Comparison of globulin mobilization and cysteine proteinases in embryonic axes and cotyledons during germination and seedling growth of vetch (Vicia sativa L.)

Abstract

Vicilin and legumin, the storage globulins of mature dry vetch (Vicia sativa L.) seeds, are found in protein bodies which are present not only in the cotyledons, but also in the radicle, axis and shoot (together, for reasons of simplicity, here called axis). When at 24 h after the start of imbibition (hai) the radicle breaks through the seed coat a major part of the globulins in the axis has already been degraded, whereas in the cotyledons globulin breakdown cannot yet be detected. Globulin mobilization starts with the degradation of vicilin. At 48 hai when globulin mobilization in the cotyledons just begins, the axis is already nearly depleted of globulins. Mobilization of storage globulin is probably brought about by a complex of different cysteine proteinases (CPRs). The papain-like CPR2 and CPR4, and the legumain-like VsPB2, together with their mRNAs, are already present in axes and cotyledons of dry seeds. This means that they must have been formed during seed maturation. Additional papain-like CPRs are formed later during germination and seedling growth. CPR4 and VsPB2 together with their corresponding mRNAs become undetectable as germination and seedling growth proceed. VsPB2 and VsPB2-mRNA are substituted by the homologous legumain-like proteinase B and its mRNA. The composition of stored and newly formed CPRs undergoes developmental changes which differ between axes and cotyledons. It is concluded that storage globulin mobilization in germinating vetch seeds is started by stored CPRs, whereas the mobilization of the bulk of globulin is predominantly mediated by CPRs which are formed de novo.

Impact of biosynthesized silver nanoparticles on protein and carbohydrate contents in seeds of Pisum sativum L.

“…Total proteins were extracted with 100 mM tris-HCL buffer (pH 8.0) containing 150 mM NaCl and 1 µ mL -1 a-mercapto-ethanol. Proteins were extracted in the dark for 15 min, centrifuged at 15,000 g at 4 °C for 20 min (Schlereth et al 2000). The supernatant was stored for subsequent analysis.…”

Expression of Sweet Potato Senescence-Associated Cysteine Proteases Affect Seed and Silique Development and Stress Tolerance in Transgenic Arabidopsis

“…It was the first proteinase ever known which in vitro extensively degraded native phaseolin, the major storage globulin of this grain legume (Senyuk et al, 1998). In vetch (Vicia sativa) seeds, the legumain-like VsPB2 and proteinase B together with additional papain-like cysteine proteinases were responsible for the bulk breakdown and mobilization of storage globulins during seed germination (Schlereth et al, 2000). In Arabidopsis, the seed protein profiles were compared between the wild type and a seed-type vacuolar processing enzyme VPE mutant using a two dimensional gel/mass spectrometric analysis.…”

“…Papain-like cysteine protease such as CPR2 and CPR4 are found in cotyledon and axis of dry and imbibed seeds. Gene expression studies concluded that storage globulin mobilization in germinating vetch seeds is started by the stored cysteine proteases (CPRs), however, the bulk globulin mobilization is mediated by de novo synthesized CPRs (Schlereth et al, 2000;Schlereth et al, 2001;Tiedemann et al, 2001). These data suggest that papain-like cysteine proteases may play physiological roles and functions in association with seed storage globulin protein degradation and mobilization during seed germination and seedling growth.…”

“…However, sweet potato SPAE is in close association with plant vacuolar processing enzymes of seeds from phylogenetic analysis (Chen et al, 2004). Vacuolar processing enzymes have been reported to be in association with the degradation and mobilization of globulin storage proteins during seed germination and seedling growth in Phaseolus vulgaris (Senyuk et al, 1998), Vigna mungo , Vicia sativa (Schlereth et al, 2000;Schlereth et al, 2001), and Arabidopsis thaliana (Gruis et al, 2002). In Vigna mungo, VmPE-1 has been demonstrated to increase in the cotyledons of germinating seeds and was involved in the post-translational processing of a vacuolar cysteine endopeptidase, designated SH-EP, which degraded seed storage proteins (Okamoto & www.intechopen.com Transgenic Plants -Advances and Limitations 244 Minamikawa, 1999).…”

“…However, SPCP2 exhibited high amino acid sequence identities with plant papainlike cysteine proteases, such as Phaseolus vulgaris CP2, Vicia sativa CPR2, and Vigna mungo SH-EP. These papain-like cysteine proteases together with vacuolar processing enzymes have been implicated in association with the degradation and mobilization of globulin storage proteins during seed germination and seedling growth in Phaseolus vulgaris (Senyuk et al, 1998), Vigna mungo , and Vicia sativa (Schlereth et al, 2000;Schlereth et al, 2001). These reports provide a possible explanation for the altered phenotypic characteristics observed in transgenic Arabidopsis plants, and suggest that sweet potato SPCP2 may have an enzymatic function similar to papain-like cysteine proteases, including Vigna mungo SH-EP and Vicia sativa CPR2 for protein degradation and nutrient recycling during leaf senescence.…”