A viviparous mutant of maize exhibiting permanent water stress symptoms
| Autor: | Antonino Malgioglio, Priscilla S. Manzotti, Diego Durantini, Nicoletta La Rocca, Gabriella Consonni, A. Giulini, Giuseppe Gavazzi, Francesca Dalla Vecchia, Nicoletta Rascio |
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| Jazyk: | angličtina |
| Rok vydání: | 2011 |
| Předmět: |
Stomatal conductance
Physiology ZEAXANTHIN EPOXIDASE Mutant MOLYBDENUM COFACTOR SULFURASE Plant Science Biology chemistry.chemical_compound Gene expression Arabidopsis thaliana ABSCISIC-ACID BIOSYNTHESIS ALDEHYDE OXIDASE GENE-EXPRESSION LOCUS ENCODES 9-CIS-EPOXYCAROTENOID DIOXYGENASE XANTHINE DEHYDROGENASE ARABIDOPSIS-THALIANA DROUGHT Abscisic acid Abiotic stress Molybdenum cofactor sulfurase fungi food and beverages Plant physiology biology.organism_classification Biochemistry chemistry Agronomy and Crop Science |
| Popis: | In maize vivipary, the precocious germination of the seed while it is still attached to the ear is a reliable phenotype for the identification of mutants impaired in the biosynthesis or response to abscisic acid (ABA). Here we present the characterization of a new allele of vp10, a gene encoding for a cofactor (MoCo) required for the last step of ABA biosynthesis. The lesion in this gene leads to a reduction in the endogenous ABA level. Embryonic messenger RNAs of the ABA inducible genes glb1, lea3, and rab17 are barely detectable, although their level increases when stimulated by exogenous ABA administration. These findings confirm that the mutant can be ascribed to a defect in ABA biosynthesis. In the absence of water stress, mutant plants grow like wild-type siblings; however when mutant tissues are exposed to air they differ from non-mutant ones by showing a higher rate of water loss, of transpiration and of stomatal conductance. These events are restored to almost normal values by adding exogenous ABA. All these defects are ascribable to an impairment in the regulation of stomatal opening since, in contrast to wild-type, some of the mutant stomata exhibit partially or totally open rims. The defect in ABA biosynthesis is also associated with loss of regulation of the expression of rab17 and rab28, two genes expressed in vegetative tissues under abiotic stress. These genes are constitutively expressed in the mutant plant tissues independently of the water regime applied. Thus this mutant may provide a tool for the study of molecular mechanisms underlying drought-stress responses in crop plants. |
| Databáze: | OpenAIRE |
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