Quantification of Ethylene Production in Tomato Leaves Infected by .

Ethylene is a gaseous plant hormone controlling fruit ripening, flower opening, leaf senescence as well as abscission, and disease symptom development. Ethylene plays a critical role in the bacterial pathogen ()-elicited symptom development in tomato. This protocol describes the measurement of ethylene gas produced by tomato leaves infected with .

Functional Analysis of Plant Defense Suppression and Activation by the Xanthomonas Core Type III Effector XopX.

Many phytopathogenic type III secretion effector proteins (T3Es) have been shown to target and suppress plant immune signaling but perturbation of the plant immune system by T3Es can also elicit a plant response. XopX is a "core" Xanthomonas T3E that contributes to growth and symptom development during Xanthomonas euvesicatoria infection of tomato but its functional role is undefined. We tested the effect of XopX on several aspects of plant immune signaling.

Xanthomonas type III effector XopD desumoylates tomato transcription factor SlERF4 to suppress ethylene responses and promote pathogen growth.

XopD, a type III secretion effector from Xanthomonas euvesicatoria (Xcv), the causal agent of bacterial spot of tomato, is required for pathogen growth and delay of host symptom development. XopD carries a C-terminal SUMO protease domain, a host range determining nonspecific DNA-binding domain and two EAR motifs typically found in repressors of stress-induced transcription. The precise target(s) and mechanism(s) of XopD are obscure.

Trichomes as dangerous lollipops: do lizards also use caterpillar body and frass odor to optimize their foraging?

When attacked by herbivores, plants produce toxic secondary metabolites that function as direct defenses, as well as indirect defenses that attract and reward predators of the offending herbivores. These indirect defenses include both nutritive rewards such as extra floral nectar, as well as informational rewards, such as the production and release of volatile compounds that betray the location of feeding herbivores to predators. Herbivory of Nicotiana attenuata by the tobacco hornworm (Manduca larvae) alters the volatile profiles of both the plant and larval headspace.

An ecological analysis of the herbivory-elicited JA burst and its metabolism: plant memory processes and predictions of the moving target model.

Background: Rapid herbivore-induced jasmonic acid (JA) accumulation is known to mediate many induced defense responses in vascular plants, but little is known about how JA bursts are metabolized and modified in response to repeated elicitations, are propagated throughout elicited leaves, or how they directly influence herbivores.

Methodology/principal Findings: We found the JA burst in a native population of Nicotiana attenuata to be highly robust despite environmental variation and we examined the JA bursts produced by repeated elicitations with Manduca sexta oral secretions (OS) at whole- and within-leaf spatial scales. Surprisingly, a 2(nd) OS-elicitation suppressed an expected JA burst at both spatial scales, but subsequent elicitations caused more rapid JA accumulation in elicited tissue.