Taro (Colocasia esculenta) Transformed with a Wheat Oxalate Oxidase Gene for Improved Resistance to Taro Pathogen Phytophthora colocasiae

Abstract

<jats:p>Production of taro [<jats:italic>Colocasia esculenta</jats:italic> (L.) Schott], a tropical root crop, is declining in many areas of the world as a result of the spread of diseases such as Taro leaf blight (TLB). Taro cv. Bun Long was transformed through <jats:italic>Agrobacterium tumefaciens</jats:italic> with the oxalate oxidase (OxO) gene <jats:italic>gf2.8</jats:italic> from wheat (<jats:italic>Triticum aestivum</jats:italic>). Insertion of this gene was confirmed by polymerase chain reaction (PCR) and Southern blot analysis. One independent transformed line contained one gene insertion (g5), whereas a second independent line contained four copies of the gene. Reverse transcriptase PCR (RT-PCR) confirmed the expression of this gene in line g5. Histochemical analysis of the enzyme oxalate oxidase confirmed its activity increased in the leaves of line g5. A bioassay for resistance to TLB used zoospores of <jats:italic>Phytophthora colocasiae</jats:italic> to inoculate tissue-cultured plantlets. Transgenic line g5 showed the complete arrest of this disease; in contrast, the pathogen killed non-transformed plants by 12 days after inoculation. A second bioassay, in which spores of <jats:italic>P. colocasiae</jats:italic> were inoculated onto disks of leaves of one-year-old potted plants, confirmed that transgenic line g5 had greatly increased resistance to this pathogen. This is the first report to demonstrate that genetic transformation of a crop species with an OxO gene could confer increased resistance to a pathogen (<jats:italic>P. colocasiae</jats:italic>) that does not secrete oxalic acid (OA).</jats:p>

Developing Blight-Tolerant American Chestnut Trees

“…Many potentially useful crops have been developed at universities using the tools of GE, but few have even attempted federal regulatory review. Examples (limited to crops transformed with the oxalate oxidase) include hybrid poplar (Liang et al 2001), soybean (Donaldson et al 2001), corn (Ramputh (Hu et al 2003), tomato (Walz et al 2008), rice (Molla et al 2013), and taro (He et al 2013). The university-developed crop plant that may have come closest was peanut (Hu et al 2015(Hu et al , 2016, which was submitted to the USDA but later withdrawn after facing the complications and high costs of the EPA registration.…”

Dual RNA-Sequencing of Eucalyptus nitens during Phytophthora cinnamomi Challenge Reveals Pathogen and Host Factors Influencing Compatibility

“…The over-expression of specific PR genes have conferred tolerance against various Phytophthora spp. (Alexander et al, 1993 ; Fagoaga et al, 2001 ; Sarowar et al, 2009 ; Pushin et al, 2010 ; Acharya et al, 2013 ; He et al, 2013 ).…”

Genetic engineering and genome editing technologies as catalyst for Africa’s food security: the case of plant biotechnology in Nigeria

“…Agrobacterium -mediated transformation of cocoyam (Bun long Cv.) with rice chitinase gene chi11 and wheat oxalate oxidase gene gf2.8 led to the production of a transgenic potato that is resistant to Sclerotium rolfsii and Phytophthora colocasiae ( He et al, 2008 , 2013 ). This method appeared to be more promising, because its transformation efficiency is high (between 1% and 3%), opening up a greater opportunity for other crops than what was obtained for the particle bombardment method (<0.5%).…”