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The Scion/Rootstock Genotypes and Habitats Affect Arbuscular Mycorrhizal Fungal Community in Citrus.

Song F, Pan Z, Bai F, An J, Liu J, Guo W, Bisseling T, Deng X, Xiao S - Front Microbiol (2015)

Bottom Line: However, the AMF community structure of citrus is largely unknown.Over 7,40,000 effective sequences were obtained from 77 citrus root samples.These sequences were assigned to 75 AMF virtual taxa, of which 66 belong to Glomus, highlighting an absolute dominance of this AMF genus in symbiosis with citrus roots.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Horticultural Plant Biology (Ministry of Education), Key Laboratory of Horticultural Crop Biology and Genetic Improvement (Central Region, Ministry of Agriculture), College of Horticulture and Forestry Sciences, Huazhong Agricultural University Wuhan, China.

ABSTRACT
Citrus roots have rare root hairs and thus heavily depend on arbuscular mycorrhizal fungi (AMF) for mineral nutrient uptake. However, the AMF community structure of citrus is largely unknown. By using 454-pyrosequencing of 18S rRNA gene fragment, we investigated the genetic diversity of AMF colonizing citrus roots, and evaluated the impact of habitats and rootstock and scion genotypes on the AMF community structure. Over 7,40,000 effective sequences were obtained from 77 citrus root samples. These sequences were assigned to 75 AMF virtual taxa, of which 66 belong to Glomus, highlighting an absolute dominance of this AMF genus in symbiosis with citrus roots. The citrus AMF community structure is significantly affected by habitats and host genotypes. Interestingly, our data suggests that the genotype of the scion exerts a greater impact on the AMF community structure than that of the rootstock where the physical root-AMF association occurs. This study not only provides a comprehensive assessment for the community composition of the AMF in citrus roots under different conditions, but also sheds novel insights into how the AMF community might be indirectly influenced by the spatially separated yet metabolically connected partner-the scion-of the grafted citrus tree.

No MeSH data available.


Related in: MedlinePlus

PCA of variations in citrus AMF community from citrus trees of different genotypes. (A) AMF community of four citrus seedlings, i.e., WC (Cirange), WP (Poncirus), WIS (Lime × Orange), and WPR (Poncirus × Red Tangerine), and three scion/rootstock combinations, i.e., WPH (Orange/Poncirus), WPM (Mandarin/Poncirus), WPB (Pummelo/Poncirus) were separated into three groups based on different scion/rootstock genotypes. (B) AMF community of two scion/rootstock combinations (XPN, Newhall/Poncirus; XPM, Mandarin/Poncirus) were separated into two groups based on the different scion genotypes. (C) AMF community of two scion/rootstock combinations (HPN/HPNS: Newhall/Poncirus; HQN: Newhall/Zhique) were separated into two groups based on the rootstock genotypes. (D) AMF community of three scion/rootstock combinations (CJM, Mandarin/Yuzu; CPM, Mandarin/Poncirus; CRM, Mandarin/Red tangerine) were separated into three groups based on different rootstock genotypes. (E) AMF community of three scion/rootstock combinations (YCP, Ponkan/Cirange; YPM, Madarin/Poncirus; YPP, Ponkan/Poncirus) were separated into two groups based on different scion genotypes. (F) AMF communities of the two approach-grafted rootstocks from a single tree (FPN, Newhall sweet orange/Poncirus; FRN, Newhall sweet orange/Red tangerine) could not be grouped based on the different rootstock genotypes.
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Figure 4: PCA of variations in citrus AMF community from citrus trees of different genotypes. (A) AMF community of four citrus seedlings, i.e., WC (Cirange), WP (Poncirus), WIS (Lime × Orange), and WPR (Poncirus × Red Tangerine), and three scion/rootstock combinations, i.e., WPH (Orange/Poncirus), WPM (Mandarin/Poncirus), WPB (Pummelo/Poncirus) were separated into three groups based on different scion/rootstock genotypes. (B) AMF community of two scion/rootstock combinations (XPN, Newhall/Poncirus; XPM, Mandarin/Poncirus) were separated into two groups based on the different scion genotypes. (C) AMF community of two scion/rootstock combinations (HPN/HPNS: Newhall/Poncirus; HQN: Newhall/Zhique) were separated into two groups based on the rootstock genotypes. (D) AMF community of three scion/rootstock combinations (CJM, Mandarin/Yuzu; CPM, Mandarin/Poncirus; CRM, Mandarin/Red tangerine) were separated into three groups based on different rootstock genotypes. (E) AMF community of three scion/rootstock combinations (YCP, Ponkan/Cirange; YPM, Madarin/Poncirus; YPP, Ponkan/Poncirus) were separated into two groups based on different scion genotypes. (F) AMF communities of the two approach-grafted rootstocks from a single tree (FPN, Newhall sweet orange/Poncirus; FRN, Newhall sweet orange/Red tangerine) could not be grouped based on the different rootstock genotypes.

