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Assessment of cell wall glycomolecules in BLC function

 

Principal investigator: Maité Victré-Gibouin/ Azeddine Driouich

Participants:

PhD students: Romain castilleux


Project:

We have previously shown that, unlike Arabidopsis wild-type, qua1-1 mutant (affected in HG synthesis; Bouton et al., 2002), produces isolated BLC and a very abundant mucilage (Durand et al., 2009; Driouich et al., 2010) (Fig. 2a). The qua1-1 mutant provides ideal material to test the relative performance of border cells when they are kept adherent (in the WT) or allowed to separate. We will compare the response of qua1-1 versus wild-type BLC when the roots are challenged with elicitors/pathogens. The impact of the mucilage will also be assessed. Interestingly, we have found that the mucilage secreted by qua1-1 mutant is enriched in arabinogalactan-proteins (AGP) and xylogalacturonan (XGA) epitopes (Durand et al., 2009) (Fig. 2b). XGA is an -(14)-linked D-galacturonic acid chain highly substituted with -D-xylose (Zandleven et al., 2005). Cell wall XGA has been postulated to be more resistant to pathogen-induced degradation than HG (Willats et al., 2004; Jensen et al., 2008). Furthermore, the mutants xgd1 and xgd2, deficient in XGA synthesis, are available and will be used to test whether a deficiency in XGA in both BLC and mucilage makes the root more vulnerable to pathogen invasion. Similarly, available AGP mutants will be also examined. We will also take advantage of the mutant fez, that does not produce BLC (Willemsen et al., 2008), to further assess the role of BLC in root defence.