scholarly journals Construction of high-density genetic maps and detection of QTLs associated with Huanglongbing infection in citrus

2018 ◽  
Author(s):  
Ming Huang ◽  
Mikeal L. Roose ◽  
Qibin Yu ◽  
Dongliang Du ◽  
Yi Zhang ◽  
...  
Keyword(s):  
Sweet Orange ◽  
High Density ◽  
Poncirus Trifoliata ◽  
Genetic Maps ◽  
Trifoliate Orange ◽  
High Coverage ◽  
Time Points ◽  
Ct Value ◽  
Starting Point ◽  
Liberibacter Asiaticus

AbstractNo true resistance to Huanglongbing (HLB), a citrus disease associated with infection ofCandidatusLiberibacter asiaticus (CLas), is found within commercial citrus cultivars, though trifoliate orange (Poncirus trifoliata) has been described as resistant or tolerant. Through genotyping an intergeneric F1population by Genotyping-by-Sequencing, high-density SNP-based genetic maps were constructed separately for trifoliate orange and sweet orange (Citrus sinensis). Both genetic maps exhibited high synteny and high coverage of citrus genome. After exposure to intense HLB pressure for two years, Ct value of qPCR forCLas detection in leaves throughout ten time points during the next three years was above 35 in trifoliate oranges, under 28 in sweet oranges, and ranged from 24 to 38 and exhibited obvious segregation among progenies. Phenotypic data of percentage of healthy trees showed high correlation with the Ct value. By mapping the two traits at all time points, a total of nine clusters of QTLs were detected, of which five, respectively located on LG-t7 and LG-t8 of trifoliate orange map and LG-s3, LG-s5 and LG-s9 of sweet orange map, collectively explained a major part of the phenotypic variation. This study provides a starting point for citrus breeding to support long-term control of this devastating disease.Highlight1). Constructed the first high-density genetic map for trifoliate orange (Poncirus trifoliata)2). The first report on identification of QTLs related to Huanglongbing in citrus.AbbreviationsACPAsian citrus psyllidCLasCandidatusLiberibacter asiaticuscMcentiMorgansCtCycle thresholdHLBHuanglongbingIMInterval mappingKWKruskal-WallisLGLinkage groupLODLogarithm of oddsQTLQuantitative trait locusRADRestriction site associated DNArMQMrestricted multiple QTL mappingSNPSingle nucleotide polymorphism.

scholarly journals Canopy health, but not Candidatus Liberibacter asiaticus Ct values, are correlated with fruit yield in Huanglongbing affected sweet orange trees

2021 ◽  
Author(s):  
Amit Levy ◽  
Taylor Livingston ◽  
Chunxia Wang ◽  
Diann Achor ◽  
Tripti Vashisth
Keyword(s):  
Sweet Orange ◽  
Field Trials ◽  
Fruit Yield ◽  
Ct Value ◽  
Independent Field ◽  
Canopy Volume ◽  
Candidatus Liberibacter ◽  
Liberibacter Asiaticus ◽  
Almost All ◽  
Orange Trees

AbstractIn Florida, almost all citrus trees are infected with Huanglongbing (HLB), caused by the gram-negative, intracellular phloem limited bacteria Candidatus liberibacter asiaticus (CLas). Distinguishing between the severely and mildly sick trees is important for managing the groves and testing new HLB therapies. A mildly sick tree is one that produces higher fruit yield, compared to a severely sick tree, but measuring yields is laborious and time consuming. Here we characterized HLB affected sweet orange trees in the field in order to identify the specific traits that are correlated with the yields. We found that canopy volume, fruit detachment force (FDF) and the percentage of photosynthetically active radiation interception in the canopy (%INT) were positively correlated with fruit yields. Specifically, %INT measurements accurately distinguished between mild and severe trees in independent field trials. We could not find a difference in the Ct value between high and low producing HLB trees. Moreover, Ct values did not always agree with the number of CLas in the phloem that were visualized by transmission electron microscopy. Overall, our work identified an efficient way to distinguish between severe and mild HLB trees in Florida by measuring %INT and suggests that health of the canopy is more important for yields than the Ct value.

