BioMed Central, BMC Plant Biology, 1(20), 2020
DOI: 10.1186/s12870-020-2295-8
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AbstractBackgroundIn recent years, the planting area of sweet corn in China has expanded rapidly. Some new varieties with high yields and good adaptabilities have emerged. However, the improvement of edible quality traits, especially through the development of varieties with thin pericarp thickness, has not been achieved to date. Pericarp thickness is a complex trait that is the key factor determining the edible quality of sweet corn. Genetic mapping combined with transcriptome analysis was used to identify candidate genes controlling pericarp thickness.ResultsTo identify novel quantitative trait loci (QTLs) for pericarp thickness, a sweet corn BC4F3population of 148 lines was developed using the two sweet corn lines M03 (recurrent parent) and M08 (donor parent). Additionally, a high-density genetic linkage map containing 3876 specific length amplified fragment (SLAF) tags was constructed and used for mapping QTLs for pericarp thickness. Interestingly, 14 QTLs for pericarp thickness were detected, and one stable QTL (qPT10–5)was detected across multiple years, which explained 7.78–35.38% of the phenotypic variation located on chromosome 10 (144,631,242-145,532,401). Forty-two candidate genes were found within the target region ofqPT10–5. Moreover, of these 42 genes, five genes (GRMZM2G143402,GRMZM2G143389,GRMZM2G143352,GRMZM6G287947, andAC234202.1_FG004) were differentially expressed between the two parents, as revealed by transcriptome analysis. According to the gene annotation information, three genes might be considered candidates for pericarp thickness.GRMZM2G143352andGRMZM2G143402have been annotated as AUX/IAA transcription factor and ZIM transcription factor, respectively, whileGRMZM2G143389has been annotated as FATTY ACID EXPORT 2, chloroplastic.ConclusionsThis study identified a major QTL and candidate genes that could accelerate breeding for the thin pericarp thickness variety of sweet corn, and these results established the basis for map-based cloning and further functional research.