Vacuolar processing enzyme activates programmed cell death in the apical meristem inducing loss of apical dominance

Paula Teper-Bamnolker; Yossi Buskila; Eduard Belausov; Dalia Wolf; Adi Doron-Faigenboim; Shifra Ben-Dor; Renier A L Van der Hoorn; Amnon Lers; Dani Eshel

doi:10.1111/pce.13044

Vacuolar processing enzyme activates programmed cell death in the apical meristem inducing loss of apical dominance

Plant Cell Environ. 2017 Oct;40(10):2381-2392. doi: 10.1111/pce.13044. Epub 2017 Aug 25.

Authors

Paula Teper-Bamnolker¹, Yossi Buskila^{1

2}, Eduard Belausov³, Dalia Wolf⁴, Adi Doron-Faigenboim⁵, Shifra Ben-Dor⁶, Renier A L Van der Hoorn⁷, Amnon Lers¹, Dani Eshel¹

Affiliations

¹ Department of Postharvest and Food Sciences, ARO, Agricultural Research Organization, The Volcani Center, HaMacabim 68, 75359, Rishon LeZion, Israel.
² The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Robert H. Smith Faculty of Agriculture Food and Environment, The Hebrew University of Jerusalem, Herzl 267, 76100, Rehovot, Israel.
³ Department of Ornamental Horticulture, ARO, Agricultural Research Organization, The Volcani Center, HaMacabim 68, 75359, Rishon LeZion, Israel.
⁴ Department of Vegetables and Field Crops, ARO, Agricultural Research Organization, The Volcani Center, HaMacabim 68, 75359, Rishon LeZion, Israel.
⁵ Institute of Plant Sciences, ARO, The Volcani Center, HaMacabim 68, 75359, Rishon LeZion, Israel.
⁶ Department of Biological Services, Weizmann Institute of Science, Herzl 234, 7610001, Rehovot, Israel.
⁷ Plant Chemetics Laboratory, Department of Plant Sciences, University of Oxford, South Parks Road Oxford, OX1 3RB, Oxford, UK.

PMID: 28755442
DOI: 10.1111/pce.13044

Abstract

The potato (Solanum tuberosum L.) tuber is a swollen underground stem that can sprout in an apical dominance (AD) pattern. Bromoethane (BE) induces loss of AD and the accumulation of vegetative vacuolar processing enzyme (S. tuberosum vacuolar processing enzyme [StVPE]) in the tuber apical meristem (TAM). Vacuolar processing enzyme activity, induced by BE, is followed by programmed cell death in the TAM. In this study, we found that the mature StVPE1 (mVPE) protein exhibits specific activity for caspase 1, but not caspase 3 substrates. Optimal activity of mVPE was achieved at acidic pH, consistent with localization of StVPE1 to the vacuole, at the edge of the TAM. Downregulation of StVPE1 by RNA interference resulted in reduced stem branching and retained AD in tubers treated with BE. Overexpression of StVPE1 fused to green fluorescent protein showed enhanced stem branching after BE treatment. Our data suggest that, following stress, induction of StVPE1 in the TAM induces AD loss and stem branching.

Keywords: Solanum tuberosum (potato); apical dominance (AD); caspase; stem branching; tuber apical meristem (TAM); vacuolar processing enzyme (VPE).

MeSH terms

Apoptosis* / drug effects
Apoptosis* / genetics
Caspase 1 / metabolism
Cysteine Endopeptidases / metabolism*
Gene Expression Regulation, Plant / drug effects
Gene Silencing / drug effects
Green Fluorescent Proteins / metabolism
Hydrocarbons, Brominated / pharmacology
Hydrogen-Ion Concentration
Meristem / cytology*
Meristem / drug effects
Meristem / enzymology*
Meristem / genetics
Plant Tubers / drug effects
Plant Tubers / enzymology
Plant Tubers / genetics
Solanum tuberosum / drug effects
Solanum tuberosum / enzymology*
Solanum tuberosum / genetics

Substances

Hydrocarbons, Brominated
Green Fluorescent Proteins
Cysteine Endopeptidases
vacuolar processing enzyme
Caspase 1
bromoethane