Gall-forming arthropods are highly specialized herbivores that, in combination with their hosts, produce extended phenotypes with unique morphologies [1]. Many are economically important, and others have improved our understanding of ecology and adaptive radiation [2]. However, the mechanisms that these arthropods use to induce plant galls are poorly understood. We sequenced the genome of the Hessian fly (Mayetiola destructor; Diptera: Cecidomyiidae), a plant parasitic gall midge and a pest of wheat (Triticum spp.), with the aim of identifying genic modifications that contribute to its plant-parasitic lifestyle. Among several adaptive modifications, we discovered an expansive reservoir of potential effector proteins. Nearly 5% of the 20,163 predicted gene models matched putative effector gene transcripts present in the M. destructor larval salivary gland. Another 466 putative effectors were discovered among the genes that have no sequence similarities in other organisms. The largest known arthropod gene family (family SSGP-71) was also discovered within the effector reservoir. SSGP-71 proteins lack sequence homologies to other proteins, but their structures resemble both ubiquitin E3 ligases in plants and E3-ligase-mimicking effectors in plant pathogenic bacteria. SSGP-71 proteins and wheat Skp proteins interact in vivo. Mutations in different SSGP-71 genes avoid the effector-triggered immunity that is directed by the wheat resistance genes H6 and H9. Results point to effectors as the agents responsible for arthropod-induced plant gall formation.

No abstract

Insect Pest Problems in Chickpea Chickpea (C. arietinum L.) is the third most important legume crop in the world, after dry beans and peas (FAO, 2003). It is cultivated in 42 countries in South Asia, North and Central America, the Mediterranean region, West Asia and North and East Africa. In recent years, it has become an important crop in Australia, Canada and the USA. Nearly 60 insect species are known to feed on chickpea (Reed et al., 1987) (Table 25.1). The important insect pests damaging chickpea in different regions are: • Wireworms: false wireworm-Gonocephalum spp.; • Cutworm: black cutworm-A. ipsilon (Hfn.) and turnip moth-A. segetum Schiff.; • Termite: Microtermes obesi (Holm.) and Odontotermes sp.; • Leaf-feeding caterpillars: cabbage looper-Trichoplusia ni (Hub.), leaf caterpillarS. exigua (Hub.

The pod borer [Helicoverpa armigera Hubner (Lepidoptera: Noctuidae)] is responsible for causing up to 90% damage in chickpea due to its regular occurrence from the vegetative growth to the pod formation stage. In order to manage this problem, growers are tempted to increase the amounts of pesticides, but indiscriminate or injudicious use of pesticides has resulted in residues in the food chain, pesticide resistance, and pest resurgence, in addition to causing harm to non-targeted beneficial organisms and the environment. Here, we reviewed the sustainable approaches to reduce the incidence of pod borer and achieve sustainability in chickpea production systems through the adoption of an integrated approach involving host plant resistance, good agronomic practices, and judicious use of chemical and biological methods. We found that the following major points have been reported to reduce the survival and damage of pod borer: (1) use of resistant varieties (the cheapest and the best method of pod borer management); (2) implementing a number of good agronomic practices, such as early sowing with optimum planting density and fertilizer levels, including inter/trap crops (coriander, mustard, linseed, sunflower, sorghum, and marigold) and installing animated bird perches and T-perches at 2 m distance of predatory zones; and (3) monitoring pod borer through pheromone traps (which is also necessary to understand the major factors influencing pest population and to make the pest control program more effective). Integrating all of these approaches with biological control has shown some encouraging results for sustainable pod borer management and has resulted in high chickpea yields. This review highlights examples of successful management approaches from past studies that were implemented in experimental and farmers' fields. These approaches can be explored as reproducible practices for managing the pest in locations with similar H. armigera concerns. We conclude that an integrated approach is most effective for long-term sustainable management programs.

Sunn pest, Eurygaster integriceps, Puton, infested and uninfested wheat seeds were obtained from the International Center for Agriculture Research in the Dry Areas (ICARDA), Aleppo, Syria, with the primary objective to identify the type of enzyme deposited by the Sunn pest on the wheat responsible for the gluten degradation. Enzyme levels were extremely low due to the enzyme being secreted by the insect in localized areas on the seed. Only extract from the infested wheat contained glutenase activity. Anion exchange, Cu(2+) sepharose, and gel filtration chromatography were used to partially purify and enrich protein samples from both infested wheat and uninfested wheat. An SDS-gluten assay was used to show gluten specificity while a commercially available chromogenic proline peptide, benzyloxycarbonyl-Gly-Pro-p-nitroanalide (ZGPpNA), was utilized to identify fractions containing the active proline specific enzyme activity and to determine Michaelis-Menten kinetics. Despite low levels of enzyme on the infested wheat, the enzyme was partially purified and enriched exhibiting a specific activity of 4.5 U/mg of total protein for gluten in a SDS gluten assay (1 U of enzyme activity was defined as the decrease in gel height in millimeters in 1 h) and exhibited a high-affinity Km of 65 microM for ZGPpNA, cleaving at the carboxy terminus of the proline residue. The enzyme exhibited optimal activity between pH 8 and 10.0 at temperatures between 20 degrees and 35 degrees C. The enzyme was identified to be a prolyl endoprotease.