Planta

, Volume 227, Issue 3, pp 681–695

Virus-induced silencing of Comt, pAmt and Kas genes results in a reduction of capsaicinoid accumulation in chili pepper fruits

  • Ma del Rosario Abraham-Juárez
  • Ma del Carmen Rocha-Granados
  • Mercedes G. López
  • Rafael Francisco Rivera-Bustamante
  • Neftalí Ochoa-Alejo
Original Article

DOI: 10.1007/s00425-007-0651-7

Cite this article as:
del Rosario Abraham-Juárez, M., del Carmen Rocha-Granados, M., López, M.G. et al. Planta (2008) 227: 681. doi:10.1007/s00425-007-0651-7

Abstract

Capsaicinoids are responsible for the pungent taste of chili pepper fruits of Capsicum species. Capsaicinoids are biosynthesized through both the phenylpropanoid and the branched-fatty acids pathways. Fragments of Comt (encoding a caffeic acid O-methyltransferase), pAmt (a putative aminotransferase), and Kas (a β-keto-acyl-[acyl-carrier-protein] synthase) genes, that are differentially expressed in placenta tissue of pungent chili pepper, were individually inserted into a Pepper huasteco yellow veins virus (PHYVV)-derived vector to determine, by virus-induced gene silencing, irrespective of whether these genes are involved in the biosynthesis of capsaicinoids. Reduction of the respective mRNA levels as well as the presence of related siRNAs confirmed the silencing of these three genes. Morphological alterations were evident in plants inoculated with PHYVV::Comt and PHYVV::Kas constructs; however, plants inoculated with PHYVV::pAmt showed no evident alterations. On the other hand, fruit setting was normal in all cases. Biochemical analysis of placenta tissues showed that, indeed, independent silencing of all three genes led to a dramatic reduction in capsaicinoid content in the fruits demonstrating the participation of these genes in capsaicinoid biosynthesis. Using this approach it was possible to generate non-pungent chili peppers at high efficiency.

Keywords

CapsaicinoidsCapsicumChili pepperVirus-induced gene silencingPepper huasteco yellow veins virus

Abbreviations

Acl1

Acyl carrier protein gene

ACS

Acyl-CoA synthase

AT3

Putative acyltransferase gene

BAHD

BEAT, AHCTs, HCBT and DAT superfamily

BCAT

Branched-chain amino acid transferase

BSA

Bovine serum albumin

4CL

4-Coumarate-CoA ligase

Comt

Caffeic acid O-methyltransferase gene

csy1

Capsaicin synthase gene

C3H

Coumaroyl shikimate/quinate 3-hydroxylase

C4H

Cinnamic acid 4-hydroxylase

dpa

Days post-anthesis

dpi

Days post-infection

FatA

Acyl-ACP thioesterase gene

FAS

Fatty acid synthase complex

HCT

Hydroxycinnamoyl transferase

Kas

β-keto-acyl-[acyl-carrier-protein] synthase gene

PAL

Phenylalanine ammonia-lyase

pAmt

Putative aminotransferase gene

PTGS

Post-transcriptional gene silencing

PHYVV

Pepper huasteco yellow veins virus

siRNA

Small interfering RNA

VIGS

Virus-induced gene silencing

WT

Wild-type

Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  • Ma del Rosario Abraham-Juárez
    • 1
  • Ma del Carmen Rocha-Granados
    • 1
    • 3
  • Mercedes G. López
    • 2
  • Rafael Francisco Rivera-Bustamante
    • 1
  • Neftalí Ochoa-Alejo
    • 1
  1. 1.Departamento de Ingeniería Genética de PlantasCentro de Investigación y de Estudios Avanzados del IPN (Cinvestav) Campus GuanajuatoIrapuatoMexico
  2. 2.Departamento de Biotecnología y BioquímicaCentro de Investigación y de Estudios Avanzados del IPN (Cinvestav) Campus GuanajuatoIrapuatoMexico
  3. 3.Facultad de Agrobiología “Presidente Juárez”Universidad Michoacana de San Nicolás de HidalgoUruapanMexico