投稿者: OHTAAtsushi

投稿日:

Pathogen-derived 9-methyl sphingoid base is perceived by a lectin receptor kinase in Arabidopsis

Kato, H., Nemoto, K., Shimizu, M., Abe, A., Asai, S., Ishihama, N., Daimon, T., Ojika, M., Kawakita, K., Onai, K., Shirasu, K., Ishiura, M., Takemoto, D., Takano, Y. and Terauchi, R. (2021). Pathogen-derived 9-methyl sphingoid base is perceived by a lectin receptor kinase in Arabidopsis. BioRxiv, 2021.10.18.464766. https://doi.org/10.1101/2021.10.18.464766

Abstruct

In plants, many invading microbial pathogens are recognized by cell-surface pattern recognition receptors (PRRs), inducing defense responses; yet how PRRs perceive pathogen sphingolipids remains unclear. Here, we show that the ceramide Pi-Cer D from a plant pathogenic oomycete Phytophthora infestans triggers defense responses in Arabidopsis. Pi-Cer D is cleaved by an Arabidopsis apoplastic ceramidase, NCER2, and the resulting 9-methyl-branched sphingoid base is recognized by a plasma membrane lectin receptor-like kinase, RDA2. Importantly, 9-methyl-branched sphingoid base, which is unique to microbes, induces plant immune responses by interacting with RDA2. Loss of RDA2 or NCER2 function compromised Arabidopsis resistance against an oomycete pathogen, indicating that these are crucial for defense. We provide new insights that help elucidate the recognition mechanisms of pathogen-derived lipid molecules in plants.

Fig. 4. A model for the recognition of pathogen-derived ceramide in plants. Pi-Cer D is cleaved by plant apoplastic ceramidase NCER2 into 9-methyl sphingoid base. 9-methyl sphingoid base is recognized by a lectin-receptor kinase, RDA2/SphingR, which then induces defense responses that include WRKY33 gene expression and enhances immunity against pathogen infection.
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Population Genomics of Yams: Evolution and Domestication of Dioscorea Species

Sugihara, Y., Kudoh, A., Oli, M. T., Takagi, H., Natsume, S., Shimizu, M., Abe, A., Asiedu, R., Asfaw, A., Adebola, R. & Terauchi, R. (2021). Population Genomics of Yams: Evolution and Domestication of Dioscorea Species. In: Population Genomics. Springer, Cham. https://doi.org/10.1007/13836_2021_94

Abstruct

Yam is a collective name of tuber crops belonging to the genus Dioscorea. Yam is important not only as a staple food crop but also as an integral component of society and culture of the millions of people who depend on it. However, due to its regional importance, yam has long been regarded as an “orphan crop” lacking a due global attention. Although this perception is changing with recent advances in genomics technologies, domestication processes of most yam species are still ambiguous. This is mainly due to the complicated evolutionary history of Dioscorea species caused by frequent hybridization and polyploidization, which is possibly caused by dioecy that imposed obligate outcrossing to the species of Dioscorea. In this chapter, we provide an overview of the evolution of Dioscorea and address the domestication of yam from population genomics perspectives by focusing on the processes of hybridization and polyploidization. A review is given to the recent population genomics studies on the hybrid origin of D. rotundata in West and Central Africa, the global dispersion of D. alata through human migrations, and the whole-genome duplication of the South America species of D. trifida. In the end, we give a summary of current understanding of sex-determination system in Dioscorea.

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Genome Analyses Reveal the Hybrid Origin of the Staple Crop White Guinea Yam (Dioscorea rotundata)

Yu Sugihara, Kwabena Darkwa, Hiroki Yaegashi, Satoshi Natsume, Motoki Shimizu, Akira Abe, Akiko Hirabuchi, Kazue Ito, Kaori Oikawa, Muluneh Tamiru-Oli, Atsushi Ohta, Ryo Matsumoto, Agre Paterne, David De Koeyer, Babil Pachakkil, Shinsuke Yamanaka, Satoru Muranaka, Hiroko Takagi, Ben White, Robert Asiedu, Hideki Innan, Asrat Asfaw, Patrick Adebola, Ryohei Terauchi (2020). Genome Analyses Reveal the Hybrid Origin of the Staple Crop White Guinea Yam (Dioscorea rotundata). PNAS, 117 (50) 31987-31992; DOI: 10.1073/pnas.2015830117.

Abstract

White Guinea yam (Dioscorea rotundata) is an important staple tuber crop in West Africa. However, its origin remains unclear. In this study, we resequenced 336 accessions of white Guinea yam and compared them with the sequences of wild Dioscorea species using an improved reference genome sequence of D. rotundata. In contrast to a previous study suggesting that D. rotundata originated from a subgroup of Dioscorea praehensilis, our results suggest a hybrid origin of white Guinea yam from crosses between the wild rainforest species D. praehensilis and the savannah-adapted species Dioscorea abyssinica. We identified a greater genomic contribution from D. abyssinica in the sex chromosome of Guinea yam and extensive introgression around the SWEETIE gene. Our findings point to a complex domestication scenario for Guinea yam and highlight the importance of wild species as gene donors for improving this crop through molecular breeding.