保护酶CAT在木薯种质抗螨中的功能初步研究

Preliminary Study of The Function of Catalase in Cassava Resistance to Mite

为验证保护酶CAT在木薯抗螨中的功能,测定分析了朱砂叶螨取食抗、感螨木薯种质后,CAT的表达量和酶活分别在木薯和朱砂叶螨中的变化情况。结果表明,一方面,朱砂叶螨取食1 d和8 d后,感螨木薯种质BRA900体内Me CAT1的表达量和CAT总酶活仅分别较为害前提高1.11倍、1.24倍和1.06倍、1.15倍,而在抗螨木薯种质C1115体内则分别较为害前提高2.75倍、2.62倍和2.36倍、2.38倍,均显著高于感螨木薯水平。另一方面,朱砂叶螨取食感螨种质BRA900 1 d和8 d后,保护酶Tc CAT的基因表达量和CAT酶活分别是为害前的1.13倍、0.98倍和1.02倍、0.99倍,而取食抗螨木薯种质C1115 1 d和8 d后分别降低至为害前的0.57倍、0.61倍和0.52倍、0.61倍,均显著低于取食感螨木薯水平。以上结果初步证实了保护酶CAT在木薯中被诱导能够缓解朱砂叶螨造成的氧化损伤,在朱砂叶螨中被抑制不利于取食为害,从而形成木薯抗螨性的功能。本研究为将CAT作为基因资源应用于抗螨木薯种质创制提供了理论基础。

In order to validate the function of catalase（ CAT） in cassava resistance to mite, we determined the changes of transcriptions and activities of CAT in either cassava or Tetranychus cinnabarinus after the mite-resistant and mite-susceptible cassava cultivars were damaged by T. cinnabarinus. The results showed that, in one hand, compared to the same leaves before damaged by T. cinnabarinus, the transcriptions of Me CAT1 and total activities of CAT in leaves of 1 d and 8 d-damaged mite-susceptible cassava cultivar BRA900 was 1.11- and1.24-fold, 1.06- and 1.15-fold, respectively, while the corresponding multiples of transcriptions in 1 d and 8 d-damaged leaves of mite-resistant cassava cultivar C1115 was 2.75- and 2.62-fold, and was 2.36- and 2.38-fold of total activities, respectively, which were both significantly higher than the levels of BRA900. In the other hand,when T. cinnabarinus feeding on BRA900 for 1 d and 8 d, the transcriptions of Tc CAT and activities of CAT in T. cinnabarinus was 1.13 and 0.98-fold, 1.02- and 0.99-fold compared to those before feeding, respectively, while the corresponding multiples of transcriptions in T. cinnabarinus feeding on C1115 was 0.57- and 0.61-fold, and were 0.52- and 0.61-fold of total activities, respectively, which were both significantly lower than the levels of BRA900. These results preliminarily demonstrated that the induction of CAT could release oxidative damage caused by T. cinnabarinus, and the suppression of CAT could inhibit the feeding adaption of T. cinnabarinus,which both contribute to cassava resistance to mite. This study provides a theoretical basis for molecular breeding of mite-resistance cassava.