Sugar composition not only affects fruit flavor but is also an important determinant of fruit taste and consumer preference.In this study,changes in the sugar content and sugar-metabolizing enzymes were investigated f...Sugar composition not only affects fruit flavor but is also an important determinant of fruit taste and consumer preference.In this study,changes in the sugar content and sugar-metabolizing enzymes were investigated from different sections of various fruit development phases of‘Hongshuijing’pitaya(Hylocereus monacanthus).Genes related to sugar metabolism were also screened by transcriptome analyses.The results indicated that glucose was the major sugar in mature pitaya fruit,and was mainly regulated by vacuolar acid invertase(VAI)and sucrose synthase(SS)(degradative direction).Sugar accumulation varied in pulp between different sections of the pitaya fruit.VAI,neutral invertase(NI)and SS(degradative direction)are crucial enzymes for sugar accumulation in pitaya.The expression of 17 genes related to sucrose metabolism obtained from seven databases[NCBI non-redundant protein database(Nr),NCBI non-redundant nucleotide sequence database(Nt),EuKaryotic Orthologous Groups(KOG),The Protein Families(Pfam),Kyoto Encyclopedia of Genes and Genomes(KEGG),Swiss-prot,and Gene Ontology(GO)]were analyzed in different pitaya pulp sections.HpVAI1 had the highest relative expression level on the 29th day after pollination(DAP).Positive correlations were found between HpVAI1 expression and VAI activity;HpNI4 and NI activity;HpSS2,HpSS5,and SS activity(synthetic direction),indicating that HpVAI1,HpNI4,and HpSS2 and HpSS5 were involved in the regulation of VAI,NI,and SS(synthetic direction),respectively.HpVAI1 and HpNI4 regulated sucrose degradation and the accumulation of glucose and fructose,while HpSS2 and HpSS5 regulated sucrose synthesis.These results suggest that HpVAI1 plays a key role in sugar metabolism during fruit development of‘Hongshuijing’pitaya.The results of this study provide new information about sugar metabolism in pitaya fruit that could help improve fruit quality and the breeding of new cultivars.展开更多
Sucrose synthase(SUS,EC 2.4.1.13)is widely considered as a key enzyme involved in plant sucrose metabolism,and the gene family encoding different SUS isozymes has been identified and characterized in several plant spe...Sucrose synthase(SUS,EC 2.4.1.13)is widely considered as a key enzyme involved in plant sucrose metabolism,and the gene family encoding different SUS isozymes has been identified and characterized in several plant species.However,to date scant information about the SUS genes is available in Litchi chinensis Sonn.Here,we identified five SUS genes in litchi.These Lc SUSs shared high levels of similarity in both nucleotide and amino acid sequences.Their gene structure,phylogenetic relationships,and expression profiles were characterized.Gene structure analysis indicated that the Lc SUSs have similar exon-intron structures.Phylogenetic analysis revealed that the five members could be classified into three groups(LcSUS1 and LcSUS2 in SUSⅡ,LcSUS4 and LcSUS5 in SUSⅢ,and LcSUS3 in SUSⅠ),demonstrating evolutionary conservation in the SUS family across litchi and other plant species.The expression levels of Lc SUSs were investigated via real-time PCR in various tissues and different developmental stages of aril.For tissues and organs,Lc SUSs exhibited distinct but partially redundant expression profiles in litchi,being predominantly expressed in young leaves(sink).During aril development,the expression pattern of LcSUS1 was consistent with the trend of sugar accumulation,indicating it may play important roles in determination of sink strength in aril.Moreover,transcript levels of LcSUS2,LcSUS4,and LcSUS5 varied between cultivars with different hexose/sucrose ratios,which may regulate the sugar composition in aril.Our results provide insights into physiological functions of SUS genes in litchi,especially roles in regulating sugar accumulation in aril.展开更多
Phonological period and fruit quality of Jingganghongnuo （JGHN） grafted on the rootstocks of Feizixiao （FZX）, Heiye （HY） and Huaizhi （HZ） respectively were recorded and comparatively studied from 2015 to 2017....Phonological period and fruit quality of Jingganghongnuo （JGHN） grafted on the rootstocks of Feizixiao （FZX）, Heiye （HY） and Huaizhi （HZ） respectively were recorded and comparatively studied from 2015 to 2017. The results showed that the whitish millets and flowering stage of JGHN grafted on FZX and HY rootstocks were respectively 3-17 days and 1-3 days earlier than those on HZ. While the fruit maturation stage was 5-7 days ahead of in the same comparative situation. Compared to fruits grafted on HZ, mean fruit weight of JGHN grafted on HY and FZX were 38.1% and 35.8% bigger respectively than that on HZ. In addition, more closely heart-shaped and brighter pericarp color of JGHN fruit were observed with rootstock of HZ than that with other two kinds of rootstocks. In terms of aborted-seed rates of JGHN, average value with rootstock FZX was 81.7%, which was 58.0% higher than that with HY, and 2.49 times of those with HZ. Vc content of JGHN grafted on HY and FZX were 30.47 and 25.86 mg/100 g respectively, significantly higher than that grafted on HZ. TSS and TA of JGHN grafted on HZ were 17.8% and 0.14%, both were obviously higher than that grafted on FZX and HY.展开更多
