Publishing type：Research paper (scientific journal)   Publisher：Wiley  

Summary

The sexual reproductive organs of bryophytes – in which gametes necessary for fertilization are produced, namely, male antheridia and female archegonia – are formed from vegetative haploid gametophytes. In dioicous bryophytes such as Marchantia polymorpha, the genes within the sex‐determining regions in distinct sexual strains have been identified. However, in monoicous bryophytes such as Physcomitrium patens, how the two sex fates are specified on the same gametophyte remained unknown.

Here, we identified an RWP‐RK domain‐containing transcription factor in P. patens, PpRKD, as a factor required for the development of female organs, based on the absence of archegonia in loss‐of‐function Pprkd mutants and the specific expression of PpRKD in archegonia.

When ectopically induced, the expression of PpRKD resulted in the repression of antheridial development and the emergence of archegonium‐like organs. Furthermore, the young primordia inside the antheridial bundle displayed typical archegonial division patterns, suggesting that PpRKD confer female fate to antheridium primordia.

This study represents the first instance where the function of sex determination has been identified among RKD orthologs in land plants. This finding should provide a new framework for the molecular evolutionary context of the genes in the RKD family, considering the recent elucidation of their roles in algae.

DOI： 10.1111/nph.20262

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Publishing type：Research paper (scientific journal)   Publisher：Oxford University Press (OUP)  

Abstract

Woody cells generate lignocellulosic biomass, which is a promising sustainable bioresource for wide industrial applications. Woody cell differentiation in vascular plants, including the model plant poplar (Populus trichocarpa), is regulated by a set of NAC family transcription factors, the VASCULAR-RELATED NAC-DOMAIN (VND), NAC SECONDARY CELL WALL THICKENING PROMOTING FACTOR (NST)/SND, and SOMBRERO (SMB) (VNS)-related proteins, but the precise contributions of each VNS protein to wood quality are unknown. Here, we performed a detailed functional analysis of the poplar SMB-type VNS proteins PtVNS13–PtVNS16. PtVNS13–PtVNS16 were preferentially expressed in the roots of young poplar plantlets, similar to the Arabidopsis thalianaSMB gene. PtVNS13 and PtVNS14, as well as the NST-type PtVNS11, suppressed the abnormal root cap phenotype of the Arabidopsis sombrero-3 mutant, whereas the VND-type PtVNS07 gene did not, suggesting a functional gap between SMB- or NST-type VNS proteins and VND-type VNS proteins. Overexpressing PtVNS13–PtVNS16 in Arabidopsis seedlings and poplar leaves induced ectopic xylem-vessel-like cells with secondary wall deposition, and a transient expression assay showed that PtVNS13–16 transactivated woody-cell-related genes. Interestingly, although any VNS protein rescued the pendant stem phenotype of the Arabidopsis nst1-1 nst3-1 mutant, the resulting inflorescence stems exhibited distinct cell wall properties: poplar VNS genes generated woody cell walls with higher enzymatic saccharification efficiencies compared with Arabidopsis VNS genes. Together, our data reveal clear functional diversity among VNS proteins in woody cell differentiation and demonstrate a novel VNS-based strategy for modifying woody cell wall properties toward enhanced utilization of woody biomass.

DOI： 10.1093/pcp/pcab102

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Other Link： https://academic.oup.com/pcp/article-pdf/62/12/1963/42230280/pcab102.pdf

Publishing type：Research paper (scientific journal)   Publisher：Springer Science and Business Media LLC  

DOI： 10.1007/s11103-021-01148-6

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Other Link： https://link.springer.com/article/10.1007/s11103-021-01148-6/fulltext.html

Publishing type：Research paper (scientific journal)   Publisher：Oxford University Press (OUP)  

Abstract

Vascular plants have two types of water-conducting cells, xylem vessel cells (in angiosperms) and tracheid cells (in ferns and gymnosperms). These cells are commonly characterized by secondary cell wall (SCW) formation and programmed cell death (PCD), which increase the efficiency of water conduction. The differentiation of xylem vessel cells is regulated by a set of NAC (NAM, ATAF1/2 and CUC2) transcription factors, called the VASCULAR-RELATED NAC-DOMAIN (VND) family, in Arabidopsis thaliana Linne. The VNDs regulate the transcriptional induction of genes required for SCW formation and PCD. However, information on the transcriptional regulation of tracheid cell differentiation is still limited. Here, we performed functional analysis of loblolly pine (Pinus taeda Linne) VND homologs (PtaVNS, for VND, NST/SND, SMB-related protein). We identified five PtaVNS genes in the loblolly pine genome, and four of these PtaVNS genes were highly expressed in tissues with tracheid cells, such as shoot apices and developing xylem. Transient overexpression of PtaVNS genes induced xylem vessel cell-like patterning of SCW deposition in tobacco (Nicotiana benthamiana Domin) leaves, and up-regulated the promoter activities of loblolly pine genes homologous to SCW-related MYB transcription factor genes and cellulose synthase genes, as well as to cysteine protease genes for PCD. Collectively, our data indicated that PtaVNS proteins possess transcriptional activity to induce the molecular programs required for tracheid formation, i.e., SCW formation and PCD. Moreover, these findings suggest that the VNS–MYB-based transcriptional network regulating water-conducting cell differentiation in angiosperm and moss plants is conserved in gymnosperms.

DOI： 10.1093/treephys/tpz106

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Other Link： http://academic.oup.com/treephys/advance-article-pdf/doi/10.1093/treephys/tpz106/32360222/tpz106.pdf

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1093/pcp/pcz154

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J-GLOBAL

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J-GLOBAL

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J-GLOBAL

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J-GLOBAL

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