  A late blight resistant potato plant overexpresses a gene coding for alpha-galactosidase upon infection by Phytophthora infestans; ; et al in Biologia Plantarum (2006), 50(2), 265-271 Late blight of potato, caused by Phytophthora infestans was studied by using a resistant clone of potato on one side and a susceptible clone on the other side. A gene coding putatively for an alpha ... [more ▼] Late blight of potato, caused by Phytophthora infestans was studied by using a resistant clone of potato on one side and a susceptible clone on the other side. A gene coding putatively for an alpha-galactosidase has been isolated by mRNA reverse transcription polymerase chain reaction differential display and was shown to be differentially expressed between the resistant and the susceptible clone. alpha-Galactosidases catalyse the hydrolysis of alpha-1,6 linked alpha-galactose residues from oligosaccharides and it could be shown in the present work that raffinose content decreases at 30 h after infection by P. infestans in the resistant clone. [less ▲] Detailed reference viewed: 20 (1 ULg)Restart of lignification in micropropagated walnut shoots coincides with rooting induction; Kevers, Claire  ; et alin Biologia Plantarum (2003), 47(1), 1-5 The lignin content of walnut shoots did not change during in vitro shoot Multiplication. Lignin content started to increase as soon as shoots were passed to a rooting medium with auxin. Exogenous auxin ... [more ▼] The lignin content of walnut shoots did not change during in vitro shoot Multiplication. Lignin content started to increase as soon as shoots were passed to a rooting medium with auxin. Exogenous auxin (applied for rooting) Caused a transient elevation of the endogenous free indoleacetic acid (IAA) content with a Simultaneous decrease of peroxidase activity. These events typically marked the completion of the rooting inductive phase (before any visible histological event. that is before the cell divisions beginnin- the rootin- initiation phase). This meant that either the given exogenous auxin or the endogenous IAA has served as signal for the stimulation of lignification. Continued increase of lignification in the shoots required completion of root formation; this increase indeed was slown down when root emergence did not occur. It was further shown that lionification varied conversely to the content of the Soluble Phenol Content. itself apparently being related to the activity of phenylalanine ammonia-lyase activity. [less ▲] Detailed reference viewed: 45 (1 ULg)Flow cytometry estimation of nuclear size and ploidy level of habituated calli of sugar beetKevers, Claire ; Greimers, Roland ; Franck, Thierry et alin Biologia Plantarum (1999), 42(3), 321-332 A fully habituated (auxin- and cytokinin-independent) self-regenerating (organogenic) sugar beet cell line (HO) and a fully habituated non-organogenic one (HNO) derived from the former one, were analyzed ... [more ▼] A fully habituated (auxin- and cytokinin-independent) self-regenerating (organogenic) sugar beet cell line (HO) and a fully habituated non-organogenic one (HNO) derived from the former one, were analyzed as to their nuclear size and DNA content. Flow cytometry and image analysis were used and cells of certified diploid leaves of the same sugar beet strain served as controls. The HNO cells had been shown previously to have many characteristics of cancerous cells. The analyses made on leaves and HNO cells indicated the presence of only one population of cycling cells. In HO cells. two cycling populations were detected: the first one had the same DNA content as the leaves while the second one contained two fold more DNA than the first population. HNO cells showed the higher nuclear size and DNA content. HNO cells also showed evidence of aneuploidy. Thus, nuclear size, DNA content and ploidy level increase together with the neoplasic progression to culminate in HNO cells with the loss of organogenic totipotency. [less ▲] Detailed reference viewed: 50 (2 ULg)Biosynthesis of 5-aminolevulinic acid via the Shemin pathway in a green sugar beet callus; ; et al in Biologia Plantarum (1998), 40(4), 493-497 5-Aminolevulinic acid synthase (ALAS) has been detected in a normal (auxin- and cytokinin-dependent) green sugar beet callus under light and under darkness. ALAS activity was lower when the callus was ... [more ▼] 5-Aminolevulinic acid synthase (ALAS) has been detected in a normal (auxin- and cytokinin-dependent) green sugar beet callus under light and under darkness. ALAS activity was lower when the callus was grown under light. The supply of precursors of the Shemin pathway (glycine and succinate) to dark-grown callus enhanced considerably the capacity of the 5-aminolevulinic acid (ALA) formation. Glutamate, gamma-aminobutyrate or a-ketoglutarate also increased ALA accumulation. Such an accumulation was also obtained after inhibition of polyamine synthesis. The results show that glutamate or its derivatives might feed the Shemin pathway in conditions preventing glutamate to be used through the Beale pathway. [less ▲] Detailed reference viewed: 45 (1 ULg) |
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