Plant Molecular Biology

, 68:423

Silencing of a BYPASS1 homolog results in root-independent pleiotrophic developmental defects in Nicotiana benthamiana

Article

DOI: 10.1007/s11103-008-9384-7

Cite this article as:
Kang, Y.W., Kim, R.N., Cho, H.S. et al. Plant Mol Biol (2008) 68: 423. doi:10.1007/s11103-008-9384-7

Abstract

The Arabidopsis bypass1 mutant (bps1) exhibits defective shoot and root growth that is associated with constitutive production of a root-derived carotenoid-related signal (Van Norman et al., Curr Biol 14:1739–1746, 2004). Since the identity of the signal and the function of BPS1 are still unknown, we investigated effects of BPS1 depletion in Nicotiana benthamiana to elucidate BPS1 function in plant growth and development. The predicted protein of NbBPS1, a BPS1 homolog of N. benthamiana, contains a central transmembrane domain, and a NbBPS1:GFP fusion protein was mainly associated with the endoplasmic reticulum. Virus-induced gene silencing (VIGS) of NbBPS1 resulted in pleiotrophic phenotypes, including growth retardation and abnormal leaf development. At the cellular level, the plants exhibited hyperproliferation of the cambial cells and defective xylem differentiation during stem vascular development. Hyperactivity of the cambium was associated with an elevated auxin and cytokinin response. In contrast, the leaves had reduced numbers of cells with increased cell size and elevated endoreduplication. Cell death in NbBPS1 VIGS leaves started with vacuole collapse, followed by degeneration of the organelles. Interestingly, these phenotypes were mainly caused by silencing of NbBPS1 in the aerial parts of the plants, different from the case of the Arabidopsis bps1 mutant. These results suggest that NbBPS1 plays a role in the control of cell division and differentiation in the cambium of N. benthamiana, and BPS homologs may have a diverse function in different tissues and in different species.

Keywords

Cell deathEndoreduplicationER targetingHyperproliferationPromoter-GUS fusionVirus-induced gene silencing

Supplementary material

11103_2008_9384_MOESM1_ESM.ppt (1.7 mb)
Supplementary Fig. 1 Phenotype variability in the NbBPS1 VIGS lines and silencing of NbBPS1 in the stem. (a) Relative phenotype severity. The average number of abnormal leaves of TRV:BPS1(U) lines was approximately 57% of that of TRV:BPS1(C) lines at 25 DAI (7.3 leaves; n = 50). (b) Semiquantitative RT-PCR analysis of the NbBPS1 mRNA levels in the stem using BPS1-C2 primers. RT-PCR showed significantly reduced PCR products in both lines relative to the TRV:GFP lines, indicating that the endogenous level of NbBPS1 transcripts is reduced in the stem tissueSupplementary Fig. 2 Effects of fluridone treatment on the NbBPS1 VIGS phenotype. (a) Fluridone (FL) treatment fully rescued the growth arrest and partially rescued the abnormal leaf morphology of the NbBPS1 VIGS plants at 22 DAI. VIGS plants were irrigated with 0.1% ethanol with or without fluoridone (0, 0.1 and 10 μM) from 2 DAI to 22 DAI. (b) Effects of fluridone on plant height of the NbBPS1 VIGS plants at 22 DAI. Relative height (%) was calculated comparing to the height of TRV control treated with 0.1% ethanol (PPT 1735 kb)

Copyright information

© Springer Science+Business Media B.V. 2008

Authors and Affiliations

  1. 1.Department of BiologyYonsei UniversitySeoulKorea
  2. 2.Plant Genome Research CenterKorea Research Institute of Bioscience and BiotechnologyTaejonKorea
  3. 3.Department of Plant SciencesSeoul National UniversitySeoulKorea