| The root of purple-fleshed sweetpotato are purple,both inside and outside,and has high anthocyanin content.Anthocyanin plays an important role in sensory toning,besides,its antioxidant,anti-aging,lower blood sugar,anti-tumor and other physiological health care or medicinal fuction has also been highly valued.At present,there are many reports about tinting and anthocyanin synthetical metabolism of blossom and yield fruit on aboveground parts of plants,but few studies have been reported about the synthesis and regulation of anthocyanin in plant underground tissues.In this study,we analyzed the physiological indexes and the protein expression level of anthocyanin synthesis pathway of purple-fleshed sweetpotato treated by transplanting in different periods and shading hoping that these results will provide preliminary physiological and molecular basis for the synthesis and accumulation of anthocyanin from purple-flesh sweetpotato,and provide a theoretical and practical basis of variety cultivation and breeding of sweet potato with high anthocyanin at the same time.Purple-fleshed sweetpotato and common sweet potato were used for this study.The plant transplanted in May which under natural light was treated as control group,the plants which under weak light shade(60%)and transplanted in June were as treatment group.During the different tuber swelling period(after transplanted for 60 d,80 d,100 d,130 d),Both the aboveground and underground parts of the materials were measured soluble sugar content,starch content and the anthocyanin content.Combined with these physiological indexes,we analyzed how transplant period and light intensity affected the quality of sweet potatoes,especially on sugars and flavonoids metabolism in different organizations.Some anthocyanin key enzymes specificity antibodies,such as chalcone synthase antibody Anti-CHS,anthocyanin synthase antibody Anti-ANS and flavonoids3-gluconic base transferase antibody Anti-3 GT were made for studying the light and temperature control laws of anthocyanin biosynthesis in the tubers and leaves of the sweet potato from the key enzyme expression level.Based on the above experimental content and data analysis,the main conclusions are as follows:1?The light intensity had significant effect on the carbohydrate metabolism andanthocyanin accumulation of sweet potato in the early stage of root expansion.The results showed that the content of soluble sugar in aboveground tissue was significantly increased when the purple-fleshed sweet potatoes had been shaded for 80 days.Specificly,the content of soluble in the leaf and stem was increased by 215-270%.In addition,the starch content in aboveground decreased significantly and the starch content of leaf decreased by 82%.The accumulation of anthocyanin in the leaf and root was only account for 50% of the control group.In the mature root of purple sweet potato the content of sugar and anthocyanin was not significantly different from that of control group,but the yield of root was significantly reduced.In the common sweet potato the sugar accumulation has a similar change,but the content of anthocyanin is very low.2?The different transplanting period had significant effect on the accumulation rate of sweet potato during the expansion stage.Delayed transplanting treatment significantly affected the whole growth and development period of the roots.The photosynthetic capacity in leaf,petiole and stem of the aboveground tissues increased especially after planting 80 d to 100,thus accelerated the process of carbohydrate accumulation in the roots and shortened the development time of sweet potato.The biomass and yield of root tuber has been significantly reduced due to the shortened development time.The results showed that the contribution rate of photosynthate in petiole was increased.After planting80 d,the soluble sugar and starch content of sweet potato petiole were higher than that of control 57% and 365% respectively.Delayed transplanting treatment allows the plants to make full use of the photosynthetic function of the above-mentioned tissues to carry out photosynthesis,to achieve rapid expansion of potato root.The accumulation of anthocyanin in delayed transplanted purple potato showed the synergistic regulation of the aboveground and underground tissues.3?The relationship between sugar and anthocyanin metabolism in purple-fleshed sweetpotato.Under different light and temperature conditions,the correlation between anthocyanin content and soluble sugar level in leaves and tubers was inconsistent In the control group,the leaves and tubers were positive correlated but not significant.In the shade group,the leaves and tubers showed negative correlation.In addition,the sugar and starch content of the leaf of shade group soluble were negatively correlated and extremely significant,soluble sugar and anthocyanin content in the tuber showed significantlynegative correlation,the soluble sugar content in different organizations were very significant and showed positive correlation.We speculated that due to the lack of light intensity,the low level of photosynthetic product supply reduced the amount of soluble sugar convert to starch,and the synthesis of anthocyanin consumed part of soluble sugar.The starch content and anthocyanin content in the tuber of 60% shade and delaying transplanting group were negatively correlated but not significant,which suggesting that starch degraded into the precursor substance for anthocyanin synthesis.4?The key enzymes of sweet potato anthocyanin synthesis were regulated by light,temperature and soluble sugar content.The expression of CHS and 3GT protein in the roots of common sweet potato under different light and temperature conditions were positively correlated with soluble sugar content,which means the expression of CHS and3 GT protein were regulated by soluble sugar level.And when the purple-fleshed sweetpotatoes had been cultivated for 80 days,CHS and 3GT protein showed the immediately response to sugar in the leaves.Under different temperature and light conditions,CHS protein expression correlation in tuber organization and leaf,CHS protein and soluble sugar content correlation in tuber were consistent in common sweet potato and purple-fleshed sweetpotato.Besides,CHS protein and soluble sugar content correlation was opposite in leaf and root,which showed the effect of soluble sugar on the expression level of CHS was reversed in leaves and roots of common sweet potato and purple-fleshed sweetpotato.ANS protein can be only detected in the tuber of purple-fleshed sweetpotato. |
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