The characterization and candidate gene isolation for a novel male-sterile mutant ms40 in maize

Abstract

Maize male sterile mutant 40 (ms40) was obtained from the progeny of ethyl methanesulfonate (EMS) treated inbred line RP125. Genetic analysis showed that it was controlled by a single recessive nuclear gene. Cytological observation of anthers revealed that abnormal cuticles and disappearing of Ubisch bodies presented in ms40. Moreover, its tapetum exhibited delayed degradation and blocked the formation of abnormal microspore. Using map-based cloning, ms40 locus was located in a 282-kb interval on chromosome 4, ve annotated genes were predicted within this region. PCR-based sequencing detected a single nonsynonymous SNP (G>A) which changed glycine (G) to arginine (A) in the seventh exon of Zm00001d053895, while no difference was found for the other four genes between ms40 and RP125. Zm00001d053895 encodes the bHLH transcription factor bHLH51 which protein was located at nuclear. Phylogenetic analysis presented that bHLH51 had the highest homology with Sb04g001650, a tapetum degeneration retardation (TDR) bHLH transcription factor in Sorghum bicolor. Co-expression analysis exposed a total of 1192 genes coexpressed with Zm00001d053895 in maize, 647 out of 1192 were anther-speci c genes. In summary, these ndings are conducive to the marker-assisted selection of ms40 in hybrid breeding and laid a foundation for further studies on the mechanisms of male fertility. Key MessagesA novel genic male sterile mutant ms40 was obtained by EMS treated RP125. The key candidate gene bHLH51 located on chromosome 4 was identi ed by map based cloning. This study furtherly enriched the male sterile gene resource for both production application and theoretical study of abortion mechanism.

The Loss-Function of the Male Sterile Gene ZmMs33/ZmGPAT6 Results in Severely Oxidative Stress and Metabolic Disorder in Maize Anthers

“…This inference is confirmed by the results of GO and KEGG enrichment analyses in which the functions of DEGs are closely related to abiotic stress responses. Moreover, 11 reported maize GMS genes encoding TFs, including the key regulator genes modulating tapetal development ( ZmbHLH122 , ZmbHLH51 , and ZmMs84 ) [ 10 , 61 , 62 ] are changed in transcription levels in ms33-6038 anthers, which strengthen transcriptional reprogramming by directly impairing the expression of target genes. Thus, ZmMs33 deficiency disturbs the expression of genes involved in both the stress response and the regulatory network of male reproduction, which brings about genome-wide transcriptional reprogramming.…”