scholarly journals Citrus Pentaploids from Small Seeds of Diploid × Diploid Crosses

HortScience ◽  
1991 ◽  
Vol 26 (3) ◽  
pp. 292-293 ◽  
Author(s):  
Iwao Oiyama ◽  
Shozo Kobayashi
Keyword(s):  
Sweet Orange ◽  
Poncirus Trifoliata ◽  
Seed Parent ◽  
Trifoliate Orange

Seedlings from some small seeds of diploid × diploid crosses using `Miyauchi iyokan' (Citrus iyo Hort. ex Tanaka) as the seed parent were found to be pentaploid (2n = 5x = 45). The growth of pentaploid seedlings was extremely weak on their own roots, but was much more vigorous when micrografted on seedlings of tetraploid trifoliate orange [Poncirus trifoliata (L.) Raf.]. Diploid `Miyauchi iyokan' produced hexaploid seedlings from small seeds in addition to triploid and tetraploid seedlings from normal seeds when crossed with tetraploid `Funadoko' (C. funadoko Hort. ex Y. Tanaka) and `Trovita' sweet orange [C. sinensis (L.) Osbeck]. Based on this phenomenon, the origin of pentaploids is discussed.

Elsinoe fawcettii. [Descriptions of Fungi and Bacteria].

1974 ◽  
Author(s):  
A. Sivanesan
Keyword(s):  
Geographical Distribution ◽  
Short Distance ◽  
Sweet Orange ◽  
Poncirus Trifoliata ◽  
Sour Orange ◽  
Trifoliate Orange ◽  
Geographical Factors ◽  
Rain Splash ◽  
Satsuma Orange

Abstract A description is provided for Elsinoe fawcettii. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Confined to a small number of genera and species within the Rutaceae (Winston et al., 1925), the degree and range of susceptibility within this group varying according to varietal, climatic, or geographical factors (Peltier & Frederich, 1924; Brun, 1971; 3, 210). Plants most frequently recorded as susceptible include sour orange, rough and sweet lemon, grapefruit, tangerine, mandarin (some varieties), king and satsuma orange, trifoliate orange (Poncirus trifoliata), calamondin (Citrus mitts) and the pointed leaf papeda (C. hystrix). Kumquats (Fortunella spp.) and most varieties of sweet orange and lime are generally more resistant although instances of infection on these hosts are known (Brun, 1971; 37, 165) DISEASE: Sour orange scab (common citrus scab, lemon, grapefruit scab, etc. according to host). GEOGRAPHICAL DISTRIBUTION: Widespread in many citrus growing areas where suitable rainfall conditions occur (CMI Map 125, ed. 3, 1966). TRANSMISSION: Predominantly by short distance rain splash, also by wind (Yamada, 1961), mites or insects (9, 647; Brun, 1971). The fungus overwinters in old scab lesions (Winston, 1923).

scholarly journals Tree Growth and Production of Rainfed Valencia Sweet Orange Grafted onto Trifoliate Orange Hybrid Rootstocks under Aw Climate

Agronomy ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2533
Author(s):  
Eduardo Augusto Girardi ◽  
Antonio Juliano Ayres ◽  
Luiz Fernando Girotto ◽  
Leandro Peña
Keyword(s):  
Sweet Orange ◽  
Poncirus Trifoliata ◽  
Trifoliate Orange ◽  
Promising Alternative ◽  
Rangpur Lime ◽  
Volkamer Lemon ◽  
Canopy Volume ◽  
Supplementary Irrigation ◽  
The Cross ◽  
Swingle Citrumelo

