Index
|
Search
|
Home
|
Table of Contents
Afzal, M., M. Kawase, H. Nakayama, and K. Okuno. 1996. Variation in
electrophoregrams of total seed protein and Wx protein in foxtail
millet. p. 191-195. In: J. Janick (ed.), Progress in new crops. ASHS Press,
Alexandria, VA.
Variation in Electrophoregrams of Total Seed Protein and Wx Protein in
Foxtail Millet
Muhammad Afzal, Makoto Kawase, Hiroki Nakayama, and Kazutoshi Okuno
- METHODOLOGY
- RESULTS
- Intraspecific Variation and Geographical Distribution of Total Seed Protein
- Intraspecific Variation and Geographical Distribution of Wx Protein
- Variation and Geographical Distribution in Foxtail Millet in East Asia
- SUMMARY
- REFERENCES
- Table 1
- Table 2
- Fig. 1
- Fig. 2
- Fig. 3
- Fig. 4
Foxtail millet (Setaria italica Beauv.) was one of the crops which was
domesticated in the early stages of agriculture and has been cultivated across
Eurasia continent from tropical to temperate regions. Today it is a staple
food in India and northeastern China.
Intraspecific variation of foxtail millet and its geographical distribution has
been discussed on the basis of protein polymorphism by de Wet et al. (1979).
They suggested a mechanism for domestication due to germplasm exchange based on
a comparison of the variation in seed storage proteins of wild and cultivated
species of Setaria from western Europe, Afghanistan, and East Central
China. Jusuf and Pernes (1985) studied the genetic diversity of landraces
collected from East Asia, India, the former U.S.S.R and Europe using
discriminant analysis of data scored for 10 isozyme loci and found clear
regional differences among samples tested.
Starch granule bound polypeptide, Wx protein, is responsible for amylose
production and has been detected as a single band of approximately 60 kDa in
maize (Echt and Schwartz 1981), rice (Sano 1984), grain amaranths (Konishi et
al. 1985) and potato (Hovenkamp-Hermelink et al. 1987). In foxtail millet,
accessions showing low amylose content in endosperm starch were found in Japan,
Taiwan, Philippines, and Indonesia (Takei et al. 1989). Nakamura et al. (1990)
detected Wx protein in a few Japanese landraces of foxtail millet, which
were glutinous, non-glutinous and low amylose strains. A close relation
between amylose content and level of Wx protein was recognized.
This report deals with intraspecific variation and the geographical
distribution of total seed protein and Wx protein in foxtail millet
landraces.
A total of 217 landraces of foxtail millet were used in this study (Table 1).
SDS-polyacrylamide gel electrophoresis (SDS-PAGE) of crude proteins extracted
from seed samples followed the method of Laemmli (1970). Starch granule bound
protein (Wx protein) was isolated and analyzed using SDS-PAGE (Echt and
Schwartz 1981). Amylose content in endosperm starch was colorimetrically
determined on a dry weight basis using Autoanalyzer II (BRAN+LUEBBE).
Variation in electrophoregrams of total seed protein was observed in the range
of 20 to 30 kDa and about 60 kDa. Based on the combination of 4 protein bands
(Fig. 1 a,b,c and d) detected between 20 and 30 kDa, landraces were classified
into six different types based on electrophoregrams (Fig. 2). They were
designated protein type A (with bands a,b,c), type B (b,c), type C (a,b), type
D (c), type E (b), and type F (b,d). A geographical cline of SDA-PAGE
electrophoregram was observed, despite the limited number of landraces from
Thailand, Myanmar, and Indonesia (Table 1). Distribution of type A is confined
to India and countries to the west. Type B, the second most frequent type, is
distributed in East Asia, except for Japan and Korea, and west of Pakistan.
Type C is found in Japan and Europe. Type D is distributed in China, Taiwan,
and Indonesia. Type E is the most common type and widespread throughout
Eurasia. Type F occurs in Japan, Korea, and China. Landraces from India and
Pakistan were relatively uniform for protein types.
