外源NO对棉胚珠离体培养色素积累和纤维发育的影响

Effects of Exogenous Nitric Oxide on the Pigment Accumulation and Fiber Development of Cotton in Vitro

为探究外源NO对棉花色素合成和纤维发育的影响,以棕色棉和白色棉花后2 d的胚珠为材料,利用NO供体硝普钠(SNP)处理棉纤维,测定纤维发育中的相关生理生化指标及与色素合成相关基因的表达量。结果表明,100μmol·L-1SNP处理促进了棕色棉胚珠鲜质量的增加和白色棉纤维的伸长;DMACA染色显示,原花青素(PAs)分布在棕色棉胚珠种皮和纤维中,而白色棉则仅在种皮中存在;外源NO促进了白色棉和棕色棉胚珠纤维中总黄酮和PAs的合成,但抑制了棕色棉纤维素的合成;色素合成关键酶基因(Gh CHS、Gh F3H、Gh DFR、Gh ANS、Gh ANR)在离体过程中整体呈下降趋势,但SNP处理上调了棕色棉中各基因的表达;外源NO促进了棕色棉胚珠纤维中Gh TT12的表达;外源NO在纤维发育早期(10 DAC、15 DAC)抑制了棕色棉胚珠纤维中Gh Exp1的表达,促进了白色棉胚珠纤维中Gh Exp1的表达。本研究结果为进一步揭示外源NO对棉花色素合成和纤维发育提供了参考。

To investigate the effects of exogenous NO on the pigment synthesis and fiber development of cotton,the ovule of cotton of a brown fiber line and a white fiber line,after anthesis for two days were cultured in vitro,cotton and the cotton fiber cultured in vitro was treated by sodium nitroprussiate（NO donor,SNP）,the physiological and biochemical indexes in fiber development and the expression of genes related to pigment synthesis were measured. The results showed that 100 μmol·L-1 SNP treatment increased the fresh weight of ovule in brown cotton and the elongation of white cotton fiber. DMACA staining showed that proanthocyanidin（PAs） were distributed in the ovule,testa and fiber of brown cotton,while was found only in the testa of white cotton. Exogenous NO promoted the synthesis of total flavonoids and PAs in ovule fibers of white cotton and brown cotton,but inhibited the synthesis of cellulose in brown cotton. The key enzyme genes of pigment（Gh CHS、Gh F3 H、Gh DFR、Gh ANS、Gh ANR） in the whole process declined in vitro,but the treatment by SNP increased the expression of genes in brown cotton. Exogenous NO promoted the expression of Gh TT12 in brown cotton and could inhibit the expression of Gh Exp1 at early stage of fiber development（10 DAC,15 DAC） in brown cotton,while promoted the expression of Gh Exp1 in white cotton. This study provided a reference for further studies on the pigment synthesis and fiber development of cotton under exogenous NO.