Browsing by Author "Matus, JT"

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    Identification and characterization of a novel tobacco mosaic virus resistance N gene homologue in Nicotiana tabacum plants
    (2004) Stange, C; Matus, JT; Elorza, A; Arce-Johnson, P
    Nicotiana tabacum cv. Xanthi nn plants are susceptible to infection by most tobamoviruses (TMV). However, such plants display a partial hypersensitive resistance response (HR-like response) to TMV-Cg. The genetic mechanism of the HR-like response has yet not been determined, but it may involve a gene with a function similar to that of a resistance gene, responsible for HR in resistant plants. We have cloned a gene homologous to the resistance N gene, named NH, from Nicotiana Xanthi nn plants. The coding region of NH is 5.028 base pairs ( bp) long and has 82.6% nucleotide identity with the N gene. In contrast to the N gene, the NH gene lacks intron 4 and does not have sites for alternative splicing of intron 3. Analysis of its sequence revealed that NH belongs to the TIR/NSB/LRR gene class. We were able to detect stable levels of NH-transcript in Nicotiana Xanthi nn plants from 0 to 18 h post-inoculation (hpi) with TMV-Cg. Transcript levels increased slightly at 24 hpi and dropped below basal values at 48 hpi. The NH transcript was also detected in a range of resistant Nicotiana plants ( N. tabacum Xanthi NN,N. glutinosa, N. glauca and N. rustica) suggesting that NH is a homologue of the N gene, rather than an allele. We have cloned and characterised the NH gene ( GenBank acc. no. bankit598573 AY535010) from nn susceptible plants and postulate that this gene might be involved in the HR-like response seen in these plants.