Redox regulation and storage processes during maturation in kernels of Triticum durum

Abstract

Metabolic changes during the development and maturation of Triticum durum Desf. (L.) kernels were studied, with particular emphasis on changes in the redox state of ascorbate and glutathione, as well as in the activities of the enzymes responsible for the recycling of their oxidized forms (ascorbic free radical reductase, EC 1.6.5.4; dehydroascorbate reductase, EC 1.8.5.1; glutathione reductase, EC 1.6.4.2) and for detoxification or utilization of hydrogen peroxide (ascorbate peroxidase, EC 1.11.1.11; catalase, EC 1.11.1.6). In parallel with this analysis, the production and storage of reserve compounds was studied, in particular, soluble carbohydrates (mono- di-saccharides and fructans) and the transition from sulphydryl groups to disulphide bridges into proteins. The results indicate that both the activities of the ascorbate and glutathione redox enzymes and that of catalase are high before the start of drying maturation, after which they decrease. Moreover, analysis of the redox state of ascorbate and glutathione pairs and the sulphydryl to disulphide transition into proteins suggests that these three parameters are tightly related during kernel maturation, thus confirming the involvement of the two redox pairs in protein maturation as well as in protection against reactive oxygen species. The physiological implications of the changes in cellular redox state and in soluble carbohydrates for the acquisition of desiccation tolerance and reaching the resting phase in orthodox seeds are also discussed.

Integrated Proteomic and Cytological Study of Rice Endosperms at the Storage Phase

“…12,33,44 The respective up-and downregulation of SOD and APX proteins in the rice endosperm ( Figure 8) was consistent with the expression profiles of the 2 protein types in wheat seeds, which are involved in desiccation of cereal seeds. 45,46 Aberrantly reduced expression of SOD in viviparous 1 kernels of maize led to a premature induction of endosperm PCD. 5 Our proteomic results showed that several or most of the proteins involved in diverse metabolism/cellular processes including energy metabolism and starch synthesis were coexpressed at a significantly similar level with SOD, APX, or glyoxalase I (Supplemental Table S7).…”

Buthionine sulfoximine (BSO)-mediated improvement in cultured embryo quality in vitro entails changes in ascorbate metabolism, meristem development and embryo maturation

“…BSO may promote transcription of these proteins by increasing the synthesis of ABA (Belmonte et al 2006), as shown by Kermode (1995). Alternatively, the BSO-induced oxidized glutathione environment may stimulate post-translational mechanisms which facilitate folding and assembling of newly synthesized storage proteins, as suggested by De Gara et al (2003). Increased accumulation of LEAs and storage products would improve the post-embryonic performance of the embryos.…”

Assessing wheat (Triticum aestivum L.) genetic diversity using quality traits, amplified fragment length polymorphisms, simple sequence repeats and proteome analysis

“…Arrows represent proteins identified by mass spectrometry. decrease oxidative damage during seed development and germination (Pallanca & Smirnoff, 1999;De Gara et al, 2003) and provide antioxidant defense when acquiring desiccation tolerance (Baily et al, 2001). Among the AsA-glutathione cycle enzymes, DHAR had the highest increase in percentage during seed development (De Gara et al, 2003).…”

“…decrease oxidative damage during seed development and germination (Pallanca & Smirnoff, 1999;De Gara et al, 2003) and provide antioxidant defense when acquiring desiccation tolerance (Baily et al, 2001). Among the AsA-glutathione cycle enzymes, DHAR had the highest increase in percentage during seed development (De Gara et al, 2003). Because there is shortage of AsA in seeds (Arrigoni et al, 1992), DHAR activity during early seed germination can protect the small AsA pool from oxidation (Pallanca & Smirnoff, 1999).…”