Effect of Wx Protein Deficiencies in Wheat Endosperm on Content and Properties of Starch

To gain a accurate result,an improved SDS-PAGE and STS-PCR were used to identificate Wx protein combination of 24 wheat varieties.The starch properties of those varieties were measured.The effect of Wx protein dosage and composition on starch composition and properties were studied.It was found that any null mutation of Wx gene could result in obvious reduction of amylose,and the amylose content decreased more with the increase of number of Wx gene deficiencies,the amylose content of waxy wheat is barely zero.Under the genetic backgrounds of the materials used,the Wx-A1 protein subunit take the most important role to the synthesis of amylose.But the influence of Wx protein deficiencies to starch content and amylopectin content is little.The Wx protein deficiencies resulted in the increase of flour swelling power,peak,through,breakdown and final visc of pasting properties and the decrease of setback and pasting temperature.The dosage effect of Wx protein also existed on starch properties.The deficiency of Wx-B1 protein subunit resulted in the most obvious improvement of starch properties.The identification of Wx protein subunits and its selection index in the early generation of crossed were also discussed.We can identify the Wx protein subunit by SDS-PAGE and STS-PCR simultaneously,and both the swelling power and Am/Ap ratio are good selection indexes for the early generation of crosses.