Fruits and vegetables are an essential part of a healthy diet, providing humans with vitamins, phytonutrients, and minerals. They are significantly vulnerable, however, to post-harvest diseases caused by numerous fung...Fruits and vegetables are an essential part of a healthy diet, providing humans with vitamins, phytonutrients, and minerals. They are significantly vulnerable, however, to post-harvest diseases caused by numerous fungal and bacterial pathogens. These pathogens can cause significant quantitative and qualitative losses from harvest to consumption during the handling and storage processes. Chemical fungicides are commonly used but are likely to leave residues on the produce, rendering short shelf-life produce, such as berries, unsuitable for human consumption. Identifying eco-friendly methods to control post-harvest disease is, therefore, of utmost importance. The presence of antifungal constituents in the roots of Poncirus trifoliata extracts was detected by thin layer chromatography-based bioautography. The active constituents were isolated and identified by bioautography assay-guided fractionation using flash chromatography followed by spectroscopic techniques. In this study, xanthoxyletin, demethylsuberosin, dentatin, nordentatin, ponfolin, and clausarin were isolated from the root extracts. The antifungal activity of these compounds was moderate to weak compared to the commercial fungicide captan. This study reports the isolation and identification of natural compounds from Poncirus trifoliata that exhibited antifungal activity against Colletotrichum fragariae and Botrytis cinerea, two major post-harvest pathogens.展开更多
Huanglongbing(HLB)is the most destructive bacterial disease of citrus worldwide.While most citrus varieties are susceptible to HLB,Poncirus trifoliata,a close relative of Citrus,and some of its hybrids with Citrus are...Huanglongbing(HLB)is the most destructive bacterial disease of citrus worldwide.While most citrus varieties are susceptible to HLB,Poncirus trifoliata,a close relative of Citrus,and some of its hybrids with Citrus are tolerant to HLB.No specific HLB tolerance genes have been identified in P.trifoliata but recent studies have shown that constitutive disease resistance(CDR)genes were expressed at much higher levels in HLB-tolerant Poncirus hybrids and the expression of CDR genes was modulated by Candidatus Liberibacter asiaticus(CLas),the pathogen of HLB.The current study was undertaken to mine and characterize the CDR gene family in Citrus and Poncirus and to understand its association with HLB tolerance in Poncirus.We identified 17 CDR genes in two citrus genomes,deduced their structures,and investigated their phylogenetic relationships.We revealed that the expansion of the CDR family in Citrus seems to be due to segmental and tandem duplication events.Through genome resequencing and transcriptome sequencing,we identified eight CDR genes in the Poncirus genome(PtCDR1-PtCDR8).The number of SNPs was the highest in PtCDR2 and the lowest in PtCDR7.Most of the deletion and insertion events were observed in the UTR regions of Citrus and Poncirus CDR genes.PtCDR2 and PtCDR8 were in abundance in the leaf transcriptomes of two HLB-tolerant Poncirus genotypes and were also upregulated in HLB-tolerant,Poncirus hybrids as revealed by real-time PCR analysis.These two CDR genes seem to be good candidate genes for future studies of their role in citrus-CLas interactions.展开更多
