Dept. of Agronomy, Beijing Agric. University, Ma-Lian-Wa, Beijing 100094 China
Esterase isozymes in rice have been investigated by a number of Chinese workers, although the use of different methods make it difficult to compare the results with one another. A trial comparison between results of various workers based on some distinct characteristics of bands is presented in Table 1.
We have examined a total of 1,270 strains of Asian landraces and the common wild rice (O. rufipogon), using sprouting seeds the extract of which exhibited all bands clearly. Electrophoresis was performed on polyacrylamide gel (PAGE) with Tris-citric acid buffer adjusted at pH 8.9. The conditions were 200V for 0.5 hour and 300V for 3 hrs at 4 deg C. The band running fastest was taken as 1A (10.5 cm from origin) as it was most clearly recognizable, and the band nearest the origin was numbered 14A (5.2 cm). Staining was made as follows: alpha and beta naphthyl acetate as main constituents of substrate, and fast blue RR salt as staining element. These were put together in 5 ml acetone, and the solution was poured into 100 ml phosphoric acid buffer adjusted at pH 6.4 to prepare the staining solution.
Table 1. Comparison of esterase isozyme bands reported by different
workers
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Present Fu Wu Qian Yu Zhu Nakaga-
author Chu-Xia Miao-Shen Young-Wen Wen-Jin Yin-Guo hra, M
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1A 7A 7A 12A 14A 13A --
5A 6A 6A -- 12A 10A 7A
7A 5A 5A 9A 10A 7A 6A
8A 4A 4A 8A 8A 5A -
10A 3A 3A 7A 7A - -
11A 3A 3A 7A 6A - -
13A 2A - - - - -
14A 2A 2A 6A - - -
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Table 2. Frequency of esterase isozyme bands found in different varietal
groups
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Variety No. of Frequency in %
group vars. 1A 2A 3A 4A 4aA 5A 6A 7A 8A 10A 11A 13A 14A
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Hsien, 98 100 7.1 3.6 0 17.9 17.3 13.3 71.9 100 0 83.7 16.3 0
India
Aus 34 91.2 8.8 4.4 0 35.3 0 8.8 97.1 100 2.9 17.6 79.4 0
Keng, 34 100 41.2 7.4 13.2 32.4 0 45.6 32.4 98.5 82.4 14.7 0 2.9
India
Bulu 17 97.1 35.3 29.4 0 50.0 0 64.7 35.3 100 88.2 11.8 0 0
Tjcreh 6 100 0 0 0 0 66.7 8.3 33.2 100 0 100 0 0
Nuda 135 100 24.0 11.1 0.7 33.3 0.7 42.6 25.9 98.9 90.0 10.0 0 0
Hsien, 54 100 5.6 7.4 0 9.3 48.1 7.4 22.2 100 0 100 0 0
China
Keng, 57 100 56.2 40.4 1.8 45.6 0 63.2 8.8 100 94.7 3.5 0 1.8
China
O. rufi- 24 100 22.9 8.3 0 20.8 4.2 25.0 22.9 97.9 0 0 0 100
pogon
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The frequencies of bands 1A to 14A found in different varietal groups are
shown in Table 2. Bands 1A and 8A were common to all the strains, with the
exception of a few. 11A was characteristic of Hsien (Indica) varieties, with
5A as an auxiliary band. 5A was also frequent in Tjereh varieties of
Indonesia. 13A was found only in Aus and some Inidan Hsien varieties. 14A
was peculiar to the common wild rice, and was also found in a few Keng
(Japonica) varieties of India and China. 10A was characteristic of Keng
varieties, with 4aA and 6A as auxiliary bands. 4aA was stained black and
differed in color from 4A and other bands which were stained red. It was
frequent in Keng and Bulu varieties. Thus, the esterase isozymes were found
to be useful for distinguishing between the Hslen and Keng types, although
other diagnostic characters should also be taken into account for classifying
Nuda (hairless), Rayada (long-duration deepwater rice) and other special
varieties.The genetic control of these bands was examined in 30 varietal crosses. Bands 11A, 13A and 14A were codominant and were dominant over 10A. These bands were controlled by alleles at a new locus which was found to be located on chromosome 1. We have designated this locus as Est-10 in addition to the nine loci for esterase listed by Morishima and Glaszmann (1990, p.52). Bands 5A and 7A were also codominant and were dominant over the null allele. These bands were controlled by alleles at Est-2 locus which is located on chromosome 6.
References
Morishima, H. and J. C. Glaszmann, 1990. Current status of isozyme symbols. RGN 7: 50-57.