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The UDP-glucose: glycoprotein glucosyltransferase (UGGT), a key enzyme in ER quality control, plays a significant role in plant growth as well as biotic and abiotic stress in Arabidopsis thaliana.

Blanco-Herrera F, Moreno AA, Tapia R, Reyes F, Araya M, D'Alessio C, Parodi A, Orellana A - BMC Plant Biol. (2015)

Bottom Line: Here, we show that two mutant alleles in the At1g71220 locus have none or reduced UGGT activity.These results show that a lack of UGGT activity alters plant vegetative development and impairs the response to several abiotic and biotic stresses.Moreover, our results uncover an unexpected role of UGGT in the incorporation of UDP-Glucose into the ER lumen in Arabidopsis thaliana.

View Article: PubMed Central - PubMed

Affiliation: Centro de Biotecnología Vegetal, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Avenida República 217, Santiago, 837-0146, RM, Chile. mblanco@unab.cl.

ABSTRACT

Background: UDP-glucose: glycoprotein glucosyltransferase (UGGT) is a key player in the quality control mechanism (ER-QC) that newly synthesized glycoproteins undergo in the ER. It has been shown that the UGGT Arabidopsis orthologue is involved in ER-QC; however, its role in plant physiology remains unclear.

Results: Here, we show that two mutant alleles in the At1g71220 locus have none or reduced UGGT activity. In wild type plants, the AtUGGT transcript levels increased upon activation of the unfolded protein response (UPR). Interestingly, mutants in AtUGGT exhibited an endogenous up-regulation of genes that are UPR targets. In addition, mutants in AtUGGT showed a 30% reduction in the incorporation of UDP-Glucose into the ER suggesting that this enzyme drives the uptake of this substrate for the CNX/CRT cycle. Plants deficient in UGGT exhibited a delayed growth rate of the primary root and rosette as well as an alteration in the number of leaves. These mutants are more sensitive to pathogen attack as well as heat, salt, and UPR-inducing stressors. Additionally, the plants showed impairment in the establishment of systemic acquired resistance (SAR).

Conclusions: These results show that a lack of UGGT activity alters plant vegetative development and impairs the response to several abiotic and biotic stresses. Moreover, our results uncover an unexpected role of UGGT in the incorporation of UDP-Glucose into the ER lumen in Arabidopsis thaliana.

No MeSH data available.


Related in: MedlinePlus

Mutant plants are over-sensitive to ER stress. Arabidopsis wild type and AtUGGT mutant plants were grown in MS media supplemented with 250 μM SA (a and c) or 0.1 μg/ml TUN (b) and (d) for 2 weeks. a and b. Photos of representative plants from different genotypes grown in SA or TUN, respectively. c and d. Eighty plants of each genotype were grown in SA or TUN, respectively, and were weighed in triplicates. The average values of three independent replicates (n = 240) are shown; error bars represent ± SD. Statistical significance was determined by ANOVA. Asterisks indicate a Tukey's test p-value < 0.01
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Fig9: Mutant plants are over-sensitive to ER stress. Arabidopsis wild type and AtUGGT mutant plants were grown in MS media supplemented with 250 μM SA (a and c) or 0.1 μg/ml TUN (b) and (d) for 2 weeks. a and b. Photos of representative plants from different genotypes grown in SA or TUN, respectively. c and d. Eighty plants of each genotype were grown in SA or TUN, respectively, and were weighed in triplicates. The average values of three independent replicates (n = 240) are shown; error bars represent ± SD. Statistical significance was determined by ANOVA. Asterisks indicate a Tukey's test p-value < 0.01

Mentions: To evaluate the sensitivity of the AtUGGT mutants to ER-stress, we grew the plants in the presence of tunicamycin and salicylic acid, which are two plant UPR-inducers [23]. Both allelic AtUGGT mutants were more sensitive to these compounds than the wild type (Fig. 9a and b). We also observed a significant decrease in fresh weight (Fig. 9c and d) when mutants were grown under these conditions. No differences were observed in the fresh weight of AtUGGT mutants compared to wild type plants in absence of ER stress (Additional file 7).Fig. 9


The UDP-glucose: glycoprotein glucosyltransferase (UGGT), a key enzyme in ER quality control, plays a significant role in plant growth as well as biotic and abiotic stress in Arabidopsis thaliana.

