光受体和OsPIN1基因家族表达对水稻根负向光性的影响

摘要

To explore effects of light receptor and polar auxin(IAA)transport on negative phototropism in rice root,the root of wild-type Japonica rice‘ Zhonghua11 ’ and its over-expressed OsPIN1a transgenic rice were used as materials in this paper.The root tips of both varieties were treated by unilateral light irradiation,after which the RNA was extracted and reverse transcriptase-polymerase chain reaction(RT-PCR)was adopted to synthesize cDNA as template.Semi-quantitative RT-PCR was conducted to detect expressions of light receptor and 4 OsPIN1a genes.Curvatures of negative phototropism were measured using a protractor,and confocal laser scanning microscopy was used to observe localization of OsPIN1a-GFP in root tip.Results showed that,after unilateral light irradiation,expressions of light receptor gene and 4OsPIN1a family genes in both varieties increased significantly and a relatively higher expression was observed in transgenic rice.In addition,OsPIN1b-GFP in shaded side was higher than that in irradiated side of transgenic rice.Negative phototropic bending was more apparent in transgenic rice than in wild type.It was indicated that light induced over-expression of light receptor genes and 4OsPIN1a family genes perhaps accelerated IAA polar transport,thus leading to rapid formation of negative phototropic curvature in transgenic rice root.%为了探讨根尖光受体及生长素极性运输在水稻根负向光性中的作用,以超表达OsPIN1b转基因和野生型水稻(‘中花11’)种子根尖为材料,在根尖受单侧光照不同时间后,提取根尖RNA,反转录合成cDNA,通过半定量PCR检测3种光受体和OsPIN1基因家族4个基因表达差异,用激光共聚焦电子显微镜观察根尖融合表达蛋白OsPIN1b-GFP的定位,测量根负向光性弯曲程度.结果发现:用单侧光照射后,转基因与野生型水稻根尖光受体基因表达量均明显提高,OsPIN1基因家族4个基因表达量也得到提高,但转基因水稻的这几个基因的表达量较野生型高,在转基因水稻根尖发现细胞向光侧的OsPIN1 b-GFP荧光强度明显弱于背光侧,水稻根负向光性角度也显著大于野生型.结果说明,水稻根尖受到单侧光照射后,提高了光受体和IAA极性输出载体基因的表达量,促进IAA极性运输,诱导根尖负向光性形成,由于转基因水稻的相关基因表达量高于野生型,所以根尖的负向光性弯曲角度明显大于野生型.