Distribution of defense-related enzimatic activities in the organs of quiescent seeds of Phaseolus vulgaris L.

RAMOS, A. L.; JOSE GUILLERMO SEIJO; ISHIKI, C.; IWAMOTO, T.

BIOSCIENCE, BIOTECHNOLOGY AND BIOCHEMISTRY

JAPAN SOC BIOSCI BIOTECHN AGROCHEM

Año: 1998 vol. 62 p. 54 - 59

0916-8451

Synopsis Analysis of quiescent seed extracts of two Phaseolus vulgaris L. cultivars revealed high activities of chitinase (EC 3.2.1.14), chitobiase (EC 3.2.1.30) and (-N-acetylhexosaminidase (EC 3.2.1.52) in whole seeds and their dissected organs (cotyledons, axis and seed coat). Chitinase was the main activity detected in whole seed extracts, followed by B-N-acetylhexosaminidase and, in lesser magnitude, chitobiase. Concerning enzyme activity distribution in the seed extracts, chitinase was found high in all organs, chitobiase in the seed coat and B-N-acetylhexosaminidase mainly in the axis. In terms of specific activity, all three enzymes coincided with an extraordinary higher activity present in seed coat extracts than the other extracts. Seeds of P. vulgaris L. cv. Surattowonder with soft white seed coat were compared with that of cv. Maisugata with red and hard seed coat . The cultivars showed similar distribution patterns of activities among their seed organs, although quantitative discrepancies were found between cultivars, which seems to be expressing intrinsic attributes of seed coat. In addition, Surattowonder showed higher specific activities of these three enzymes in seed coat extracts than Maisugata, especially referring to chitinase. Relation of these enzymes to defence in the two cultivars is discussed.