Novel resources to investigate leaf plasmodesmata formation in C and C monocots.

Plasmodesmata (PD) are nanochannels that facilitate cell-to-cell transport in plants. More productive and photosynthetically efficient C plants form more PD at the mesophyll (M)-bundle sheath (BS) interface in their leaves than their less efficient C relatives. In C leaves, PD play an essential role in facilitating the rapid metabolite exchange between the M and BS cells to operate a biochemical CO concentrating mechanism, which increases the CO partial pressure at the site of Rubisco in the BS cells and hence photosynthetic efficiency.

The role of SWEET4 proteins in the post-phloem sugar transport pathway of Setaria viridis sink tissues.

In the developing seeds of all higher plants, filial cells are symplastically isolated from the maternal tissue supplying photosynthate to the reproductive structure. Photoassimilates must be transported apoplastically, crossing several membrane barriers, a process facilitated by sugar transporters. Sugars Will Eventually be Exported Transporters (SWEETs) have been proposed to play a crucial role in apoplastic sugar transport during phloem unloading and the post-phloem pathway in sink tissues.

A single promoter-TALE system for tissue-specific and tuneable expression of multiple genes in rice.

In biological discovery and engineering research, there is a need to spatially and/or temporally regulate transgene expression. However, the limited availability of promoter sequences that are uniquely active in specific tissue-types and/or at specific times often precludes co-expression of multiple transgenes in precisely controlled developmental contexts. Here, we developed a system for use in rice that comprises synthetic designer transcription activator-like effectors (dTALEs) and cognate synthetic TALE-activated promoters (STAPs).

Measuring Plasmodesmata Density on Cell Interfaces of Monocot Leaves Using 3D Immunolocalization and Scanning Electron Microscopy.

Quantification of plasmodesmata density on cell interfaces of plant tissues, particularly of leaves, has been a long-standing challenge. Using electron microscopy alone to quantify plasmodesmata is difficult because of the limited surface area coverage per image and hence the need to examine large numbers of sections for robust quantification. Fluorescence microscopy provides the larger surface area coverage per image but can only visualize pit fields and not individual plasmodesma.

Dark respiration rates are not determined by differences in mitochondrial capacity, abundance and ultrastructure in C leaves.

Our understanding of the regulation of respiration in C plants, where mitochondria play different roles in the different types of C photosynthetic pathway, remains limited. We examined how leaf dark respiration rates (R ), in the presence and absence of added malate, vary in monocots representing the three classical biochemical types of C photosynthesis (NADP-ME, NAD-ME and PCK) using intact leaves and extracted bundle sheath strands. In particular, we explored to what extent rates of R are associated with mitochondrial number, volume and ultrastructure.