Transgenic cucumbers harboring the 54-kDa putative gene of Cucumber fruit mottle mosaic tobamovirus are highly resistant to viral infection and protect non-transgenic scions from soil infection.
Cucumber fruit mottle mosaic tobamovirus (CFMMV) causes severe mosaic symptoms and yellow mottling on leaves and fruits and, occasionally, severe wilting of cucumber (Cucumis sativus L.) plants. No genetic source of resistance against this virus has been identified in cucumber. The gene coding for the putative 54-kDa replicase gene of CFMMV was cloned into an Agrobacterium tumefaciens binary vector, and transformation was performed on cotyledon explants of a parthenocarpic cucumber cultivar. R1 seedlings were screened for resistance to CFMMV by symptom expression, back inoculation on an alternative host and ELISA. From a total of 14 replicase-containing R1 lines, eight resistant lines were identified. Line 144--homozygous for the putative 54-kDa replicase gene--was immune to CFMMV infection by mechanical and graft inoculation, and to root infection following planting in CFMMV-infested soil. A substantial delay of symptom appearance was observed following infection by three additional cucurbit-infecting tobamoviruses. When used as a rootstock, line I44 protected susceptible cucumber scions from soil infection by CFMMV. This paper is the first report on protection of a susceptible cultivar against a soil-borne viral pathogen, by grafting onto a transgenic rootstock.
Gal-On
Amit
A
Department of Virology, Agricultural Research Organization, The Volcani Center, POB 6, Bet Dagan 50250, Israel. amitg@volcani.agri.gov.il
Wolf
Dalia
D
Antignus
Yehezkel
Y
Patlis
Larisa
L
Ryu
Ki Hyun
KH
Min
Byoung Eun
BE
Pearlsman
Malenia
M
Lachman
Oded
O
Gaba
Victor
V
Wang
Yongzeng
Y
Shiboleth
Yoel Moshe
YM
Yang
Jee
J
Zelcer
Aaron
A
D001483:Base Sequence; D018553:Cucumis sativus / Q000235:genetics* / Q000821:virology*; D017931:DNA Primers; D009029:Mosaic Viruses / Q000235:genetics* / Q000472:pathogenicity; D030821:Plants, Genetically Modified / Q000235:genetics* / Q000821:virology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012988:Soil Microbiology
D017931:DNA Primers