水稻双组分系统基因干旱胁迫表达谱分析

利用全基因组表达芯片,系统分析干旱胁迫条件下水稻双组分信号系统(two component system,TCS)相关基因在其不同发育阶段、不同组织以及抗旱能力不同的株系中的表达谱变化特征.结果表明,双组分信号系统基因在干旱胁迫环境下的表达具明显的时空特异性,表现为不同组织的TCS基因干旱胁迫表达谱差异较大,而同一组织内表达谱相似,其中生殖生长期(幼穗分化期和孕穗期)两个叶片材料中TCS基因表达谱最为接近;与细胞分裂素信号传导负向调控相关的A型应答调控器在旱胁迫下表达下调,而与CK信号传导正向调控相关的B型应答调控器呈现明显上调趋势,推测与干旱胁迫下CK信号传导增强有关,同时乙烯受体基因在干旱胁迫环境下的表达下调,从激素间相互关系的角度更好地印证了上述推测;与拟南芥细胞分裂素受体基因(AHK2、AHK3和AHK5)序列相似的磷酸感应激酶基因HK5和HK3在干旱胁迫下表达上调,与拟南芥中不依赖细胞分裂素的AHK5序列接近的HK6则表达下调,进一步验证上述推测;干旱胁迫下抗旱能力不同的水稻株系其TCS基因表达谱没有明显差异,推测TCS基因差异表达可能源于对干旱胁迫反应,而其表达对抗旱能力的增强还有待进一步研究.

Differential Expression of Rice Two-Component Element Genes under Drought Stress

In order to explore the temporal and spatial expression patterns of rice two component system (TCS) genes under drought stress and the relationship between expression of TCS genes and drought resistance ability, a whole rice genome microarray was used to analyze the expression profile of rice TCS genes under drought in different organs at different developmental stages and among rice lines with different drought resistance abilities. Results showed that the TCS genes were expressed in a temporal-spatial specific manner under drought stress in rice, behaved with great difference among the expression patterns of different rice organs and quite similarpatterns within same tissues; type-A response regulator (RR) genes which may act as negative regulator of cytokinin signaling were mostly repressed by drought, while type-B RR genes which may play a role in positive regulation of cytokinin signaling were mostly induced by drought, these changes were supposed to be related with the enhancement of CK signaling under drought stress, this suppose was confirmed by the down regulation of ethylene receptor genes under drought from cross-talk of different plant hormones signaling; the HisKinase genes (HK5 and HK3) which is homolog with CK receptor genes (AHK2, AHK3, and CRE1) in Arabidopsis were induced by drought, while HK6 which is homolog with AHK5 (cytokinin-independent 2, CKI2)was drought repressed, these results provided a further confirmation of above suppose. The analysis of TCS genes expression profiling in drought resistant introgression lines and IR64 under drought stress did not find significant difference among the expression patterns of different rice lines, this maybe indicates that the TCS genes were related to drought responsiveness, but their effect to the enhancement of drought resistance still need further research.