Blanco-Herrera F, Moreno AA, Tapia R, Reyes F, Araya M, D'Alessio C, Parodi A, Orellana A - BMC Plant Biol. (2015)

Mutant plants are over-sensitive to ER stress. Arabidopsis wild type and AtUGGT mutant plants were grown in MS media supplemented with 250 μM SA (a and c) or 0.1 μg/ml TUN (b) and (d) for 2 weeks. a and b. Photos of representative plants from different genotypes grown in SA or TUN, respectively. c and d. Eighty plants of each genotype were grown in SA or TUN, respectively, and were weighed in triplicates. The average values of three independent replicates (n = 240) are shown; error bars represent ± SD. Statistical significance was determined by ANOVA. Asterisks indicate a Tukey's test p-value < 0.01
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4465474&req=5

Fig9: Mutant plants are over-sensitive to ER stress. Arabidopsis wild type and AtUGGT mutant plants were grown in MS media supplemented with 250 μM SA (a and c) or 0.1 μg/ml TUN (b) and (d) for 2 weeks. a and b. Photos of representative plants from different genotypes grown in SA or TUN, respectively. c and d. Eighty plants of each genotype were grown in SA or TUN, respectively, and were weighed in triplicates. The average values of three independent replicates (n = 240) are shown; error bars represent ± SD. Statistical significance was determined by ANOVA. Asterisks indicate a Tukey's test p-value < 0.01
Mentions: To evaluate the sensitivity of the AtUGGT mutants to ER-stress, we grew the plants in the presence of tunicamycin and salicylic acid, which are two plant UPR-inducers [23]. Both allelic AtUGGT mutants were more sensitive to these compounds than the wild type (Fig. 9a and b). We also observed a significant decrease in fresh weight (Fig. 9c and d) when mutants were grown under these conditions. No differences were observed in the fresh weight of AtUGGT mutants compared to wild type plants in absence of ER stress (Additional file 7).Fig. 9

Bottom Line: Here, we show that two mutant alleles in the At1g71220 locus have none or reduced UGGT activity.These results show that a lack of UGGT activity alters plant vegetative development and impairs the response to several abiotic and biotic stresses.Moreover, our results uncover an unexpected role of UGGT in the incorporation of UDP-Glucose into the ER lumen in Arabidopsis thaliana.

View Article: PubMed Central - PubMed

Affiliation: Centro de Biotecnología Vegetal, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Avenida República 217, Santiago, 837-0146, RM, Chile. mblanco@unab.cl.

ABSTRACT

Background: UDP-glucose: glycoprotein glucosyltransferase (UGGT) is a key player in the quality control mechanism (ER-QC) that newly synthesized glycoproteins undergo in the ER. It has been shown that the UGGT Arabidopsis orthologue is involved in ER-QC; however, its role in plant physiology remains unclear.

Results: Here, we show that two mutant alleles in the At1g71220 locus have none or reduced UGGT activity. In wild type plants, the AtUGGT transcript levels increased upon activation of the unfolded protein response (UPR). Interestingly, mutants in AtUGGT exhibited an endogenous up-regulation of genes that are UPR targets. In addition, mutants in AtUGGT showed a 30% reduction in the incorporation of UDP-Glucose into the ER suggesting that this enzyme drives the uptake of this substrate for the CNX/CRT cycle. Plants deficient in UGGT exhibited a delayed growth rate of the primary root and rosette as well as an alteration in the number of leaves. These mutants are more sensitive to pathogen attack as well as heat, salt, and UPR-inducing stressors. Additionally, the plants showed impairment in the establishment of systemic acquired resistance (SAR).

Conclusions: These results show that a lack of UGGT activity alters plant vegetative development and impairs the response to several abiotic and biotic stresses. Moreover, our results uncover an unexpected role of UGGT in the incorporation of UDP-Glucose into the ER lumen in Arabidopsis thaliana.

No MeSH data available.


Related in: MedlinePlus