The 'independent action hypothesis' (IAH) states that each pathogen individual has a non-zero probability of causing host death and that pathogen individuals act independently. IAH has not been rigorously tested. In this paper, we (i) develop a probabilistic framework for testing IAH and (ii) demonstrate that, in two out of the six virus-insect pathosystems tested, IAH is supported by the data....

Pathogen attack and the plant's response to this attack affect herbivore oviposition preference and larval performance. Introduction of major resistance genes against Phytophthora infestans (Rpi-genes), the cause of the devastating late blight disease, from wild Solanum species into potato changes the plant-pathogen interaction dynamics completely, but little is known about the effects on non-t...

Plant responses to herbivores are complex. 108 cDNA clones representing genes relating to plant responses to chewing insect-feeding, pathogen infection, wounding and other stresses were collected. Northern blot and cDNA array analysis were employed to investigate gene expression regulated by piercing-sucking insect, brown planthopper (BPH), Nilaparvata lugens (Homoptera: Dephacidae) on both the...

In nature, herbivorous insects and plant pathogens are generally abundant when plants are flowering. Thus, plants face a diversity of attackers during their reproductive phase. Plant responses to one attacker can interfere with responses to a second attacker, and phytohormones that orchestrate plant reproduction are also involved in resistance to insect and pathogen attack. We quantified phytoh...

Huanglongbing (HLB) or citrus greening disease is a destructive disease of citrus worldwide, which is associated with Candidatus Liberibacter asiaticus. This phloem-limited fastidious pathogen is transmitted by the Asian citrus psyllid, Diaphorina citri, and appears to be an intracellular pathogen that maintains an intimate association with the psyllid or the plant throughout its life cycle. Th...

Diaphorina citri is a serious insect pest of citrus and an vector Candidatus Liberibacter asiaticus (CLas) that causes Huanglongbing disease (citrus greening). In this study, we investigated the effect CLas pathogen on life history parameters D. at different temperature regimes. Our results demonstrated survival rate first to fifth instar CLas-positive CLas-negative fluctuate with change in ove...

Fungal pathogens of plants and insects infect their hosts by direct penetration of the cuticle. Plant and insect cuticles are covered by a hydrocarbon-rich waxy outer layer that represents the first barrier against infection. However, the fungal genes that underlie insect waxy layer degradation have received little attention. Here we characterize the single cytochrome P450 monoxygenase family 5...

Some plant pathogens form obligate relationships with their insect vector and are vertically transmitted via eggs analogous to insect endosymbionts. Whether insect endosymbionts manipulate plant defenses to benefit their insect host remains unclear. The tomato psyllid, Bactericerca cockerelli (Sulc), vectors the endosymbiont "Candidatus Liberibacter psyllaurous" (Lps) during feeding on tomato (...

Insects and other arthropods are the most important vectors of plant pathogens. The majority of plant pathogens are disseminated by arthropod vectors such as aphids, beetles, leafhoppers, planthoppers, thrips and whiteflies. Transmission of plant pathogens and the challenges in managing insect vectors due to insecticide resistance are factors that contribute to major food losses in agriculture....

Our laboratory found that silverleaf whitefly (SLW; Bemisia argentifolii Bellows & Perring) feeding alters host plant physiology and chemistry. The SLW induces a number of host plant defenses, including pathogenesis-related (PR) protein accumulation (e.g., chitinases, beta-1,3-glucanases, peroxidases, chitosanases, etc.). Induction of the PR proteins by SLW feeding occurs in various plant speci...