Brazil is the largest producer of sweet orange and its juice in the world. Extensive cultivated area is located under an Aw climate in the North–Northwest of the state of São Paulo and the Triângulo of Minas Gerais state, being subjected to severe drought events. Although 56% of the orchards are irrigated in these regions, there is a need for drought tolerant rootstocks as an alternative to traditional genotypes such as Rangpur lime and Volkamer lemon, which are susceptible to the endemic citrus sudden death disease (CSD). In this sense, the tree size and production of Valencia sweet orange grafted onto 23 rootstock genotypes were evaluated over a ten-year period in rainfed cultivation at 7.0 m × 3.0 m spacing. Most evaluated types resulted from the cross of Poncirus trifoliata with Citrus, but two interspecific hybrids of Citrus (Sunki mandarin × Rangpur lime hybrids), the Barnes trifoliate orange and a tetraploid selection of Swingle citrumelo were also tested. Tropical Sunki mandarin was used as the reference control. Those hybrids coming from the cross of Sunki × Flying Dragon induced large tree sizes to Valencia sweet orange as well as the other citrandarins, Tropical Sunki mandarin and the Sunki mandarin × Rangpur lime hybrids, whereas only the tetraploid Swingle citrumelo behaved as a dwarfing rootstock, decreasing the canopy volume by 77% compared to that induced by the most vigorous citrandarin 535. The citrandarins 543 and 602 and the citrange C38 induced the highest mean fruit production, 67.2 kg·tree−1, but they also caused pronounced alternate bearing and only the hybrid 543 led to a high production efficiency consistently. Graft incompatibility symptoms were not observed over the evaluation period, and the canopy shape of Valencia sweet orange was also influenced by the rootstocks tested. Two citrandarins and one citrange were selected as the most promising alternative rootstocks for Valencia sweet orange grown under an Aw climate, even though productivity would likely benefit from supplementary irrigation.

scholarly journals Adventitious Juice Vesicles Produced from the Exocarp in the Citrinae (Aurantioideae)

HortScience ◽  
1992 ◽  
Vol 27 (7) ◽  
pp. 843-846
Author(s):  
Brent Tisserat ◽  
Paul D. Galletta
Keyword(s):  
Sweet Orange ◽  
Poncirus Trifoliata ◽  
Citrus Reticulata ◽  
Trifoliate Orange ◽  
Oil Glands ◽  
Immature Fruit ◽  
Fruit Surface

Some cultivars of mandarin (Citrus reticulata Blanco), sweet orange [Citrus sinensis (L.) Osb.], and trifoliate orange [Poncirus trifoliata (L.) Raf.] were found to have adventitious juice vesicles originating from their exocarp (peel). Several hundred green vesicles may be initiated from curvilinear stylar peel depressions of immature fruit. These vesicles develop similarly to juice vesicles from the endocarp except that, as the fruit matures, exocarp adventitious vesicles die prematurely and degenerate into a fruit surface blemish. Evidence suggests that juice vesicles and oil glands are homologous and merit reconsideration in ontological studies.

scholarly journals Ability of `Valencia' Sweet Orange to Cold-acclimate on Cold-sensitive Citron Rootstock

HortScience ◽  
1992 ◽  
Vol 27 (11) ◽  
pp. 1201-1203 ◽  
Author(s):  
G. Yelenosky ◽  
J.C.V. Vu
Keyword(s):  
Cold Acclimation ◽  
Citrus Sinensis ◽  
Sweet Orange ◽  
Freeze Tolerance ◽  
Poncirus Trifoliata ◽  
Trifoliate Orange ◽  
Cold Sensitive ◽  
Cold Hardy ◽  
Orange Trees ◽  
Better Than

Greenhouse-grown l-year-old sweet orange trees [Citrus sinensis (L.) Osbeck cv. Valencia] on cold-hardy trifoliate orange [Poncirus trifoliata (L.) Raf.] and cold-sensitive citron (C. medica L.) rootstocks were exposed to cold-acclimation conditions and freeze-tested at -6.7C for 4 hours in a temperature-programed walk-in freezer room. Nonhardened trees generally did not survive the freeze, whereas cold-hardened trees survived with no wood kill on either rootstock. Essentially, all leaves died or abscised during the subsequent 5 weeks in the greenhouse. Freeze survival did not separate rootstocks nor did supercooling in separate trials where Yalencia' wood reached –8.8C before apparent nucleation. Increases in concentration of carbohydrates and proline and decreases in water content in Yalencia' leaves during cold hardening were generally associated with increased freeze tolerance. Other tests, that matched 9-month-old seedlings of citron with trifoliate orange rootstock, showed clear differences in the superior cold acclimation of trifoliate orange over citron, which, however, performed better than expected.

