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Overexpression of UV-DAMAGED DNA BINDING PROTEIN 1 links plant development and phytonutrient accumulation in high pigment-1 tomato.

Azari R, Reuveni M, Evenor D, Nahon S, Shlomo H, Chen L, Levin I - J. Exp. Bot. (2010)

Bottom Line: However, whole-plant overexpression of DDB1, required to substantiate its effects on seedling and plant development and to couple them with fruit phenotypes, has heretofore been unsuccessful.This overexpression resulted in statistically significant reversion to the non-mutant developmental phenotypes, including more than a full quantitative reversion.Cumulatively, these results provide the missing link between DDB1 and its effects on tomato plant development.

View Article: PubMed Central - PubMed

Affiliation: Institute of Plant Sciences, Agricultural Research Organization, Volcani Center, PO Box 6, Bet Dagan 50250, Israel.

ABSTRACT
Fruits of tomato plants carrying the high pigment-1 mutations hp-1 and hp-1(w) are characterized by an increased number of plastids coupled with enhanced levels of functional metabolites. Unfortunately, hp-1 mutant plants are also typified by light-dependent retardation in seedling and whole-plant growth and development, which limits their cultivation. These mutations were mapped to the gene encoding UV-DAMAGED DNA BINDING PROTEIN 1 (DDB1) and, recently, fruit-specific RNA interference studies have demonstrated an increased number of plastids and enhanced carotenoid accumulation in the transgenic tomato fruits. However, whole-plant overexpression of DDB1, required to substantiate its effects on seedling and plant development and to couple them with fruit phenotypes, has heretofore been unsuccessful. In this study, five transgenic lines constitutively overexpressing normal DDB1 in hp-1 mutant plants were analysed. Eleven-day-old seedlings, representing these lines, displayed up to approximately 73- and approximately 221-fold overexpression of the gene in hypocotyls and cotyledons, respectively. This overexpression resulted in statistically significant reversion to the non-mutant developmental phenotypes, including more than a full quantitative reversion. This reversion of phenotypes was generally accompanied by correlated responses in chlorophyll accumulation and altered expression of selected light signalling genes: PHYTOCHROME A, CRYPTOCHROME 1, ELONGATED HYPOCOTYL 5, and the gene encoding CHLOROPHYLL A/B-BINDING PROTEIN 4. Cumulatively, these results provide the missing link between DDB1 and its effects on tomato plant development.

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Reversion of the hp-1 developmental phenotype in 11-d-old tomato seedlings following overexpression of normal DDB1 under the three light conditions [AC +/+, normal AC seedling; AC hp-1/hp-1, hp-1 mutant seedling in the AC background; AZ hp-1/hp-1, azygous hp-1 mutant seedling; DDB113–DDB117, T3 hp-1 mutant seedlings overexpressing normal DDB1 under the CaMV 35S promoter; seedling phenotypes under the yellow screen and white light are presented in a review article by Azari et al. (2010)].
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fig2: Reversion of the hp-1 developmental phenotype in 11-d-old tomato seedlings following overexpression of normal DDB1 under the three light conditions [AC +/+, normal AC seedling; AC hp-1/hp-1, hp-1 mutant seedling in the AC background; AZ hp-1/hp-1, azygous hp-1 mutant seedling; DDB113–DDB117, T3 hp-1 mutant seedlings overexpressing normal DDB1 under the CaMV 35S promoter; seedling phenotypes under the yellow screen and white light are presented in a review article by Azari et al. (2010)].

Mentions: A representative 11-d-old seedling of each of the transgenic and non-transgenic lines, germinated and grown under the three light conditions, is presented in Fig. 2. This figure demonstrates the reversion of phenotype obtained in the transgenic lines, which was visually more explicit under the two photomorphogenic conditions. Analysis of hypocotyl length showed that the seedlings of all five transgenic lines shared statistically significantly longer hypocotyls than the hp-1 control lines under white light and the yellow screen (Table 2). However, this apparent reversion of phenotype appeared to be incomplete because all transgenic lines were characterized by reduced average hypocotyl length compared with the normal control line (AC +/+). Under the yellow screen, these reductions were statistically significant, but under white light only two lines, DDB113 and DDB115, showed significantly reduced average hypocotyl length compared with the normal control line. In total darkness, the differences in average hypocotyl length among lines were markedly decreased. This reduced effect of the transgene could be attributed to the much lower up-regulation of DDB1 obtained in total darkness compared with the other two light conditions (Table 1), also indicating that the 35S promoter is directly or indirectly affected by light. Although in total darkness, all transgenic lines displayed longer average hypocotyl length compared with the hp-1 genotypes (Table 2), in two of the transgenic lines, DDB116 and DDB117, this effect was not statistically significant. On the other hand, the average hypocotyl length of two transgenic lines, DDB114 and DDB115, was not statistically different from that of the normal isogenic line (AC +/+). This indicated that a reversion of phenotype in hypocotyl development was also obtained in total darkness and that the reduced hypocotyl length of the hp-1 line under skotomorphogenic conditions could be attributed to the action of the mutant DDB1 gene.


