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Transforming a NEP 1 toxin gene into two Fusarium spp. to enhance mycoherbicide activity on Orobanche —failure and success
Author(s) -
Meir Sagit,
Amsellem Ziva,
AlAhmad Hani,
Safran Einat,
Gressel Jonathan
Publication year - 2009
Publication title -
pest management science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.296
H-Index - 125
eISSN - 1526-4998
pISSN - 1526-498X
DOI - 10.1002/ps.1736
Subject(s) - biology , botany , gene , orobanche , toxin , microbiology and biotechnology , genetics , germination
BACKGROUND: The NEP 1 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) NEP 1 transformants was hypervirulent. NEP 1 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 NEP 1 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 NEP 1‐like protein. NEP 1 expression of most F. oxysporum transformants was suppressed, suggesting that the native gene and the transgene silence each other. The sequence of the putative NEP 1 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 NEP 1‐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. Copyright © 2009 Society of Chemical Industry