All landraces analyzed could be classified into three groups based on the level
of Wx protein. One group had a thick band, a second group a thin band
(Fig. 3) and a third group no band. Amylose content of each group was 20 to
35% (non-waxy), 8.5 to 15.6% (intermediate), and close to 0% (waxy)
respectively, and corresponded to the visual estimate of level of Wx
protein. The intermediate and waxy groups were found only in East Asia and
Southeast Asia (Fig. 4), which is in agreement with the previous report by
Sakamoto (1979) and Takei et al. (1989).
In addition, the distribution of these groups is similar to the geographical
distribution of waxy endosperm found in six other crop species described by
Sakamoto (1982). The regulatory mechanism of the intermediate type is not
clear. A regulatory gene (du) lowering Wx protein level and
amylose content has been found in rice (Okuno et al. 1983). Lowering amylose
content is considered to be controlled by alleles at wx locus or any
independent loci of wx locus. Gene(s) controlling intermediate level of
Wx protein and low amylose content (whether du-like
trans-element or Wx allele) should be genetically examined.
Based on the polymorphism of total seed protein, the center of diversity could
not be clearly identified. As mentioned above, types A,D and F distributed
particularly in the western half of Eurasia, Taiwan and Philippines, and East
Asia, respectively. Out of 18 possible phenotypes based on the variation in
total seed protein and level of Wxprotein, thirteen types were observed (Table 2) and five or six of all the phenotypes existed in Taiwan, Japan, and China.
Positive type for phenol coloration was primarily found in Taiwan, Philippines,
Nepal, and India (Kawase and Sakamoto 1982 Table 2). Jusuf and Pernes (1985)
suggested six regional groups including China-Korea-Japan, Taiwan-Okinawa
islands of Japan, India-Kenya, former U.S.S.R., Central Europe, and France,
according to discriminant analysis for 10 isozyme loci. Furthermore, most
landraces from China, Korea, and Japan (except for the Okinawa islands) belong
to the same group for hybrid sterility, while major part of those from Taiwan
and Okinawa were included in different group (Kawase and Sakamoto 1987).
Variation in electrophoregrams of total seed protein was observed in the range
of 20 to 30 kDa and about 60 kDa in 217 landraces of foxtail millet collected
across the Eurasia. Based on the combination of 4 protein bands (Fig. 1 a,b,c,
and d), landraces were classified into six different types (Fig. 2). A
geographical cline of electrophoregrams was observed (Table 1). Based on the
level of starch granule bound polypeptide (Wx protein), these 2l7
landraces weredivided into, non-waxy, intermediate, and waxy starch types (Fig. 3). The intermediate and waxy types were found only in East Asia and Southeast
Asia (Fig. 4).
- De Wet, J.M.J., L.L. Oestry-Stidd, and J.I. Cubero. 1979. Origins and evolution
of foxtail millets. J. d'Agr. Trad. Bota. Appl. 26:53-64.
- Echt, C.G. and D. Schwartz. 1981. Evidence for the inclusion of controlling
elements within the structural gene at waxy locus in maize. Genetics
99:275-284.
- Hovenkamp-Hermelink, J.H.M., E. Jacobsen, A.S. Ponstein, R.G.F. Visser, C.H.
Vos-Scheperkeuter, E.W. Bijmolt, J.N. de Vries, B. Witholt, and W.J. Feenstra.
1987. Isolation of an amylose free starch mutant of the potato (Solanum
tuberosum L.). Theor. Appl. Genet. 75:217-221.
- Jusuf, M. and J. Pernes. 1985. Genetic variability of foxtail millet
(Setaria italica Beauv.): Electrophoretic study of five isoenzyme
systems. Theor. Appl. Genet. 71:385-391.
- Kawase, M. and S. Sakamoto. 1982. Geographical distribution and genetic
analysis of phenol color reaction in foxtail millet, Setaria italica
(L.) P. Beauv. Theor. Appl. Genet. 63:117-119.
- Kawase, M. and S. Sakamoto. 1987. Geographical distribution of landrace groups
classified by hybrid pollen sterility in foxtail millet, Setaria italica
(L.) P. Beauv. Japan. J. Breed. 37:1-9.
- Konishi, Y., H. Nojima, K. Okuno, M. Asaoka, and H. Fuwa. 1985.
