New Waxy allele wx-Reina found in Chinese waxy maize

Abstract

Waxy gene mutations cause the stickiness of maize grains. China is rich in waxy maize landraces and is considered to be the origin of waxy maize. At present, the Waxy alleles found in Chinese waxy maize include wx-D7, wx-D10, wx-Cin4, and wx-124, of which wx-Cin4 and wx-124 are characterized as transposon insertion mutations. The Yunnan area has the most abundant Chinese waxy maize; however, there are still a large number of waxy maize landraces with unknown Waxy alleles. In this study, 20 waxy maize landraces from Yunnan Province of China were used as research materials for waxy gene analysis, and a new Waxy allele was detected. Molecularly, this allele is characterized by an ~ 5.4-Kb retrotransposon Reina inserted in the tenth intron of the Waxy gene, and we named this allele wx-Reina. Reina is a member of the long terminal repeat (LTR) retrotransposon family. This Reina transposon has the same LTR sequence at both ends, so this mutation is a newly formed mutation. Through reverse transcription PCR (RT-PCR) analysis, we found that Reina insertion results in the deletion of exons 10 and 11 in the transcript of wx-Reina, so its original gene function is lost. The discovery of wx-Reina further enriches the knowledge of types of waxy alleles in Chinese waxy maize. Combined with our previous studies, we believe that transposon activity is one of the main driving forces for the formation of Waxy gene alleles in Chinese waxy maize.