Discovery of candidate genes related to carotenoid accumulation based on yellow sarcocarp bud mutation peach resource

The carotenoid composition and content in the yellow sarcocarp peach are a direct indicator of quality. Therefore, discoveries regarding the identification of candidate genes related to carotenoid accumulation and their regulatory mechanisms would be beneficial for yellow sarcocarp peach breeding. In this study, the white sarcocarp peach cultivar '21shiji' (21SJ) and its unique yellow sarcocarp bud mutation individual (21BM) were used for carotenoid determination and candidate gene discovery based on UPLC-APCI-MS/MS and RNA-seq. In total, 11 carotenoid compositions showed significant differences between '21SJ' and '21BM', including four carotenes and seven xanthophylls. Furthermore, the accumulation of beta-carotene, zeaxanthin, beta-cryptoxanthin, antheraxanthin, violaxanthin, and capsanthin showed different tendencies between '21SJ' and '21BM' during the ripening stage and influenced '21BM' yellow sarcocarp formation. Using transcriptome analysis, we found that the differential expression of candidate genes PpZEP, PpVDE1, PpCCD4, and PpCCS were major influencing factors. Two transfactors, PpbHLH14 and PpMYB73, were significantly related to PpZEP, PpVDE1, PpCCD4, and PpCCS expression and carotenoid accumulation after weighted gene co-expression network analysis. The identified structural genes and transcription factors in this study will further enrich carotenoid accumulation regu-latory mechanism in peach and will provide an important theoretical reference for yellow sarcocarp peach breeding.