways such as phagosomes, RNA transport, and amino acid metabolism with Arabidopsis in response to the infestation by aphids and whiteflies.

Ivacaftor is approved in the USA for the treatment of cystic fibrosis (CF) in patients with a G551D-CFTR mutation or one of eight other CFTR mutations. A series of in vitro experiments conducted early in the development of ivacaftor indicated ivacaftor and metabolites may have the potential to inhibit cytochrome P450 (CYP) 2C8, CYP2C9, CYP3A, and CYP2D6, as well as P-glycoprotein (P-gp). Based on these results, a series of clinical drug-drug interaction (DDI) studies were conducted to evaluate the effect of ivacaftor on sensitive substrates of CYP2C8 (rosiglitazone), CYP3A (midazolam), CYP2D6 (desipramine), and P-gp (digoxin). In addition, a DDI study was conducted to evaluate the effect of ivacaftor on a combined oral contraceptive, as this is considered an important comedication in CF patients. The results indicate ivacaftor is a weak inhibitor of CYP3A and P-gp, but has no effect on CYP2C8 or CYP2D6. Ivacaftor caused non-clinically significant increases in ethinyl estradiol and norethisterone exposure. Based on these results, caution and appropriate monitoring are recommended when concomitant substrates of CYP2C9, CYP3A and/or P-gp are used during treatment with ivacaftor, particularly drugs with a narrow therapeutic index, such as warfarin.

BackgroundRoot length and its architecture govern the adaptability of plants to various stress conditions, including drought stress. Genetic variations in root growth, length, and architecture are genotypes dependent. In this study, we compared the drought-induced transcriptome of four genotypes of Gossypium herbaceum that differed in their drought tolerance adaptability. Three different methodologies, namely, microarray, pyrosequencing, and qRT–PCR, were used for transcriptome analysis and validation.ResultsThe variations in root length and growth were found among four genotypes of G.herbaceum when exposed to mannitol-induced osmotic stress. Under osmotic stress, the drought tolerant genotypes Vagad and GujCot-21 showed a longer root length than did by drought sensitive RAHS-14 and RAHS-IPS-187. Further, the gene expression patterns in the root tissue of all genotypes were analyzed. We obtained a total of 794 differentially expressed genes by microarray and 104928 high-quality reads representing 53195 unigenes from the root transcriptome. The Vagad and GujCot-21 respond to water stress by inducing various genes and pathways such as response to stresses, response to water deprivation, and flavonoid pathways. Some key regulatory genes involved in abiotic stress such as AP2 EREBP, MYB, WRKY, ERF, ERD9, and LEA were highly expressed in Vagad and GujCot-21. The genes RHD3, NAP1, LBD, and transcription factor WRKY75, known for root development under various stress conditions, were expressed specifically in Vagad and GujCot-21. The genes related to peroxidases, transporters, cell wall-modifying enzymes, and compatible solutes (amino acids, amino sugars, betaine, sugars, or sugar alcohols) were also highly expressed in Vagad and Gujcot-21.ConclusionOur analysis highlights changes in the expression pattern of genes and depicts a small but highly specific set of drought responsive genes induced in response to drought stress. Some of these genes were very likely to be involved in drought stress signaling and adaptation, such as transmembrane nitrate transporter, alcohol dehydrogenase, pyruvate decarboxylase, sucrose synthase, and LEA. These results might serve as the basis for an in-depth genomics study of Gossypium herbaceum, including a comparative transcriptome analysis and the selection of genes for root traits and drought tolerance.

Carotenoids are isoprenoid pigments that upon oxidative cleavage lead to the production of norisoprenoids that have profound effect on flavor and aromas of agricultural products. The biosynthetic pathway to norisoprenoids in carrots (Daucus carota L.) is still largely unknown. We found the volatile norisoprenoids farnesylacetone, α-ionone, and β-ionone accumulated in Nairobi, Rothild, and Purple Haze cultivars but not in Yellowstone and Creme de Lite in a pattern reflecting their carotenoid content. A cDNA encoding a protein with carotenoid cleavage dioxygenase activity, DcCCD1, was identified in carrot and was overexpressed in Escherichia coli strains previously engineered to produce different carotenoids. The recombinant DcCCD1 enzyme cleaves cyclic carotenes to generate α- and β-ionone. No cleavage products were found when DcCCD1 was co-expressed in E. coli strains accumulating non-cyclic carotenoids, such as phytoene or lycopene. Our results suggest a role for DcCCD1 in carrot flavor biosynthesis.