The red-flesh mutant Hong Anliu sweet orange is of high nutritional value due to its lycopene accumulation.Our previous studies on this mutant fruits suggested that photosynthesis and oxidative stress could promote the formation of mutation trait.However,leaf rather than fruit is the major part for some important biological processes such as photosynthesis.In this study,we analyzed the proteomic alteration in leaves of the red-flesh mutant Hong Anliu vs.its wild type （WT）.Ten differentially expressed proteins were identified,of which two were involved in photosynthesis,three in oxidative stress,two in defense,and three in metabolism.The high up-regulation of photosynthetic proteins proved the hypothesis that enhanced photosynthesis could provide and transport more substrates into mutant fruits for carotenoid biosynthesis.Similar to the previous results in fruits,anti-oxidative proteins were highly up-regulated in leaves,suggesting the whole plant of Hong Anliu suffered from enhanced oxidative stress.Proteins involved in defense and metabolism were also identified,and their possible roles in the mutation were discussed.
Low temperature storage is widely applied to maintain citrus postharvest fruit quality. In this study, the transcriptional and metabolic changes in the pulp tissue of Citrus reticulata Blanco cv. ＂Ponkan＂ were studied for three successive months under cold storage by Affymetrix Citrus GeneChip and gas chromatography, respectively. As many as 2 161 differentially expressed transcripts were identified based on the bayesian hierarchical model. The statistical analysis of gene ontology revealed that defense/stress-related genes were induced quickly, while autophagy-related genes were overrepresented in the late sampling stages, suggesting that the functional shift may coincide with the subsequent steps of chilling development. We further classified the potential regulatory components and concluded that ethylene may play the crucial role in chilling development in this non-climacteric fruit. To cope with complex events, 53 upregulated transcription factors represented regulatory candidates. Within these, the AP2-EREBP, C2H2 and AS2 gene family were overrepresented. Cold storage also causes alterations in various metabolic pathways; a keen interest is paid in deciphering expression changes of soluble sugar genes as increased evidence that soluble sugars act as both osmolytes and metabolite signal molecules. Our results will likely facilitate further studies in this field with promising genetic candidates during chilling.
Andan Zhu Wenyun Li Junli Ye Xiaohua Sun Yuduan Ding Yunjiang Cheng Xiuxin Deng
