Fragaria×Ananassa Duch. cv. Toyonoka is a main variety of strawberry in Japan, but it is susceptible to a pathogenic fungus, Sphaerotheca humuli. Rice chitinase gene under the control of cauliflower mosaic virus (CaMV) 35S promoter was introduced into the strawberry plants using Agrobacterium tumefaciens. The transgenic plants showed an increased resistance to the powdery mildew, S. humuli.
This is the first report of the production of transgenic durum wheat. A f transformation system or common wheat through particle bombardment of scutellar tissues of immature embryos was successfully applied to emmer wheat. Three emmer wheats, Triticum durum var. reichenbachii, T. durum var. agricunum and T. aethiopicum Jakubz., were used in the transformation experiments. The scutellar tissues isolated from immature seeds were bombarded with a plasmid, pDM302 containing the bialaphos-resistant gene (bar) under control of the rice actin 1 gene (Act1) promoter. In T. durum var. agricunum, 25 bialaphos-resistant plants were independently regenerated from each green-spotted calli. On the other hand, no bialaphos-resistant plants were recovered from the other two emmer wheat, T. durum var. reichenbachii and T. aethiopicum. Most regenerated plants grew into mature and fertile plants. The integration and inheritance of the bar gene were confirmed by the PCR amplification and Southern analysis in T0 and T1 plants. All 25 plants showed the positive band of the bar gene. The frequency of transformation was 1.17 % (25 independent transformants/2144 immature embryos).
Chalcone synthase (CHS) is a key enzyme in the biosynthesis of all classes of flavonoids in plants. An antisense or sense CHS cDNA of tea under the regulation of a tapetum-specific promoter of rice was introduced into tobacco by Agrobacterium-mediated transformation. A reduction in the number of fertile pollen grains was observed in four out of 27 antisense CHS transformants and in five out of 26 sense CHS transformants. The distorted pollen grains of transformants lacked starch and flavonols. Fluorescein diacetate staining indicated abortion started at the late uninucleate microspore stage. The antisense or sense transgene would affect the pollen fertility.
An improvement in the production of β-thujaplicin (hinokitiol) by the Cupressus lusitanica suspension cell cultures is described. For cell growth, a sufficient supply of nutrients was necessary but Fe (II) had an inhibitory effect. The cells grew well in a modified Gamborg B5 medium (IS-1) containing Fe of 0.01mM which is one tenth of that in the original B5 medium. On the contrary, insufficient inorganic nutrients and excess Fe were effective for the β-thujaplicin production. Thus, the cells accumulated 22mg of β-thujaplicin/g dry cell weight in 3 days after elicitation, when 20g/l glucose was used as a carbon source in the other modified Gamborg B5 medium (IS-2) which contained 0.25mM Fe and major nutrients at 0.1 strength of the original B5 medium. The glucose dose can be greatly reduced without seriously affecting the β-thujaplicin production level, if a proper osmotic pressure regulator is present in the medium.
Transgenic hairy roots of Perilla frutescens var. crispa were obtained using an Agrobacterium-Ri binary vector system. The chimeric uidA gene encoding β-glucuronidase (GUS) flanked by the TR2′ promoter for mannopine synthase was introduced in the plant genome by Agrobacterium-mediated transformation by means of scratching stems of young plants. The adventitious roots which arose on the infected sites were excised, and the several clones of root tissue could be maintained on hormone-free agar medium. The transgenic states of these clones were confirmed by Southern blot hybridization. Expression of the uidA gene in the transgenic tissues was indicated by in vitro enzyme assay and histochemical staining of GUS activity. More than half of hairy roots which emerged were confirmed to be doubly transformed with T-DNAs from Ri and binary Ti plasmids.