Pyrosequencing the Bemisia tabaci Transcriptome Reveals a Highly Diverse Bacterial Community and a Robust System for Insecticide Resistance

BACKGROUND: Bemisia tabaci (Gennadius) is a phloem-feeding insect poised to become one of the major insect pests in open field and greenhouse production systems throughout the world. The high level of resistance to insecticides is a main factor that hinders continued use of insecticides for suppression of B. tabaci. Despite its prevalence, little is known about B. tabaci at the genome level. To fill this gap, an invasive B. tabaci B biotype was subjected to pyrosequencing-based transcriptome analysis to identify genes and gene networks putatively involved in various physiological and toxicological processes. METHODOLOGY AND PRINCIPAL FINDINGS: Using Roche 454 pyrosequencing, 857,205 reads containing approximately 340 megabases were obtained from the B. tabaci transcriptome. De novo assembly generated 178,669 unigenes including 30,980 from insects, 17,881 from bacteria, and 129,808 from the nohit. A total of 50,835 (28.45%) unigenes showed similarity to the non-redundant database in GenBank with a cut-off E-value of 10-5. Among them, 40,611 unigenes were assigned to one or more GO terms and 6,917 unigenes were assigned to 288 known pathways. De novo metatranscriptome analysis revealed highly diverse bacterial symbionts in B. tabaci, and demonstrated the host-symbiont cooperation in amino acid production. In-depth transcriptome analysis indentified putative molecular markers, and genes potentially involved in insecticide resistance and nutrient digestion. The utility of this transcriptome was validated by a thiamethoxam resistance study, in which annotated cytochrome P450 genes were significantly overexpressed in the resistant B. tabaci in comparison to its susceptible counterparts. CONCLUSIONS: This transcriptome/metatranscriptome analysis sheds light on the molecular understanding of symbiosis and insecticide resistance in an agriculturally important phloem-feeding insect pest, and lays the foundation for future functional genomics research of the B. tabaci complex. Moreover, current pyrosequencing effort greatly enriched the existing whitefly EST database, and makes RNAseq a viable option for future genomic analysis

Alliances Between Corporate and Fair Trade Brands: Examining the Antecedents of Overall Evaluation of the Co-branded Product

International audienceThis research investigates the potential for a ‘‘fair’’ co-branding operation. A major corporate brand is fictitiously allied with a Fair Trade labelling organizationbrand. The sample for the study is composed of 540 respondents, representative of the French population. By considering commercial brands and Fair Trade labels asdissimilar in terms of customers’ perceived Fair Trade orientations, this article studies (1) how this lack of similarity impacts perceived congruence between both entities (i.e. perceived relevancy and expectancy of the alliance) and how prior brand attitudes and congruence influence customers’ evaluation of the co-branded product. The results of this research demonstrate that: Consumer prior brand attitudes toward the partner brands influence very little customers’ evaluation. (2) Perceived similarity of the partner brands has a strong influence toward congruence of the co-branding operation. Results also indicate that congruence (measured as relevancy and expectancy) has a strong influence upon customers’ evaluation. An inverted U-shaped relationship exists between perceived similarity and relevancy of the alliance, and between expectancy and customers’ evaluation. The results obtained through the test of a partial least square model, and inverted U-shaped hypothesis, represent a new insight into co-branding theory. The high discursive power of fair co-branding is a key issue: the corporate brand provides the alliance with its leading position, while the Fair Trade brand provides the ethical attribute