A preliminary investigation on proteins produced by iron resistant and iron sensitive rice varieties

Abstract

K.P.R.N. Attanayake and D.M. Sirisena

Ferrous toxicity is a major problem in rice (Oryza sativa L.) cultivation in flooded acid soils. There are some varieties of rice that can tolerate iron toxicity to a certain extent. However, the mechanism of resistance to ferrous ion is not known yet. The objective of this study was to extract total protein from iron sensitive and iron resistant rice plants, by two different methods and compare the protein profiles. Bw 272-6b (sensitive variety) and Bw 267-3 (tolerant variety) were used in this experiment. The seeds of both varieties were germinated and grown in culture solution used by Bower and Tamimi (1979). When plants were 21 days old ferrous stress was introduced into each variety by adding 250 mg/l Fe+2 to the culture solution and control pots from each variety were maintained. After 28 days, total protein was extracted from the leaves by two different methods as described by Leon et al., (1999) and Thalia et al., (1999). Proteins were separated by SDS Poly Acrylamide Gel Electrophoresis (SDS-PAGE). A clear separation of protein bands was observed from the method described by Thalia et al., (1999) while from the other method smears of protein bands were observed. Although not clearly visible there is a difference between the banding patterns of proteins isolated from ferrous resistant and sensitive varieties. Some bands present in the protein profile of iron-sensitive variety are not seen in the protein profile of iron resistant variety. This difference may be due to different response of the two varieties to ferrous stress.