水稻苗期感染SRBSDV后赤霉素相关基因表达量及赤霉素含量的变化

为明确水稻在苗期被南方水稻黑条矮缩病毒(Southern rice black-streaked dwarf virus,SRBSDV)浸染后植株体内赤霉素合成相关基因表达量和赤霉素含量的变化情况,利用q RT-PCR技术检测水稻在3叶期感染SRBSDV后的5个时期Os01g0883800、Os03g0856700、Os07g0169700三个赤霉素的生物合成基因表达量;采用高效液相色谱法检测GH998和Y11植株感染SRBSDV后的赤霉素含量;观察GH998病株施用外源赤霉素后病症的缓解效果。结果表明,感染SRBSDV后在GH998叶片中,以在第0天为对照组,Os01g0883800和Os07g0169700相对表达量最大分别下调25.6倍和21.1倍,Os03g0856700在第3天相对表达量下调20.5倍,在第6天上调2.3倍;在茎中,Os01g0883800、Os07g0169700、Os03g0856700的相对表达量在第3天分别下调8.5倍、6.4倍和1.4倍。在Y11叶片中Os01g0883800、Os03g0856700和Os07g0169700相对表达量最大下调分别为6.6倍,42.7倍和16.9倍;在茎中,Os01g0883800、Os07g0169700相对表达量最大下调分别为5.3倍和10.5倍;Os03g0856700在第3天时表达量上调1.5倍,在第12天下调2.8倍。GH998感染SRBSDV后植株体内赤霉素含量显著降低;施用外源赤霉素能缓解SRBSDV部分病症,表现为株高、剑叶长、剑叶宽和根长等均增加。

Analysis of the expression levels of the genes involved in gibberellin biosynthesis and gibberellin contents in rice during seedling stage after being infected by Southern rice black-streaked dwarf virus

To detect the expression levels of the genes involved in gibberellin (GA) biosynthesis and GA contents after infection with Southern rice black-streaked dwarf virus (SRBSDV) during rice seedling stage, and investigate the effect of application of exogenous GA on controlling the disease symptoms caused by SRBSDV, quantitative real-time PCR (qRT-PCR) method was applied to measure the changes in the expression levels of three genes, including Os01g0883800, Os03g0856700 and Os07g0169700, involved in GA biosynthesis during five stages after the rice seedlings were infected by SRBSDV in the three-leaf stage. High-performance liquid chromatography (HPLC) was used to determine the GA contents in leaves and stems of SRBSDV-infected plants of Y11 and GH998, and the exogenous GA₃ was applied to SRBSDV-infected plants. The results showed that the expression levels of both Os01g0883800 and Os07g0169700 in leaves of SRBSDV-infected GH998 were down-regulated by 25.6-fold and 21.1-fold respectively, while that of Os03g0856700 was down-regulated by 20.5-fold at the 3rd day and then up-regulated by 2.3-fold at the 6th day. The expression levels of Os01g0883800, Os07g0169700, Os03g0856700 were down-regulated by 8.5-fold, 6.4-fold and 1.4-fold on the 3rd day in stems of GH998, respectively. The expression levels of Os01g0883800, Os03g0856700 and Os07g0169700 in leaves of Y11 were down-regulated by 6.6-fold, 42.7-fold and 16.9-fold, respectively; the expression levels of Os01g0883800 and Os07g0169700 were down-regulated by 5.3-fold and 10.5-fold in the stems of Y11, respectively, and that of Os03g0856700 was up-regulated by 1.5-fold at the 3rd day and then up-regulated by 2.8-fold at the 12th day. The GA content was significantly decreased within plants of GH998 infected by SRBSDV. Application of exogenous GA₃ could effectively relieve the symptoms caused by SRBSDV infection, and the plant height, flag leaf length, and flag leaf width and root length increased without exception.