The local auxin distribution characteristics in the roots,stems,and leaves of stably transformed plantlets of trifoliate orange(Poncirus trifoliata)with auxin reporter system DR5::GUS-YFP were elucidated in this resea...The local auxin distribution characteristics in the roots,stems,and leaves of stably transformed plantlets of trifoliate orange(Poncirus trifoliata)with auxin reporter system DR5::GUS-YFP were elucidated in this research.The auxin response maxima could be observed in the apex of the root tip,primary phloem of the tender stem,and the margin of the young leaves according to the activity of theβ-glucuronidase(GUS)reporter gene triggered by the auxin responsive DR5 promoter.Auxin responses in the apex of the root tips increased when treated with synthetic auxin 1-naphthylacetic acid(NAA),but decreased when treated with the auxin polar transportation inhibitor 2,3,5-triiodobenzoic acid(TIBA).These results indicated that the DR5 reporter system worked in P.trifoliata for auxin distribution and response observation.Trifoliate orange is highly susceptible to citrus canker disease.Auxin accumulation was observed visually in the invasion sites of the detached leaves inoculated with Xanthomonas axonopodis pv.citri(Xac)by GUS staining;the upregulated expression of the YFP,GH3.1,GH3.9,and SAUR genes assessed by quantitative real-time PCR(qRT-PCR)also identified auxin accumulation in the inoculated tissues following Xac infection.Overall,these findings indicated that the plantlets of P.trifoliata engineered with the auxin reporter gene provided a promising system for studying auxin responses during Xac infection.展开更多
Huanglongbing(HLB)is the most devastating disease for citrus worldwide.Candidatus Liberibacter asiaticus(C Las),vectored by Asian citrus psyllid(ACP,Diaphorina citri Kuwayama),is the most common pathogen causing the d...Huanglongbing(HLB)is the most devastating disease for citrus worldwide.Candidatus Liberibacter asiaticus(C Las),vectored by Asian citrus psyllid(ACP,Diaphorina citri Kuwayama),is the most common pathogen causing the disease.Commercial citrus varieties are highly susceptible to HLB,whereas trifoliate orange(Poncirus trifoliata)is considered highly tolerant to HLB.An F1 segregating population and their parent trifoliate orange and sweet orange,which had been exposed to intense HLB pressure for three years,was evaluated for disease symptoms,ACP colonization,C Las titer and tree vigor repeatedly for two to three years.Trifoliate orange and sweet orange showed significant differences for most of the phenotypic traits,and the F1 population exhibited a large variation.A high-density SNP-based genetic map with 1402 markers was constructed for trifoliate orange,which exhibited high synteny and high coverage of its reference genome.A total of 26 quantitative trait locus(QTLs)were identified in four linkage groups LG-t6,LG-t7,LG-t8 and LG-t9,of which four QTL clusters exhibit a clear co-localization of QTLs associated with different traits.Through genome-wide analysis of gene expression in response to C Las infection in‘Flying Dragon’and‘Larger-Flower DPI-50-7’trifoliate orange,85 differentially expressed genes were found located within the QTL clusters.Among them,seven genes were classified as defense or immunity protein which exhibited the highest transcriptional change after C Las infection.Our results indicate a quantitative genetic nature of HLB tolerance and identified candidate genes that should be valuable for searching for genetic solutions to HLB through breeding or genetic engineering.展开更多
In the framework of searching for new pectin sources to partially compensate for domestic and regional demands, the peel (albedo) of the “non-comestible” fruit of Poncirus trifoliata was investigated using a relativ...In the framework of searching for new pectin sources to partially compensate for domestic and regional demands, the peel (albedo) of the “non-comestible” fruit of Poncirus trifoliata was investigated using a relatively simple experimental design for optimization, in which only the variable was the extraction pH (1.0, 1.5, and 2.0) on the basis of our previous studies on diverse