Pest Management Science (2009) 65, 588-595

Sagit Meir, Ziva Amsellem, Hani Al-Ahmad, Einat Safran and Jonathan Gressel (2009)
Transforming a NEP1 toxin gene into two Fusarium spp. to enhance mycoherbicide activity on Orobanche - failure and success
Pest Management Science 65 (5), 588-595
Abstract: BACKGROUND: The NEP1 gene encoding a fungal toxin that successfully conferred hypervirulence when transformed into Colletotrichum coccodes (Wallr.) Hughes attacking Abutilon theophrasti (L.) Medic. was tested to ascertain if it would enhance pathogenicity of Fusarium species to Orobanche aegyptiaca Pers. parasitising crops.
RESULTS: None of the Fusarium oxysporum (#CNCM I-1622) NEP1 transformants was hypervirulent. NEP1 transformants of a new but unnamed Fusarium sp. (#CNCM I-1621 - previously identified as F. arthrosporioides) killed Orobanche more rapidly than the wild type. Transformed lines of both species were NEP1 PCR positive, as was the wild type of F. oxysporum #CNCM I-1622 and five other formae speciales of F. oxysporum. All six wild-type formae speciales of F. oxysporum tested excrete minute amounts of immunologically and bioassay-detectable NEP1-like protein. NEP1 expression of most F. oxysporum transformants was suppressed, suggesting that the native gene and the transgene silence each other. The sequence of the putative NEP1 gene in Fusarium oxysporum #CNCM I-1622 differs from the sequence in the toxin-overproducing strain of F. oxysporum f. sp. erythroxyli in four or five amino acids in the first exon.
CONCLUSION: Wild-type Fusarium sp. #CNCM I-1621 does not contain a NEP1-like gene, explaining why it seemed amenable to transformation with high expression, and its virulence was probably enhanced by not cosuppressing the endogenous gene as occurred with Fusarium oxysporum #CNCM I-1622.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Jonathan Gressel

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
genetical engin./transgenic plants

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Phelipanche aegyptiaca (weed)
Fusarium oxysporum (weed pathogen)	Phelipanche aegyptiaca (weed)