Limits...
Salicylic acid biosynthesis is enhanced and contributes to increased biotrophic pathogen resistance in Arabidopsis hybrids.

Yang L, Li B, Zheng XY, Li J, Yang M, Dong X, He G, An C, Deng XW - Nat Commun (2015)

Bottom Line: Heterosis, the phenotypic superiority of a hybrid over its parents, has been demonstrated for many traits in Arabidopsis thaliana, but its effect on defence remains largely unexplored.Here, we show that hybrids between some A. thaliana accessions show increased resistance to the biotrophic bacterial pathogen Pseudomonas syringae pv. tomato (Pst) DC3000.Comparisons of transcriptomes between these hybrids and their parents after inoculation reveal that several key salicylic acid (SA) biosynthesis genes are significantly upregulated in hybrids.

View Article: PubMed Central - PubMed

Affiliation: 1] Peking-Yale Joint Center for Plant Molecular Genetics and Agro-Biotechnology, State Key Laboratory of Protein and Plant Gene Research, The Peking-Tsinghua Center for Life Sciences, School of Advanced Agricultural Sciences and School of Life Sciences, Peking University, Beijing 100871, China [2] Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520, USA.

ABSTRACT
Heterosis, the phenotypic superiority of a hybrid over its parents, has been demonstrated for many traits in Arabidopsis thaliana, but its effect on defence remains largely unexplored. Here, we show that hybrids between some A. thaliana accessions show increased resistance to the biotrophic bacterial pathogen Pseudomonas syringae pv. tomato (Pst) DC3000. Comparisons of transcriptomes between these hybrids and their parents after inoculation reveal that several key salicylic acid (SA) biosynthesis genes are significantly upregulated in hybrids. Moreover, SA levels are higher in hybrids than in either parent. Increased resistance to Pst DC3000 is significantly compromised in hybrids of pad4 mutants in which the SA biosynthesis pathway is blocked. Finally, increased histone H3 acetylation of key SA biosynthesis genes correlates with their upregulation in infected hybrids. Our data demonstrate that enhanced activation of SA biosynthesis in A. thaliana hybrids may contribute to their increased resistance to a biotrophic bacterial pathogen.

No MeSH data available.


Related in: MedlinePlus

Bacterial defence phenotypes of Arabidopsis thaliana F1 hybrids and their parents.(a) Phenotypes of F1 hybrids and their parents 5 dpi with MgCl2 (10 mM). Fsc and Fcs, reciprocal F1 hybrids, where maternal line is Sei-0 and Col-0, respectively; Fac and Fca, reciprocal F1 hybrids, where maternal line is Aa-0 and Col-0, respectively. (b) Phenotypes of F1 hybrids and their parents 5 dpi with Pseudomonas syringae pv. tomato (Pst) DC3000 (1 × 105 c.f.u. ml−1). (c) Bacterial titer (log10) of F1 hybrids and their parents 0 dpi and 5 dpi with Pst DC3000 (1 × 105 c.f.u. ml−1). **P<0.01 between hybrids and parents (Student's t-test). Bacterial growth is expressed as mean values of viable bacteria per gram of leaf tissue±s.d.. Error bars indicate s.d.. Data are shown as mean±s.d. (n=8, n means biological replication).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4490401&req=5

f1: Bacterial defence phenotypes of Arabidopsis thaliana F1 hybrids and their parents.(a) Phenotypes of F1 hybrids and their parents 5 dpi with MgCl2 (10 mM). Fsc and Fcs, reciprocal F1 hybrids, where maternal line is Sei-0 and Col-0, respectively; Fac and Fca, reciprocal F1 hybrids, where maternal line is Aa-0 and Col-0, respectively. (b) Phenotypes of F1 hybrids and their parents 5 dpi with Pseudomonas syringae pv. tomato (Pst) DC3000 (1 × 105 c.f.u. ml−1). (c) Bacterial titer (log10) of F1 hybrids and their parents 0 dpi and 5 dpi with Pst DC3000 (1 × 105 c.f.u. ml−1). **P<0.01 between hybrids and parents (Student's t-test). Bacterial growth is expressed as mean values of viable bacteria per gram of leaf tissue±s.d.. Error bars indicate s.d.. Data are shown as mean±s.d. (n=8, n means biological replication).

Mentions: To investigate whether increased resistance to biotrophic bacterial pathogens exists in certain A. thaliana hybrids, we crossed 20 accessions (Supplementary Table 1) reciprocally with Arabidopsis ecotype Columbia-0 (Col-0) and evaluated the resulting hybrids and their parents for resistance to the pathogenic bacterium Pst DC3000. We investigated leaf phenotypes 1–5 days after pathogen infiltration, and found that the differences between parents and hybrids were most significant at 5 days post infiltration (dpi). Figure 1 shows the leaves of hybrids and their parents from two representative crosses at 5 days after infiltration with Pst DC3000 at 1 × 105 colony-forming units (c.f.u.) per ml. We found obvious chlorotic symptoms on the leaves of the three parental accessions (Col-0, Sei-0 and Aa-0) and on the two F1 hybrids Aa-0 × Col-0 (represented by Fac) and Col-0 × Aa-0 (represented by Fca) in which Aa-0 or Col-0 was the maternal line, respectively (Fig. 1b). In contrast, chlorotic symptoms were rarely observed on the leaves of the two F1 hybrids from the cross between Sei-0 and Col-0 (Sei-0 × Col-0 and Col-0 × Sei-0, represented by Fsc and Fcs, respectively; Fig. 1b).