Mentions: To assess whether genotypes of citrus rootstocks and/or scions influence the AMF community composition, we selected the seven samples (corresponding to 21 replicated plots) from Wuhan for a single PCA analysis based on genotypes of seedlings or scion/rootstock genotype combinations. Specifically, three of these seven samples were collected from citrus trees with distinct scions grafted onto the same type of rootstock, i.e., (i) Washington navel orange (Citrus sinensis) grafted onto Poncirus (Poncirus trifoliate) designated Orange/Poncirus, (ii) Mandarin (Citrus reticulate) grafted onto Poncirus, designated Mandarin/Poncirus, and (iii) HB pummelo (Citrus grandis) grafted onto Poncirus) designated Pummelo/Poncirus. The remaining four samples were collected from seed-derived plants (i.e., seedlings) of four different genotypes, i.e., (i) Poncirus, (ii) Citrange (Citrus sinensis × Poncirus trifoliate), (iii) an allotetraploid originated from cell fusion of India lime and Sunki orange designated Lime × Orange, and (iv) a hybrid originated from hybridization between Poncirus and Red tangerine, designated Poncirus × Tangerine. Interestingly, as shown in Figure 4A, these seven samples were clustered into three groups. Group 1 on the upper right side of the PCA plot includes samples from Poncirus seedlings (green) or Mandarin/Poncirus (yellow); Group 2 on the lower right side includes samples from Pummelo/Poncirus (violet), and Orange/Poncirus (orange); Group 3 on the upper left side includes samples from seedlings of Citrange (red), the Poncirus × Tangerine hybrid (brown) or the Lime × Orange allotetraploid (blue), all of which are genetically distinct from Poncirus. These results suggest that while the genotypes of the sampled roots clearly influence their AMF community structures, the genotypes of the scions may also impose a significant impact on the AMF community structures of the rootstock as evidenced by distinct clustering between Mandarin/Poncirus (yellow) and Pummelo/Poncirus (violet) or Orange/Poncirus (orange) (Figure 4A). To further evaluate the above inference, we performed PCA analyses for the two samples derived from Poncirus rootstocks grafted with two different scions (i.e., Newhall sweet orange/Poncirus and Mandarin/Poncirus) in the same orchard at Xunwu (Figure 4B), the three samples collected from Hanzhong [i.e., two from the same Newhall sweet orange/Poncirus combination in two neighboring orchards, one from Newhall sweet orange/Zhique (Citrus ichangensi × Poncirus trifoliate)] (Figure 4C), and the three samples from the same orchard at Chengdu [i.e., Mandarin/Yuzu (Citrus junos)], Mandarin/Poncirus and Mandarin/Red tangerine (Citrus tangerinaHort) (Figure 4D). The replicate plots of these samples were generally clustered either according to the genotypes of the scions (Figure 4B) or the rootstocks (Figures 4C,D).


