The Analysis Of F Ruit Quality And Genes Expression In Yanxiwanlu Ponkan And Its Early-ripening Mutant

Citrus yields the most fruits in the world. Since in China the C itrus industry is mainly edible, the cultivation of mid-season leads to the excessive amount of citrus. Hence, the cultivation of new ripening varieties, which can meet customers’ demand for fresh citrus, can improve the citrus market in C hina. In this study, we test the physiological qualities including the fruit quality, color agent and ABA contents of Yanxiwanlu Ponkan and its Early-ripening bud mutant. And the Real-time PCR experiments are also adopted to test the related gene expression in tartaric acid, carotenoids, ABA and ethylene passways. The following main conclusions can be reached through the synthesis of the two experiments:1.In terms of color transition, the Early- ripening bud mutant’s begins about 30 days earlier than that of Yanxiwanlu Ponkan, and so does the carotenoid accumulation of the former than of the latter. And in terms of the fruit quality, the formation of titratable acid of the former is also earlier than that of Yanxiwanlu Ponkan, while the result of the tests of tartaric acid shows that the two varieties went through similar changes.The only difference lies in the timing: the formation of tartaric acid in Early-ripening bud mutant began was about 30 days earlier than that in Yanxiwanlu Ponkan. The remarkable difference turned up from 200 days to 244 days after flowering.2.As for hormone, the contents of ABA in Precocious bud mutant was significant higher than that of Yanxiwanlu Ponkan from the 244-day after flowering. The results from the experiment of Real-time PCR relating to 21 genes, the relative gene expression of Early-ripening bud mutant differs greatly from that of Yanxiwanlu Ponkan. The gene Cs NCED1 was consistent with ABA expression pattern and it is significantly up-regulated in Early-ripening bud mutation. In addition, the experiment of Real-time PCR related to genes in ethylene biosynthesis and signal trancduction pathways shows that 7 genes are up-regulated, including the two crucial genes Cs ACO1 and Cs ACO2, which indicates that ethylene and ABA play an important role in early- maturing.