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Multiple interval QTL mapping and searching for PSTOL1 homologs associated with root morphology, biomass accumulation and phosphorus content in maize seedlings under low-P.

Azevedo GC, Cheavegatti-Gianotto A, Negri BF, Hufnagel B, E Silva Lda C, Magalhaes JV, Garcia AA, Lana UG, de Sousa SM, Guimaraes CT - BMC Plant Biol. (2015)

Bottom Line: Multiple interval mapping models for single (MIM) and multiple traits (MT-MIM) were combined and revealed 13 genomic regions significantly associated with the target traits in a complementary way.QTL mapping strategies adopted in this study revealed complementary results for single and multiple traits with high accuracy.Some QTLs, mainly the ones that were also associated with yield performance in other studies, can be good targets for marker-assisted selection to improve P-use efficiency in maize.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Biologia Geral, Universidade Federal de Minas Gerais, Avenida Presidente Antônio Carlos, 6627, Belo Horizonte, MG, 31270-901, Brazil. gabrielcorradiazevedo@yahoo.com.br.

ABSTRACT

Background: Modifications in root morphology are important strategies to maximize soil exploitation under phosphorus starvation in plants. Here, we used two multiple interval models to map QTLs related to root traits, biomass accumulation and P content in a maize RIL population cultivated in nutrient solution. In addition, we searched for putative maize homologs to PSTOL1, a gene responsible to enhance early root growth, P uptake and grain yield in rice and sorghum.

Results: Based on path analysis, root surface area was the root morphology component that most strongly contributed to total dry weight and to P content in maize seedling under low-P availability. Multiple interval mapping models for single (MIM) and multiple traits (MT-MIM) were combined and revealed 13 genomic regions significantly associated with the target traits in a complementary way. The phenotypic variances explained by all QTLs and their epistatic interactions using MT-MIM (23.4 to 35.5 %) were higher than in previous studies, and presented superior statistical power. Some of these QTLs were coincident with QTLs for root morphology traits and grain yield previously mapped, whereas others harbored ZmPSTOL candidate genes, which shared more than 55 % of amino acid sequence identity and a conserved serine/threonine kinase domain with OsPSTOL1. Additionally, four ZmPSTOL candidate genes co-localized with QTLs for root morphology, biomass accumulation and/or P content were preferentially expressed in roots of the parental lines that contributed the alleles enhancing the respective phenotypes.

Conclusions: QTL mapping strategies adopted in this study revealed complementary results for single and multiple traits with high accuracy. Some QTLs, mainly the ones that were also associated with yield performance in other studies, can be good targets for marker-assisted selection to improve P-use efficiency in maize. Based on the co-localization with QTLs, the protein domain conservation and the coincidence of gene expression, we selected novel maize genes as putative homologs to PSTOL1 that will require further validation studies.

No MeSH data available.


a Frequency distribution of traits evaluated in 145 maize RILs grown in low-P (2.5 μM). The P-efficient (L3) and the P-inefficient (L22) parental lines are indicated by arrows. b Root system of the parental lines (L3 and L22) and two extreme RILs (RIL 66 and 113) after 13 days cultivated in nutrient solution under low-P
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Fig1: a Frequency distribution of traits evaluated in 145 maize RILs grown in low-P (2.5 μM). The P-efficient (L3) and the P-inefficient (L22) parental lines are indicated by arrows. b Root system of the parental lines (L3 and L22) and two extreme RILs (RIL 66 and 113) after 13 days cultivated in nutrient solution under low-P

Mentions: Significant genetic variation in root morphology traits, biomass accumulation and phosphorus content in the seedlings were observed for the RIL population with high broad sense heritability estimates, which ranged from 0.65 for root:shoot dry weight ratio to 0.82 for root length (Additional file 1: Table S1). The P-efficient line, L3, tended to present superior phenotypic measurements for all traits compared with the P-inefficient line L22, with the exception of root diameter and root:shoot ratio (Fig. 1a). The range of the phenotypic variation in the RILs was larger than both parents, suggesting transgressive segregation for all phenotypic traits (Fig. 1a). The RILs showing extreme root systems in comparison with their parental lines were highlighted in the Fig. 1b. The parental lines belonged to distinct heterotic groups (L3, flint and L22, dent) [43], were genetically divergent based on SNP markers [44] and contrasted for grain yield in low-P soil [45] and for root morphology traits in nutrient solution [46].Fig. 1


Multiple interval QTL mapping and searching for PSTOL1 homologs associated with root morphology, biomass accumulation and phosphorus content in maize seedlings under low-P.

