Biology subjects

Riemann, M.

Publications and source records attributed to Riemann, M..

2 recordsLinked to original sources

bioRxiv2022

Genetic analysis of the rice jasmonate receptors reveals specialized function for OsCOI2

O_LICOI1-mediated perception of jasmonate is critical for plant development and responses to environmental stresses. Monocots such as rice have two groups of COI genes due to gene duplication: OsCOI1a and OsCOI1b that are functionally equivalent to the dicotyledons COI1 on one hand and OsCOI2 whose function remains unclear. C_LIO_LIIn order to assess the function of OsCOI2 and its functional redundancy with COI1 genes, we developed a series of rice mutants in the 3 genes OsCOI1a, OsCOI1b and OsCOI2 by CRISPR Cas9 and characterized their phenotype and responses to jasmonate. C_LIO_LICharacterization of OsCOI2 uncovered important roles in root, leaf and flower development. In particular, we show that crown root growth inhibition by jasmonate relies on OsCOI2 and not OsCOI1a or OsCOI1b in rice, revealing a major function for the non-canonical OsCOI2 in jasmonate-dependent control of rice root growth. C_LIO_LICollectively, these results point to a specialized function of OsCOI2 in the regulation of plant development in rice and indicate that sub-functionalisation of jasmonate receptors has occurred in the monocot phylum. C_LI

plant biology↗

bioRxiv2022

Is cold-induced nuclear import of CBF4 regulating freezing tolerance?

C-repeat binding factors (CBFs) are crucial transcriptional activators in plant responses to low temperature. CBF4 differs by a slower, but more persistent regulation and its role in cold acclimation. Cold acclimation is of accentuated relevance for the tolerance to late spring frosts as they become progressively common as consequence of blurred seasonality in the context of global climate change. In the current study, we explore the functions of CBF4 from grapevine, VvCBF4. Overexpression of VvCBF4 fused to GFP in tobacco BY-2 cells confers cold tolerance. Furthermore, this protein shuttles from the cytoplasm to the nucleus in response to cold stress, associated with accumulation of transcripts for other CBFs and the cold responsive gene ERD10d. This response differs for chilling as compared to freezing and is regulated differently by upstream signalling involving oxidative burst, proteasome activity and jasmonate synthesis. This difference between chilling and freezing is also seen in the regulation of CBF4 transcripts in leaves from different grapevines differing in their cold tolerance. We propose the quality of cold stress is transduced by different upstream signals inducing nuclear import to regulate other CBF factor and activate COR genes.

molecular biology↗