Biology subjects

Heo, J.-o.

Publications and source records attributed to Heo, J.-o..

3 recordsLinked to original sources

bioRxiv2022

Pectin cell wall remodeling through PLL12 and callose deposition through polar CALS7 are necessary for long-distance phloem transport

In plants, the phloem distributes photosynthetic products for metabolism and storage over long distances. It relies on specialized cells, the sieve elements, which are enucleated and interconnected through large so-called sieve pores in their adjoining cell walls. Reverse genetics identified PECTATE LYASE LIKE 12 (PLL12) as critical for plant growth and development. Using genetic complementation, we establish that PLL12 enzyme activity is required exclusively late during cell differentiation. Physiological assays suggested a role specifically in phloem long distance transport while short distance symplastic transport does not require PLL12. Exploiting CALLOSE SYNTHASE 7 (CALS7) as a polar fluorescent marker, we identified structural defects in sieve pores in pll12. Due to the serial arrangement of sieve elements in the phloem, such defects should affect a plants ability specifically for symplastic transport over long distances.

plant biology↗

bioRxiv2021

An Arabidopsis root phloem pole cell atlas reveals PINEAPPLE genes as transitioners to autotrophy

Single cell sequencing has recently allowed the generation of exhaustive root cell atlases. However, some cell types are elusive and remain underrepresented. Here, we use a second- generation single cell approach, where we zoom in on the root transcriptome sorting with specific markers to profile the phloem poles at an unprecedented resolution. Our data highlight the similarities among the developmental trajectories and gene regulatory networks communal to protophloem sieve element (PSE) adjacent lineages in relation to PSE enucleation, a key event in phloem biology. As a signature for early PSE-adjacent lineages, we have identified a set of DNA-binding with one finger (DOF) transcription factors, the PINEAPPLEs (PAPL), that act downstream of PHLOEM EARLY DOF (PEAR) genes, and are important to guarantee a proper root nutrition in the transition to autotrophy. Our data provide a holistic view of the phloem poles that act as a functional unit in root development.

plant biology↗

bioRxiv2021

Analysis of phloem trajectory links tissue maturation to cell specialization.

The mechanisms that allow cells in the plant meristem to coordinate tissue-wide maturation gradients with specialized cell networks are critical for indeterminate growth. Here, we reconstructed the protophloem developmental trajectory of 19 cells from cell birth to terminal differentiation at single cell resolution in the Arabidopsis root. We found that cellular specification is mediated near the stem cell niche by PHLOEM EARLY DOF (PEAR) transcription factors. However, the PEAR dependent differentiation program is repressed by a broad gradient of PLETHORA (PLT) transcription factors, which directly inhibit PEARs own direct target ALTERED PHLOEM DEVELOPMENT (APL). The dissipation of PLT gradient around 7 cells from the stem cell activates APL expression, and a subsequent transitional network that results in a "seesaw" pattern of mutual inhibition over developmental time. Together, we provide a mechanistic understanding of how morphogen-like maturation gradients interface with cell-type specific transcriptional regulators to stage cellular differentiation.

plant biology↗