pectin sources. The results showed that the yield of pectin (7.4%-19.8%) was strongly influenced by the extraction pH when the other parameters, namely the solid to liquid extractant (S/L) ratio, temperature (T °C), and time (t) were fixed to 1:25 (w/v), 75°C, and 90 min, respectively. Likewise, the galacturonic acid content (GalA: 61.4%-79.2%), total neutral sugar content (TNS: 9.1%-22.5%), degree of branching (3.5%-13.9%), homogalacturonan (HG) to rhamnogalacturonan-I (RG-I) ratio (2.2-5.6), degree of methylesterification (DM: 54-77), viscosity average molecular weight (Mν: 57-82), and gelling capacity (GC: 124-158) were all affected by the extraction pH. The optimum pH for producing pectin with good yield, quality characteristics (GalA > 65%, DM > 60, Mν > 80 kDa), and gelling capacity (GC > 150), from the peel of P. trifoliata fruit, was found to be pH 1.5.展开更多
The immature fruits of Poncirus trifoliate are used as a medicine for the treatment of gastrointestinal disorders,inflammation,and allergies in East Asia.However,their effect on colon cancer cells remains unclear.We i...The immature fruits of Poncirus trifoliate are used as a medicine for the treatment of gastrointestinal disorders,inflammation,and allergies in East Asia.However,their effect on colon cancer cells remains unclear.We investigated the effect of the immature fruit of P.trifoliate extract on colorectal adenocarcinoma.The extract of the immature fruit of P.trifoliata inhibited the proliferation of CT-26 cells compared with untreated cells and it induced autophagy and apoptosis through the protein kinase B/mammalian target of rapamycin and 5'-AMP-activated protein kinase pathways.The number of autophagic vacuoles and autophage markers increased in response to the extract.At later time-points,apoptosis increased dose/time-dependently.In CT-26 cells pre-treated a pan-caspase inhibitor prior to P.trifoliata immature fruit extract treatment,we did not find any change in pro-caspase 3 and pro-PARP levels.Additionally,in cells pre-treated autphage inhibitor,SQSTM1/p62 and LC3AB,pro-caspase 3 and pro-PARP levels did not change.Our results indicate the molecular mechanisms that the extract of the immature fruit of P.trifoliata induces apoptosis in colorectal carcinoma cells by inducing mitochondrial autophagy.In this study,we provided a draft for further investigate the use of MEPT for colorectal cancer inhibition.展开更多
Based on the former constructed ＇Tyrl＇ locus genetic map in family 9145, from LB6-2 [Clementine mandarin （C. reticulata） × Hamlin orange （C. sinensis）] × Swingle citrumelo （C. paradise × P. trifo...Based on the former constructed ＇Tyrl＇ locus genetic map in family 9145, from LB6-2 [Clementine mandarin （C. reticulata） × Hamlin orange （C. sinensis）] × Swingle citrumelo （C. paradise × P. trifoliata）, 9 markers were chosen for application in evaluating their effectiveness in marker-assisted selection （MAS） for citrus rootstock breeding program from many F1 progeny of Poncirus trifoliata. As the mapping revealed that these markers were estimated within a range of 12.1 cM in the linkage group, and among them, SCO07 co-segregated with ＂Tyrl＇, and 7A4R as the closest to ＇Tyrl＇ with a distance of 1.5 cM, these markers were basically fitful to go MAS screening. The results of screening P. trifoliata F1 progeny indicated that all the markers were inherited in codominant fashion and most of them were heterozygous on PT （Pomery of P. trifoliata）., marker 4L17R/CfoI and 7A4（1407）/BfaI were proved to be consistently reliable for accurate scoring of genotypes and the revealed polymorphism was basically coincided with the citrus nematode resistant phenotype within tested populations. The polymorphic genotype with marker 4L17R/Cfol was found completely matched up with the phenotype of individuals that conferred high resistance to citrus nematode when the USDA hybrid rootstocks were screened. Utilization of these markers, especially the highly specific 4L17R/Cfol and 7A4（1407）/Bfal, should result in great benefit to world citrus industry for early selection in rootstock-breeding program.展开更多
