Author: OHTAAtsushi

This paper has been published in which Prof. Terauchi is the corresponding author.

Shimizu, M., Hirabuchi, A., Sugihara, Y., Abe, A., Takeda, T., Kobayashi, M., Hiraka, Y., Kanzaki, E., Oikawa, K., Saitoh, H., Thorsten, L., J, B. M., Kamoun, S. & Terauchi, R. (2022). A genetically linked pair of NLR immune receptors shows contrasting patterns of evolution. Proceedings of the National Academy of Sciences, 119(27), e2116896119. https://doi.org/10.1073/pnas.2116896119

Abstract

Throughout their evolution, plant nucleotide-binding leucine-rich-repeat receptors (NLRs) have acquired widely divergent unconventional integrated domains that enhance their ability to detect pathogen effectors. However, the functional dynamics that drive the evolution of NLRs with integrated domains (NLR-IDs) remain poorly understood. Here, we reconstructed the evolutionary history of an NLR locus prone to unconventional domain integration and experimentally tested hypotheses about the evolution of NLR-IDs. We show that the rice (Oryza sativa) NLR Pias recognizes the effector AVR-Pias of the blast fungal pathogen Magnaporthe oryzae. Pias consists of a functionally specialized NLR pair, the helper Pias-1 and the sensor Pias-2, that is allelic to the previously characterized Pia pair of NLRs: the helper RGA4 and the sensor RGA5. Remarkably, Pias-2 carries a C-terminal DUF761 domain at a similar position to the heavy metal–associated (HMA) domain of RGA5. Phylogenomic analysis showed that Pias-2/RGA5 sensor NLRs have undergone recurrent genomic recombination within the genus Oryza, resulting in up to six sequence-divergent domain integrations. Allelic NLRs with divergent functions have been maintained transspecies in different Oryza lineages to detect sequence-divergent pathogen effectors. By contrast, Pias-1 has retained its NLR helper activity throughout evolution and is capable of functioning together with the divergent sensor-NLR RGA5 to respond to AVR-Pia. These results suggest that opposite selective forces have driven the evolution of paired NLRs: highly dynamic domain integration events maintained by balancing selection for sensor NLRs, in sharp contrast to purifying selection and functional conservation of immune signaling for helper NLRs.

This paper has been published in which Prof. Terauchi is the corresponding author.

Natsume, S., Sugihara, Y., Kudoh, A., Oikawa, K., Shimizu, M., Ishikawa, Y., Nishihara, M., Abe, A., Innan, H., & Terauchi, R. (2022). Genome Analysis Revives a Forgotten Hybrid Crop Edo-dokoro in the Genus Dioscorea. Plant and Cell Physiology, pcac109. https://doi.org/10.1093/pcp/pcac109

Abstract

A rhizomatous Dioscorea crop “Edo-dokoro” was described in old records of Japan, but its botanical identify has not been characterized. We found that Edo-dokoro is still produced by four farmers in Tohoku-machi of Aomori Prefecture, Japan. Rhizomes of Edo-dokoro are a delicacy to the local people and are sold in the markets. Morphological characters of Edo-dokoro suggest its hybrid origin between the two species, D. tokoro and D. tenuipes. Genome analysis revealed that Edo-dokoro is likely originated by hybridization of a male D. tokoro to a female D. tenuipes, followed by a backcross with a male plant of D. tokoro. Edo-dokoro is a typical minor crop possibly maintained for more than 300 years but now almost forgotten from the public. We hypothesize that there are many such uncharacterized genetic heritages passed over generations by small scale farmers that await serious scientific investigation for future use and improvement by using modern genomics information.

REVIEW ARTICLE

Adachi, H., & Kamoun, S. (2022). NLR receptor networks in plants. Essays in Biochemistry, EBC20210075. https://doi.org/10.1042/EBC20210075

Abstract

To fight off diverse pathogens and pests, the plant immune system must recognize these invaders; however, as plant immune receptors evolve to recognize a pathogen, the pathogen often evolves to escape this recognition. Plant–pathogen co-evolution has led to the vast expansion of a family of intracellular immune receptors-nucleotide-binding domain and leucine-rich repeat proteins (NLRs). When an NLR receptor recognizes a pathogen ligand, it activates immune signaling and thus initiates defense responses. However, in contrast with the model of NLRs acting individually to activate resistance, an emerging paradigm holds that plants have complex receptor networks where the large repertoire of functionally specialized NLRs function together to act against the large repertoire of rapidly evolving pathogen effectors. In this article, we highlight key aspects of immune receptor networks in plant NLR biology and discuss NLR network architecture, the advantages of this receptor network system, and the evolution of the NLR network in asterid plants.