Discovery of a wide variety of α-1,6-cyclized β-1,2-glucan synthases: a new entrance for host-microbe interactions.

Motouchi, S.; Kim, I.; Ishiguro, A.; Niu, K.; Komba, S.; Kashima, T.; Kitano, Y.; Nakai, H.; Nakajima, M.

doi:10.1101/2025.04.21.649730

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bioRxiv · 10.1101/2025.04.21.649730

Discovery of a wide variety of α-1,6-cyclized β-1,2-glucan synthases: a new entrance for host-microbe interactions.

Motouchi, S.·Kim, I.·Ishiguro, A.·Niu, K.·Komba, S.·Kashima, T.·Kitano, Y.·Nakai, H.·Nakajima, M.

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Abstract

-1,6-Cyclized {beta}-1,2-glucans (C{beta}G) are established virulence factors in Xanthomonas, yet functional breadth and distribution of C{beta}Gs in nature have remained unclear. Here, we biochemically identified enzymes synthesizing C{beta}Gs with specific chain lengths, exhibiting potential natural occurrence of various C{beta}Gs. Structural analyses identify subtle variations in a loop, named Loop X, as a key determinant of product size, leading to understanding of the whole picture of the mechanism that controls the sizes. We further demonstrated that C{beta}G composed of 13 glucose units contributes to plant-virulence in Ralstonia pseudosolanacearum, expanding the functional scope of virulence-associated cyclic glucans. Overall, it provides the potential targets for regulating various plant-microbe interactions and also serves as a vital lead to discovering unknown host-microbe interactions with significant potential for agricultural applications.

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Motouchi, S., Kim, I., Ishiguro, A., Niu, K., Komba, S., Kashima, T., Kitano, Y., Nakai, H., Nakajima, M.. 2025-04-21. Discovery of a wide variety of α-1,6-cyclized β-1,2-glucan synthases: a new entrance for host-microbe interactions.. https://doi.org/10.1101/2025.04.21.649730

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