【目的】探究枳橙砧木对沃柑树体及果实品质的影响,为筛选桂南地区沃柑适宜的砧木提供理论依据。【方法】在广西南宁市武鸣区采取长期定位试验,对嫁接在枳橙上的沃柑果实品质进行持续3年(2018—2020年)的研究,以资阳香橙砧、枳砧和红橘...【目的】探究枳橙砧木对沃柑树体及果实品质的影响,为筛选桂南地区沃柑适宜的砧木提供理论依据。【方法】在广西南宁市武鸣区采取长期定位试验,对嫁接在枳橙上的沃柑果实品质进行持续3年(2018—2020年)的研究,以资阳香橙砧、枳砧和红橘砧沃柑为对照,分析其树体指标(砧木干周、接穗干周、干周差、株高、挂果数量)及果实品质指标(单果重、果实横径、纵径、果形指数、果皮厚度、可食率、维生素C、可溶性固形物、柠檬酸、总糖、固酸比)等的变化。【结果】综合3年数据可知,枳橙砧沃柑在单果重、挂果数量和部分品质指标上优于其他砧木,3年平均挂果数为299个,单果重为143.07 g,维生素C含量为19.92 mg/100 m L,可溶性固形物含量为12.51%,柠檬酸含量为0.584%,总糖含量为12.46%,固酸比为21.42。枳橙砧与枳砧相比,呈现出生长势强,挂果数量多等优势,但与香橙砧相比,差异不显著(P>0.05,下同);结合单果重表现,枳橙砧沃柑无明显的下降趋势,与香橙砧沃柑相比,均能持续稳产。枳橙砧沃柑的果实品质整体表现低于枳砧沃柑,但进入丰产期后,二者品质差异不显著。对比其他3种砧木,红橘砧沃柑整体表现较差,主要为挂果数量较少,果实品质指标不理想,其中3年平均挂果数量为185个。【结论】枳橙砧沃柑在桂南地区综合表现较好,可考虑枳橙砧作为桂南地区沃柑的适宜砧木;但枳橙砧不适宜在缺锌较严重的地块种植,且在生产中,枳橙砧应控制树势,适时修剪,不适宜密植。展开更多
【目的】从枳[Poncirus trifoliata(L.)Raf.]中克隆SBP类[SQUAMOSA(SQUA)promoter-binding-like]转录因子基因SPL9和SPL13全长,构建SPL9和SPL13亚细胞定位表达载体验证其是否具有核定位功能,利用荧光定量PCR研究其在枳不同组织的表达特...【目的】从枳[Poncirus trifoliata(L.)Raf.]中克隆SBP类[SQUAMOSA(SQUA)promoter-binding-like]转录因子基因SPL9和SPL13全长,构建SPL9和SPL13亚细胞定位表达载体验证其是否具有核定位功能,利用荧光定量PCR研究其在枳不同组织的表达特性,初步确定SPL9和SPL13在枳生长发育过程中的作用。【方法】利用生物信息学结合RACE技术以枳花器官的cDNA为模板,克隆出SPL9和SPL13基因全长,分别命名Pt-SPL9和Pt-SPL13,大小分别是1519bp和1824bp,在GenBank的登录号分别是FJ502237和FJ502238;构建Pt-SPL9和Pt-SPL13亚细胞定位载体35S-GW-FJ502237/FJ502238-GFP,基因枪转化洋葱表皮细胞,暗培养24h后激光共聚焦显微镜下观察;利用SYBR Green I实时定量RT-PCR方法检测Pt-SPL9和Pt-SPL13在根、茎、叶、花序、花和果等不同组织中的表达。【结果】生物信息学分析表明,Pt-SPL9和Pt-SPL13的cDNA序列中都有microRNA156的识别位点,Pt-SPL9与金鱼草、拟南芥和玉米SPL9的同源性分别为48.9%、42.5%和41.7%;Pt-SPL13与拟南芥SPL13、水稻的SPL16和玉米的TGA1同源性分别为40.8%、38.1%和35.8%。Pt-SPL9和Pt-SPL13与其它植物的SBP一样有着高度保守的序列,即SBP结构域和一个双向核定位信号KRXXXRRRK。亚细胞定位结果表明,Pt-SPL9和Pt-SPL13均定位于细胞核中。SYBR Green I实时定量RT-PCR结果表明,Pt-SPL9和Pt-SPL13在各个器官均有表达,但表达量不同,Pt-SPL9在茎中的表达量最高,在花和叶中的表达量次之,在根、花芽和幼果中的表达量最低;Pt-SPL13在幼果中的表达量最高,在茎和花芽中的表达量相当,其次为叶,在花和根中的表达量很低。【结论】转录因子Pt-SPL9和Pt-SPL13均具有核定位功能,Pt-SPL9和Pt-SPL13对枳的茎和果实的发育可能有着重要作用。展开更多
文摘Fruits and vegetables are an essential part of a healthy diet, providing humans with vitamins, phytonutrients, and minerals. They are significantly vulnerable, however, to post-harvest diseases caused by numerous fungal and bacterial pathogens. These pathogens can cause significant quantitative and qualitative losses from harvest to consumption during the handling and storage processes. Chemical fungicides are commonly used but are likely to leave residues on the produce, rendering short shelf-life produce, such as berries, unsuitable for human consumption. Identifying eco-friendly methods to control post-harvest disease is, therefore, of utmost importance. The presence of antifungal constituents in the roots of Poncirus trifoliata extracts was detected by thin layer chromatography-based bioautography. The active constituents were isolated and identified by bioautography assay-guided fractionation using flash chromatography followed by spectroscopic techniques. In this study, xanthoxyletin, demethylsuberosin, dentatin, nordentatin, ponfolin, and clausarin were isolated from the root extracts. The antifungal activity of these compounds was moderate to weak compared to the commercial fungicide captan. This study reports the isolation and identification of natural compounds from Poncirus trifoliata that exhibited antifungal activity against Colletotrichum fragariae and Botrytis cinerea, two major post-harvest pathogens.
基金ZD acknowledges financial support of this study from the Citrus Research and Development Foundation,Inc.(CDRF)(Project#108766 and#105077)from the USDA-NIFA Citrus Disease Research and Extension(CDRE)Program(Grant No.2015-70016-23027).