scholarly journals High-Density Genetic Map Construction and Identification of QTLs Controlling Leaf Abscission Trait in Poncirus trifoliata

2021 ◽  
Vol 22 (11) ◽  
pp. 5723
Author(s):  
Yuan-Yuan Xu ◽  
Sheng-Rui Liu ◽  
Zhi-Meng Gan ◽  
Ren-Fang Zeng ◽  
Jin-Zhi Zhang ◽  
...  
Keyword(s):  
Qtl Mapping ◽  
Linkage Map ◽  
Genetic Map ◽  
Expression Patterns ◽  
High Density ◽  
Poncirus Trifoliata ◽  
Leaf Abscission ◽  
Comparative Genomic ◽  
Map Comparison ◽  
Genomic Studies

A high-density genetic linkage map is essential for genetic and genomic studies including QTL mapping, genome assembly, and comparative genomic analysis. Here, we constructed a citrus high-density linkage map using SSR and SNP markers, which are evenly distributed across the citrus genome. The integrated linkage map contains 4163 markers with an average distance of 1.12 cM. The female and male linkage maps contain 1478 and 2976 markers with genetic lengths of 1093.90 cM and 1227.03 cM, respectively. Meanwhile, a genetic map comparison demonstrates that the linear order of common markers is highly conserved between the clementine mandarin and Poncirus trifoliata. Based on this high-density integrated citrus genetic map and two years of deciduous phenotypic data, two loci conferring leaf abscission phenotypic variation were detected on scaffold 1 (including 36 genes) and scaffold 8 (including 107 genes) using association analysis. Moreover, the expression patterns of 30 candidate genes were investigated under cold stress conditions because cold temperature is closely linked with the deciduous trait. The developed high-density genetic map will facilitate QTL mapping and genomic studies, and the localization of the leaf abscission deciduous trait will be valuable for understanding the mechanism of this deciduous trait and citrus breeding.

scholarly journals Genome of a citrus rootstock and global DNA demethylation caused by heterografting

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Yue Huang ◽  
Yuantao Xu ◽  
Xiaolin Jiang ◽  
Huiwen Yu ◽  
Huihui Jia ◽  
...  
Keyword(s):  
Sweet Orange ◽  
Epigenetic Modification ◽  
Epigenetic Modifications ◽  
Genetic Effects ◽  
Dna Demethylation ◽  
Poncirus Trifoliata ◽  
Protein Coding ◽  
Horticultural Crops ◽  
Citrus Rootstock ◽  
Methylome Analysis

AbstractGrafting is an ancient technique used for plant propagation and improvement in horticultural crops for at least 1,500 years. Citrus plants, with a seed-to-seed cycle of 5–15 years, are among the fruit crops that were probably domesticated by grafting. Poncirus trifoliata, a widely used citrus rootstock, can promote early flowering, strengthen stress tolerance, and improve fruit quality via scion–rootstock interactions. Here, we report its genome assembly using PacBio sequencing. We obtained a final genome of 303 Mb with a contig N50 size of 1.17 Mb and annotated 25,680 protein-coding genes. DNA methylome and transcriptome analyses indicated that the strong adaptability of P. trifoliata is likely attributable to its special epigenetic modification and expression pattern of resistance-related genes. Heterografting by using sweet orange as scion and P. trifoliata as rootstock and autografting using sweet orange as both scion and rootstock were performed to investigate the genetic effects of the rootstock. Single-base methylome analysis indicated that P. trifoliata as a rootstock caused DNA demethylation and a reduction in 24-nt small RNAs (sRNAs) in scions compared to the level observed with autografting, implying the involvement of sRNA-mediated graft-transmissible epigenetic modifications in citrus grafting. Taken together, the assembled genome for the citrus rootstock and the analysis of graft-induced epigenetic modifications provide global insights into the genetic effects of rootstock–scion interactions and grafting biology.

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