The Scion/Rootstock Genotypes and Habitats Affect Arbuscular Mycorrhizal Fungal Community in Citrus.

Song F, Pan Z, Bai F, An J, Liu J, Guo W, Bisseling T, Deng X, Xiao S - Front Microbiol (2015)

PCA of variations in citrus AMF community from citrus trees of different genotypes. (A) AMF community of four citrus seedlings, i.e., WC (Cirange), WP (Poncirus), WIS (Lime × Orange), and WPR (Poncirus × Red Tangerine), and three scion/rootstock combinations, i.e., WPH (Orange/Poncirus), WPM (Mandarin/Poncirus), WPB (Pummelo/Poncirus) were separated into three groups based on different scion/rootstock genotypes. (B) AMF community of two scion/rootstock combinations (XPN, Newhall/Poncirus; XPM, Mandarin/Poncirus) were separated into two groups based on the different scion genotypes. (C) AMF community of two scion/rootstock combinations (HPN/HPNS: Newhall/Poncirus; HQN: Newhall/Zhique) were separated into two groups based on the rootstock genotypes. (D) AMF community of three scion/rootstock combinations (CJM, Mandarin/Yuzu; CPM, Mandarin/Poncirus; CRM, Mandarin/Red tangerine) were separated into three groups based on different rootstock genotypes. (E) AMF community of three scion/rootstock combinations (YCP, Ponkan/Cirange; YPM, Madarin/Poncirus; YPP, Ponkan/Poncirus) were separated into two groups based on different scion genotypes. (F) AMF communities of the two approach-grafted rootstocks from a single tree (FPN, Newhall sweet orange/Poncirus; FRN, Newhall sweet orange/Red tangerine) could not be grouped based on the different rootstock genotypes.
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Related In: Results  -  Collection