Salicylic acid biosynthesis is enhanced and contributes to increased biotrophic pathogen resistance in Arabidopsis hybrids.

Yang L, Li B, Zheng XY, Li J, Yang M, Dong X, He G, An C, Deng XW - Nat Commun (2015)

Bacterial defence phenotypes of Arabidopsis thaliana F1 hybrids and their parents.(a) Phenotypes of F1 hybrids and their parents 5 dpi with MgCl2 (10 mM). Fsc and Fcs, reciprocal F1 hybrids, where maternal line is Sei-0 and Col-0, respectively; Fac and Fca, reciprocal F1 hybrids, where maternal line is Aa-0 and Col-0, respectively. (b) Phenotypes of F1 hybrids and their parents 5 dpi with Pseudomonas syringae pv. tomato (Pst) DC3000 (1 × 105 c.f.u. ml−1). (c) Bacterial titer (log10) of F1 hybrids and their parents 0 dpi and 5 dpi with Pst DC3000 (1 × 105 c.f.u. ml−1). **P<0.01 between hybrids and parents (Student's t-test). Bacterial growth is expressed as mean values of viable bacteria per gram of leaf tissue±s.d.. Error bars indicate s.d.. Data are shown as mean±s.d. (n=8, n means biological replication).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4490401&req=5

f1: Bacterial defence phenotypes of Arabidopsis thaliana F1 hybrids and their parents.(a) Phenotypes of F1 hybrids and their parents 5 dpi with MgCl2 (10 mM). Fsc and Fcs, reciprocal F1 hybrids, where maternal line is Sei-0 and Col-0, respectively; Fac and Fca, reciprocal F1 hybrids, where maternal line is Aa-0 and Col-0, respectively. (b) Phenotypes of F1 hybrids and their parents 5 dpi with Pseudomonas syringae pv. tomato (Pst) DC3000 (1 × 105 c.f.u. ml−1). (c) Bacterial titer (log10) of F1 hybrids and their parents 0 dpi and 5 dpi with Pst DC3000 (1 × 105 c.f.u. ml−1). **P<0.01 between hybrids and parents (Student's t-test). Bacterial growth is expressed as mean values of viable bacteria per gram of leaf tissue±s.d.. Error bars indicate s.d.. Data are shown as mean±s.d. (n=8, n means biological replication).
Mentions: To investigate whether increased resistance to biotrophic bacterial pathogens exists in certain A. thaliana hybrids, we crossed 20 accessions (Supplementary Table 1) reciprocally with Arabidopsis ecotype Columbia-0 (Col-0) and evaluated the resulting hybrids and their parents for resistance to the pathogenic bacterium Pst DC3000. We investigated leaf phenotypes 1–5 days after pathogen infiltration, and found that the differences between parents and hybrids were most significant at 5 days post infiltration (dpi). Figure 1 shows the leaves of hybrids and their parents from two representative crosses at 5 days after infiltration with Pst DC3000 at 1 × 105 colony-forming units (c.f.u.) per ml. We found obvious chlorotic symptoms on the leaves of the three parental accessions (Col-0, Sei-0 and Aa-0) and on the two F1 hybrids Aa-0 × Col-0 (represented by Fac) and Col-0 × Aa-0 (represented by Fca) in which Aa-0 or Col-0 was the maternal line, respectively (Fig. 1b). In contrast, chlorotic symptoms were rarely observed on the leaves of the two F1 hybrids from the cross between Sei-0 and Col-0 (Sei-0 × Col-0 and Col-0 × Sei-0, represented by Fsc and Fcs, respectively; Fig. 1b).

Bottom Line: Heterosis, the phenotypic superiority of a hybrid over its parents, has been demonstrated for many traits in Arabidopsis thaliana, but its effect on defence remains largely unexplored.Here, we show that hybrids between some A. thaliana accessions show increased resistance to the biotrophic bacterial pathogen Pseudomonas syringae pv. tomato (Pst) DC3000.Comparisons of transcriptomes between these hybrids and their parents after inoculation reveal that several key salicylic acid (SA) biosynthesis genes are significantly upregulated in hybrids.

View Article: PubMed Central - PubMed

Affiliation: 1] Peking-Yale Joint Center for Plant Molecular Genetics and Agro-Biotechnology, State Key Laboratory of Protein and Plant Gene Research, The Peking-Tsinghua Center for Life Sciences, School of Advanced Agricultural Sciences and School of Life Sciences, Peking University, Beijing 100871, China [2] Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, Connecticut 06520, USA.

ABSTRACT
Heterosis, the phenotypic superiority of a hybrid over its parents, has been demonstrated for many traits in Arabidopsis thaliana, but its effect on defence remains largely unexplored. Here, we show that hybrids between some A. thaliana accessions show increased resistance to the biotrophic bacterial pathogen Pseudomonas syringae pv. tomato (Pst) DC3000. Comparisons of transcriptomes between these hybrids and their parents after inoculation reveal that several key salicylic acid (SA) biosynthesis genes are significantly upregulated in hybrids. Moreover, SA levels are higher in hybrids than in either parent. Increased resistance to Pst DC3000 is significantly compromised in hybrids of pad4 mutants in which the SA biosynthesis pathway is blocked. Finally, increased histone H3 acetylation of key SA biosynthesis genes correlates with their upregulation in infected hybrids. Our data demonstrate that enhanced activation of SA biosynthesis in A. thaliana hybrids may contribute to their increased resistance to a biotrophic bacterial pathogen.

No MeSH data available.


Related in: MedlinePlus