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Overexpression of a peach CBF gene in apple: a model for understanding the integration of growth, dormancy, and cold hardiness in woody plants.

Wisniewski M, Norelli J, Artlip T - Front Plant Sci (2015)

Bottom Line: In particular, several putative MdDAM genes, associated with the dormancy-cycle in other species of woody plants in the Rosaceae, exhibited different patterns of expression in the T166 vs.Additionally, for the first time a putative APETALA2/Ethylene-responsive transcription factor, originally described in poplar and shown to regulate the timing of bud break, was shown to be associated with the timing of bud break in apple.Since the overexpression of PpCBF1 in apple results in a dramatic alteration in cold acclimation, dormancy, and growth, this transgenic line (T166) may represent a useful model for studying the integration of these seasonal life-cycle parameters.

View Article: PubMed Central - PubMed

Affiliation: United States Department of Agriculture - Agricultural Research Service Kearneysville, WV, USA.

ABSTRACT
The timing of cold acclimation and deacclimation, dormancy, and budbreak play an integral role in the life cycle of woody plants. The molecular events that regulate these parameters have been the subject of much study, however, in most studies these events have been investigated independently of each other. Ectopic expression of a peach CBF (PpCBF1) in apple increases the level of both non-acclimated and acclimated freezing tolerance relative to the non-transformed control, and also inhibits growth, induces early bud set and leaf senescence, and delays bud break in the spring. The current study examined differences in the seasonal expression of genes (CBF, DAM, RGL, and EBB) that have been reported to be associated with freezing tolerance, dormancy, growth, and bud break, respectively, in the PpCBF1 T166 transgenic apple line and the non-transformed M.26 control. Results indicated that expression of several of these key genes, including MdDAM, MdRGL, and MdEBB was altered in transgenic T166 trees relative to non-transformed M.26 trees. In particular, several putative MdDAM genes, associated with the dormancy-cycle in other species of woody plants in the Rosaceae, exhibited different patterns of expression in the T166 vs. M.26 trees. Additionally, for the first time a putative APETALA2/Ethylene-responsive transcription factor, originally described in poplar and shown to regulate the timing of bud break, was shown to be associated with the timing of bud break in apple. Since the overexpression of PpCBF1 in apple results in a dramatic alteration in cold acclimation, dormancy, and growth, this transgenic line (T166) may represent a useful model for studying the integration of these seasonal life-cycle parameters.

No MeSH data available.


Related in: MedlinePlus

MdDAM transcript accumulation kinetics from bud tissue during winter and early spring vary between genes. (A)MdDAM1. (B)MdDAM3. MdDAM2 was not detected. Blue circles: non-transformed M.26; Red triangles: Line T166.
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Figure 7: MdDAM transcript accumulation kinetics from bud tissue during winter and early spring vary between genes. (A)MdDAM1. (B)MdDAM3. MdDAM2 was not detected. Blue circles: non-transformed M.26; Red triangles: Line T166.

Mentions: Bioinformatic analysis identified four putative DAM genes in the apple genome as listed in Genomic Database for the Rosaceae (GDR) (http://www.rosaceae.org) (Figure S2). Three (MDP0000527190, MDP0000322567, MDP0000259294,) bear high similarity to reported DAM genes in pear (Saito et al., 2013), and an additional predicted gene (MDP0000209705) was also considered due to its similarity to the other putative DAM genes. We have annotated three of these genes thusly: MDP0000322567 = MdDAM1 (KP164996), MDP0000259294 = MdDAM2 (KP164997), and MDP0000209705 = MdDAM3 (KP164998). Despite the use of several primers (Table S1) and protocol adjustments no measurable expression was observed for MDP0000527190 in either bark or bud tissues. As such, it was not assigned an MdDAM designation. Seasonal expression of the other three putative DAM genes in bark tissues collected from trees of M.26 and T166 are presented in Figure 6. Similar patterns of expression were observed for MdDAM1 in both genotypes (Figure 6A). Levels of expression rose in the fall, reached a maximum in November/December and then declined reaching a minimum in April. In contrast, levels of expression for MdDAM2 began to increase in mid-summer, reached a maximum in September/October and declined and remained low throughout the winter and spring months (Figure 6B). Notably, MdDAM2 expression was higher in January–March in the T166 trees, and a brief rapid increase in the expression level of MdDAM2 was observed during April/May (Figure 6B). The pattern of MdDAM3 was similar in both genotypes except for a single spike in expression in the T166 trees during April/May (Figure 6C). This was similar to the spike in expression observed for MdDAM2 (Figure 6B). In bud tissues, expression of MdDAM1 and MdDAM3 were the only DAM genes for which products could be obtained by RT-qPCR (Figure 7). In contrast to bark tissues, where expression levels of MdDAM1 were similar, the level of expression differed significantly in bud tissues (Figure 7A) collected from the transgenic (T166) and non-transformed (M.26) trees. Overall the expression level of MdDAM1 was higher during the winter months and then declined during the spring in both genotypes. In buds of T166 plants, however, several spikes in expression were observed in early spring. A similar trend was observed for the level of expression of MdDAM3 in bud tissues of both genotypes, however, in the case of buds from T166 trees only a single spike in expression was observed (Figure 7B).


