谷子类受体蛋白激酶基因SiRLK35在水稻中对盐胁迫的响应

【目的】盐胁迫影响作物的产量和品质,而作物的耐盐性受特定基因的调控。在前期获得谷子类受体蛋白激酶基因SiRLK35过表达水稻株系的基础上,拟结合植株在盐胁迫下的表型,对部分盐胁迫指标及响应基因的表达模式进行检测和验证,解析谷子SiRLK35参与盐害响应的可能机制。【方法】 选取谷子SiRLK35过表达水稻株系,分别为过表达株系（over-expression,OE）-1（OE-1）、OE-2和OE-3,以野生型中花11为对照,实时荧光定量PCR（quantitative real-time PCR,qRT-PCR）检测各株系中SiRLK35的表达情况;分别用含0、150和200 mmol·L ^-1 NaCl的MS培养液处理三叶期的对照及转基因株系幼苗,观察其表型,统计150 mmol·L ^-1 NaCl处理3 d后苗长及根长;用150 mmol·L ^-1 NaCl处理四叶期幼苗,统计处理14 d后材料干重、死亡率和死叶率,对各材料的耐盐性进行评价;进一步挑选SiRLK35过表达程度高且耐盐表型好的OE-1株系,利用3,3'-二氨基联苯胺（3,3'-Diaminobenzidine,DAB)和氮蓝四唑（nitrotetrazolium blue chloride,NBT）染色检测其胁迫下过氧化物积累及超氧化物歧化酶（superoxide dismutase,SOD）和过氧化物酶（peroxidase,POD）的活性;并对部分盐害响应基因的表达模式进行检测。 【结果】 谷子SiRLK35在株系OE-1中的相对表达量最高;150 mmol·L ^-1NaCl处理3 d幼苗后,中花11苗长和根长的生长受抑制程度均大于SiRLK35过表达株系,其中OE-1的受抑制程度最小;四叶期幼苗经150 mmol·L ^-1 NaCl处理14 d后,转基因株系地上部和地下部干重降低幅度均低于对照,且幼苗死亡率和死叶率均低于对照;盐胁迫下对照过氧化染色反应明显,O ^2-和H₂O₂的积累均高于过表达植株,SOD和POD抗氧化酶活性均高于对照;部分盐害响应基因在SiRLK35过表达株系中表现为上调,其中,OsLEA3在盐处理24 h的相对表达量是对照中的1.9倍。 【结论】 谷子SiRLK35异源转化水稻获得的过表达株系对盐胁迫具有一定的抗性,SiRLK35可通过调控抗氧化酶活性及相关信号途径,从而参与盐害响应。

Response of Receptor-Like Protein Kinase Gene SiRLK35 of Foxtail Millet to Salt in Heterologous Transgenic Rice

【Objective】Salt stress affects the crop yield and quality, while the crop salt tolerance is regulated by specific genes. Using heterogeneous over-expressed rice lines (OE-1, OE-2, and OE-3) of foxtail millet receptor-like protein kinase gene SiRLK35, the possible mechanisms of SiRLK35 under salinity will be dissected on phenotypic, physiological and molecular levels. 【Method】 The expressions of SiRLK35 in OE-1, OE-2, and OE-3 were analyzed by qRT-PCR. The phenotypes of three-leaf stage seedlings treated with 0, 150 and 200 mmol·L ^-1 NaCl were observed, and the lengths of seedlings and roots were measured after treated with 150 mmol·L ^-1 NaCl for 3 days. The dry weights, death rate and dead leaf rate of four-leaf stage seedlings that treated with 150 mmol·L ^-1 NaCl for 14 days were also measured. OE-1with the highest SiRLK35 expression was further used for DAB and NBT dyeing analysis. The activities of partial antioxidases, and expression patterns of marker genes were detected. 【Result】 There was the highest SiRLK35 expression level in OE-1. The growth of control and OE seedlings were all inhibited under 150 mmol·L ^-1 NaCl. The decreased levels of dry weight, the death rate and dead leaf rate of OE rice were all lower than those of the control, together with the less accumulation of O ^2- and H₂O₂, and the higher activities of antioxidases under salinity. Partial of salt responsive genes were up-regulated in SiRLK35 OE lines, especially the OsLEA3 was induced about 1.9 times higher after treated with NaCl for 24 h. 【Conclusion】 SiRLK35 OE rice lines have tolerance under salinity, and the gene SiRLK35 of foxtail millet could participate in salt response by regulation the activities of antioxidases and related signal pathways.