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Genome-wide gene expression analysis supports a developmental model of low temperature tolerance gene regulation in wheat (Triticum aestivum L.).

Laudencia-Chingcuanco D, Ganeshan S, You F, Fowler B, Chibbar R, Anderson O - BMC Genomics (2011)

Bottom Line: We compared the expression of genes in winter-habit (winter Norstar and winter Manitou) and spring-habit (spring Manitou and spring Norstar)) cultivars, wherein the locus for the vernalization gene Vrn-A1 was swapped between the parental winter Norstar and spring Manitou in the derived near-isogenic lines winter Manitou and spring Norstar.Functional assignments using GO annotations showed that genes involved in transport, oxidation-reduction, and stress response were highly represented.The results support the developmental model of LT tolerance gene regulation and demonstrate the complex genotype by environment interactions that determine LT adaptation in winter annual cereals.

View Article: PubMed Central - HTML - PubMed

Affiliation: Genomics and Gene Discovery Unit, USDA-ARS WRRC, Albany, CA 94710, USA. debbie.laudencia@ars.usda.gov

ABSTRACT

Background: To identify the genes involved in the development of low temperature (LT) tolerance in hexaploid wheat, we examined the global changes in expression in response to cold of the 55,052 potentially unique genes represented in the Affymetrix Wheat Genome microarray. We compared the expression of genes in winter-habit (winter Norstar and winter Manitou) and spring-habit (spring Manitou and spring Norstar)) cultivars, wherein the locus for the vernalization gene Vrn-A1 was swapped between the parental winter Norstar and spring Manitou in the derived near-isogenic lines winter Manitou and spring Norstar. Global expression of genes in the crowns of 3-leaf stage plants cold-acclimated at 6°C for 0, 2, 14, 21, 38, 42, 56 and 70 days was examined.

Results: Analysis of variance of gene expression separated the samples by genetic background and by the developmental stage before or after vernalization saturation was reached. Using gene-specific ANOVA we identified 12,901 genes (at p < 0.001) that change in expression with respect to both genotype and the duration of cold-treatment. We examined in more detail a subset of these genes (2,771) where expression was highly influenced by the interaction between these two main factors. Functional assignments using GO annotations showed that genes involved in transport, oxidation-reduction, and stress response were highly represented. Clustering based on the pattern of transcript accumulation identified genes that were up or down-regulated by cold-treatment. Our data indicate that the cold-sensitive lines can up-regulate known cold-responsive genes comparable to that of cold-hardy lines. The levels of expression of these genes were highly influenced by the initial rate and the duration of the gene's response to cold. We show that the Vrn-A1 locus controls the duration of gene expression but not its initial rate of response to cold treatment. Furthermore, we provide evidence that Ta.Vrn-A1 and Ta.Vrt1 originally hypothesized to encode for the same gene showed different patterns of expression and therefore are distinct.

Conclusion: This study provides novel insight into the underlying mechanisms that regulate the expression of cold-responsive genes in wheat. The results support the developmental model of LT tolerance gene regulation and demonstrate the complex genotype by environment interactions that determine LT adaptation in winter annual cereals.

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Phenotypic response to cold-treatment. A) Final leaf number (FLN) and B) Low-temperature tolerance (LT50) of winter Norstar and spring Manitou and the near isogenic lines spring Norstar and winter Manitou acclimated at 6°C for 0 to 98 days (SE of data points = 0.62).
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Figure 1: Phenotypic response to cold-treatment. A) Final leaf number (FLN) and B) Low-temperature tolerance (LT50) of winter Norstar and spring Manitou and the near isogenic lines spring Norstar and winter Manitou acclimated at 6°C for 0 to 98 days (SE of data points = 0.62).

Mentions: We investigated the phenotypic response to cold of the four genetic stocks we used in this experiment by measuring their final leaf number (FLN) and their tolerance to cold temperature (LT50). The parental cultivars, winter Norstar and spring Manitou, and the NILs, spring Norstar and winter Manitou, were evaluated over 16 cold treatment periods at 6°C under a 16-hour (long) day. Analyses of variance showed that genotype, the duration of cold treatment and their interactions were highly significant (P < 0.001) for LT50 and FLN indicating that there were measurable differences in the response to cold treatment (Figure 1 and Table 1).


