Apple ripening is controlled by a NAC transcription factor

Autor: Charles F. Forney, Jocelyn K. C. Rose, Trevor H. Yeats, Zhaoqi Zhang, Karen Burgher-MacLellan, Julia Vrebalov, James G. Giovannoni, Sean Myles, Sophie Watts, Daryl J. Somers, Jun Song, Yihi Gong, Zoë Migicovsky
Rok vydání: 2019
Předmět:
Popis: Softening is a hallmark of ripening in fleshy fruits, and has both desirable and undesirable implications for texture and postharvest stability. Accordingly, the timing and extent of ripening and associated textural changes are key targets for improving fruit quality through breeding. Previously, we identified a large effect locus associated with harvest date and firmness in apple (Malus domestica) using genome-wide association studies (GWAS). Here, we present additional evidence that polymorphisms in or around a transcription factor gene,NAC18.1, may cause variation in these traits. First, we confirmed our previous findings with new phenotype and genotype data from ∼800 apple accessions. In this population, we compared a genetic marker withinNAC18.1to markers targeting three other firmness-related genes currently used by breeders (ACS1,ACO1, andPG1), and found that theNAC18.1marker was the strongest predictor of both firmness at harvest and firmness after three months of cold storage. By sequencingNAC18.1across 18 accessions, we revealed two predominant haplotypes containing the single nucleotide polymorphism (SNP) previously identified using GWAS, as well as dozens of additional SNPs and indels in both the coding and promoter sequences.NAC18.1encodes a protein with high similarity to the NON-RIPENING (NOR) transcription factor, a regulator of ripening in tomato (Solanum lycopersicum). To test whether these genes are functionally orthologous, we introduced bothNAC18.1transgene haplotypes into the tomatonormutant and showed that both haplotypes complement thenorripening deficiency. Taken together, these results indicate that polymorphisms inNAC18.1may underlie substantial variation in apple firmness through modulation of a conserved ripening program.
Databáze: OpenAIRE