In silico and expression analyses of fasciclin-like arabinogalactan proteins reveal functional conservation during embryo and seed development

Abstract

Key messageThe fasciclin-like arabinogalactan proteins organization into four groups is conserved and may be related to specific roles in developmental processes across angiosperms.AbstractFasciclin-like arabinogalactan proteins (FLAs) are a subclass of arabinogalactan proteins (AGPs), which contain fasciclin-like domains in addition to typical AGP domains. FLAs are present across all embryophytes, and despite their low overall sequence similarity, conserved regions that define the fasciclin functional domain (FAS) have been identified, suggesting that the cell adhesion property is also conserved. FLAs in Arabidopsis have been organized into four subgroups according to the number and distribution of functional domains. Recent studies associated FLAs with cell wall-related processes where domain organization seemed to be related to functional roles. In Arabidopsis, FLAs containing a single FAS domain were found to be important for the integrity and elasticity of the plant cell wall matrix, and FLAs with two FAS domains and two AGP domains were found to be involved in maintaining proper cell expansion under salt stress conditions. The main purpose of the present work was to elucidate the expression pattern of selected FLA genes during embryo and seed development using RT-qPCR. AtFLA8 and AtFLA10, two Arabidopsis genes that stood out in previous microarray studies of embryo development, were further examined using promoter-driven gene reporter analyses. We also studied the expression of cork oak FLA genes and found that their expression partially parallels the expression patterns of the putative AtFLA orthologs. We propose that the functional organization of FLAs is conserved and may be related to fundamental aspects of embryogenesis and seed development across angiosperms. Phylogenetic studies were performed, and we show that the same basic four-subgroup organization described for Arabidopsis FLA gene classification is valid for most Arabidopsis FLA orthologs of several plant species, namely poplar, corn and cork oak.Electronic supplementary materialThe online version of this article (10.1007/s00497-019-00376-7) contains supplementary material, which is available to authorized users.

Photooxidative stress-inducible orange and pink water-soluble astaxanthin-binding proteins in eukaryotic microalga

“…Fasciclin domains are conserved in secretory and membrane-anchored proteins in humans, higher plants, and microalgae, such as fasciclin I in Drosophila 38 , human periostins 39 , plant arabinogalactan proteins 40 and SOS5 41 , and the volvox cell adhesion molecule Algal-CAM 33 . These fasciclin family proteins have recently been found to be involved in multiple functions that are not limited to cell adhesion and proliferation, and they are also associated with multiple aspects of human health and disease 42 , plant reproduction 43 , and microbial stress responses, including a high-light response found in a cyanobacterial ortholog 44 . To our knowledge, none of these proteins have been reported to bind lipids, including carotenoids, or to possess antioxidative activity.…”

FASCICLIN-LIKE 18 Is a New Player Regulating Root Elongation in Arabidopsis thaliana

“…The FLA gene-family in Arabidopsis is composed of 21 genes ( Supplementary Figure 1 ; Schultz et al, 2000 ; Johnson et al, 2003 ; MacMillan et al, 2010 ; Costa et al, 2019 ; Shafee et al, 2020 ). He et al (2019) revised this number and suggested there are only 20 FLA genes in Arabidopsis .…”

“…The Arabidopsis FLA genes were classified into four groups based on the number of FAS domains (one or two), the number of AGP domains (one or two), and whether they contain a predicted GPI-anchor modification site ( Johnson et al, 2003 ; MacMillan et al, 2010 ). Phylogenetic studies suggest that these four groups are maintained throughout the evolution of land plants ( Costa et al, 2019 ; He et al, 2019 ; Shafee et al, 2020 ). FLA18 was classified as part of group B which contains FLA15 , FLA16 , FLA17 and FLA18 .…”

Identification and expression profiling of toxic boron-responsive microRNAs and their targets in sensitive and tolerant wheat cultivars

“…ARABINOGALACTAN-PROTEIN11 (FLA11), FLA6 and FLA13 that are known to play roles in plant growth, development, and adaptation to environmental conditions by participating in cell-matrix adhesion (Costa et al 2019), thereby interacting with the cytoskeleton (Sardar et al, 2006). FLAs are included in the Arabinogalactan-protein (AGP) family (Schultz et al, 2002), which are embedded in the plasma membrane with the help of a glycosylphosphatidylinositol (GPI) anchor or found in the extracellular matrix attached to the cell wall (Showalter, 2001).…”