Overexpression of a peach CBF gene in apple: a model for understanding the integration of growth, dormancy, and cold hardiness in woody plants.

Wisniewski M, Norelli J, Artlip T - Front Plant Sci (2015)

MdDAM transcript accumulation kinetics from bud tissue during winter and early spring vary between genes. (A)MdDAM1. (B)MdDAM3. MdDAM2 was not detected. Blue circles: non-transformed M.26; Red triangles: Line T166.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4343015&req=5

Figure 7: MdDAM transcript accumulation kinetics from bud tissue during winter and early spring vary between genes. (A)MdDAM1. (B)MdDAM3. MdDAM2 was not detected. Blue circles: non-transformed M.26; Red triangles: Line T166.
Mentions: Bioinformatic analysis identified four putative DAM genes in the apple genome as listed in Genomic Database for the Rosaceae (GDR) (http://www.rosaceae.org) (Figure S2). Three (MDP0000527190, MDP0000322567, MDP0000259294,) bear high similarity to reported DAM genes in pear (Saito et al., 2013), and an additional predicted gene (MDP0000209705) was also considered due to its similarity to the other putative DAM genes. We have annotated three of these genes thusly: MDP0000322567 = MdDAM1 (KP164996), MDP0000259294 = MdDAM2 (KP164997), and MDP0000209705 = MdDAM3 (KP164998). Despite the use of several primers (Table S1) and protocol adjustments no measurable expression was observed for MDP0000527190 in either bark or bud tissues. As such, it was not assigned an MdDAM designation. Seasonal expression of the other three putative DAM genes in bark tissues collected from trees of M.26 and T166 are presented in Figure 6. Similar patterns of expression were observed for MdDAM1 in both genotypes (Figure 6A). Levels of expression rose in the fall, reached a maximum in November/December and then declined reaching a minimum in April. In contrast, levels of expression for MdDAM2 began to increase in mid-summer, reached a maximum in September/October and declined and remained low throughout the winter and spring months (Figure 6B). Notably, MdDAM2 expression was higher in January–March in the T166 trees, and a brief rapid increase in the expression level of MdDAM2 was observed during April/May (Figure 6B). The pattern of MdDAM3 was similar in both genotypes except for a single spike in expression in the T166 trees during April/May (Figure 6C). This was similar to the spike in expression observed for MdDAM2 (Figure 6B). In bud tissues, expression of MdDAM1 and MdDAM3 were the only DAM genes for which products could be obtained by RT-qPCR (Figure 7). In contrast to bark tissues, where expression levels of MdDAM1 were similar, the level of expression differed significantly in bud tissues (Figure 7A) collected from the transgenic (T166) and non-transformed (M.26) trees. Overall the expression level of MdDAM1 was higher during the winter months and then declined during the spring in both genotypes. In buds of T166 plants, however, several spikes in expression were observed in early spring. A similar trend was observed for the level of expression of MdDAM3 in bud tissues of both genotypes, however, in the case of buds from T166 trees only a single spike in expression was observed (Figure 7B).

Bottom Line: In particular, several putative MdDAM genes, associated with the dormancy-cycle in other species of woody plants in the Rosaceae, exhibited different patterns of expression in the T166 vs.Additionally, for the first time a putative APETALA2/Ethylene-responsive transcription factor, originally described in poplar and shown to regulate the timing of bud break, was shown to be associated with the timing of bud break in apple.Since the overexpression of PpCBF1 in apple results in a dramatic alteration in cold acclimation, dormancy, and growth, this transgenic line (T166) may represent a useful model for studying the integration of these seasonal life-cycle parameters.

View Article: PubMed Central - PubMed

Affiliation: United States Department of Agriculture - Agricultural Research Service Kearneysville, WV, USA.

ABSTRACT
The timing of cold acclimation and deacclimation, dormancy, and budbreak play an integral role in the life cycle of woody plants. The molecular events that regulate these parameters have been the subject of much study, however, in most studies these events have been investigated independently of each other. Ectopic expression of a peach CBF (PpCBF1) in apple increases the level of both non-acclimated and acclimated freezing tolerance relative to the non-transformed control, and also inhibits growth, induces early bud set and leaf senescence, and delays bud break in the spring. The current study examined differences in the seasonal expression of genes (CBF, DAM, RGL, and EBB) that have been reported to be associated with freezing tolerance, dormancy, growth, and bud break, respectively, in the PpCBF1 T166 transgenic apple line and the non-transformed M.26 control. Results indicated that expression of several of these key genes, including MdDAM, MdRGL, and MdEBB was altered in transgenic T166 trees relative to non-transformed M.26 trees. In particular, several putative MdDAM genes, associated with the dormancy-cycle in other species of woody plants in the Rosaceae, exhibited different patterns of expression in the T166 vs. M.26 trees. Additionally, for the first time a putative APETALA2/Ethylene-responsive transcription factor, originally described in poplar and shown to regulate the timing of bud break, was shown to be associated with the timing of bud break in apple. Since the overexpression of PpCBF1 in apple results in a dramatic alteration in cold acclimation, dormancy, and growth, this transgenic line (T166) may represent a useful model for studying the integration of these seasonal life-cycle parameters.

No MeSH data available.


Related in: MedlinePlus