PROTEIN-PATTERNS AND SUPEROXIDE-DISMUTASE ACTIVITY IN NONMYCORRHIZAL AND ARBUSCULAR MYCORRHIZAL PISUM-SATIVUM L PLANTS

There are few reports in relation to the role of specific proteins in the mycorrhizal symbiosis. Among the changes in the protein expression as a consequence of the arbuscular mycorrhizal symbiosis, only one ca se related to changes in superoxide dismutase (SOD; EC 1.15.1.1) activ ity has been reported in the red clover- Glomus mosseae symbiosis. In this paper, the symbiotic system formed by a leguminous plant, Pisum s ativum, and the fungus Glomus mosseae is studied in terms of protein p atterns and SOD activity in both mycorrhizal and non-mycorrhizal roots . Our results show that among the differential polypeptides separated by SDS-PAGE, one with a molecular weight of 32.0 kDa, and a protein wi th an isoelectric point of pI 4.9 appeared strongly expressed in mycor rhizal roots. A partial purification of the related polypeptide could be achieved by DEAE-cellulose chromatography. A higher SOD activity wa s also detected in mycorrhizal pea roots, although both mycorrhizal an d non-mycorrhizal roots showed the same isoenzymatic pattern for SODs: two Mn-SODs (I and II) and two Cu,Zn-SODs (I and II) were detected, C u,Zn-SOD I being the most abundant isozyme in both types of roots. A s imilar pattern of SOD isozymes (Mn-SODs I and II, and Cu,Zn-SODs I and II) was also found in nodules of mycorrhizal and non-mycorrhizal pea roots. However, in nodules Mn-SOD II was the main isozyme. The bacteri al nature of this isozyme is postulated in this report.