Auxins, the hidden player in chloroplast development.

Throughout decades of plant research, the plant hormones known as auxins have been found to be of vital importance in most plant development processes. Indole-3-acetic acid (IAA) represents the most common auxin in plants and can be synthesized from its tryptophan precursor, which is synthesized in the chloroplast. The chloroplast constitutes an organelle of great relevance to plants since the photosynthesis process by which plants get most of their energy is carried out there.

Overview of the Role of Cell Wall DUF642 Proteins in Plant Development.

The DUF642 protein family is found exclusively in spermatophytes and is represented by 10 genes in Arabidopsis and in most of the 24 plant species analyzed to date. Even though the primary structure of DUF642 proteins is highly conserved in different spermatophyte species, studies of their expression patterns in Arabidopsis have shown that the spatial-temporal expression pattern for each gene is specific and consistent with the phenotypes of the mutant plants studied so far. Additionally, the regulation of DUF642 gene expression by hormones and environmental stimuli was specific for each gene, showing both up- and down-regulation depending of the analyzed tissue and the intensity or duration of the stimuli.

BIIDXI, a DUF642 cell wall protein, is involved in hypocotyl growth via auxin efflux.

Auxin is involved in hypocotyl elongation in response to different environmental factors. BIIDXI is a cell wall DUF642 protein that participates in the regulation of the degree of pectin-methylesterification of the cell wall in different tissues, including hypocotyls. Under continuous light, bdx-1 seedlings presented longer hypocotyls than those of WT, while BIIDXI-overexpressed hypocotyls were auxin resistant.

Cell Wall Localization of Two DUF642 Proteins, BIIDXI and TEEBE, during Early Inoculation.

The root-knot nematode infects a variety of plants, including . During migration, root-knot nematodes secrete different proteins to modify cell walls, which include pectolytic enzymes. However, the contribution of host cell wall proteins has not been described during this process.

Degree of pectin methyl esterification in endosperm cell walls is involved in embryo bending in Arabidopsis thaliana.

The endosperm is a transitory structure involved in proper embryo elongation. The cell walls of mature seed endosperm are generally composed of a uniform distribution of cellulose, unesterified homogalacturonans, and arabinans. Recent studies suggest that changes in cell wall properties during endosperm development could be related to embryo growth.

The cell wall DUF642 At2g41800 (TEB) protein is involved in hypocotyl cell elongation.

In plants, the cell wall is a complex and dynamic structure comprising high molecular weight carbohydrates and proteins. The cell wall plays an important role in several stages of the plant life cycle, including cell division, elongation and differentiation. The DUF642 family of cell wall proteins is highly conserved in spermatophytes and might be involved in pectin structural modifications.