Analysis of high pI α-Amy-1 gene family members expressed in late maturity α-amylase in wheat (Triticum aestivum L.)

Late maturity alpha-amylase (LMA) is a genetic defect involving the synthesis of high pI isozymes of alpha-amylase encoded by alpha-Amy-1 genes during the later stages of grain development. The aims of this investigation were to determine both the number of expressed alpha-Amy-1 genes and their relative transcript abundance. Sub-cloning and sequencing of expressed high pI alpha-amylase genes in developing wheat seeds revealed three insertion/deletion patterns in the 3' untranslated region and numerous single nucleotide polymorphisms at the 3' end of alpha-Amy-1. The genetic variations defined 36 alpha-Amy-1 gene sequences that were expressed on the onset of LMA in doubled haploid progenies (SpM25, SpM52 and SpM127) derived from the cross Spica (LMA)/Maringa (non-LMA). Five isoelectric point groups were predicted based on the translated partial coding sequences. The potential application of quantitative real-time RT-PCR in screening wheat genotypes for LMA is discussed.