贮藏温度影响泰国青柚采后果皮失绿的比较转录组学分析OA

The peel color is a critical indicator influencing the commercial value of Thai green pomelo(Citrus maxima)fruit.However,the effects of storage temperature on peel color alterations remain unclear.In this study,fruit at 80％maturity were stored at 5,15,and 25℃for 15 d to investigate temperature-dependent peel color changes through comparative transcriptomic analyses integrated with phenotypic and physiological data.The results showed that storage temperature significantly affected the peel color of Thai green pomelos.Storage at 5℃delayed the de-greening,whereas rapid changes in de-greening were occurred under 15 and 25℃conditions.After 15 d of storage,the total chlorophyll contents respectively decreased by 21.93％,64.53％and 86.74％at 5,15 and 25℃,while total flavonoid contents increased by 8.56％,27.03％and 35.46％,respectively.Compared to pre-storage(0 d),the differentially expressed genes(DEGs)identified after 5 d of storage at 5 and 15℃were significantly enriched in several pathways,plant hormone signal transduction,while DEGs from storage at 25℃were significantly enriched in pathways carbon metabolism.After 5 d of storage,DEGs generated at 15 or 25℃compared to those at 5℃were significantly enriched in pigment biosynthesis or metabolism-related pathways,such as porphyrin and chlorophyll metabolism,photosynthetic antenna proteins,the phenylpropanoid biosynthesis,and flavonoid biosynthesis.DEGs that were upregulated were also significantly enriched in the phenylpropanoid biosynthesis and porphyrin and chlorophyll metabolism pathways,weighted gene co-expression network analysis revealed that genes in the magenta and yellow modules were negatively correlated with total chlorophyll content,while that in the brown module showed a significant positive correlation with total chlorophyll content.Furthermore,119 transcription factor genes that closely related to the process of peel de-greening were identified,with the highest numbers belonging to the MYB,ERF,and bHLH families.Additionally,strong correlations were observed between the expression of MYB,ERF,and bHLH transcription factor genes and genes related to chlorophyll degradation.qRT-PCR analysis indicated that storage at 15 and 25℃significantly upregulated the expression of genes related to chlorophyll metabolism and flavonoid biosynthesis during the early storage period.In conclusion,storage temperature significantly affects the de-greening of Thai green pomelo peels.Storage at 5℃effectively delays the de-greening,while storage at 15 and 25℃accelerates that progress.15 and 25℃storage facilitated the de-greening by influencing the expression of genes associated with chlorophyll metabolism and flavonoid biosynthesis,possibly involving MYB,ERF,and bHLH transcription factors induced by these temperatures in Thai green pomelos.