Overexpression of UV-DAMAGED DNA BINDING PROTEIN 1 links plant development and phytonutrient accumulation in high pigment-1 tomato.

Azari R, Reuveni M, Evenor D, Nahon S, Shlomo H, Chen L, Levin I - J. Exp. Bot. (2010)

Reversion of the hp-1 developmental phenotype in 11-d-old tomato seedlings following overexpression of normal DDB1 under the three light conditions [AC +/+, normal AC seedling; AC hp-1/hp-1, hp-1 mutant seedling in the AC background; AZ hp-1/hp-1, azygous hp-1 mutant seedling; DDB113–DDB117, T3 hp-1 mutant seedlings overexpressing normal DDB1 under the CaMV 35S promoter; seedling phenotypes under the yellow screen and white light are presented in a review article by Azari et al. (2010)].
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2921201&req=5

fig2: Reversion of the hp-1 developmental phenotype in 11-d-old tomato seedlings following overexpression of normal DDB1 under the three light conditions [AC +/+, normal AC seedling; AC hp-1/hp-1, hp-1 mutant seedling in the AC background; AZ hp-1/hp-1, azygous hp-1 mutant seedling; DDB113–DDB117, T3 hp-1 mutant seedlings overexpressing normal DDB1 under the CaMV 35S promoter; seedling phenotypes under the yellow screen and white light are presented in a review article by Azari et al. (2010)].
Mentions: A representative 11-d-old seedling of each of the transgenic and non-transgenic lines, germinated and grown under the three light conditions, is presented in Fig. 2. This figure demonstrates the reversion of phenotype obtained in the transgenic lines, which was visually more explicit under the two photomorphogenic conditions. Analysis of hypocotyl length showed that the seedlings of all five transgenic lines shared statistically significantly longer hypocotyls than the hp-1 control lines under white light and the yellow screen (Table 2). However, this apparent reversion of phenotype appeared to be incomplete because all transgenic lines were characterized by reduced average hypocotyl length compared with the normal control line (AC +/+). Under the yellow screen, these reductions were statistically significant, but under white light only two lines, DDB113 and DDB115, showed significantly reduced average hypocotyl length compared with the normal control line. In total darkness, the differences in average hypocotyl length among lines were markedly decreased. This reduced effect of the transgene could be attributed to the much lower up-regulation of DDB1 obtained in total darkness compared with the other two light conditions (Table 1), also indicating that the 35S promoter is directly or indirectly affected by light. Although in total darkness, all transgenic lines displayed longer average hypocotyl length compared with the hp-1 genotypes (Table 2), in two of the transgenic lines, DDB116 and DDB117, this effect was not statistically significant. On the other hand, the average hypocotyl length of two transgenic lines, DDB114 and DDB115, was not statistically different from that of the normal isogenic line (AC +/+). This indicated that a reversion of phenotype in hypocotyl development was also obtained in total darkness and that the reduced hypocotyl length of the hp-1 line under skotomorphogenic conditions could be attributed to the action of the mutant DDB1 gene.

Bottom Line: However, whole-plant overexpression of DDB1, required to substantiate its effects on seedling and plant development and to couple them with fruit phenotypes, has heretofore been unsuccessful.This overexpression resulted in statistically significant reversion to the non-mutant developmental phenotypes, including more than a full quantitative reversion.Cumulatively, these results provide the missing link between DDB1 and its effects on tomato plant development.

View Article: PubMed Central - PubMed

Affiliation: Institute of Plant Sciences, Agricultural Research Organization, Volcani Center, PO Box 6, Bet Dagan 50250, Israel.

ABSTRACT
Fruits of tomato plants carrying the high pigment-1 mutations hp-1 and hp-1(w) are characterized by an increased number of plastids coupled with enhanced levels of functional metabolites. Unfortunately, hp-1 mutant plants are also typified by light-dependent retardation in seedling and whole-plant growth and development, which limits their cultivation. These mutations were mapped to the gene encoding UV-DAMAGED DNA BINDING PROTEIN 1 (DDB1) and, recently, fruit-specific RNA interference studies have demonstrated an increased number of plastids and enhanced carotenoid accumulation in the transgenic tomato fruits. However, whole-plant overexpression of DDB1, required to substantiate its effects on seedling and plant development and to couple them with fruit phenotypes, has heretofore been unsuccessful. In this study, five transgenic lines constitutively overexpressing normal DDB1 in hp-1 mutant plants were analysed. Eleven-day-old seedlings, representing these lines, displayed up to approximately 73- and approximately 221-fold overexpression of the gene in hypocotyls and cotyledons, respectively. This overexpression resulted in statistically significant reversion to the non-mutant developmental phenotypes, including more than a full quantitative reversion. This reversion of phenotypes was generally accompanied by correlated responses in chlorophyll accumulation and altered expression of selected light signalling genes: PHYTOCHROME A, CRYPTOCHROME 1, ELONGATED HYPOCOTYL 5, and the gene encoding CHLOROPHYLL A/B-BINDING PROTEIN 4. Cumulatively, these results provide the missing link between DDB1 and its effects on tomato plant development.

Show MeSH