Os01g0841500 - Revision history

Xysj1981: /* References */

2017-03-08T05:38:28Z

‎References

Xysj1981: /* Phenotypic analysis */

2017-03-08T05:38:20Z

‎Phenotypic analysis

Xysj1981: /* Annotated Information */

2017-03-08T05:37:36Z

‎Annotated Information

Xysj1981: /* Annotated Information */

2017-03-08T05:37:22Z

‎Annotated Information

Xysj1981 at 05:37, 8 March 2017

2017-03-08T05:37:09Z

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Xysj2012: /* Structured Information */

2015-05-13T07:39:20Z

‎Structured Information

Cloud27: /* Function */

2014-06-06T15:49:49Z

‎Function

Cloud27: /* Evolution */

2014-06-06T15:49:28Z

‎Evolution

Cloud27: /* Function */

2014-06-06T15:44:08Z

‎Function

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Cloud27: /* Function */

2014-06-06T15:39:44Z

‎Function

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 ==Structured Information==

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 * overexpression of OsMYB3R-2 in rice led to higher transcript levels of several G2/M phase-specific genes, including '''''OsCycB1;1, OsCycB2;1, OsCycB2;2, and OsCDC20.1''''' than those in '''''OsMYB3R-2''''' antisense lines or wild-type plants in response to cold treatment.
 * Flow cytometry analysis revealed an increased cell mitotic index in overexpressed transgenic lines of '''''OsMYB3R-2''''' after cold treatment.
-* Furthermore, resistance to cold stress in the transgenic plants overexpressing OsCycB1;1 was also enhanced. The level of cellular free proline was increased in the overexpressed rice lines of '''''OsMYB3R-2''''' and '''''OsCycB1;1''''' transgenic plants compared with wild-type plants under the cold
+* Furthermore, resistance to cold stress in the transgenic plants overexpressing OsCycB1;1 was also enhanced. The level of cellular free proline was increased in the overexpressed rice lines of '''''OsMYB3R-2''''' and '''''OsCycB1;1''''' transgenic plants compared with wild-type plants under the cold treatment.
 * These results suggest that '''''OsMYB3R-2''''' targets '''''OsCycB1;1''''' and regulates the progress of the cell cycle during chilling stress.
 * '''''OsCPT1''''', which may be involved in the dehydration-responsive element-binding factor 1A pathway, showed the same transcription pattern in response to cold as did OsCycB1;1 in transgenic rice.

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 ==Annotated Information==
-[[File:Os01g08415002.jpg|right|thumb|627px|'''Figure 2.''' ''Phenotype analysis of the T2 generation of OsMYB3R-2 transgenic rice.<ref name="ref1" />.'']]
+[[File:Os01g08415002.jpg|right|thumb|527px|'''Figure 2.''' ''Phenotype analysis of the T2 generation of OsMYB3R-2 transgenic rice.<ref name="ref1" />.'']]
 ===Gene Symbol===

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 ==Annotated Information==
-[[File:Os01g08415002.jpg|right|thumb|427px|'''Figure 2.''' ''Phenotype analysis of the T2 generation of OsMYB3R-2 transgenic rice.<ref name="ref1" />.'']]
+[[File:Os01g08415002.jpg|right|thumb|627px|'''Figure 2.''' ''Phenotype analysis of the T2 generation of OsMYB3R-2 transgenic rice.<ref name="ref1" />.'']]
 ===Gene Symbol===

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 ==Structured Information==
 [[Category:Genes]]
 [[Category:Japonica mRNA]]

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 We further examined the expression patterns of genes related to the cell cycle (Supplemental Table S2). Compared with the expression levels of types A and D cyclins, the expression levels of the type B cyclin genes OsCycB1;1, OsCycB2;1, OsCycB2;2, and OsCDC20.1 were suppressed by cold treatment in both the wild-type and antisense plants. In the OsMYB3R-2-overexpressed lines under cold treatment, expression patterns of those type B cyclin genes were the same as those at room temperature (25℃; Fig. 7A).
 To test whether the cold tolerance phenotype could be reproduced by overexpressing OsCycBs, transgenic rice overexpressing OsCycB1;1 as well as RNA interference (RNAi) lines (Supplemental Fig. S2) were tested for cold stress. The results showed that less than 58% of wild-type seedlings could survive after the treatment for 72 h, whereas more than 67% of overexpressed OsCycB1;1 seedlings could survive and grow normally (Fig. 7B). In contrast, less than 33% of OsCycB1;1-RNAi seedlings could resume growth under normal growth conditions. Our data showed that the overexpressing lines of OsCycB1;1 enhanced the tolerance to chilling stress compared with the wild type. This suggests that OsCycB1 is likely to be one of the downstream genes regulated by OsMYB3R-2 under chilling stress.
-     To investigate whether there is any relationship between Pro level and resistance to cold stress in OsCycB1;1-overexpressing transgenic rice plants, the level of cellular free Pro was monitored. The results showed that under normal growth conditions (25℃), the levels of cellular free Pro were similar in both wildtype and OsCycB1;1 transgenic rice at a range of 120 to 124 mg g21 fresh weight of material (Fig. 7C). In contrast, after cold treatment (2℃), the level of free Pro in OsCycB1;1-overexpressing transgenic rice increased substantially, with 243 mg g21 fresh weight compared with 197 mg g21 fresh weight in the wild type and 185 mg g21 fresh weight in OsCycB1;1-RNAi plants. These results of the changed pattern for cellular free Pro were similar to those in OsMYB3R-2 transgenic plants. Taken together, the data suggested that OsCycB1;1 was directly regulated by OsMYB3R-2, which was involved in the tolerance to cold in rice.
+To investigate whether there is any relationship between Pro level and resistance to cold stress in OsCycB1;1-overexpressing transgenic rice plants, the level of cellular free Pro was monitored. The results showed that under normal growth conditions (25℃), the levels of cellular free Pro were similar in both wildtype and OsCycB1;1 transgenic rice at a range of 120 to 124 mg g21 fresh weight of material (Fig. 7C). In contrast, after cold treatment (2℃), the level of free Pro in OsCycB1;1-overexpressing transgenic rice increased substantially, with 243 mg g21 fresh weight compared with 197 mg g21 fresh weight in the wild type and 185 mg g21 fresh weight in OsCycB1;1-RNAi plants. These results of the changed pattern for cellular free Pro were similar to those in OsMYB3R-2 transgenic plants. Taken together, the data suggested that OsCycB1;1 was directly regulated by OsMYB3R-2, which was involved in the tolerance to cold in rice.
 [[File:Os01g08415007.jpg|thumb|caption]]
 Based on the results of the expression levels of cyclins, we monitored the mitotic index of OsMYB3R- 2-overexpressed lines under cold conditions. Mitotic index is defined as the ratio between the number of cells in mitosis and the total number of cells, which is used as a measure for the proliferation status of a cell population. Flow cytometry revealed that the DNA content of the OsMYB3R-2-overexpressed lines increased at 4℃ compared with the wild type under normal (28℃) and cold (4℃) conditions (Fig. 8, A–D). Thus, the overexpressing lines possessed more cells in the G2/M phase, especially under the cold conditions. Under the normal conditions, the overexpressing lines showed a higher mitotic index than wild-type and antisense lines. Under cold conditions, in contrast, the mitotic index in the overexpressing lines was markedly higher than that of the wild type, and the index of the antisense lines was notably lower than that of the wild type under cold stress (Fig. 8E). The decreased percentage of the mitotic index under cold stress compared with normal conditions (28℃) was 24.3%, 11.6% to 14.5%, and 33.5% to 38.6% in the wild type, the overexpressing lines, and the antisense lines, respectively. The changes in the mitotic index correlated to the expression pattern of OsMYB3R-2. Therefore, we conclude that OsMYB3R-2-overexpressing lines possess more cells at the G2/M cell cycle phase, which promoted an increased mitosis.

