P. Norouzi, D. Cai, M. A. Malboobi, B. Yazdi Samadi,
Volume 7, Issue 3 (10-2003)
Abstract
OF2 and VAP genes, probably involved in signal transduction of sugarbeet nematode resistance, have already been cloned in bacterial vector by AFLP molecular marker and a two-hybrid system, respectively. To examine their capability to introduce resistance in sugarbeet, the genes were transferred to plant expression vectors. For this reason, OF2 gene after isolation was inserted within T-DNA of pAM194 binary vector, downstream of CaMV35S constitutive promoter and also inserted within T-DNA of modified pBin121 binary vector, downstream of HS1pro-1 gene inducing promoter (responsible for nematode resistance). VAP gene after isolation was inserted within T-DNA of pAM194 plasmid, downstream of CaMV35S constitutive promoter. Thus, three new constructs were made in which genes of signal transduction pathway were expressed to give beet cyst nematode resistance. These plasmids were separately transferred to Agrobacterium rhizogenes, strain AR15834. In the next step, petiole explants of sugarbeet were inoculated with the bacterial cells. Transformation-derived hairy roots were analyzed by GUS staining and/or PCR and were then inoculated with nematode larvae. Primary results showed partial resistance against nematode larvae in some hairy roots. As a result, this resistance can be related to OF2 and VAP genes effect.
A. Shadmehr, P. Norouzi, G.h. Garosi, N. Yavari,
Volume 11, Issue 42 (1-2008)
Abstract
In this research, after optimization of sterilizing cyst and larvae of second stage of Heterodera schachtii, the possibility of using nematode on seedlings of sugar beet (Beta vulgaris L.) in in vitro condition was studied for developing larvae to cyst. For this purpose, non sterile cysts were extracted from infected soil and hatched into zinc chloride solution with concentration of 0.5gl-1. Then, for preparation of sterile second stage larvae, several sterilizing treatments were used . Mean comparisons were performed between sterilized live larvae number by Duncan's method. Results showed that 70% ethanol for 1 minute followed by 5% sodium hypochlorite for 5 minutes and 0.1% sodium hypochlorite for 20 minutes were the best treatments for disinfecting cysts and larvae, respectively. In the next step, two nematode susceptible sugar beet varieties were applied to produce cyst from the larvae in in vitro culture. PGoB medium containing different hormonal compositions was used to produce hairy roots and inoculation of seedling with sterilized larvae. After nematode inoculation tests, were the stained cysts were observed under stereomicroscope and counted 40 days later. Five to twelve cysts were formed on the roots of each seedling from two varieties. As a result, it seems that this technique can be used for sugar beet germplasm evaluation to screen nematode resistant genotypes in in vitro controlled condition.
