| Rice production is affected by many factors, height as one of the important agronomic traits, and is closely related to rice yield and stability. A reasonable plant type is the basis of fertility and morphological characteristics of high-yielding varieties. Dwarf plants prone to lodging and reduction the production. Plants too short can cause the blades overlap intensive and low efficiency of light energy. The moderate dwarf varieties have strong ability of lodging resistance and suitable for high density planting. The plant group has high efficiency of light energy. Thus dwarfing breeding is very important to improve rice production. Therefore, further study of dwarf mutants and plant hormone metabolic properties is very important to promote crop dwarf breeding and clarify the mechanism and regulation of plant growth and development. This research mainly to discuss rice dwarf mutant oscbl5agronomic traits, pollen fertility, cell morphology and its response to hormones while studying mutations oscbl5gene function and its mutant plant height and regulation of pollen sterility.In this study, rice T-DNA Insertional mutant oscbl5, wild type Hwayoung were used as the research materials. Cell morphology, agronomic traits were evaluated in germination period and seedling stage separately. Pollen fertility, agronomic traits and pollen morphology of each period of anther development were evaluated in reproductive development stage. Mutant oscbl5, wild type Hwayoung were treated by exogenous plant growth regulator and comparative analysis of the results. The q-PCR assay was developed to estimate the gibberellin key metabolic enzyme genes expression levels in oscbl5and Hwayoung. Then the full coding sequence and the promoter sequence of OsCBL5gene were cloned. Transient expression vector was constructed to carry out the subcellular localization. Complimentation vector was established for gene functional verification by Agrobacterium-mediated transformation of rice. The main results were followings: (1) In this experiment, OSCBL5gene promoter and full coding sequence were successfully cloned. After series of studies on T-DNA insertional mutants of OsCBL5gene in rice, it could be concluded that the most obvious manifestation of the mutant plant OSCBL5is the dwarf plants while the angle between the blade and leaf sheath junction significantly less than the wild type and the leaves showed upright, twisting, thickened, dark green and other that compared with the wild type. Mutant height of about35cm, about40%of wild-type, under normal growth conditions, the mutant can be heading, but hardly bear seeds, stem elongation not obvious. The mutant plant oscbl5, wild type Hwayoung germination rate is80%but20%oscbl5mutant seedlings are albino. The seed setting rate of oscbl5was4.92%, Hwayoung was85.02%.(2) Oscbl5anther significant bending, smaller and the number of pollen significantly less than Hwayoung. Fertile pollen of oscbl5was10.7%, Hwayoung was87.3%. The semi-thin sections that each period of oscbl5and Hwayoung anther development results shows:in the early development of mutant pollen is consistent with the wild type. After formation of microspores Majority pollen is gradually deformed, wrinkled loss of activity.(3) The length of wild type Hwayoung parenchyma cells is about2times to the mutant plant. Plant oscbl5was treated by exogenous plant growth regulator for2weeks in leaf as one period. The group that sprays50mg/L GA3on the plant height growth was9.5cm. Spraying30mg/L gibberellin biosynthesis inhibitor paclobutrazol (PP333) in plant height growth was1.3cm. Spraying water in plant height growth was3.5cm. The results showed that the mutant oscbl5is GA3-sensitive mutants. The sensitivity of the GA on Hwayoung was greater than on oscbl5. The q-PCR assay was developed to estimate the gibberellin key metabolic enzyme genes expression levels in oscbl5and Hwayoung. The results showed that oscbl5gibberellin key metabolic enzyme genes expression levels in the synthesis of biologically active GAs were less than half of Hwayoung.(4) Through the analysis of the amino acid sequence encoded by the OsCBL5gene. OsCBL5gene is a member of the CBL protein family.(5) Transient expression vector was constructed to carry out the subcellular localization. The result indicated that the protein encoded by OsCBL gene was a membrane protein and it may be involved in GA signal transduction in plants. |
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