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Kiyosue, T.

Publications and source records attributed to Kiyosue, T..

3 recordsLinked to original sources

Initiation of asexual reproduction by the AP2/ERF gene GEMMIFER in Marchantia polymorpha

Plants can propagate their own clones through asexual reproduction. Genetic and hormonal factors regulating asexual reproduction have begun to be elucidated in the liverwort Marchantia polymorpha, which produce asexual propagules called gemmae within the gemma cups. Here, we report an AP2/ERF family gene, GEMMIFER (MpGMFR), as a key regulator of asexual reproduction in M. polymorpha. Suppression of MpGMFR function using genome editing and amiRNA results in the loss of gemma and gemma cup formation. In contrast, activation of MpGMFR function using a dexamethasone inducible system promotes gemma and/or gemma cup formation depending on the induction conditions. Notably, transient strong activation of MpGMFR induced gemma initial cells at the meristem, which develop into mature gemmae capable of reproducing as new individuals after detachment. These results show that MpGMFR is necessary and sufficient for the initiation of asexual reproduction at the meristem. MpGMFR expression was detected from the meristem through to the early stages of gemma development including the gemma cup floor cells. MpGMFR expression precedes the expression of GEMMA CUP-ASSOCIATED MYB1 (MpGCAM1) in early gemma development, supporting the notion that MpGMFR initiates asexual reproduction. We anticipate this finding to be a foundation to study the evolution of extra meristem formation in plant bodies that may have made a significant contribution to the prosperity of plants on land.

plant biology↗

Control of stem cell behavior by CLE-JINGASA signaling in the shoot apical meristem in Marchantia polymorpha

Land plants undergo indeterminate growth by the activity of meristems in both gametophyte (haploid) and sporophyte (diploid) generations1-3. In the sporophyte of the flowering plant Arabidopsis thaliana, the apical meristems are located at the shoot and root tips, in which a number of regulatory gene homologs are shared for their development, implying deep evolutionary origins4-7. However, little is known about their functional conservation with gametophytic meristems in distantly related land plants such as bryophytes8-17, even though genomic studies have revealed the subfamily-level diversity of regulatory genes is mostly conserved throughout land plants18-23. Here we show that a NAM/ATAF/CUC (NAC) domain transcription factor, JINGASA (MpJIN), acts downstream of CLV3/ESR-related (CLE) peptide signaling and controls stem cell behavior in the gametophytic shoot apical meristem of the liverwort Marchantia polymorpha. We found that MpJIN shows heterogeneous expression in space and time within the stem cell zone, associated with the loss and de novo specification of stem cell identity at the branching event. Consistent with the expression pattern, induction of MpJIN results in ectopic periclinal cell division in the stem cell zone and meristem termination. Comparative expression analysis suggests that the function of JIN/FEZ subfamily genes was shared between the shoot apical meristems in the gametophyte and sporophyte generations in early land plants but was lost in certain lineages including the flowering plant A. thaliana.

plant biology↗

An evolutionarily conserved coreceptor gene is essential for CLAVATA signaling in Marchantia polymorpha

Growth and development of land plants are controlled by CLAVATA3/EMBRYO SURROUNDING REGION-related (CLE) family of peptide hormones. In contrast to the genetic diversity of CLE family in flowering plants, the liverwort Marchantia polymorpha possesses a minimal set of CLE, MpCLE1(TDIF homolog) and MpCLE2 (CLV3 homolog). MpCLE1 and MpCLE2 peptides exert distinct function at the apical meristem of M. polymorpha gametophyte via specific receptors, MpTDIF RECEPTOR (MpTDR) and MpCLAVATA1 (MpCLV1), respectively, both belonging to the subclass XI of leucine-rich repeat receptor-like kinases (LRR-RLKs). Biochemical and genetic studies in Arabidopsis have shown that TDR/PXY family and CLV1/BAM family recognize the CLE peptide ligand in a heterodimeric complex with a member of subclass-II coreceptors. Here we show that three LRR-RLK genes of M. polymorpha are classified into subclass II, representing three distinct subgroups evolutionarily conserved in land plants. To address the involvement of subclass-II coreceptors in M. polymorpha CLE signaling, we performed molecular genetic analysis on one of them, MpCLAVATA3 INSENSITIVE RECEPTOR KINASE (MpCIK). Two knockout alleles for MpCIK formed narrow apical meristems marked by promMpYUC2:GUS marker, which were not expanded by MpCLE2 peptide treatment, phenocopying Mpclv1. Loss of sensitivity to MpCLE2 peptide was also observed in gemma cup formation in both Mpclv1 and Mpcik. Biochemical analysis using a Nicotiana benthamiana transient expression system revealed weak association between MpCIK and MpCLV1, as well as MpCIK and MpTDR. While MpCIK may also participate in MpCLE1 signaling, our data show that the conserved CLV3-CLV1-CIK module functions in M. polymorpha, controlling meristem activity for development and organ formation for asexual reproduction.

plant biology↗