Rapid translation of genome sequences into meaningful biological information hinges on the integration of multiple experimental and informatics methods into a cohesive platform. Despite the explosion in the number of genome sequences available, such a platform does not exist for filamentous fungi. Here we present the development and application of a functional genomics and informatics platform for a model plant pathogenic fungus, Magnaporthe oryzae. In total, we produced 21,070 mutants through large-scale insertional mutagenesis using Agrobacterium tumefaciens-mediated transformation. We used a high-throughput phenotype screening pipeline to detect disruption of seven phenotypes encompassing the fungal life cycle and identified the mutated gene and the nature of mutation for each mutant. Comparative analysis of phenotypes and genotypes of the mutants uncovered 202 new pathogenicity loci. Our findings demonstrate the effectiveness of our platform and provide new insights on the molecular basis of fungal pathogenesis. Our approach promises comprehensive functional genomics in filamentous fungi and beyond.

Although the central branches of the dorsal root ganglion (DRG) sensory neurons do not spontaneously regenerate, a conditioning peripheral injury can promote their regeneration. A potential role of macrophages in axonal regeneration was proposed, but it has not been critically addressed whether macrophages play an essential role in the conditioning injury model. After sciatic nerve injury (SNI) in rats, the number of macrophages in DRGs gradually increased by day 7. The increase persisted up to 28 d and was accompanied by upregulation of inflammatory mediators, including oncomodulin. A macrophage deactivator, minocycline, reduced the macrophage number and expressions of the inflammatory mediators. Molecular signatures of conditioning effects were abrogated by minocycline, and enhanced regenerative capacity was substantially attenuated both in vitro and in vivo. Delayed minocycline infusion abrogated the SNI-induced long-lasting heightened neurite outgrowth potential, indicating a role for macrophages in the maintenance of regenerative capacity. Intraganglionic cAMP injection also resulted in an increase in macrophages, and minocycline abolished the cAMP effect on neurite outgrowth. However, conditioned media (CM) from macrophages treated with cAMP did not exhibit neurite growth-promoting activity. In contrast, CM from neuron-macrophage cocultures treated with cAMP promoted neurite outgrowth greatly, highlighting a requirement for neuron-macrophage interactions for the induction of a proregenerative macrophage phenotype. The growth-promoting activity in the CM was profoundly attenuated by an oncomodulin neutralizing antibody. These results suggest that the neuron-macrophage interactions involved in eliciting a proregenerative phenotype in macrophages may be a novel target to induce long-lasting regenerative processes after axonal injuries in the CNS.

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CNS neurons in adult mammals do not spontaneously regenerate axons after spinal cord injury. Preconditioning peripheral nerve injury allows the dorsal root ganglia (DRG) sensory axons to regenerate beyond the injury site by promoting expression of regenerationassociated genes. We have previously shown that peripheral nerve injury increases the number of macrophages in the DRGs and that the activated macrophages are critical to the enhancement of intrinsic regeneration capacity. The present study identifies a novel chemokine signal mediated by CCL2 that links regenerating neurons with proregenerative macrophage activation. Neutralization of CCL2 abolished the neurite outgrowth activity of conditioned medium obtained from neuron-macrophage cocultures treated with cAMP. The neuron-macrophage interactions that produced outgrowth-promoting conditioned medium required CCL2 in neurons and CCR2/CCR4 in macrophages. The conditioning effects were abolished in CCL2-deficient mice at 3 and 7 d after sciatic nerve injury, but CCL2 was dispensable for the initial growth response and upregulation of GAP-43 at the 1 d time point. Intraganglionic injection of CCL2 mimicked conditioning injury by mobilizing M2-like macrophages. Finally, overexpression of CCL2 in DRGs promoted sensory axon regeneration in a rat spinal cord injury model without harmful side effects. Our data suggest that CCL2-mediated neuron-macrophage interaction plays a critical role for amplification and maintenance of enhanced regenerative capacity by preconditioning peripheral nerve injury. Manipulation of chemokine signaling mediating neuron-macrophage interactions may represent a novel therapeutic approach to promote axon regeneration after CNS injury.