Genome-wide gene expression analysis supports a developmental model of low temperature tolerance gene regulation in wheat (Triticum aestivum L.).

Laudencia-Chingcuanco D, Ganeshan S, You F, Fowler B, Chibbar R, Anderson O - BMC Genomics (2011)

Phenotypic response to cold-treatment. A) Final leaf number (FLN) and B) Low-temperature tolerance (LT50) of winter Norstar and spring Manitou and the near isogenic lines spring Norstar and winter Manitou acclimated at 6°C for 0 to 98 days (SE of data points = 0.62).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3141665&req=5

Figure 1: Phenotypic response to cold-treatment. A) Final leaf number (FLN) and B) Low-temperature tolerance (LT50) of winter Norstar and spring Manitou and the near isogenic lines spring Norstar and winter Manitou acclimated at 6°C for 0 to 98 days (SE of data points = 0.62).
Mentions: We investigated the phenotypic response to cold of the four genetic stocks we used in this experiment by measuring their final leaf number (FLN) and their tolerance to cold temperature (LT50). The parental cultivars, winter Norstar and spring Manitou, and the NILs, spring Norstar and winter Manitou, were evaluated over 16 cold treatment periods at 6°C under a 16-hour (long) day. Analyses of variance showed that genotype, the duration of cold treatment and their interactions were highly significant (P < 0.001) for LT50 and FLN indicating that there were measurable differences in the response to cold treatment (Figure 1 and Table 1).

Bottom Line: We compared the expression of genes in winter-habit (winter Norstar and winter Manitou) and spring-habit (spring Manitou and spring Norstar)) cultivars, wherein the locus for the vernalization gene Vrn-A1 was swapped between the parental winter Norstar and spring Manitou in the derived near-isogenic lines winter Manitou and spring Norstar.Functional assignments using GO annotations showed that genes involved in transport, oxidation-reduction, and stress response were highly represented.The results support the developmental model of LT tolerance gene regulation and demonstrate the complex genotype by environment interactions that determine LT adaptation in winter annual cereals.

View Article: PubMed Central - HTML - PubMed

Affiliation: Genomics and Gene Discovery Unit, USDA-ARS WRRC, Albany, CA 94710, USA. debbie.laudencia@ars.usda.gov

ABSTRACT

Background: To identify the genes involved in the development of low temperature (LT) tolerance in hexaploid wheat, we examined the global changes in expression in response to cold of the 55,052 potentially unique genes represented in the Affymetrix Wheat Genome microarray. We compared the expression of genes in winter-habit (winter Norstar and winter Manitou) and spring-habit (spring Manitou and spring Norstar)) cultivars, wherein the locus for the vernalization gene Vrn-A1 was swapped between the parental winter Norstar and spring Manitou in the derived near-isogenic lines winter Manitou and spring Norstar. Global expression of genes in the crowns of 3-leaf stage plants cold-acclimated at 6°C for 0, 2, 14, 21, 38, 42, 56 and 70 days was examined.

Results: Analysis of variance of gene expression separated the samples by genetic background and by the developmental stage before or after vernalization saturation was reached. Using gene-specific ANOVA we identified 12,901 genes (at p < 0.001) that change in expression with respect to both genotype and the duration of cold-treatment. We examined in more detail a subset of these genes (2,771) where expression was highly influenced by the interaction between these two main factors. Functional assignments using GO annotations showed that genes involved in transport, oxidation-reduction, and stress response were highly represented. Clustering based on the pattern of transcript accumulation identified genes that were up or down-regulated by cold-treatment. Our data indicate that the cold-sensitive lines can up-regulate known cold-responsive genes comparable to that of cold-hardy lines. The levels of expression of these genes were highly influenced by the initial rate and the duration of the gene's response to cold. We show that the Vrn-A1 locus controls the duration of gene expression but not its initial rate of response to cold treatment. Furthermore, we provide evidence that Ta.Vrn-A1 and Ta.Vrt1 originally hypothesized to encode for the same gene showed different patterns of expression and therefore are distinct.

Conclusion: This study provides novel insight into the underlying mechanisms that regulate the expression of cold-responsive genes in wheat. The results support the developmental model of LT tolerance gene regulation and demonstrate the complex genotype by environment interactions that determine LT adaptation in winter annual cereals.

Show MeSH