Biochemical and molecular characterisation of exogenous cytokinin application on grain filling in rice
Abstract Background Poor filling of grains in the basal spikelets of large size panicles bearing numerous spikelets has been a major limitation in attempts to increase the rice production to feed the world’s increasing population. Considering that biotechnological intervention could play important r...
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| Format: | Article |
| Language: | English |
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BMC
2018-05-01
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| Series: | BMC Plant Biology |
| Subjects: | |
| Online Access: | http://link.springer.com/article/10.1186/s12870-018-1279-4 |
| _version_ | 1818041897272213504 |
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| author | Binay Bhushan Panda Sudhanshu Sekhar Sushant Kumar Dash Lamboder Behera Birendra Prasad Shaw |
| author_facet | Binay Bhushan Panda Sudhanshu Sekhar Sushant Kumar Dash Lamboder Behera Birendra Prasad Shaw |
| author_sort | Binay Bhushan Panda |
| collection | DOAJ |
| description | Abstract Background Poor filling of grains in the basal spikelets of large size panicles bearing numerous spikelets has been a major limitation in attempts to increase the rice production to feed the world’s increasing population. Considering that biotechnological intervention could play important role in overcoming this limitation, the role of cytokinin in grain filling was investigated based on the information on cell proliferating potential of the hormone and reports of its high accumulation in immature seeds. Results A comparative study considering two rice varieties differing in panicle compactness, lax-panicle Upahar and compact-panicle OR-1918, revealed significant difference in grain filling, cytokinin oxidase (CKX) activity and expression, and expression of cell cycle regulators and cytokinin signaling components between the basal and apical spikelets of OR-1918, but not of Upahar. Exogenous application of cytokinin (6-Benzylaminopurine, BAP) to OR-1918 improved grain filling significantly, and this was accompanied by a significant decrease in expression and activity of CKX, particularly in the basal spikelets where the activity of CKX was significantly higher than that in the apical spikelets. Cytokinin application also resulted in significant increase in expression of cell cycle regulators like cyclin dependent kinases and cyclins in the basal spikelets that might be facilitating cell division in the endosperm cells by promoting G1/S phase and G2/M phase transition leading to improvement in grain filling. Expression studies of type-A response regulator (RR) component of cytokinin signaling indicated possible role of OsRR3, OsRR4 and OsRR6 as repressors of CKX expression, much needed for an increased accumulation of CK in cells. Furthermore, the observed effect of BAP might not be solely because of it, but also because of induced synthesis of trans-zeatin (tZ) and N6-(Δ2-isopentenyl)adenine (iP), as reflected from accumulation of tZR (tZ riboside) and iPR (iP riboside), and significantly enhanced expression of an isopentenyl transferase (IPT) isoform. Conclusion The results suggested that seed-specific overexpression of OsRR4 and OsRR6, and more importantly of IPT9 could be an effective biotechnological intervention towards improving the CK level of the developing caryopses leading to enhanced grain filling in rice cultivars bearing large panicles with numerous spikelets, and thereby increasing their yield potential. |
| first_indexed | 2024-12-10T08:37:43Z |
| format | Article |
| id | doaj.art-06844edb629b444aa038a7597bec08aa |
| institution | Directory Open Access Journal |
| issn | 1471-2229 |
| language | English |
| last_indexed | 2024-12-10T08:37:43Z |
| publishDate | 2018-05-01 |
| publisher | BMC |
| record_format | Article |
| series | BMC Plant Biology |
| spelling | doaj.art-06844edb629b444aa038a7597bec08aa2022-12-22T01:55:56ZengBMCBMC Plant Biology1471-22292018-05-0118111910.1186/s12870-018-1279-4Biochemical and molecular characterisation of exogenous cytokinin application on grain filling in riceBinay Bhushan Panda0Sudhanshu Sekhar1Sushant Kumar Dash2Lamboder Behera3Birendra Prasad Shaw4Institute of Life SciencesInstitute of Life SciencesNational Rice Research InstituteNational Rice Research InstituteInstitute of Life SciencesAbstract Background Poor filling of grains in the basal spikelets of large size panicles bearing numerous spikelets has been a major limitation in attempts to increase the rice production to feed the world’s increasing population. Considering that biotechnological intervention could play important role in overcoming this limitation, the role of cytokinin in grain filling was investigated based on the information on cell proliferating potential of the hormone and reports of its high accumulation in immature seeds. Results A comparative study considering two rice varieties differing in panicle compactness, lax-panicle Upahar and compact-panicle OR-1918, revealed significant difference in grain filling, cytokinin oxidase (CKX) activity and expression, and expression of cell cycle regulators and cytokinin signaling components between the basal and apical spikelets of OR-1918, but not of Upahar. Exogenous application of cytokinin (6-Benzylaminopurine, BAP) to OR-1918 improved grain filling significantly, and this was accompanied by a significant decrease in expression and activity of CKX, particularly in the basal spikelets where the activity of CKX was significantly higher than that in the apical spikelets. Cytokinin application also resulted in significant increase in expression of cell cycle regulators like cyclin dependent kinases and cyclins in the basal spikelets that might be facilitating cell division in the endosperm cells by promoting G1/S phase and G2/M phase transition leading to improvement in grain filling. Expression studies of type-A response regulator (RR) component of cytokinin signaling indicated possible role of OsRR3, OsRR4 and OsRR6 as repressors of CKX expression, much needed for an increased accumulation of CK in cells. Furthermore, the observed effect of BAP might not be solely because of it, but also because of induced synthesis of trans-zeatin (tZ) and N6-(Δ2-isopentenyl)adenine (iP), as reflected from accumulation of tZR (tZ riboside) and iPR (iP riboside), and significantly enhanced expression of an isopentenyl transferase (IPT) isoform. Conclusion The results suggested that seed-specific overexpression of OsRR4 and OsRR6, and more importantly of IPT9 could be an effective biotechnological intervention towards improving the CK level of the developing caryopses leading to enhanced grain filling in rice cultivars bearing large panicles with numerous spikelets, and thereby increasing their yield potential.http://link.springer.com/article/10.1186/s12870-018-1279-4Cytokinin oxidaseCytokinin treatment6-BenzylaminopurineCell cycle regulatorsChromosomal endoreduplicationOryza sativa |
| spellingShingle | Binay Bhushan Panda Sudhanshu Sekhar Sushant Kumar Dash Lamboder Behera Birendra Prasad Shaw Biochemical and molecular characterisation of exogenous cytokinin application on grain filling in rice BMC Plant Biology Cytokinin oxidase Cytokinin treatment 6-Benzylaminopurine Cell cycle regulators Chromosomal endoreduplication Oryza sativa |
| title | Biochemical and molecular characterisation of exogenous cytokinin application on grain filling in rice |
| title_full | Biochemical and molecular characterisation of exogenous cytokinin application on grain filling in rice |
| title_fullStr | Biochemical and molecular characterisation of exogenous cytokinin application on grain filling in rice |
| title_full_unstemmed | Biochemical and molecular characterisation of exogenous cytokinin application on grain filling in rice |
| title_short | Biochemical and molecular characterisation of exogenous cytokinin application on grain filling in rice |
| title_sort | biochemical and molecular characterisation of exogenous cytokinin application on grain filling in rice |
| topic | Cytokinin oxidase Cytokinin treatment 6-Benzylaminopurine Cell cycle regulators Chromosomal endoreduplication Oryza sativa |
| url | http://link.springer.com/article/10.1186/s12870-018-1279-4 |
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