Putative fasciclin-like arabinogalactan-proteins (FLA) in wheat (Triticum aestivum) and rice (Oryza sativa): identification and bioinformatic analyses

Abstract

Putative plant adhesion molecules include arabinogalactan-proteins having fasciclin-like domains. In animal, fasciclin proteins participate in cell adhesion and communication. However, the molecular basis of interactions in plants is still unknown and none of these domains have been characterized in cereals. This work reports the characterization of 34 wheat (Triticum aestivum) and 24 rice (Oryza sativa) Fasciclin-Like Arabinogalactan-proteins (FLAs). Bioinformatics analyses show that cereal FLAs share structural characteristics with known Arabidopsis FLAs including arabinogalactan-protein and fasciclin conserved domains. At least 70% of the wheat and rice FLAs are predicted to be glycosylphosphatidylinositol-anchored to the plasma membranes. Expression analyses determined from the relative abundance of ESTs in the publicly available wheat EST databases and from RNA gel blots indicate that most of these genes are weakly expressed and found mainly in seeds and roots. Furthermore, most wheat genes were down regulated by abiotic stresses except for TaFLA9 and 12 where cold treatment induces their expression in roots. Plant fasciclin-like domains were predicted to have 3-D homology with FAS1 domain of the fasciclin I insect neural cell adhesion molecule with an estimated precision above 70%. The structural analysis shows that negatively charged amino acids are concentrated along the beta1-alpha3-alpha4-beta2 edges, while the positively charged amino acids are concentrated on the back side of the folds. This highly charged surface distribution could provide a way of mediating protein-protein interactions via electrostatic forces similar to many other adhesion molecules. The identification of wheat FLAs will facilitate studying their function in plant growth and development and their role in stress response.

Screen of Genes Linked to High-Sugar Content in Stems by Comparative Genomics

“…The most reduced transcript has a fasciclin domain. This domain has been shown to be involved in cell adhesion (Table 1) [10,22].…”

“…These proteins are structural components that mediate the interaction between the plasma membrane and the cell wall. However, their specific role in plants is still unknown [10]. A loss-of-function mutant in the Arabidopsis gene fasciclin-like arabinogalactan 4 (AtFLA4) displayed thinner cell walls and increased sensitivity to salinity [46].…”

A Glucurono(arabino)xylan Synthase Complex from Wheat Contains Members of the GT43, GT47, and GT75 Families and Functions Cooperatively

“…To determine the DNA sequences of all wheat GT (TaGT) genes, we developed an in-house Java script to screen wheat EST databases (from The Institute for Genome Research [TIGR] and the National Center for Biotechnology Information [NCBI]). This script was successfully used to identify 34 fasciclinlike arabinogalactan proteins in wheat (Faik et al, 2006). Table I summarizes the number of ESTs identified, the number of unique contigs, the number of fulllength sequences, and the number of the orthologs in the rice genome for each gene family/group described here.…”

Bioengineering of Male Sterility in Rice (Oryza sativa L.)

“…The MTR1 locus is located on chromosome 12, containing two putative fasciclin domains, FAS1-1 (amino acids 254-356) and FAS1-2 (amino acids 435-535), which are indispensible for role of MTR1 in anther development and pollen maturation. Fasciclin domain is also known to be an extracellular module putatively mediates cell adhesion (Faik et al 2006;MacMillan et al 2010). Ruiz and Daniell (2005) demonstrated the role of phaA gene which encodes β-ketothiolase from bacterium Acinetobacter into the chloroplast genome of tobacco under the control of chloroplast promoter psbA.…”