Azevedo GC, Cheavegatti-Gianotto A, Negri BF, Hufnagel B, E Silva Lda C, Magalhaes JV, Garcia AA, Lana UG, de Sousa SM, Guimaraes CT - BMC Plant Biol. (2015)

a Frequency distribution of traits evaluated in 145 maize RILs grown in low-P (2.5 μM). The P-efficient (L3) and the P-inefficient (L22) parental lines are indicated by arrows. b Root system of the parental lines (L3 and L22) and two extreme RILs (RIL 66 and 113) after 13 days cultivated in nutrient solution under low-P
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4492167&req=5

Fig1: a Frequency distribution of traits evaluated in 145 maize RILs grown in low-P (2.5 μM). The P-efficient (L3) and the P-inefficient (L22) parental lines are indicated by arrows. b Root system of the parental lines (L3 and L22) and two extreme RILs (RIL 66 and 113) after 13 days cultivated in nutrient solution under low-P
Mentions: Significant genetic variation in root morphology traits, biomass accumulation and phosphorus content in the seedlings were observed for the RIL population with high broad sense heritability estimates, which ranged from 0.65 for root:shoot dry weight ratio to 0.82 for root length (Additional file 1: Table S1). The P-efficient line, L3, tended to present superior phenotypic measurements for all traits compared with the P-inefficient line L22, with the exception of root diameter and root:shoot ratio (Fig. 1a). The range of the phenotypic variation in the RILs was larger than both parents, suggesting transgressive segregation for all phenotypic traits (Fig. 1a). The RILs showing extreme root systems in comparison with their parental lines were highlighted in the Fig. 1b. The parental lines belonged to distinct heterotic groups (L3, flint and L22, dent) [43], were genetically divergent based on SNP markers [44] and contrasted for grain yield in low-P soil [45] and for root morphology traits in nutrient solution [46].Fig. 1

Bottom Line: Multiple interval mapping models for single (MIM) and multiple traits (MT-MIM) were combined and revealed 13 genomic regions significantly associated with the target traits in a complementary way.QTL mapping strategies adopted in this study revealed complementary results for single and multiple traits with high accuracy.Some QTLs, mainly the ones that were also associated with yield performance in other studies, can be good targets for marker-assisted selection to improve P-use efficiency in maize.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Biologia Geral, Universidade Federal de Minas Gerais, Avenida Presidente Antônio Carlos, 6627, Belo Horizonte, MG, 31270-901, Brazil. gabrielcorradiazevedo@yahoo.com.br.

ABSTRACT

Background: Modifications in root morphology are important strategies to maximize soil exploitation under phosphorus starvation in plants. Here, we used two multiple interval models to map QTLs related to root traits, biomass accumulation and P content in a maize RIL population cultivated in nutrient solution. In addition, we searched for putative maize homologs to PSTOL1, a gene responsible to enhance early root growth, P uptake and grain yield in rice and sorghum.

Results: Based on path analysis, root surface area was the root morphology component that most strongly contributed to total dry weight and to P content in maize seedling under low-P availability. Multiple interval mapping models for single (MIM) and multiple traits (MT-MIM) were combined and revealed 13 genomic regions significantly associated with the target traits in a complementary way. The phenotypic variances explained by all QTLs and their epistatic interactions using MT-MIM (23.4 to 35.5 %) were higher than in previous studies, and presented superior statistical power. Some of these QTLs were coincident with QTLs for root morphology traits and grain yield previously mapped, whereas others harbored ZmPSTOL candidate genes, which shared more than 55 % of amino acid sequence identity and a conserved serine/threonine kinase domain with OsPSTOL1. Additionally, four ZmPSTOL candidate genes co-localized with QTLs for root morphology, biomass accumulation and/or P content were preferentially expressed in roots of the parental lines that contributed the alleles enhancing the respective phenotypes.

Conclusions: QTL mapping strategies adopted in this study revealed complementary results for single and multiple traits with high accuracy. Some QTLs, mainly the ones that were also associated with yield performance in other studies, can be good targets for marker-assisted selection to improve P-use efficiency in maize. Based on the co-localization with QTLs, the protein domain conservation and the coincidence of gene expression, we selected novel maize genes as putative homologs to PSTOL1 that will require further validation studies.

No MeSH data available.