(go to
KOMUGI Home) (go
to WIS List) (go to NO.91
Contents)
Materials and methods
T durum cv. Ailanmai, a tetraploid wheat landrace
of Jianyang, Sichuan, was collected and maintained in Triticeae
Research Institute, Sichuan Agricultural University, China. The
accession of S. africanum was obtained from Missouri
Botanical Garden, USA. The fertile amphiploid between T. durum
cv. Ailanmai and S. africanum were kindly provided by
Prof. Jiang H. R. of Sichuan Agricultural University (Jiang et al.
1992). Wheat line Moulin with subunit 17+18 encoded by Glu-B1
was obtained from Prof. P. I. Payne of Plant Breeding Institute,
Cambridge, U.K..
Chromosome counts were performed after the Feulgen squash method and
the silver - staining procedure was according to the method of
Lacadena et al. (1984). Giemsa-C banding technique was described by
Ren and Zhang (1995).
Acid polyacylamide gel electrophoresis (APAGE) separation of
endosperm gliadin was conducted following the method reported by Cook
(1987). According to the procedure of Ng and Bushuk (1987), glutenin
subunits were separated by sodium dodecyl sulphate-polyacrylamide gel
electrophoresis (SDS-PAGE). The determination of HMW-glutenin
subunits was described by Payne and Lawrence (1983) with the bread
wheat lines Chinese Spring and Moulin as references.
The amphiploid with 2n=42 were evaluated on their seedling resistance
to powdery mildew and adults-plant to stripe rust with reference to
its parents. The plants are grown at the field in Dujiangyan,
Sichuan, where has a favorable environment for stripe rust and
powdery mildew epidemics. The adult plants were inoculated by new
physiological strains CYR-30 and CYR-31 of wheat stripe rust in
China, provided by Plant Protection Institute, Sichuan Academy of
Agricultural Sciences. The powdery mildew isolates collected from
Pingshan, Sichuan, were applied to inoculate the seedling. Stripe
rust and powdery mildew response observation referred to Ma et al.
(1995) and Zeller et al. (1993), respectively.
Results
Feulgen staining indicated that the euploid of the amphiploid
with 2n=42 chromosomes contained only two pairs of chromosomes with
nucleolus organizer region (NOR) (Fig. 1). It
was also supported by the results of silver-staining, which indicated
that 4 stained nucleolus organizer regions (Ag-NORs) were observed in
the metaphase cells analyzed (data not shown). Theoretically, the
parents of the amphiploid would carry three pairs of chromosomes with
NOR, in which two pairs from T. durum cv.
Ailanmai, one pair from S. africanum. Furthermore,
Giemsa-C banding dearly indicated that four NOR existed in the
chromosomes 1B and 6B from T. durum (Fig.
2), when compared with the standard C-banding karyotypes
(Gill et al. 1991). Thus, the nucleoli from S. africanum
chromosomes did not express in the amphiploid.
The composition of glutenin was analyzed by SDS-PAGE (Fig.
3). The high molecular weight glutenin subunits (HMW-GS) of
Ailanmai contained subunit 2* of Glu-A1, and two close bands
existed between subunits 7 and 8 referred by Glu-B1 of Chinese
Spring. The slow-moving band is stronger which would be the x-type of
the subunit, and the fast-moving band had the same mobility as
subunit 18 contained in the wheat line Moulin. In comparison
with the description of HMW-GS in T. durum, it is concluded
that two bands belong to Glu- B1IV, which were named as
subunits 23 + 18 by Branlard et al (1989). Glutenin band
slightly faster than subunit 2 in S. africanum with the
same mobility as strong bands encoded by Sec-3 of S.
cereale (Shewry and Miller 1983), was quite weak. By
observing the band pattern of the amphiploid, it is easily concluded
that both HMW and low molecular weight (LMW) glutenin in the
amphiploid overlapped those of its parents.
<--Back
| -->Next
(go to
KOMUGI Home) (go
to WIS List) (go to NO.91
Contents)