基金supported by grants from the Key Science and Technology Planning Project of Guangzhou (Grant No. 201904020015)Science and Technology Program of Zhanjiang (Grant No. 2019A01003)+1 种基金Key Realm R&D Program of Guangdong Province (Grant No. 2018B020202011)Science and Technology Program of Guangzhou (Grant Nos. 202002020060, 201704020003 and 2014Y2-00164)
文摘Sugar composition not only affects fruit flavor but is also an important determinant of fruit taste and consumer preference.In this study,changes in the sugar content and sugar-metabolizing enzymes were investigated from different sections of various fruit development phases of‘Hongshuijing’pitaya(Hylocereus monacanthus).Genes related to sugar metabolism were also screened by transcriptome analyses.The results indicated that glucose was the major sugar in mature pitaya fruit,and was mainly regulated by vacuolar acid invertase(VAI)and sucrose synthase(SS)(degradative direction).Sugar accumulation varied in pulp between different sections of the pitaya fruit.VAI,neutral invertase(NI)and SS(degradative direction)are crucial enzymes for sugar accumulation in pitaya.The expression of 17 genes related to sucrose metabolism obtained from seven databases[NCBI non-redundant protein database(Nr),NCBI non-redundant nucleotide sequence database(Nt),EuKaryotic Orthologous Groups(KOG),The Protein Families(Pfam),Kyoto Encyclopedia of Genes and Genomes(KEGG),Swiss-prot,and Gene Ontology(GO)]were analyzed in different pitaya pulp sections.HpVAI1 had the highest relative expression level on the 29th day after pollination(DAP).Positive correlations were found between HpVAI1 expression and VAI activity;HpNI4 and NI activity;HpSS2,HpSS5,and SS activity(synthetic direction),indicating that HpVAI1,HpNI4,and HpSS2 and HpSS5 were involved in the regulation of VAI,NI,and SS(synthetic direction),respectively.HpVAI1 and HpNI4 regulated sucrose degradation and the accumulation of glucose and fructose,while HpSS2 and HpSS5 regulated sucrose synthesis.These results suggest that HpVAI1 plays a key role in sugar metabolism during fruit development of‘Hongshuijing’pitaya.The results of this study provide new information about sugar metabolism in pitaya fruit that could help improve fruit quality and the breeding of new cultivars.
基金the Key-Area of Research and Development Program of Guangdong Province(Grant No.2018B020202011)the China Litchi and Longan Industry Technology Research System(Grant No.CARS-32-05)Yang Fan Innovative&Entrepreneurial Research Team Project(Grant No.2014YT02H013)。
文摘Sucrose synthase(SUS,EC 2.4.1.13)is widely considered as a key enzyme involved in plant sucrose metabolism,and the gene family encoding different SUS isozymes has been identified and characterized in several plant species.However,to date scant information about the SUS genes is available in Litchi chinensis Sonn.Here,we identified five SUS genes in litchi.These Lc SUSs shared high levels of similarity in both nucleotide and amino acid sequences.Their gene structure,phylogenetic relationships,and expression profiles were characterized.Gene structure analysis indicated that the Lc SUSs have similar exon-intron structures.Phylogenetic analysis revealed that the five members could be classified into three groups(LcSUS1 and LcSUS2 in SUSⅡ,LcSUS4 and LcSUS5 in SUSⅢ,and LcSUS3 in SUSⅠ),demonstrating evolutionary conservation in the SUS family across litchi and other plant species.The expression levels of Lc SUSs were investigated via real-time PCR in various tissues and different developmental stages of aril.For tissues and organs,Lc SUSs exhibited distinct but partially redundant expression profiles in litchi,being predominantly expressed in young leaves(sink).During aril development,the expression pattern of LcSUS1 was consistent with the trend of sugar accumulation,indicating it may play important roles in determination of sink strength in aril.Moreover,transcript levels of LcSUS2,LcSUS4,and LcSUS5 varied between cultivars with different hexose/sucrose ratios,which may regulate the sugar composition in aril.Our results provide insights into physiological functions of SUS genes in litchi,especially roles in regulating sugar accumulation in aril.
基金Supported by Special Program of China Litchi and Longan Research System(CARS-33-22)
文摘Phonological period and fruit quality of Jingganghongnuo （JGHN） grafted on the rootstocks of Feizixiao （FZX）, Heiye （HY） and Huaizhi （HZ） respectively were recorded and comparatively studied from 2015 to 2017. The results showed that the whitish millets and flowering stage of JGHN grafted on FZX and HY rootstocks were respectively 3-17 days and 1-3 days earlier than those on HZ. While the fruit maturation stage was 5-7 days ahead of in the same comparative situation. Compared to fruits grafted on HZ, mean fruit weight of JGHN grafted on HY and FZX were 38.1% and 35.8% bigger respectively than that on HZ. In addition, more closely heart-shaped and brighter pericarp color of JGHN fruit were observed with rootstock of HZ than that with other two kinds of rootstocks. In terms of aborted-seed rates of JGHN, average value with rootstock FZX was 81.7%, which was 58.0% higher than that with HY, and 2.49 times of those with HZ. Vc content of JGHN grafted on HY and FZX were 30.47 and 25.86 mg/100 g respectively, significantly higher than that grafted on HZ. TSS and TA of JGHN grafted on HZ were 17.8% and 0.14%, both were obviously higher than that grafted on FZX and HY.
