Unregulated Sphingolipid Biosynthesis in Gene-Edited Arabidopsis ORM Mutants Results in Nonviable Seeds with Strongly Reduced Oil Content

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  • Published: 2020-04-16
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Lateral branches are important for plant architecture and production, but how plants determine their lateral branches remains to be further understood.

A research conducted by the resarch team led by Prof. LI Yunhai at Institute of Genetics and Developmental Biology of Chinese Academy of Sciences reports that the CUP-SHAPED COTYLEDON2 (CUC2)/CUC3-DA1-UBIQUITIN-SPECIFIC PROTEASE15 (UBP15) regulatory module controls the initiation of axillary meristems, thereby determining the number of lateral branches in Arabidopsis (Arabidopsis thaliana). Mutation in the ubiquitin-dependent peptidase DA1 causes fewer lateral branches due to defects in the initiation of axillary meristems. The transcription factors CUC2 and CUC3, which regulate the axillary meristem initiation, directly bind to the DA1 promoter and activate its expression. Further results show that UBP15, which is a direct substrate of DA1 peptidase, represses the initiation of axillary meristems. Genetic analyses support that CUC2/CUC3, DA1, and UBP15 function, at least in part, in a common pathway to regulate the initiation of axillary meristems. Therefore, our findings establish a genetic and molecular framework by which the CUC2/CUC3-DA1-UBP15 regulatory module controls the initiation of axillary meristems, thereby determining plant architecture.

The research was published in The Plant Cell on April 2 as a highlighted article. Dr. LI Yu and Dr. XIA Tian graduated from University of Chinese Academy of Sciences (UCAS) are the first authors. Prof. LI Yunhai is the corresponding author, who is also a doctoral supervisor at University of Chinese Academy of Sciences. This work was supported by the National Natural Science Foundation of China.

△Figure 7. CUC2/CUC3-DA1-UBP15 Regulatory Module-Mediated Control of Axillary Meristem Initiation. CUC2 and CUC3 directly bind to the promoter region of DA1 and activate its expression. DA1 is a positive regulator of the initiation of AMs. DA1 promotes the degradation of UBP15 that represses the initiation of AMs. DA1 functions redundantly with LAS to promote the initiation of AMs. UBP15 also partially mediates the effect of LAS on the initiation of AMs.