Arabidopsis thaliana PDX1.2 is critical for embryo development and heat shock tolerance


Main conclusion

PDX1.2 is expressed in the basal part of the globular-stage embryo, and plays critical roles in development, hypocotyl elongation, and stress response.


The Arabidopsis thaliana PDX1.2 protein belongs to a small family of three members. While PDX1.1 and PDX1.3 have been extensively described and are well established to function in vitamin B6 biosynthesis, the biological role of PDX1.2 still remains elusive. Here, we show that PDX1.2 is expressed early in embryo development, and that heat shock treatment causes a strong up-regulation of the gene. Using a combined genetic approach of T-DNA insertion lines and expression of artificial micro RNAs, we can show that PDX1.2 is critically required for embryo development, and for normal hypocotyl elongation. Plants with reduced PDX1.2 expression also display reduced primary root growth after heat shock treatments. The work overall provides a set of important new findings that give greater insights into the developmental role of PDX1.2 in plants.

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Artificial microRNA




Pyridoxine biosynthesis



vitB6 :

Vitamin B6












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We would like to thank Dipika Jadav for technical support. This work was supported by DFG Grant HE3224/6–1 and NSF Grant MCB-1020673 to H.H.

Conflict of interest

The authors declare that they have no conflict of interest.

Author information



Corresponding author

Correspondence to Hanjo A. Hellmann.

Additional information

J. E. Leuendorf and S. L. Mooney equally contributed.

Electronic supplementary material

Below is the link to the electronic supplementary material.

Supplemental Fig. S1 Identification of a homozygous pdx1.2-1 mutant line. a Schematic of the SAIL T-DNA insertion, and primers used to verify that plants were hetero- or homozygous for the insertion in the endogenous PDX1.2 gene. b Representative PCR results on WT and two T2 plants transformed with an Estr-inducible PDX1.2 cDNA sense construct show identification of plants being either hetero- or homozygous for the pdx1.2-1 SAIL T-DNA insertion, respectively (PDF 68 kb)

Supplemental Fig. S2 Constitutive expression of two different amiPDX1.2 constructs lead to aborted seeds. a Schematic drawing of front and middle amiPDX1.2 constructs (triangle) and their target region in PDX1.2. b Picture of mature siliques from WT, and two amiPDX1.2 plants. c Frequency of aborted seeds in different independent amiPDX1.2 lines (PDF 273 kb)

Supplemental Fig. S3 qRT-PCR analysis of expression of PDX1.2 in different tissues. Expression level of AtPDX1.2 in the roots, rosette leaves, cauline leaves, flowers and siliques from WT background. Error bars represent standard error (PDF 72 kb)

Supplemental Fig. S4 Estradiol inducible amiPDX1.2 lines do not show significant change in root length in the presence of 2,4-D compared to WT. Seedlings were germinated and grown for five days on ATS plates with or without Estr and transferred respectively to plates with or without 50 mM 2,4-D. Root tips were marked and growth was analyzed three days after transfer. Root data are based on at least n = 30 roots. Error bars are standard deviation (PDF 70 kb)

Supplemental Fig. S5 Estr-inducible amiPDX1.2 lines have reduced hypocotyl cell elongation under dark grown conditions. Data are based on a minimum of 40 cells from at least 10 different hypocotyls per condition. Error bars are standard deviation (PDF 105 kb)

Supplementary material 6 (DOCX 18 kb)

Supplementary material 7 (DOCX 12 kb)

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Leuendorf, J.E., Mooney, S.L., Chen, L. et al. Arabidopsis thaliana PDX1.2 is critical for embryo development and heat shock tolerance. Planta 240, 137–146 (2014).

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  • Embryo development
  • Heat shock response
  • PDX family
  • Pyridoxal-5-phosphate synthase
  • Vitamin B6