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The impact of the expression of Bacillus thuringiensis protoxins in the T1C-19 (cry1C) and T2A-1 (cry2A) transgenic rice strains on the brown planthopper, Nilaparvata lugens Stål (Hemiptera: Delphacidae), was evaluated by comparing the population densities of N. lugens reared on the strains T1C-19 or T2A-1 or the parental non-Bt strain Minghui 63. Field investigations revealed that the population densities of N. lugens were similar among the T2A-1, T1C-19, and Minghui 63 rice fields. Further assessment of feeding behavior of N. lugens using electrical penetration graph (EPG) technology showed that all four strains are susceptible to N. lugens, which was evidenced by the non-significant difference in feeding behavior of N. lugens between the transgenic and non-transgenic rice plants. These results provide new evidence that Bt rice does not pose any risk on N. lugens which represents a key non-target pest species in Bt rice field in China. [ABSTRACT FROM AUTHOR]

The sharpshooter Homalodisca coagulata (Say) (Hemiptera: Cicadellidae: Cicadellinae) is an exotic vector of the Pierce's disease (PD) bacterium, Xylella fastidiosa (Wells et al.), that was first observed in California in 1989. H. coagulata has since greatly increased the threat of PD to the grape industry as well as stone fruit, nursery, and ornamental industries in California. This is the first in a series of articles that together describe how sharpshooter stylet penetration behaviors (especially intricate stylet activities, salivation, and ingestion) control transmission (i.e.. acquisition and inoculation) of X. fastidiosa. Herein, we categorized and characterized alternating current electrical penetration graph (EPG) waveforms from glass-winged sharpshooter stylet penetration on petiole of susceptible grape ('Cabernet Sauvignon'), paying special attention to waveform fine structures that are likely to be the key to detecting the instant of inoculation. We also correlated waveforms with salivary sheath termini in grape tissues. For the first time in any EPG study of leafhopper or planthopper feeding, we demonstrate through case studies of individual probes how to follow the process of stylet penetration step by step as it is occurring, including salivary sheath branching and when the stylets first puncture a xylem cell. Finally, we discuss the implications of our findings for understanding the transmission mechanism of X. fastidiosa, in comparison with hypothesized mechanisms in the literature. [ABSTRACT FROM AUTHOR]

The rapid development of agricultural biotechnology and release of new transgenic plants for agriculture has provided many economic benefits, but has also raised concern over the potential impact of transgenic plants on the environment. Considerable research has now been conducted on the effects of transgenic plants on soil microorganisms. These effects include unintentional changes in the chemical compositions of root exudates, and the direct effects of transgenic proteins on nontarget species of soil microorganisms. Most studies to date suggest that transgenic plants that have been released cause minor changes in microbial community structures that are often transient in duration. However, due to our limited knowledge of the linkage between microbial community structure and function, more work needs to be done on a case-by-case basis to further evaluate the effects of transgenic plants on soil microorganisms and soil ecosystem functions. This review summarizes the results of a variety of experiments that have been conducted to specifically test the effects of transgenic plants on soil microorganisms, and particularly examines the types of methods that are being used to study microbial interactions with transgenic plants. [ABSTRACT FROM AUTHOR]

It is known that plant viruses can change the performance of their vectors. However, there have been no reports on whether or how a semipersistent plant virus manipulates the feeding behaviors of its whitefly vectors. Cucurbit chlorotic yellows virus (CCYV) (genus Crinivirus, family Closteroviridae) is an emergent plant virus in many Asian countries and is transmitted specifically by B and Q biotypes of tobacco whitefly, Bemisia tabaci (Gennadius), in a semipersistent manner. In the present study, we used electrical penetration graph (EPG) technique to investigate the effect of CCYV on the feeding behaviors of B. tabaci. The results showed that CCYV altered feeding behaviors of both biotypes and sexes of B. tabaci with different degrees. CCYV had stronger effects on feeding behaviors of Q biotype than those of B biotype, by increasing duration of phloem salivation and sap ingestion, and could differentially manipulate feeding behaviors of males and females in both biotype whiteflies, with more phloem ingestion in Q biotype males and more non-phloem probing in B biotype males than their respective females. With regard to feeding behaviors related to virus transmission, these results indicated that, when carrying CCYV, B. tabaci Q biotype plays more roles than B biotype, and males make greater contribution than females. [ABSTRACT FROM AUTHOR]