赤霉素对盐胁迫抑制水稻种子萌发的缓解作用的蛋白质组分析

Proteome Analysis of Relieving Effect of Gibberellin on the Inhibition of Rice Seed Germination by Salt Stress

用粳稻日本晴(Oryzasativa L. cv. Nipponbare),研究了盐胁迫对水稻种子萌发的抑制作用和赤霉酸(GA3)对盐胁迫的缓解作用;分别以H2O(对照),5gL-1 NaCl(处理I),5gL-1 NaCl+100μmolL-1 GA3(处理Ⅱ)培养水稻种苗48h,提取芽中的蛋白质,利用双向电泳(2-DE)和基质辅助激光解吸电离飞行时间质谱(MALDI-TOF MS)技术分析了水稻蛋白质组的变化。结果表明,在盐胁迫条件下,日本晴种子的萌发显著受到抑制,而GA3能显著缓解这种抑制作用;用ImageMaster软件分析2-DE凝胶,发现有4个蛋白质斑点表现出显著的变化,在盐胁迫下斑点S1、S2和S3表达下调而斑点S4消失,在GA3与盐共处理时,这4个蛋白质点的表达均有不同程度的恢复;经MALDI-TOF MS分析,其中2个蛋白质斑点(S1,S3)分别被鉴定为isoflavone reductase-like蛋白与葡萄糖磷酸变位酶,这些蛋白可能与GA3提高水稻耐盐性途径相关。

Salinity stress is a major abiotic stress to most plant including rice. It has been reported that gibberellic acid （GA3） can exert a natural beneficial effect on salt stressed rice. In this paper, the effect of salt stress on rice （Oryza sativa L. cv. Nipponbare） seed germination and the effect of GA3 on salt-stressed rice were investigated. A proteomic approach was employed to further understand the relieving effect of gibbereUin on the inhibition of rice seed germination by salt stress. The 5-day-old rice seedlings were treated with H20 （control）, 5 g L^-1 NaCl （treated group Ⅰ）, and 5 g L^-1 NaCl ＋ 100μmol L^-1 GA3 （treated group Ⅱ） for 48 h respectively. The proteins extracted from buds were separated by two-dimensional gel electrophoresis （2-DE） and analyzed with Matrix Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry （MALDI-TOF MS）. The results showed that the seed germination of Nipponbare was inhibited by salt stress significantly, while GA3 could reduce the inhibition significantly. Four protein spots showed differential expression in 2-DE. Three of these proteins were down-regulated （spots 1-3） and one protein disappeared （spots 4） under salt stress. Expression levels of these proteins were recovered partly when treated with GA3 and NaCl at the same time. Two protein spots were identified as isoflavone reductase-like protein and phosphoglucomutase. These differential expression proteins may play important role in the mechanism of the relieving effect of gibberellin on the inhibition of rice germination by salt stress.