Self-incompatibility (SI) is a genetic system that promotes outcrossing by rejecting self-pollen. In the Brassicaceae the SI response is mediated by the pistil S-locus receptor kinase (SRK) and its ligand, pollen Slocus cysteine-rich (SCR) protein. Transfer of SRK-SCR gene pairs to self-fertile Arabidopsis thaliana enabled establishment of robust SI, making this transgenic self-incompatible A. thaliana an excellent platform for SI analysis. Here we report isolation of a novel A. thaliana self-incompatibility mutant, AtC24 SI mutant, induced by heavy-ion beam irradiation. We show that the AtC24 SI mutant exhibits breakdown of SI, with pollen hydration, pollen tube growth and seed set resembling the corresponding processes in wild-type (self-fertile) A. thaliana. Further reciprocal crosses indicated that some perturbed SI factor in the stigmatic cell of the AtC24 SI mutant is responsible for the observed phenotype, while the pollen response remained intact. Our results demonstrate successful application of heavy-ion beam irradiation to induce a novel A. thaliana self-incompatibility mutant useful for SI studies.
We explored the use of the medicinally important plant Centella asiatica for expression of hemagglutinin-neuraminidase (HN) protein of Newcastle disease virus (NDV) strain AF2240. HN protein is the principal target for subunit vaccine development against NDV. The full-length HN gene was cloned into a plant expression construct driven by the CaMV 35S promoter and C-terminal fusion of green fluorescence protein (GFP) as reporter system. The recombinant expression construct was transformed via particle bombardment into C. asiatica callus. Transformants were screened using GFP and selected on MS medium supplemented with 15 mg/l hygromycin. The ~1.8 kb HN mRNA transcript was detected on the putative transformants using RT-PCR. The presence of HN protein expression was further confirmed through dot blot analysis using anti-NDV chicken serum. Here we report, for the first time, the use of a novel medicinal plant as a new platform for HN protein expression.