文摘Huanglongbing(HLB)is the most destructive bacterial disease of citrus worldwide.While most citrus varieties are susceptible to HLB,Poncirus trifoliata,a close relative of Citrus,and some of its hybrids with Citrus are tolerant to HLB.No specific HLB tolerance genes have been identified in P.trifoliata but recent studies have shown that constitutive disease resistance(CDR)genes were expressed at much higher levels in HLB-tolerant Poncirus hybrids and the expression of CDR genes was modulated by Candidatus Liberibacter asiaticus(CLas),the pathogen of HLB.The current study was undertaken to mine and characterize the CDR gene family in Citrus and Poncirus and to understand its association with HLB tolerance in Poncirus.We identified 17 CDR genes in two citrus genomes,deduced their structures,and investigated their phylogenetic relationships.We revealed that the expansion of the CDR family in Citrus seems to be due to segmental and tandem duplication events.Through genome resequencing and transcriptome sequencing,we identified eight CDR genes in the Poncirus genome(PtCDR1-PtCDR8).The number of SNPs was the highest in PtCDR2 and the lowest in PtCDR7.Most of the deletion and insertion events were observed in the UTR regions of Citrus and Poncirus CDR genes.PtCDR2 and PtCDR8 were in abundance in the leaf transcriptomes of two HLB-tolerant Poncirus genotypes and were also upregulated in HLB-tolerant,Poncirus hybrids as revealed by real-time PCR analysis.These two CDR genes seem to be good candidate genes for future studies of their role in citrus-CLas interactions.
基金the National Natural Science Foundation of China(Grant No.31660564)the science and technology project of Jiangxi province(Grant Nos.20161BBF60063,151008).
文摘The local auxin distribution characteristics in the roots,stems,and leaves of stably transformed plantlets of trifoliate orange(Poncirus trifoliata)with auxin reporter system DR5::GUS-YFP were elucidated in this research.The auxin response maxima could be observed in the apex of the root tip,primary phloem of the tender stem,and the margin of the young leaves according to the activity of theβ-glucuronidase(GUS)reporter gene triggered by the auxin responsive DR5 promoter.Auxin responses in the apex of the root tips increased when treated with synthetic auxin 1-naphthylacetic acid(NAA),but decreased when treated with the auxin polar transportation inhibitor 2,3,5-triiodobenzoic acid(TIBA).These results indicated that the DR5 reporter system worked in P.trifoliata for auxin distribution and response observation.Trifoliate orange is highly susceptible to citrus canker disease.Auxin accumulation was observed visually in the invasion sites of the detached leaves inoculated with Xanthomonas axonopodis pv.citri(Xac)by GUS staining;the upregulated expression of the YFP,GH3.1,GH3.9,and SAUR genes assessed by quantitative real-time PCR(qRT-PCR)also identified auxin accumulation in the inoculated tissues following Xac infection.Overall,these findings indicated that the plantlets of P.trifoliata engineered with the auxin reporter gene provided a promising system for studying auxin responses during Xac infection.
基金supported by grants from the Citrus Research and Development Foundation,USA(Grant No.CRDF#15-010)the New Varieties Development and Management Corporation(NVDMC),on behalf of the Florida citrus industry,USA,the Fundamental Research Funds for the Central Universities,China(Grant No.2022CDJXY-004)from the USDA-NIFA-SCRI,USA(Grant No.2015-70016-2302).
文摘Huanglongbing(HLB)is the most devastating disease for citrus worldwide.Candidatus Liberibacter asiaticus(C Las),vectored by Asian citrus psyllid(ACP,Diaphorina citri Kuwayama),is the most common pathogen causing the disease.Commercial citrus varieties are highly susceptible to HLB,whereas trifoliate orange(Poncirus trifoliata)is considered highly tolerant to HLB.An F1 segregating population and their parent trifoliate orange and sweet orange,which had been exposed to intense HLB pressure for three years,was evaluated for disease symptoms,ACP colonization,C Las titer and tree vigor repeatedly for two to three years.Trifoliate orange and sweet orange showed significant differences for most of the phenotypic traits,and the F1 population exhibited a large variation.A high-density SNP-based genetic map with 1402 markers was constructed for trifoliate orange,which exhibited high synteny and high coverage of its reference genome.A total of 26 quantitative trait locus(QTLs)were identified in four linkage groups LG-t6,LG-t7,LG-t8 and LG-t9,of which four QTL clusters exhibit a clear co-localization of QTLs associated with different traits.Through genome-wide analysis of gene expression in response to C Las infection in‘Flying Dragon’and‘Larger-Flower DPI-50-7’trifoliate orange,85 differentially expressed genes were found located within the QTL clusters.Among them,seven genes were classified as defense or immunity protein which exhibited the highest transcriptional change after C Las infection.Our results indicate a quantitative genetic nature of HLB tolerance and identified candidate genes that should be valuable for searching for genetic solutions to HLB through breeding or genetic engineering.
