Is there a correlation between primary cell wall (CW) composition and the expression of key CW biosynthesis and modification genes in grapevine callus under mineral stress?

Resumen

Cell wall (CW) is a dynamic structure featuring key determinants of overall plant form, growth,development, and environmental stress responses.For plants in general, the chemical structure of most CW constituents has been defined in detail.Grapevine (Vitis vinifera) is one of the most important fruit crops in the Mediterranean region.However, Vitis CW remains largely uncharacterized and research has been mostly focused onberry ripening. Extending the knowledge of grapevine CW biology is fundamental to improveplant growth and vineyard yield.Here, grapevine callus growing under mineral stress was used as a model to assess its putativeinfluence on the synthesis and modifications of Vitis CW. CWs isolated from callus tissuedeficient in nitrogen(-N), phosphorous (–P) or sulfur (-S) nutrition were analyzed by Fourier transform infrared(FTIR) spectroscopy and the spectra allowed to discriminate callus in –N and –P conditionsafter cluster and PCA analyses. Furthermore, FTIR spectra of CW after 6 weeks under –N and –P revealed a reduction in the amount of cellulose and differences in pectin composition.Updegraff data confirmed the reduction in cellulose, and following cell wall fractionation, theanalysis of total sugars suggests that the polysaccharides are more tightly bound in CWs undermineral stress; the recovery of pectins measured as uronic acids was in general similar amongthe different fractions.With the sequences obtained by in silico mining of Vitis genes from representative gene familiesassociated with CW biosynthesis and modification, a “primer toolkit” is being designed aimedto screen by quantitative real-time (qrt) RT-PCR the expression of CW-related genes in Vitiscallus under controlled mineral stress. Here we present the expression of cellulose biosynthesisgenes, namely cellulose synthases (CesAs) and β-1,4-endoglucanases (GH9a or Korrigan-like).Results will be discussed to meet the proposed question.