Mutations in the maize zeta-carotene desaturase gene lead to viviparous kernel.

Yan Chen,Kaijian Fan,Yunjun Liu,Jiankun Li,Zhenjing Ren,Dongtao Ren,Guoying Wang,Jun Zheng,Jing Xu,Yicong Du,Junjie Fu

doi:10.1371/journal.pone.0174270

Abstract

Preharvest sprouting reduces the maize quality and causes a significant yield loss in maize production. vp-wl2 is a Mutator (Mu)-induced viviparous mutant in maize, causing white or pale yellow kernels, dramatically reduced carotenoid and ABA content, and a high level of zeta-carotene accumulation. Here, we reported the cloning of the vp-wl2 gene using a modified digestion-ligation-amplification method (DLA). The results showed that an insertion of Mu9 in the first intron of the zeta-carotene desaturase (ZDS) gene results in the vp-wl2 mutation. Previous studies have suggested that ZDS is likely the structural gene of the viviparous9 (vp9) locus. Therefore, we performed an allelic test using vp-wl2 and three vp9 mutants. The results showed that vp-wl2 is a novel allele of the vp9 locus. In addition, the sequences of ZDS gene were identified in these three vp9 alleles. The vp-wl2 mutant gene was subsequently introgressed into four maize inbred lines, and a viviparous phenotype was observed with yield losses from 7.69% to 13.33%.

Highlights

Maize (Zea mays L.) is one of the major cereal crops in China and many countries
According to the criteria proposed by Robertson, the viviparous mutants have been classified into two classes [6]: Class One, in which mutant genes, including vp1/vp4, vp6, vp8, vp10/vp13, vp14, and vp15, do not affect the endosperm and seedling color; and Class Two, in which mutant genes, including vp2, vp5, vp7/ps1, vp9, vp12/lw2, y9, w3, and rea1, will alter carotenoid and chlorophyll synthesis
To further confirm that zeta-carotene desaturase (ZDS) is the causal gene of the vp9 locus, we identified the sequences of ZDS gene of three vp9 mutants

Summary

Introduction

Maize (Zea mays L.) is one of the major cereal crops in China and many countries. Preharvest sprouting is known as vivipary, which has been described since the early 1920s [1,2,3,4,5]. Approximately fifteen viviparous mutants have been identified. According to the criteria proposed by Robertson, the viviparous mutants have been classified into two classes [6]: Class One, in which mutant genes, including vp1/vp, vp6, vp, vp10/vp, vp14, and vp, do not affect the endosperm and seedling color; and Class Two, in which mutant genes, including vp, vp5, vp7/ps, vp9, vp12/lw, y9, w3, and rea, will alter carotenoid and chlorophyll synthesis. Eight viviparous loci have been cloned, and further studies are needed to examine other mutants. Maize vp1/vp mutant showed reduced sensitivity to ABA and blocked anthocyanin synthesis in aleurone and embryo tissues. The vp locus was cloned using transposon tagging, and subsequent experiments have shown that the VP1 protein may control the anthocyanin pathway by regulating the C1 gene [7]. The vp gene increases the number of vegetative phytomers and delays the juvenile-to-

Methods

Results

Discussion

Conclusion