To improve the physical and comparative map of chicken chromosome 24 (GGA24; former linkage group E49C20W21) bacterial artificial chromosome (BAC) contigs were constructed around loci previously mapped on this chromosome by linkage analysis. The BAC clones were used for both sample sequencing and BAC end sequencing. Sequence tagged site (STS) markers derived from the BAC end sequences were used for chromosome walking. In total 191 BAC clones were isolated, covering almost 30% of GGA24, and 76 STS were developed (65 STS derived from BAC end sequences and 11 STS derived within genes). The partial sequences of the chicken BAC clones were compared with sequences present in the EMBL/GenBank databases, and revealed matches to 19 genes, expressed sequence tags (ESTs) and genomic clones located on human chromosome 11q22-q24 and mouse chromosome 9. Furthermore, 11 chicken orthologues of human genes located on HSA11q22-q24 were directly mapped within BAC contigs of GGA24. These results provide a better alignment of GGA24 with the corresponding regions in human and mouse and identify several intrachromosomal rearrangements between chicken and mammals.

The physical and comparative map of GGA15 was improved by the construction of 9 BAC contigs around loci previously mapped on GGA15 by linkage analysis. In total, 240 BAC clones were isolated, covering 30-35% of GGA15, and 120 STS were developed (104 STS derived from BAC end sequences and 18 STS derived within genes). Seventeen chicken orthologues of human genes located on human Chr 22q11-q12 were directly mapped within BAC contigs of GGA15. Furthermore, the partial sequences of the chicken BAC clones were compared with sequences present in the EMBL/GenBank databases and revealed matches to 26 genes, ESTs, and genomic clones located on HSA22q11-q12 and HSA12q24. These results provide a better alignment of GGA15 with the corresponding regions in human and mouse, and improve our knowledge of the evolution and dynamics of the vertebrate genome.

Insect herbivores can directly affect plant reproduction by feeding on reproductive tissues, or indirectly by feeding on vegetative tissues for which plants are unable to compensate. Additionally, early arriving herbivores may have cascading effects on plant fitness by altering the richness and abundance of the later arriving community. Studies are divided on whether herbivory early in the development of plants can impact plant fitness and whether these effects are predominantly mediated through changes in plant development or subsequent herbivory. Obtaining insight into the generality and consistency of mediated effects on plant reproduction induced by early-season herbivory requires a comparative approach across plant species and environmental conditions. By excluding the herbivore community in an exclosure experiment and by manipulating early-season herbivory in a common garden experiment replicated across four Brassicaceae species and two years, we tested whether early-season herbivory could affect plant development, reproduction, and the herbivore communities associated with individual plants. In addition, we tested a causal hypothesis to disentangle the direct effect of herbivory on plant reproduction, and their indirect effect through changes in the development of plants. Early-season herbivory affected plant development and reproduction, but effects were highly dependent on the plant species, the inducing herbivore species, and the biotic and abiotic environment. The exploratory path analysis indicated that plant reproduction was best predicted by variation in plant development, explaining up to 90.88% of the total effect on seed production. Even though the richness and abundance of the subsequent herbivore community were conditionally affected by the initial colonising herbivore, herbivore pressure is predicted to have only minor effects on reproduction. Importantly, the effects of herbivore pressure on seed set were not direct but were mediated by changes in plant development. Synthesis: Early-season herbivory has the potential to affect plant reproduction through changes in the development of plants and, less strongly, through effects mediated by the plant-associated herbivore community. However, as plants are often able to compensate and attenuate the effects induced by herbivory, the detection, sign, and strength of effects are highly dependent on the plant species and environment.

In response to herbivory, most plant species adjust their chemical and morphological phenotype to acquire induced resistance to the attacking herbivore. Induced resistance may be an optimal defence strategy that allows plants to reduce metabolic costs of resistance in the absence of herbivores, allocate resistance to the most valuable plant tissues and tailor its response to the pattern of attack by multiple herbivore species. Moreover, plasticity in resistance decreases the potential that herbivores adapt to specific plant resistance traits and need to deal with a moving target of variable plant quality. Induced resistance additionally allows plants to provide information to other community members to attract natural enemies of its herbivore attacker or inform related neighbouring plants of pending herbivore attack. Despite the clear evolutionary benefits of induced resistance in plants, crop protection strategies to herbivore pests have not exploited the full potential of induced resistance for agriculture. Here, we present evidence that induced resistance offers strong potential to enhance resistance and resilience of crops to (multi-) herbivore attack. Specifically, induced resistance promotes plant plasticity to cope with multiple herbivore species by plasticity in growth and resistance, maximizes biological control by attracting natural enemies and, enhances associational resistance of the plant stand in favour of yield. Induced resistance may be further harnessed by soil quality, microbial communities and associational resistance offered by crop mixtures. In the transition to more sustainable ecology-based cropping systems that have strongly reduced pesticide and fertilizer input, induced resistance may prove to be an invaluable trait in breeding for crop resilience.