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Crop Biotech Update

Researchers Characterize Lignin of Rice Mutants Generated Using CRISPR-Cas9

April 17, 2019

Kyoto University scientists characterized the lignin of mutant rice developed using the CRISPR-Cas9 system. The results are published in The Plant Journal.

In a previous study, Yuri Takeda and colleagues identified a rice gene encoding coniferaldehyde 5‐hydroxylase (OsCAld5H1), which was effective in modulating syringyl (S)/guaiacyl (G) lignin composition ratio in rice, a model grass species. The OsCAld5H1‐knockdown rice lines generated using gene silencing, exhibited augmented G lignin units yet contained considerable amounts of residual S lignin units. In their latest study, they generated loss‐of‐function mutants of OsCAld5H1 using the CRISPR-Cas9 system to understand the effect of suppression of OsCAld5H1 on rice lignin structure.

Results showed that all the tested mutant lines were enriched in G units and produced considerable numbers of S units. Surprisingly, analysis showed that enrichment of G units in lignins of the mutants was limited to the non‐γ‐p‐coumaroylated units, while grass‐specific γ‐p‐coumaroylated lignin units were almost unaffected. Further analysis showed that no homologous genes of OsCAld5H1 were overexpressed in the mutants. These data suggested that CAld5H is mainly involved in the production of non‐γ‐p‐coumaroylated S lignin units, common in both eudicots and grasses, but not in the production of grass‐specific γ‐p‐coumaroylated S units in rice.

Read the research article in The Plant Journal.