抑制OsMAPK3基因表現會降低水稻對高鹽與乾旱的耐受性

Suppression of OsMAPK3 Gene Confers to Decrease Salt and Drought Tolerance in Rice (Oryza sativa L.) Seedlings

趙雲洋(Yun-Yang Chao) ； 劉麗飛(Li-Fei Liu) ； 張孟基(Men-Chi Chang)

《臺灣農業化學與食品科學》 45卷3期 (2007/06) Pp. 142-154

https://doi.org/10.6578/TJACFS.2007.018

摘要

水稻遭受非生物性逆境傷害時，會啟動Mitogen-activatedproteinkinase(MAPK)進行訊息傳遞。其調控過程仍未完全明瞭。本試驗探討OsMAPK3基因是否參與水稻對NaCl與乾旱的反應途徑，進而影響對逆境的耐受性。因此，本試驗以RNA干擾技術抑制OsMAPK3基因表現，並測定水稻三葉齡轉殖苗於NaCl和乾旱處理下之生理表現與抗氧化酵素活性。由RT-PCR結果得知，NaCl、乾旱與H2O2等非生物性逆境可誘導OsMAPK3基因之表現。在NaCl與乾旱逆境下，OsMAPK3轉殖水稻之地上部與地下部生長均受抑制，且PSII電子傳遞效率(Fv/Fm)也降低。經由轉殖與非轉殖水稻相互比較，發現抑制OsMAPK3基因表現的轉殖水稻H2O2含量較高，Ascorbateperoxidase(APX)的活性均比非轉殖水稻低，CAT與GR活性則無改變。另外，當轉殖水稻生長至成熟期時，株高與穗數明顯比非轉殖水稻矮少。綜合試驗結果可知，抑制OsMAPK3基因表現不但會影響抗氧化酵素的活性，降低水稻對NaCl與乾旱的耐受性，同時也會降低株高、穗數和穀粒減少，進而影響水稻正常的生長發育。

關鍵字

MAPK ； 乾旱 ； 鹽害 ； 過氧化氫 ； 抗氧化酵素

並列摘要

Mitogen-activated protein kinases (MAPKs) are known to be involved in plant signal transduction pathway in response to different abiotic stresses. However, the roles of MAPKs participating in rice abiotic stresses tolerance have yet to be determined. In this study, we investigated whether OsMAPK3 gene was involved in the drought and salt stress tolerance of rice. By suppression of OsMAPK3 gene with RNAi technique, we examined the tolerance capability of transgenic rice seedlings under drought and salt treatments. RT-PCR analysis showed that OsMAPK3 gene expression was induced by NaCl, drought and H2O2 treatment. Suppression of OsMAPK3 in rice resulted in lower PSII electron transfer efficiency (Fv/Fm) and inhibited the growth of root and shoot under drought and salt stresses. In contrast to non-transformant, the accumulation of H2O2 was increased in transgenic rice plants. Further analysis of antioxidant enzymatic activities showed that the ascorbate peroxidase (APX) activity was reduced but there were no change of either catalase or gluthionine reductase activities. The phenotype of suppressed OsMAPK3 transgenic rice plant showed less number of panicles and shorter height than wild type. Taken together, these results suggested that the downregulation of OsMAPK3 not only decrease the drought/salt-induced antioxidant defense but also reduces drought and salt stress tolerance of transgenic rice as reflected by short height, less number of panicles and grain weight.

並列關鍵字

MAPK ； Drought ； Salt ； Hydrogen peroxide ； Antioxidant