RESUMEN
A rice proteinase inhibitor (PI) gene OsPI8-1 was identified. Belonging to the potato inhibitor I family, this gene contains a 201bp coding region with no introns and encodes a deduced protein of 66 amino acids which holds a PI domain. There are two uniform gene copies, OsPI8-1a and OsPI8-1b, with direct-repeat arrangement and an interval span of 13 kb on rice chromosome 8, corresponding to the site of BAC clone P0528B09 (Accession No. AP004703). Reverse transcription polymerase chain reaction (RT-PCR) assays showed that both OsPI8-1a and OsPI8-1b can be expressed in wild-type 'Zhonghua No.11'. To investigate the physiological functions of OsPI8-1 in plant development, we analyzed the expression patterns of the reporter gene beta-glucuronidase (GUS) driven by OsPI8-1 promoter at different developmental stages and tissues. It was demonstrated that no GUS signals were detected in the roots. Despite that very high GUS expression was examined in the shoot apical meristem, no detectable GUS activity in the developmental domains of leaf primordium was observed. OsPI8-1 promoter showed an obvious wound-induced response in mature leaves. Little GUS activity was detected in young nodes and internodes at the seedling stage, but active GUS expression was observed near the nodes on mature culms. In the developing stage of the anther, GUS signal was specifically located in the middle layer and the endothecium between the epidermis and tapetum. In the germinating seed, GUS expression was gradually accumulated in the side of scutellar epithelium close to the embryo. These tissue-specific accumulations suggested that OsPI8-1 has multiple endogenous roles on developmental regulation. In this report, the inhibitor function of OsPI8-1 to proteolytic enzymes and the potential influence of their poise on plant development (such as seed germination, tapetum degeneration, programmed cell death, etc.) were discussed.
Asunto(s)
Regulación de la Expresión Génica de las Plantas , Genes de Plantas , Oryza/crecimiento & desarrollo , Oryza/genética , Proteínas de Plantas/genética , Secuencia de Aminoácidos , Secuencia de Bases , Bioensayo , Cromosomas de las Plantas/genética , Dosificación de Gen , Perfilación de la Expresión Génica , Germinación , Glucuronidasa/metabolismo , Meristema/citología , Meristema/metabolismo , Datos de Secuencia Molecular , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Regiones Promotoras Genéticas/genética , ARN Mensajero/genética , ARN Mensajero/metabolismo , Secuencias Repetitivas de Ácidos Nucleicos/genética , Semillas/metabolismo , Factores de Tiempo , Transformación GenéticaRESUMEN
Transposon tagging was used to isolate genes in higher plant. In this study, a delayed heading mutant caused by T-DNA insertion in rice was identified. Genetic analysis of the mutant showed that the three types of phenotype, normal heading, delayed heading and overly delayed heading in the segregating populations derived from the T-DNA heterozygotes fit the ratio of 1:2:1. Test for Basta resistance showed the delayed heading plants were all resistant while the normal heading plants were susceptible, and the ratio of resistant and susceptible plants was 3:1, which indicated that the delayed heading mutant was co-segregated with Basta resistance. The delayed heading mutant caused by T-DNA insertion was confirmed by T-DNA detection using PCR method. This delayed heading mutant will be used for isolation of the tagged gene in rice.
Asunto(s)
Elementos Transponibles de ADN , ADN Bacteriano/genética , Mutación , Oryza/genética , Oryza/crecimiento & desarrolloRESUMEN
A rice brittle culm mutant bcm581-1 which derived from the Ds transposone transformation population was found, but the mutant was identified that it was not to be induced by Ds transposone insertion through PCR. The examination of the vascular bundle and cortical fibre cells in culm under the light and electron microscope showed that, the number of cortical vascular bundle of mutant was much more, the hollow among the cortical vascular bundle was deeper, and the cell walls of cortical fibre cells were thinner than the normal. The test of culm mechanics intensity showed that the load, elongation, strain, and stress of bcm581-1 were 5-9 times lower than normal. The moisture content and the wide fibre content of culm were test, the former was 3.5% higher, but the latter was 8.12% lower than normal. The analysis of genetic segregation in F2 and F1B1 population indicated that the brittle culm mutant was controlled by one recessive gene.