文摘In the framework of searching for new pectin sources to partially compensate for domestic and regional demands, the peel (albedo) of the “non-comestible” fruit of Poncirus trifoliata was investigated using a relatively simple experimental design for optimization, in which only the variable was the extraction pH (1.0, 1.5, and 2.0) on the basis of our previous studies on diverse pectin sources. The results showed that the yield of pectin (7.4%-19.8%) was strongly influenced by the extraction pH when the other parameters, namely the solid to liquid extractant (S/L) ratio, temperature (T °C), and time (t) were fixed to 1:25 (w/v), 75°C, and 90 min, respectively. Likewise, the galacturonic acid content (GalA: 61.4%-79.2%), total neutral sugar content (TNS: 9.1%-22.5%), degree of branching (3.5%-13.9%), homogalacturonan (HG) to rhamnogalacturonan-I (RG-I) ratio (2.2-5.6), degree of methylesterification (DM: 54-77), viscosity average molecular weight (Mν: 57-82), and gelling capacity (GC: 124-158) were all affected by the extraction pH. The optimum pH for producing pectin with good yield, quality characteristics (GalA > 65%, DM > 60, Mν > 80 kDa), and gelling capacity (GC > 150), from the peel of P. trifoliata fruit, was found to be pH 1.5.
基金supported by Fund of Biomedical Research Institute,Jeonbuk National University Hospital.
文摘The immature fruits of Poncirus trifoliate are used as a medicine for the treatment of gastrointestinal disorders,inflammation,and allergies in East Asia.However,their effect on colon cancer cells remains unclear.We investigated the effect of the immature fruit of P.trifoliate extract on colorectal adenocarcinoma.The extract of the immature fruit of P.trifoliata inhibited the proliferation of CT-26 cells compared with untreated cells and it induced autophagy and apoptosis through the protein kinase B/mammalian target of rapamycin and 5'-AMP-activated protein kinase pathways.The number of autophagic vacuoles and autophage markers increased in response to the extract.At later time-points,apoptosis increased dose/time-dependently.In CT-26 cells pre-treated a pan-caspase inhibitor prior to P.trifoliata immature fruit extract treatment,we did not find any change in pro-caspase 3 and pro-PARP levels.Additionally,in cells pre-treated autphage inhibitor,SQSTM1/p62 and LC3AB,pro-caspase 3 and pro-PARP levels did not change.Our results indicate the molecular mechanisms that the extract of the immature fruit of P.trifoliata induces apoptosis in colorectal carcinoma cells by inducing mitochondrial autophagy.In this study,we provided a draft for further investigate the use of MEPT for colorectal cancer inhibition.
基金supported in part by grants from the USDA NRICGP (9201765, 9600748)USDA/National Citrus Research Council (98012205)the Florida Citrus Production Research Advisory Council, USA(942-27)
文摘Based on the former constructed ＇Tyrl＇ locus genetic map in family 9145, from LB6-2 [Clementine mandarin （C. reticulata） × Hamlin orange （C. sinensis）] × Swingle citrumelo （C. paradise × P. trifoliata）, 9 markers were chosen for application in evaluating their effectiveness in marker-assisted selection （MAS） for citrus rootstock breeding program from many F1 progeny of Poncirus trifoliata. As the mapping revealed that these markers were estimated within a range of 12.1 cM in the linkage group, and among them, SCO07 co-segregated with ＂Tyrl＇, and 7A4R as the closest to ＇Tyrl＇ with a distance of 1.5 cM, these markers were basically fitful to go MAS screening. The results of screening P. trifoliata F1 progeny indicated that all the markers were inherited in codominant fashion and most of them were heterozygous on PT （Pomery of P. trifoliata）., marker 4L17R/CfoI and 7A4（1407）/BfaI were proved to be consistently reliable for accurate scoring of genotypes and the revealed polymorphism was basically coincided with the citrus nematode resistant phenotype within tested populations. The polymorphic genotype with marker 4L17R/Cfol was found completely matched up with the phenotype of individuals that conferred high resistance to citrus nematode when the USDA hybrid rootstocks were screened. Utilization of these markers, especially the highly specific 4L17R/Cfol and 7A4（1407）/Bfal, should result in great benefit to world citrus industry for early selection in rootstock-breeding program.