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 ===Evolution===
- A genome-wide analysis identified at least 155 and 197 MYB genes in rice and Arabidopsis, respectively. Gene structure analysis revealed that MYB family genes possess relatively more number of introns in the middle as compared with C- and N-terminal regions of the predicted genes. Intronless MYB-genes are highly conserved both in rice and Arabidopsis. MYB genes encoding R2R3 repeat MYB proteins retained conserved gene structure with three exons and two introns, whereas genes encoding R1R2R3 repeat containing proteins consist of six exons and five introns. The splicing pattern is similar among R1R2R3 MYB genes in Arabidopsis. In contrast, variation in splicing pattern was observed among R1R2R3 MYB members of rice. Consensus motif analysis of 1kb upstream region (5′ to translation initiation codon) of MYB gene ORFs led to the identification of conserved and over-represented cis-motifs in both rice and Arabidopsis. Real-time quantitative RT-PCR analysis showed that several members of MYBs are up-regulated by various abiotic stresses both in rice and Arabidopsis.
+A genome-wide analysis identified at least 155 and 197 MYB genes in rice and Arabidopsis, respectively. Gene structure analysis revealed that MYB family genes possess relatively more number of introns in the middle as compared with C- and N-terminal regions of the predicted genes. Intronless MYB-genes are highly conserved both in rice and Arabidopsis. MYB genes encoding R2R3 repeat MYB proteins retained conserved gene structure with three exons and two introns, whereas genes encoding R1R2R3 repeat containing proteins consist of six exons and five introns. The splicing pattern is similar among R1R2R3 MYB genes in Arabidopsis. In contrast, variation in splicing pattern was observed among R1R2R3 MYB members of rice. Consensus motif analysis of 1kb upstream region (5′ to translation initiation codon) of MYB gene ORFs led to the identification of conserved and over-represented cis-motifs in both rice and Arabidopsis. Real-time quantitative RT-PCR analysis showed that several members of MYBs are up-regulated by various abiotic stresses both in rice and Arabidopsis.
 ===Knowledge Extension===

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 of the OsMYB3R-2 overexpression plants were still at the trefoil stage (Fig. 2B). Growth retardation was observed in transgenic plants up to the heading stage.
 [[File:Os01g08415001.jpg|thumb|caption]]
 '''Overexpression of OsMYB3R-2 Enhanced Tolerance to Chilling Stress in Rice'''
       To test the possible effect of OsMYB3R-2 expression on tolerance to chilling, the T2 transgenic and wildtype seedlings at the trefoil stage were exposed to reduced temperature (2℃) for various durations, followed by incubation at a normal growth condition in a greenhouse for 2 weeks. Fewer than 20% of the wild-type seedlings survived a cold treatment of 72 h, but none of them was able to resume growth when transferred to normal growth conditions. However, more than 50% of the OsMYB3R-2-overexpressing seedlings could survive and grow normally (Fig. 3, B and C). The survival ratio of antisense seedlings was less than that of the wild type. A time course of treatment showed drastic differences as the process was extended (Fig. 3D). The wild-type and transgenic seedlings showed no growth differences after chilling treatment for up to 48 h. In contrast, when the time of treatment was extended up to 60 h, more than 80% of the OsMYB3R-2-overexpressing plants grew normally, as compared with 55% of the wild-type seedlings and 45% of the antisense seedlings. Finally, after 84 h, neither wild-type nor antisense plants survived; in contrast, 20% of the overexpression lines were still healthy. Therefore,OsMYB3R-2 plays an important role in regulating tolerance against chilling stress in rice.