Molecular identification and chromosomal localization of genes encoding Triticum aestivum xylanase inhibitor I-like proteins in cereals

Abstract

TAXI ( Triticum aestivum xylanase inhibitor) proteins are present in wheat flour and are known to inhibit glycosyl hydrolase family 11 endoxylanases, enzymes which are commonly applied in grain processing. Here, we describe the PCR-based molecular identification of genes encoding endoxylanase inhibitors HVXI and SCXI, the TAXI-like proteins from barley ( Hordeum vulgare) and rye ( Secale cereale) respectively. The HVXI coding sequence encodes a mature protein of 384 amino acids preceded by a 19 amino acid long signal sequence. SCXI-II/III has an open reading frame encoding a signal peptide of 21 amino acids and a mature protein of 375 amino acids. As for TAXI-I, no introns were detected in the untranslated regions and coding sequences identified. These newly identified sequences allowed us to perform a multiple sequence alignment with TAXI-I and similar proteins. Rice TAXI-type proteins clustered together with the cereal endoxylanase inhibitors. Dicotyledonous proteins with sequence similarity to TAXI-I, including the tomato xyloglucan-specific endoglucanase inhibiting protein, formed a different clade. The TAXI-type proteins may hence be part of a superfamily of proteins all involved in plant responses to biotic or abiotic stress and for which a function as glycosyl hydrolase inhibitors can be suggested. The chromosomal localization of the TAXI-I gene identified on wheat chromosome 3B, of the SCXI-II/III gene identified on rye chromosome 6R, and the presence of a cluster of TAXI-like genes on rice chromosome 1, allowed us to assign the location of TAXI-like genes to the wheat-rye translocation area 3BL/6RL characterized by RFLP markers XGlb33 and Xpsr454 and isozyme Est-5. In rice, RFLP marker C1310S corresponds to a TAXI-like protein encoding sequence.

Mutational Analysis of Endoxylanases XylA and XylB from the Phytopathogen Fusarium graminearum Reveals Comprehensive Insights into Their Inhibitor Insensitivity

“…While, in recent years, much research effort has been directed towards evaluating and manipulating the influence of these inhibitors for applications of endoxylanases in biotechnological processes (11,18,27,32,40), little if anything is known about their role in plant physiology and defense. Their relevance in these contexts, though, should not be underestimated as both types of endoxylanase inhibitors described to date, i.e., Triticum aestivum xylanase inhibitor (TAXI) type (19) and xylanase inhibitor protein (XIP) type (26), are wound and pathogen inducible (23,24) and occur as multiple-isoform families widely represented within the plant kingdom (13,20,31). It remains to be demonstrated whether the recently described TLXI inhibitors (15) are also wound and/or pathogen inducible.…”

Chitinases in root nodules

“…This way, the existing signal recognition and expression-regulation pathways could have been retained (Beliën et al 2006). So far, XIPs have only been isolated from cereals, despite until recently xylanase inhibitors have been believed to be absent in rice , which is consistent with the fact that cereal cell walls contain arabinoxylan as structural components (Raedschelders et al 2004 the acyl transferase gene nodA in tobacco, singly or in combination, affected plant growth and development, indicating that plants contain chitin oligomers that NodA and NodB could modify (Schmidt et al 1993). Furthermore, in Daucus carota, chitinases were shown to be able to cleave polysaccharides on arabino-galactan proteins (AGPs) in vitro and to co-localize with AGPs in developing seeds (van Hengel et al 1998;, which in turn suggests that AGPs which have been implicated in the regulation of cell differentiation, could be the endogenous substrates for plant chitinases.…”

Soybean Basic 7S Globulin: Subunit Heterogeneity and Molecular Evolution

“…2 is high enough that we restricted the sequence data set used for evolutionary analysis to those proteins that are well characterized, 7,[12][13][14]16,[19][20][21] and to their orthologs from the Arabidopsis and Oryza genomes. The resulting tree (Fig.…”