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Figure 4: PCA of variations in citrus AMF community from citrus trees of different genotypes. (A) AMF community of four citrus seedlings, i.e., WC (Cirange), WP (Poncirus), WIS (Lime × Orange), and WPR (Poncirus × Red Tangerine), and three scion/rootstock combinations, i.e., WPH (Orange/Poncirus), WPM (Mandarin/Poncirus), WPB (Pummelo/Poncirus) were separated into three groups based on different scion/rootstock genotypes. (B) AMF community of two scion/rootstock combinations (XPN, Newhall/Poncirus; XPM, Mandarin/Poncirus) were separated into two groups based on the different scion genotypes. (C) AMF community of two scion/rootstock combinations (HPN/HPNS: Newhall/Poncirus; HQN: Newhall/Zhique) were separated into two groups based on the rootstock genotypes. (D) AMF community of three scion/rootstock combinations (CJM, Mandarin/Yuzu; CPM, Mandarin/Poncirus; CRM, Mandarin/Red tangerine) were separated into three groups based on different rootstock genotypes. (E) AMF community of three scion/rootstock combinations (YCP, Ponkan/Cirange; YPM, Madarin/Poncirus; YPP, Ponkan/Poncirus) were separated into two groups based on different scion genotypes. (F) AMF communities of the two approach-grafted rootstocks from a single tree (FPN, Newhall sweet orange/Poncirus; FRN, Newhall sweet orange/Red tangerine) could not be grouped based on the different rootstock genotypes.
Mentions: To assess whether genotypes of citrus rootstocks and/or scions influence the AMF community composition, we selected the seven samples (corresponding to 21 replicated plots) from Wuhan for a single PCA analysis based on genotypes of seedlings or scion/rootstock genotype combinations. Specifically, three of these seven samples were collected from citrus trees with distinct scions grafted onto the same type of rootstock, i.e., (i) Washington navel orange (Citrus sinensis) grafted onto Poncirus (Poncirus trifoliate) designated Orange/Poncirus, (ii) Mandarin (Citrus reticulate) grafted onto Poncirus, designated Mandarin/Poncirus, and (iii) HB pummelo (Citrus grandis) grafted onto Poncirus) designated Pummelo/Poncirus. The remaining four samples were collected from seed-derived plants (i.e., seedlings) of four different genotypes, i.e., (i) Poncirus, (ii) Citrange (Citrus sinensis × Poncirus trifoliate), (iii) an allotetraploid originated from cell fusion of India lime and Sunki orange designated Lime × Orange, and (iv) a hybrid originated from hybridization between Poncirus and Red tangerine, designated Poncirus × Tangerine. Interestingly, as shown in Figure 4A, these seven samples were clustered into three groups. Group 1 on the upper right side of the PCA plot includes samples from Poncirus seedlings (green) or Mandarin/Poncirus (yellow); Group 2 on the lower right side includes samples from Pummelo/Poncirus (violet), and Orange/Poncirus (orange); Group 3 on the upper left side includes samples from seedlings of Citrange (red), the Poncirus × Tangerine hybrid (brown) or the Lime × Orange allotetraploid (blue), all of which are genetically distinct from Poncirus. These results suggest that while the genotypes of the sampled roots clearly influence their AMF community structures, the genotypes of the scions may also impose a significant impact on the AMF community structures of the rootstock as evidenced by distinct clustering between Mandarin/Poncirus (yellow) and Pummelo/Poncirus (violet) or Orange/Poncirus (orange) (Figure 4A). To further evaluate the above inference, we performed PCA analyses for the two samples derived from Poncirus rootstocks grafted with two different scions (i.e., Newhall sweet orange/Poncirus and Mandarin/Poncirus) in the same orchard at Xunwu (Figure 4B), the three samples collected from Hanzhong [i.e., two from the same Newhall sweet orange/Poncirus combination in two neighboring orchards, one from Newhall sweet orange/Zhique (Citrus ichangensi × Poncirus trifoliate)] (Figure 4C), and the three samples from the same orchard at Chengdu [i.e., Mandarin/Yuzu (Citrus junos)], Mandarin/Poncirus and Mandarin/Red tangerine (Citrus tangerinaHort) (Figure 4D). The replicate plots of these samples were generally clustered either according to the genotypes of the scions (Figure 4B) or the rootstocks (Figures 4C,D).

Bottom Line: However, the AMF community structure of citrus is largely unknown.Over 7,40,000 effective sequences were obtained from 77 citrus root samples.These sequences were assigned to 75 AMF virtual taxa, of which 66 belong to Glomus, highlighting an absolute dominance of this AMF genus in symbiosis with citrus roots.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Horticultural Plant Biology (Ministry of Education), Key Laboratory of Horticultural Crop Biology and Genetic Improvement (Central Region, Ministry of Agriculture), College of Horticulture and Forestry Sciences, Huazhong Agricultural University Wuhan, China.

ABSTRACT
Citrus roots have rare root hairs and thus heavily depend on arbuscular mycorrhizal fungi (AMF) for mineral nutrient uptake. However, the AMF community structure of citrus is largely unknown. By using 454-pyrosequencing of 18S rRNA gene fragment, we investigated the genetic diversity of AMF colonizing citrus roots, and evaluated the impact of habitats and rootstock and scion genotypes on the AMF community structure. Over 7,40,000 effective sequences were obtained from 77 citrus root samples. These sequences were assigned to 75 AMF virtual taxa, of which 66 belong to Glomus, highlighting an absolute dominance of this AMF genus in symbiosis with citrus roots. The citrus AMF community structure is significantly affected by habitats and host genotypes. Interestingly, our data suggests that the genotype of the scion exerts a greater impact on the AMF community structure than that of the rootstock where the physical root-AMF association occurs. This study not only provides a comprehensive assessment for the community composition of the AMF in citrus roots under different conditions, but also sheds novel insights into how the AMF community might be indirectly influenced by the spatially separated yet metabolically connected partner-the scion-of the grafted citrus tree.

No MeSH data available.


Related in: MedlinePlus