Characterization of starch granules from waxy, nonwaxy, and hybrid seeds of
Amaranthus hypochondriacus L. Agr. Biol. Chem. 49:1965-1971.
- Laemmli, U.K. 1970. Cleavage of structural proteins during the assembly of the
head of bacteriophage T4. Nature 227:680-685.
- Nakamura, T., M. Yamamori, and I. Yamaguchi. 1990. Variation of starch-granule
bound protein (Wx protein) in foxtail millet and Japanese barnyard
millet (in Japanese). Japan. J. Breed. 40(Suppl.1):418-419.
- Okuno, K., H. Fuwa, and M. Yano. 1983. A new mutant gene lowering amylose
content in endosperm starch of rice, Oryza sativa L. Japan. J. Breed.
33:387-394.
- Sakamoto, S. 1979. Variation and geographical distribution in foxtail millet.
2. On non-glutinous and glutinous endosperm characters (in Japanese). Japan. J.
Breed. 29(Suppl.2):192-193.
- Sakamoto, S. 1982. Waxy endosperm and perisperm of cereals and grain amaranth
and their geographical distributions (in Japanese with English summary). J.
Jap. Soc. Starch Sci. 29:41-55.
- Sano, Y. 1984. Differential regulation of waxy gene expression in rice
endosperm. Theor. Appl. Genet. 68:467-473.
- Takei, E., H. Taira, and S. Sakamoto. 1989. Geographical variation of amylose
content in foxtail millet (Setaria italica P. Beauv.) (in Japanese).
Japan. J. Breed. 39(Suppl.2):260-261.
Table 1. Variation in SDS-PAGE electrophoregram of total seed protein
of foxtail millet.
|
| Electrophoregramsz |
| Origin | No. of strains
examined | A | B | C | D | E | F |
| Japan | 12 | -- | -- | 2 | -- | 7 | 3 |
| Okinawa (Japan) | 4 | -- | -- | -- | -- | 4 | -- |
| Korea | 9 | -- | -- | -- | -- | 8 | 1 |
| China | 14 | -- | 5 | -- | 1 | 7 | 1 |
| Taiwan | 14 | -- | 2 | -- | 4 | 8 | -- |
| Philippines | 5 | -- | 3 | -- | -- | 2 | -- |
| Indonesia | 1 | -- | -- | -- | 1 | -- | -- |
| Thailand | 2 | -- | -- | -- | -- | 2 | -- |
| Nepal | 4 | -- | -- | -- | -- | 4 | -- |
| India | 10 | 1 | -- | -- | -- | 9 | -- |
| Pakistan | 120 | 1 | 108 | -- | -- | 11 | -- |
| Afghanistan | 5 | -- | 1 | -- | -- | 4 | -- |
| Central Asia | 6 | 1 | 2 | -- | -- | 3 | -- |
| Europe | 11 | 2 | 5 | 2 | -- | 2 | -- |
| Total | 217 | 5 | 126 | 4 | 6 | 71 | 5 |
zA (bands a,b,c), B (b,c), C (a,b), D (c), E (b), F (b,d)
respectively.
Table 2. Observed protein phenotypes based on the variation in total
seed protein and level of Wx protein.
|
| Electrophoregrams |
| Wx protein level | A | B | C | D | E | F | Total |
| Waxy | 0 | 2 | 2 | 3 | 17 | 3 | 27 |
| Intermediate | 0 | 3 | 0 | 1 | 3 | 0 | 7 |
| Non-waxy | 4 | 114 | 1 | 0 | 38 | 1 | 158z |
| Not determined | 1 | 7 | 1 | 2 | 13 | 1 | 25 |
| Total | 5 | 126 | 4 | 6 | 71 | 5 | 217 |
z120 accessions were from Pakistan.
 |
 |
| Fig. 1. Four polymorphic band analyzed in electrophoregram of total seed protein. |
Fig. 2. Intraspecific variation of total seed protein in foxtail
millet. |
Fig. 3. Electrophoregram of Wx protein from non-waxy and
intermediate type of endosperm.
Fig. 4. Geographical distribution of three types of Wx protein
in foxtail millet landraces. |
Last update August 15, 1997
aw