Biotechnology. Cereals

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Cereals in Morocco. Isoenzymes and peroxidase-based identification Identification of species and varieties

In order to investigate more biochemical and molecular markers that could be of helpful support in breeding projects in cereals, isoenzymes and peroxidase enzyme fractions, resolved by gel electrophoresis, were used.

Cereals in Morocco. Varietal identification by isoenzymes

genetic variation of 7, 12, 1 and 4 varieties of bread wheat, durum wheat, triticale and barley, respectively, was evaluated by electrophoretic analysis of 6 enzyme systems.

cerel varieties

Isoenzymes studied are represented by peroxidases (POX), esterases (EST), glutamate oxaloacetate transaminase (GOT), leucine aminopeptidase (LAP), acid phosphatase (ACP) and endopeptidase (EP). Using leaf and root material, enzymes were extracted with half-diluted TAMET buffer (pH 7.0). Zymograms obtained after electrophoresis on polyacrylamide gels, showed a polymorphism giving rise to 2-8 electrophoretic phenotypes. No differences were detected within each variety.

cerals in Morocco. Isoenzymes

An isoenzyme-based key was established. It allowed the identification of 50% of varieties studied. Excepting the durum wheat Tunisian variety 'Karim', all foreign cultivars of the same species were completely identified; whereas, Moroccan varieties formed diferrent groups. This study shows the great help of isoenzymes for idrntifying cereals in Morocco.

Cereal identification by isoenzymes

Barley showed an only common LAP enzyme phenotype A, which was also found in durum wheats and the tritical varieties.

Possible relationships between cereal varieties forming different groups were, also discussed in this study. for more detail see Aouad,A., M. Mergoum & M. Baaziz (1996). Al Awamia 95, 9-19. 


Peroxidases as biochemical and molecular markers of cereal growth. Case of different varieties in Morocco.

Soluble and ionically wall-bound peroxidases of four cereal species, represented respectively by 2, 1, 2 and 3 varieties of bread wheat (Triticum aestivum), rye (Secale cereale), durum wheat (Triticum durum) and barley (Hordeum vulgare) were prepared from the root material. When grown under hydroponic culture, all varieties of barley and the bread wheat variety 'Saada' were found to be of high growth potential when compared with rye, durum wheat and the bread wheat variety 'Achtar'. The ionically wall-bound root peroxidases were relatively less represented (about 14% of total activities) in cereal varieties of high growth potential. However, soluble root peroxidases (about 86% of total activities) were abundant in the same varieties when compared with cereal varieties of limited growth.

Positive correlations between soluble root peroxidases and leaf or root fresh weights were found. When subjected to polyacrylamide gel electrophoresis, soluble cereal peroxidases were separated into acidic forms (activity zones A1 and A2) and basic ones (zones C1 and C2). The soluble acidic peroxidases exhibited species specific isoforms, which allowed a rapid and early cereal identification. Cereal peroxidases ionically bound to cell walls presented high mobilities. Their slow basic isoform was revealed at the zone C2.

cereal identification by peroxidase isoforms

The ionically wall-bound acidic forms migrated at the activity zone A2, common to acidic soluble enzymes, suggesting the presence of similar isoforms between the two extractable enzyme fractions. More details available in Aouad, Baaziz & Mergoum 200. Plant Peroxidase Newsletter 15, 13-21.

More details on plant peroxidases. theoretical and applied aspects (pdf file)


Cereals in Morocco. isoenzymes and peroxidase based identification

Recherche rapide dans ce site et les sites liés de l'auteur (Fr, Ar, Eng) - بحث سريع في هذا الموقع و المواقع المرتبطة للمؤلف :



sciences de la vie-Biochimie. Livre

 

Selected publications, communications and thesis

AOUAD, A., BAAZIZ, M. & MERGOUM, M. 2000. Quantitative and qualitative aspects of peroxidases in some Moroccan cereal varieties and their relationships with the in vitro growth potential. Plant Peroxidase Newsletter 15, 13-21.

AOUAD, A., BAAZIZ, M. & M. MERGOUM. 1999 Les peroxydases, marqueurs de la croissance et développement des céréales. deuxième Réunion Nationale des Jeunes Chercheurs en Biologie, Meknès (Maroc), 29-30 Avril. p.1.
AOUAD, A., BAAZIZ, M. & M. MERGOUM. 1999 Evaluation des peroxydases comme marqueurs de la tolérance à la salinité chez les céréales. Relation avec le calcium. In : Biotechnologies, amélioration des plantes et Sécurité alimentaire. Actualités Scientifique, AUPELF-UREF, Ed. ESTEM, Paris.pp.447-448.
AOUAD, A.& BAAZIZ, M. 1997 Evaluation des peroxydases comme marqueurs de la tolérance à la salinité chez les céréales. Relation avec l'acide ascorbique. Premier Forum de Biochimie de la Société Marocaine de Biochimie. Rabat (Maroc) 17-18 Octobre.
AOUAD, A., MERGOUM, M. & BAAZIZ, M. 1996  Etude préliminaire du polymorphisme enzymatique révélé chez quelques céréales aux premiers stades végétatifs. Al Awamia 95, 9-19.
AOUAD, A., BAAZIZ, M. & MERGOUM, M. 1996 Les peroxydases des céréales. Relation avec la résistance à la salinité. Première Rencontre Nationale des Etudiants chercheurs en Biologie, 17-19 Décembre, Marrakech, pp. 12.
AOUAD, A., BAAZIZ, M.& MERGOUM, M. 1996. Evaluation des peroxydases comme marqueurs dans l'amélioration pour la tolérance à la salinité du blé et d'autres céréales. Journées scientifiques sur l'amélioration du blé, Université Mohamed 1er, Faculté des Sciences, Oujda (Maroc), 23-25 Avril.
J'AITI, F., BENLHABIB, O., BAAZIZ, M. & EL HADRAMI, I. 1996. Androgenèse chez le  blé dur (Triticum durum L.) : effet du préconditionnement par les ovaires et relation avec les protéines totales, les esterases et les peroxydases. Journées scientifiques sur l'amélioration du blé, Université Mohamed 1er, Faculté des Sciences, Oujda (Maroc), 23-25 Avril.
AOUAD, A., BAAZIZ, M. & MERGOUM, M. 1995. Evaluation des peroxydases comme marqueurs dans la sélection des variétés de céréales résistantes à la salinité. 5èmes Journées scientifiques du Réseau Biotechnologie/Génie génétique des Plantes de l'AUPELF-UREF. Dakar (Sénégal), 13-15 Décembre.

AOUAD, A., MERGOUM, M.&BAAZIZ, M. 1994. Révélation du polymorphisme protéique et enzymatique de quelques Céréales d'adaptation variée à l'aridité.In : Acquis et perspectives de la Recherche Agronomique dans les zones arides et semi-arides du Maroc, M. El Gharous, M. Karrou, M. El Mourid eds. INRA et MIAC, Rabat (Maroc). pp. 398-409.

Selected thesis
J'AITI, F. 1997. Culture d'anthères et d'embryons immatures chez le blé dur (Triticum durum L. et T.aestivum L.) : amélioration de la régénération et caractérisation biochimique des potentialités morphogènes des tissus. Diplôme d'Etudes Supérieures, Université Cadi Ayyad, Marrakech (Maroc).

AOUAD, A. 1997. Contribution à l'étude des peroxydases des céréales en relation avec la résistance la salinité. Diplôme d'Etudes Supérieures, Université Cadi Ayyad, Marrakech (Maroc).


Cereales. Marquage biochimique et Moléculaire des especes et varietes