Expression of nodule-specific genes in Phaseolus vulgaris L.

Abstract

The identification of some nodule-specific host proteins (nodulins) from common bean (Phaseolus vulgaris L.), a tropical ureide-transporting legume, is described. Particularly, the existence and developmental expression of several abundant nodule-specific transcripts of P. vulgaris are shown, including leghemoglobin, nodulespecific uricase and a group that in vitro translates into a cluster of about 30 kDa products. The expression pattern of nodulins in effective (Fix(+)) nodules compared to ineffective (Fix(-)) ones is also presented. The modified expression of main nodulins observed between these nodules indicates that different levels and/or factors associated with their regulation are involved. The intracellular infection by Rhizobium as a decisive step in the induction of some P. vulgaris nodulins is discussed.

The expression of a chimeric Phaseolus vulgaris nodulin 30-GUS gene is restricted to the rhizobially infected cells in transgenic Lotus corniculatus nodules

“…Few of these proteins have been identified: leghemoglobin, uricase II and a nodule-enhanced glutamine synthetase [2,13,18]. In the same experiment a group of abundant transcripts encoding for proteins in the 30 kd range was detected [2]. These nodulins (Npv30), seem to be encoded by a multigene family [2,Campos et al,submitted].…”

“…30 kDa, as detected in an in vitro translation assay [2]. We isolated a gene (npv30-1) for one of the members of this family.…”

“…In common bean, Phaseolus vulgaris, the presence of around 20 nodulins is observed when nodule mRNA is translated in an in vitro assay [2]. Few of these proteins have been identified: leghemoglobin, uricase II and a nodule-enhanced glutamine synthetase [2,13,18].…”

Expression pattern of uricase II gene during root nodule development inPhaseolus vulgaris

“…The conversion of uric acid to allantoin is carried out in the nodules of tropical legumes by a nodule-specific enzyme, namely uricase 11 TM 19. Uricase II is a tetrameric enzyme that is produced exclusively in the root nodules of legumes 2~ Uricase II constitutes approximately 2% of the soluble protein extracted from mature nodules of soybean and Phaseolus21, 22. In soybean, the uricase II gene has been isolated, and its product localized within the peroxisomes of unifected cells by immunogold-labeUing analysis 23 …”

Characterization and Gene Expression of Nodulin Npv30 from Common Bean

“…Also, in pea a late nodulin gene, PsNOD6, is activated in the infected cells following the induction of the leghemoglobin genes (Kardailsky et al, 1993). In soybean and common bean, severa1 late nodulin genes have been studied and the function of some of their products have been described, for example leghemoglobin (Appleby, 1984;Lee and Verma, 1984;Campos et al, 1987), the y subunit of Gln synthetase from Phaseolus vulgaris (Lara et al, 1983;Padilla et al, 1987), uricase I1 (Bergmann et al, 1983, Sánchez et al, 19871, and SUC synthase (Thummler and Verma, 1987, among others.…”