OsGA20ox2基因过量表达对水稻性状的影响

Influence on plant architecture through the over expression of OsGA20ox2 in rice

为研究水稻赤霉素20-氧化酶2(OsGA20ox2)基因的过量表达对水稻株高和生长发育的影响,通过RT-PCR扩增OsGA20ox2基因并构建该基因的过量表达载体pS12Q,采用农杆菌介导法遗传转化水稻,获得了高秆转基因植株。获得T0代的85株中,对其叶片基因组DNA进行Hyg基因扩增,发现其中2株为转基因植株且表现为高秆。分析其T2代表型,高秆植株与对照相比,株高增加9.41%(P<0.05);穗颈长增加15.62%(P<0.05);倒1节间长度增加8.46%(P<0.05);穗长增加7.98%(P<0.05);穗粒数增加6.8%(P<0.05);分蘖数增加了12.5%(P<0.05);百粒重增加2.6%(P<0.05);开花提前10天。这些性状导致高秆植株的产量增加,生育周期缩短。RT-PCR结果显示OsGA20ox2基因在高秆植株茎中的表达高于对照,促进了水稻茎的延伸。结果表明OsGA20ox2基因的过量表达影响了水稻的株高和生长发育。

The objective of this study is to analyze the influence of the over-expression of OsGA2Oox2 on rice plant architecture. OsGA20ox2 gene was amplified by reverse transcription polymerase chain reaction（RT-PCR）and an over- expressing binary vector pS12Q based on the OsGA2Oox2 gene was constructed. Though Agrobacterium-mediated transformation of rice, taller transplants were obtained. In To generation, 85 lines were obtained and checked by amplification of Hyg gene. Two of them showed specific band by PCR and taller in height. In T2 generation,compared with control lines,taller lines increased by 9.4% ;the panicle neck length increased by 15.62%;the length of the first internode（counted from the top） increased by 8.46% ; the panicle length increased by 7.98%, the seeds per panicle increased by 6.8%, the tiller number increased by 12.5 % ;the 100-seed weight increased by 2.6% ;and the flowering time was 10 days earlier than that of the control. Moreover,the fecundity of the transgenic plants was improved and their growth cycles shortened. Based on RT-PCR analysis of OsGA20ox2 in stem,two taller lines showed stronger expression compared to their wild counterpart. These results showed that over-expression of OsGA2Oox2 gene improved rice architecture,and suggested that OsGA2Oox2 is essential for panicles and stem development.