3. Isozymes of glutamic oxalo-acetic transaminase (GOT) in Oryza species with different genomes

Xiang-Ming Wang, Ming-Jie Zhou and Yi-Cheng Cao

Genetics Laboratory, Biology Dept., Wuhan University, Wuchang, Hubei, China

GOT (E.C.2.6.1.1) plays an important role in amino-acid metabolism and protein synthesis in plants. Its variation in rice species was reported by Second and Trouslot (1980), who postulated that 14 different zymograms observed among plants of O. longistaminata and other species with genome AA could be governed by three loci each with two active alleles. However, we found that rice cultivars and their wild relatives were nearly monomorphic in GOT zymogram, and that species with different genomic constitutions had different zymograms.

Fully-expanded leaf blades were used for analysis. The leaf blades, 1 g per sample, were ground in an ice-bath with 1 ml of distilled water. Electrophoresis was made on polyacrylamide gels in glycine buffer by using an SCR-4 apparatus.

A total of 11 bands with Rf. values ranging from 0.135 to 0.535 were identified. All of 31 strains belonging to species with genome AA (O. sativa, O. sativa f. spontanea, O. perennis, O. glaberrima, and O. barthii) uniformly showed four bands at 3A, 5A, 6A, and 9A positions. But the zymograms were genome-specific, as shown in Table 1. The data suggest that GOT isozymes reflect the phylogenetic relationships of species in terms of genomic differentiation.

Table 1. Zymograms of species with different genomes.
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Genome Species   No. of                   Band identified
                 samples    1A   2A  3A  4A  5A   6A   7A   8A  9A  10A   11A
                       (Rf:.175 .20 .22 .29 .305 .355 .365 .45 .47 .505  .535)
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CCDD  latifolia;   4         +   +   +                  +            +     +
      alta

BBCC  minuta;      4         +   +   +                  +            +     +
      punctata

CC  officinalis    7                 +                  +        +   +     +

EE  australiensis  2                      +             +        +

FF brachyantha     1                 +                       +

AA sativa; etc.   31                 +        +    +             +
  (in text)
==============================================================================

Reference

Second, G. et P. Trouslot, 1980. Electrophorese d'enzymes de riz (Oryza spp.). Polymorphisme de treize zymogrammes observes parmi diverses especes sauvages et cultivees du genre Oryza. Travaus et Documents 120, ORSTOM, Paris 88pp.