文摘【目的】探究枳橙砧木对沃柑树体及果实品质的影响,为筛选桂南地区沃柑适宜的砧木提供理论依据。【方法】在广西南宁市武鸣区采取长期定位试验,对嫁接在枳橙上的沃柑果实品质进行持续3年(2018—2020年)的研究,以资阳香橙砧、枳砧和红橘砧沃柑为对照,分析其树体指标(砧木干周、接穗干周、干周差、株高、挂果数量)及果实品质指标(单果重、果实横径、纵径、果形指数、果皮厚度、可食率、维生素C、可溶性固形物、柠檬酸、总糖、固酸比)等的变化。【结果】综合3年数据可知,枳橙砧沃柑在单果重、挂果数量和部分品质指标上优于其他砧木,3年平均挂果数为299个,单果重为143.07 g,维生素C含量为19.92 mg/100 m L,可溶性固形物含量为12.51%,柠檬酸含量为0.584%,总糖含量为12.46%,固酸比为21.42。枳橙砧与枳砧相比,呈现出生长势强,挂果数量多等优势,但与香橙砧相比,差异不显著(P>0.05,下同);结合单果重表现,枳橙砧沃柑无明显的下降趋势,与香橙砧沃柑相比,均能持续稳产。枳橙砧沃柑的果实品质整体表现低于枳砧沃柑,但进入丰产期后,二者品质差异不显著。对比其他3种砧木,红橘砧沃柑整体表现较差,主要为挂果数量较少,果实品质指标不理想,其中3年平均挂果数量为185个。【结论】枳橙砧沃柑在桂南地区综合表现较好,可考虑枳橙砧作为桂南地区沃柑的适宜砧木;但枳橙砧不适宜在缺锌较严重的地块种植,且在生产中,枳橙砧应控制树势,适时修剪,不适宜密植。
文摘【目的】从枳[Poncirus trifoliata(L.)Raf.]中克隆SBP类[SQUAMOSA(SQUA)promoter-binding-like]转录因子基因SPL9和SPL13全长,构建SPL9和SPL13亚细胞定位表达载体验证其是否具有核定位功能,利用荧光定量PCR研究其在枳不同组织的表达特性,初步确定SPL9和SPL13在枳生长发育过程中的作用。【方法】利用生物信息学结合RACE技术以枳花器官的cDNA为模板,克隆出SPL9和SPL13基因全长,分别命名Pt-SPL9和Pt-SPL13,大小分别是1519bp和1824bp,在GenBank的登录号分别是FJ502237和FJ502238;构建Pt-SPL9和Pt-SPL13亚细胞定位载体35S-GW-FJ502237/FJ502238-GFP,基因枪转化洋葱表皮细胞,暗培养24h后激光共聚焦显微镜下观察;利用SYBR Green I实时定量RT-PCR方法检测Pt-SPL9和Pt-SPL13在根、茎、叶、花序、花和果等不同组织中的表达。【结果】生物信息学分析表明,Pt-SPL9和Pt-SPL13的cDNA序列中都有microRNA156的识别位点,Pt-SPL9与金鱼草、拟南芥和玉米SPL9的同源性分别为48.9%、42.5%和41.7%;Pt-SPL13与拟南芥SPL13、水稻的SPL16和玉米的TGA1同源性分别为40.8%、38.1%和35.8%。Pt-SPL9和Pt-SPL13与其它植物的SBP一样有着高度保守的序列,即SBP结构域和一个双向核定位信号KRXXXRRRK。亚细胞定位结果表明,Pt-SPL9和Pt-SPL13均定位于细胞核中。SYBR Green I实时定量RT-PCR结果表明,Pt-SPL9和Pt-SPL13在各个器官均有表达,但表达量不同,Pt-SPL9在茎中的表达量最高,在花和叶中的表达量次之,在根、花芽和幼果中的表达量最低;Pt-SPL13在幼果中的表达量最高,在茎和花芽中的表达量相当,其次为叶,在花和根中的表达量很低。【结论】转录因子Pt-SPL9和Pt-SPL13均具有核定位功能,Pt-SPL9和Pt-SPL13对枳的茎和果实的发育可能有着重要作用。
