Abiotic stresses are major limiting factors for growth, development, and productivity of crop plants. Here, we report on OsSKIPa, a rice homolog of human Ski-interacting protein (SKIP) that can complement the lethal defect of the knockout mutant of SKIP homolog in yeast and positively modulate cell viability and stress tolerance of rice. Suppression of OsSKIPa in rice resulted in growth arrest and reduced cell viability. The expression OsSKIPa is induced by various abiotic stresses and phytohormone treatments. Transgenic rice overexpressing OsSKIPa exhibited significantly improved growth performance in the medium containing stress agents (abscisic acid, salt, or mannitol) and drought resistance at both the seedling and reproductive stages. The OsSKIPa-overexpressing rice showed significantly increased reactive oxygen species-scavenging ability and transcript levels of many stress-related genes, including SNAC1 and rice homologs of CBF2, PP2C, and RD22, under drought stress conditions. More than 30 OsSKIPa-interacting proteins were identified, but most of these proteins have no matches with the reported SKIP-interacting proteins in animals and yeast. Together, these data suggest that OsSKIPa has evolved a specific function in positive modulation of stress resistance through transcriptional regulation of diverse stress-related genes in rice.
非生物脅迫是影響農(nóng)作物生長發(fā)育和產(chǎn)量的主要因素。本文我們報道了一個人類Ski互作蛋白的水稻同源蛋白OsSKIPa，該蛋白可以互補酵母SKIP同源基因敲除突變體的致死表型，正調(diào)節(jié)水稻細胞的活性和脅迫耐受性。在水稻中抑制OsSKIPa基因的表達導致生長停滯和細胞活性降低。OsSKIPa受各種非生物脅迫和激素處理誘導表達。過量表達OsSKIPa基因的轉基因植株極大提高了苗期和生殖生長期對ABA、鹽、甘露醇和干旱脅迫的耐受性。過量表達OsSKIPa的轉基因植株在干旱脅迫下清除活性氧的能力顯著提高，許多與脅迫相關基因的表達也顯著提高，包括SNAC1以及CBF2, PP2C和RD22的水稻同源基因。我們鑒定出來超過30個與OsSKIPa互作的蛋白，但其中大部分蛋白與動物和酵母中已報道的SKIP互作蛋白并不一致?？傊?，這些結果表明OsSKIPa已經(jīng)進化出來特異的功能，通過轉錄調(diào)節(jié)水稻許多脅迫相關基因的表達正調(diào)控水稻的脅迫耐受性。
結果：水稻SKIP同源基因的鑒定。 OsSKIPa可以互補酵母SKIP同源基因突變體。 抑制OsSKIPa的表達導致水稻生長停滯。 過量表達OsSKIPa基因增強水稻對脅迫的耐受性。 過量表達OsSKIPa的轉基因植株在干旱脅迫下細胞活性增強，清除活性氧的能力提高，與脅迫相關基因的表達也升高。 過量表達OsSKIPa的轉基因植株和RNAi植株的表達譜。 OsSKIPa互作蛋白的功能多樣性。
討論：OsSKIPa對細胞活性和植物生長的關鍵作用。 OsSKIPa正調(diào)節(jié)水稻的脅迫耐受性。 SKIP互作蛋白的功能多樣性。