Exploration of cross-cultivar group characteristics of a new cultivar of Prunus mume 'Zhizhang Guhong Chongcui' / 生物工程学报

'Zhizhang Guhong Chongcui' is a new cultivar of Prunus mume with cross-cultivar group characteristics. It has typical characteristics of cinnabar purple cultivar group and green calyx cultivar group. It has green calyx, white flower, and light purple xylem, but the mechanism remains unclear. In order to clarify the causes of its cross-cultivar group traits, the color phenotype, anthocyanin content and the expression levels of genes related to anthocyanin synthesis pathway of 'Zhizhang Guhong Chongcui', 'Yuxi Zhusha' and 'Yuxi Bian Lü'e' were determined. It was found that the red degree of petals, sepals and fresh xylem in branches was positively correlated with the total anthocyanin content. MYBɑ1, MYB1, and bHLH3 were the key transcription factor genes that affected the redness of the three cultivars of flowers and xylem. The transcription factors further promoted the high expression of structural genes F3'H, DFR, ANS and UFGT, thereby promoting the production of red traits. Combined with phenotype, anthocyanin content and qRT-PCR results, it was speculated that the white color of petals of 'Zhizhang Guhong Chongcui' were derived from the high expression of FLS, F3'5'H, LAR and ANR genes in other branches of cyanidin synthesis pathway, and the low expression of GST gene. The green color of sepals might be originated from the relatively low expression of F3'H, DFR and ANS genes. The red color of xylem might be derived from the high expression of ANS and UFGT genes. This study made a preliminary explanation for the characteristics of the cross-cultivar group of 'Zhizhang Guhong Chongcui', and provided a reference for molecular breeding of flower color and xylem color of Prunus mume.

SLOW DIGESTIBILITY OF CEREAL STARCH AND POSTPRANDIAL GLYCEMIC RESPONSE / 营养学报

Objective To analyze slowly the digestibility and postprandial glycemic response after consum of different cereal starch. Method Starch was quantified into different nutritional fractions using the in vitro Englyst test. Ten healthy subjects consumed 7 kinds of carbohydrate foods with 50 g normal maize starch, waxy maize starch, wheat starch, sticky rice starch, rice starch, potato starch or glucose. Blood samples from postprandial zero to 120 min after consumption of test materials were collected for measurement of glucose, glycemic index and extended glycemic index. Results Native cereal starch was ideal slowly digestible starch (SDS) and the proportion of SDS was about 50% based on Englyst test. The GI value of cereal starch was more than 90% and belonged to high glycemic index foods, but EGI was positive, regarding glucose powder as 100%. Conclusion Cereal starch with slow digestibility and similar glycemic response was a better carbohydrate material to provide a slow and prolonged release of blood glucose and maintenance of glucose homeostasis, which was potentially beneficial to health.