Effect Of Q-null And Q⁹²²⁹ Alleles On Wheat Processing Quality

Wheat is one of the three major cereal crops worldwide.As one of the main food crop,the value and use of wheat depends on its unique processing quality.With the development of economics and the improvement of living conditions,the demand for high-quality flour is increasing.Identification of elite quality genes is crucial step for improving wheat processing.We have previously demonstrated that overexpression of Q can significantly improve wheat grain protein content,wet gluten content and bread-making quality.This study further investigated the effects of two new Q alleles(Q-null and Q⁹²²⁹)on processing quality,in order to better understand the processing quality effects of the Q gene and to serve for wheat quality breeding.The main results are as follows:1.Mutant screening and Q gene cloningA new Q gene mutant 9229 was obtained by threaing the common wheat（Triticum aestivum）cultivar Shumai 482 with EMS.Sequence analysis revealed that the DNA sequenceb of Q gene of the mutant had a single nucleotide change（G-A）at 2027 bp.c DNA cloning indicated that there was a 38 bp deletion caused by the identified nucleotide replacement,resulting in a premature termination codon in the coding region of Q.To distinguish it from the wild type Q allele,the Q allele in the mutant was temporarily named Q⁹²²⁹.2.Agronomic traitsCompared with the wild type control,the Q-null mutant had higher plant height and longer ear length,but neither reached a significant level.The number of spikelets and the number of grains per spike were significantly lower.There was no significant change in the number of tillers and thousand-grain weight.Compared with the control,the plant height,panicle length and number of tillers of the Q⁹²²⁹ mutant were significantly higher.There was no significant change in the number of effective spikelets and number of grains per spike.3.Processing quality measurementThe formation time,stable time,water absorption rate and flour quality index of the Q-null mutant were all less than the control,and the variation of the flour quality index reached a significant level.The formation time,stabilization time and protein content of Q⁹²²⁹ increased compared to the control.The volume of Q⁹²²⁹ and Q-null bread were smaller than that of their control group.C-Cell data showed that the slice brightness,the number of cells and the area of cells of Q-null and Q⁹²²⁹ bread were all reduced compared with the control.